WorldWideScience

Sample records for vortex project scheduling

  1. Project Schedule Simulation

    DEFF Research Database (Denmark)

    Mizouni, Rabeb; Lazarova-Molnar, Sanja

    2015-01-01

    Despite several attempts to accurately predict duration and cost of software projects, initial plans still do not reflect real-life situations. Since commitments with customers are usually decided based on these initial plans, software companies frequently fail to deliver on time and many projects...... overrun both their budget and time. To improve the quality of initial project plans, we show in this paper the importance of (1) reflecting features’ priorities/risk in task schedules and (2) considering uncertainties related to human factors in plan schedules. To make simulation tasks reflect features......’ priority as well as multimodal team allocation, enhanced project schedules (EPS), where remedial actions scenarios (RAS) are added, were introduced. They reflect potential schedule modifications in case of uncertainties and promote a dynamic sequencing of involved tasks rather than the static conventional...

  2. Project management with dynamic scheduling baseline scheduling, risk analysis and project control

    CERN Document Server

    Vanhoucke, Mario

    2013-01-01

    The topic of this book is known as dynamic scheduling, and is used to refer to three dimensions of project management and scheduling: the construction of a baseline schedule and the analysis of a project schedule's risk as preparation of the project control phase during project progress. This dynamic scheduling point of view implicitly assumes that the usability of a project's baseline schedule is rather limited and only acts as a point of reference in the project life cycle.

  3. Individualized Project Physics in a Modular Schedule.

    Science.gov (United States)

    Cange, Francis

    1985-01-01

    Project Physics is taught at Gibault High School (Waterloo, IL) using a modular schedule and learning activity packets. A description of the course, instructional strategies used, and the learning activity packets is provided. (JN)

  4. Scheduling projects with multiskill learning effect.

    Science.gov (United States)

    Zha, Hong; Zhang, Lianying

    2014-01-01

    We investigate the project scheduling problem with multiskill learning effect. A new model is proposed to deal with the problem, where both autonomous and induced learning are considered. In order to obtain the optimal solution, a genetic algorithm with specific encoding and decoding schemes is introduced. A numerical example is used to illustrate the proposed model. The computational results show that the learning effect cannot be neglected in project scheduling. By means of determining the level of induced learning, the project manager can balance the project makespan with total cost.

  5. Scheduling of resource-constrained projects

    CERN Document Server

    Klein, Robert

    2000-01-01

    Project management has become a widespread instrument enabling organizations to efficiently master the challenges of steadily shortening product life cycles, global markets and decreasing profit margins. With projects increasing in size and complexity, their planning and control represents one of the most crucial management tasks. This is especially true for scheduling, which is concerned with establishing execution dates for the sub-activities to be performed in order to complete the project. The ability to manage projects where resources must be allocated between concurrent projects or even sub-activities of a single project requires the use of commercial project management software packages. However, the results yielded by the solution procedures included are often rather unsatisfactory. Scheduling of Resource-Constrained Projects develops more efficient procedures, which can easily be integrated into software packages by incorporated programming languages, and thus should be of great interest for practiti...

  6. Advanced Vortex Hybrid Rocket Engine (AVHRE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Orbital Technologies Corporation (ORBITEC) proposes to develop a unique Advanced Vortex Hybrid Rocket Engine (AVHRE) to achieve a highly-reliable, low-cost and...

  7. Advanced Vortex Hybrid Rocket Engine (AVHRE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a unique Advanced Vortex Hybrid Rocket Engine (AVHRE) to achieve a safe, highly-reliable, low-cost and uniquely versatile propulsion...

  8. Cockpit-based Wake Vortex Visualization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To prevent aircraft accidents due to wake vortex hazards, FAA procedures specify the minimum separation required between different categories of aircraft. However, a...

  9. Metroplex Coordinated Runway Scheduling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's System Oriented Runway Management (SORM) project is studying operational concepts and algorithms to improve the efficiency and capacity of metroplex...

  10. Scheduling in Engineering, Project, and Production Management

    Directory of Open Access Journals (Sweden)

    Chien-Ho Ko

    2015-01-01

    Full Text Available This issue presents five papers selected from the 2013 (4th International Conference on Engineering, Project, and Production Management (EPPM2013 held in Bangkok, Thailand. Three of the papers deal with scheduling problems faced in project and production management, while the remaining two focus on engineering management issues.

  11. Scheduling of Development Projects with Uncertain Iterations

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper studies the scheduling of design projects in concurrent development process with uncertain num ber of feedback revisions. An optimization based methodology that combines heuristic algorithm, artificial intelligence (fuzzy, genetic algorithm) and scheduling theory is developed. In the algorithm, weighting values of some key factors are defined by genetic algorithm. In addition, fuzzy logic is used to decide the ability coefficients of different roles taken by designers. Moreover, the process of pre-release and feedback revision is realized. Simulation example is a fraction of practical development project, and satisfied results are obtained.

  12. Mathematical programming and financial objectives for scheduling projects

    CERN Document Server

    Kimms, Alf

    2001-01-01

    Mathematical Programming and Financial Objectives for Scheduling Projects focuses on decision problems where the performance is measured in terms of money. As the title suggests, special attention is paid to financial objectives and the relationship of financial objectives to project schedules and scheduling. In addition, how schedules relate to other decisions is treated in detail. The book demonstrates that scheduling must be combined with project selection and financing, and that scheduling helps to give an answer to the planning issue of the amount of resources required for a project. The author makes clear the relevance of scheduling to cutting budget costs. The book is divided into six parts. The first part gives a brief introduction to project management. Part two examines scheduling projects in order to maximize their net present value. Part three considers capital rationing. Many decisions on selecting or rejecting a project cannot be made in isolation and multiple projects must be taken fully into a...

  13. Application of Fuzzy theory to project scheduling with critical path ...

    African Journals Online (AJOL)

    Application of Fuzzy theory to project scheduling with critical path method. ... Journal of Applied Sciences and Environmental Management. Journal Home · ABOUT ... In this paper, we analyze the project scheduling problem using fuzzy theory.

  14. Project scheduling and staffing with a multi-skilled workforce

    OpenAIRE

    Maenhout, Broos; Vanhoucke, Mario

    2011-01-01

    When scheduling projects assumptions are made with respect to the personnel resource availability. In personnel scheduling problems assumptions are made with respect to the staffing requirements. We explore how to integrate these two scheduling problems for making strategic project staffing decisions. More precisely, we determine the number of personnel and required skill mix to complete a project.

  15. Solving project scheduling problems by minimum cut computations

    NARCIS (Netherlands)

    Möhring, R.H.; Schulz, A.S.; Stork, F.; Uetz, M.J.

    2003-01-01

    In project scheduling, a set of precedence-constrained jobs has to be scheduled so as to minimize a given objective. In resource-constrained project scheduling, the jobs additionally compete for scarce resources. Due to its universality, the latter problem has a variety of applications in manufactur

  16. Distributed Research Project Scheduling Based on Multi-Agent Methods

    Directory of Open Access Journals (Sweden)

    Constanta Nicoleta Bodea

    2011-01-01

    Full Text Available Different project planning and scheduling approaches have been developed. The Operational Research (OR provides two major planning techniques: CPM (Critical Path Method and PERT (Program Evaluation and Review Technique. Due to projects complexity and difficulty to use classical methods, new approaches were developed. Artificial Intelligence (AI initially promoted the automatic planner concept, but model-based planning and scheduling methods emerged later on. The paper adresses the project scheduling optimization problem, when projects are seen as Complex Adaptive Systems (CAS. Taken into consideration two different approaches for project scheduling optimization: TCPSP (Time- Constrained Project Scheduling and RCPSP (Resource-Constrained Project Scheduling, the paper focuses on a multiagent implementation in MATLAB for TCSP. Using the research project as a case study, the paper includes a comparison between two multi-agent methods: Genetic Algorithm (GA and Ant Colony Algorithm (ACO.

  17. Project control integrating cost and schedule in construction

    CERN Document Server

    Del Pico, Wayne J

    2013-01-01

    The key to successful project control is the fusing of cost to schedule whereby the management of one helps to manage the other. Project Control: Integrating Cost and Schedule in Construction explores the reasons behind and the methodologies for proper planning, monitoring, and controlling both project costs and schedule. Filling a current void the topic of project control applied to the construction industry, it is essential reading for students and professionals alike.

  18. Probability distribution fitting of schedule overruns in construction projects

    OpenAIRE

    P E D Love; C-P Sing; WANG, X; Edwards, D.J.; H Odeyinka

    2013-01-01

    The probability of schedule overruns for construction and engineering projects can be ascertained using a ‘best fit’ probability distribution from an empirical distribution. The statistical characteristics of schedule overruns occurring in 276 Australian construction and engineering projects were analysed. Skewness and kurtosis values revealed that schedule overruns are non-Gaussian. Theoretical probability distributions were then fitted to the schedule overrun data; including the Kolmogorov–...

  19. New Proactive Time Buffer Heuristics for Robust Project Scheduling

    Science.gov (United States)

    Elshaer, Raafat; Yamamoto, Hidehiko

    Robust scheduling is aiming at constructing proactive schedules capable of dealing with multiple disruptions during project execution. Insertion a time buffer, before an activity start time, is a method to improve the robustness (stability) of a baseline schedule. In this paper, we introduce new heuristics for inserting time buffers in a given baseline schedule while the project due date is predefined and stochastic activity duration is considered. Computational results obtained from a set of benchmark projects show that the proposed heuristics capable of generating proactive schedules with acceptable quality and solution robustness.

  20. Where do we stand with fuzzy project scheduling?

    CERN Document Server

    Bonnal, Pierre; Lacoste, Germain

    2004-01-01

    Fuzzy project scheduling has interested several researchers in the past two decades; about 20 articles have been written on this issue. Contrary to stochastic project-scheduling approaches that are used by many project schedulers, and even if the axiomatic associated to the theory of probabilities is not always compatible with decision-making situations, fuzzy project-scheduling approaches that are most suited to these situations have been kept in the academic sphere. This paper starts by recalling the differences one can observe between uncertainty and imprecision. Then most of the published research works that have been done in this field are summarized. Finally, a framework for addressing the resource-constrained fuzzy project- scheduling problem is proposed. This framework uses temporal linguistic descriptors, which might become very interesting features to the project-scheduling practitioners.

  1. REPNET: project scheduling and workflow optimization for Construction Projects

    Directory of Open Access Journals (Sweden)

    Marco Alvise Bragadin

    2013-10-01

    Full Text Available Project planning and control are core processes for construction management. In practice project planning is achieved by network - based techniques like Precedence Diagramming Method (PDM.Indeed many researchers and practitioners claims that networking techniques as such do not provide a suitable model for construction projects. Construction process modeling should incorporate for specific features of resource flows through project activities. So an improved resource scheduling method for construction is developed, called REPNET, based on a precedence network plotted on a resource–space chart and presented with a flow-line chart. The heuristics of REPNET are used to carry out resource timing while optimizing processes flows and resource usage. The method has been tested on a sample project.

  2. Fuzzy Flexible Resource Constrained Project Scheduling Based on Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    查鸿; 张连营

    2014-01-01

    Both fuzzy temporal constraint and flexible resource constraint are considered in project scheduling. In order to obtain an optimal schedule, we propose a genetic algorithm integrated with concepts on fuzzy set theory as well as specialized coding and decoding mechanism. An example demonstrates that the proposed approach can assist the project managers to obtain the optimal schedule effectively and make the correct decision on skill training before a project begins.

  3. A New Schedule Estimation Technique for Construction Projects

    OpenAIRE

    D. H. Warburton, Roger

    2014-01-01

    Allen studied hundreds of construction projects and developed an accu-rate, practically useful model of their labor profiles. We combine Al-len’s labor profile with standard Earned Value Management (EVM) techniques and derive a simple, practical formula that estimates the fi-nal schedule from early project data. The schedule estimation formula is exact; it requires no approximations. The estimate is also surprisingly accurate and available early enough in the project for the project manager ...

  4. Spent nuclear fuel project integrated schedule plan

    Energy Technology Data Exchange (ETDEWEB)

    Squires, K.G.

    1995-03-06

    The Spent Nuclear Fuel Integrated Schedule Plan establishes the organizational responsibilities, rules for developing, maintain and status of the SNF integrated schedule, and an implementation plan for the integrated schedule. The mission of the SNFP on the Hanford site is to provide safe, economic, environmentally sound management of Hanford SNF in a manner which stages it to final disposition. This particularly involves K Basin fuel.

  5. Spent nuclear fuel project integrated schedule plan

    Energy Technology Data Exchange (ETDEWEB)

    Squires, K.G.

    1995-03-06

    The Spent Nuclear Fuel Integrated Schedule Plan establishes the organizational responsibilities, rules for developing, maintain and status of the SNF integrated schedule, and an implementation plan for the integrated schedule. The mission of the SNFP on the Hanford site is to provide safe, economic, environmentally sound management of Hanford SNF in a manner which stages it to final disposition. This particularly involves K Basin fuel.

  6. The Single And Multi Project Approach To Planning And Scheduling

    DEFF Research Database (Denmark)

    Andersson, Niclas

    2008-01-01

    with the challenging coordination of the work of several actors. The project planning and scheduling should, from the subcontractor’s perspective, allow for scope and flexibility so that the subcontractor can reallocate its resources at will between its ongoing projects and thereby optimise its own production. However......, reallocations of subcontracting resources lead to project interruptions which counteract on the overall productivity of the single construction project. Thus, there is a planning and scheduling conflict between the operational multi project management of the subcontracting firm and the management of single...... projects carried out by the management on site. This paper explains the single and multi project perspective on construction planning and scheduling represented by the main and the subcontractors and further, it describes how the prevailing scheduling method of today, i.e. the critical path method, conduce...

  7. Onboard Autonomous Scheduling Intelligence System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Scheduling the daily activities of the crew on a human space mission is currently a cumbersome job performed by a large team of operations experts on the ground....

  8. Oversubscribed Mission Scheduler Conflict Resolution System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The allocation and scheduling of limited communication assets to an increasing number of satellites and other spacecraft remains a complex and challenging problem....

  9. Effects of resource management regimes on project schedule

    NARCIS (Netherlands)

    Al-Jibouri, Saad H.

    2002-01-01

    This paper deals with the problem of resource scheduling within given resource constraints on a sectionalised construction project. A computer model has been developed which realistically simulates the progress of projects. A project has been selected and divided into sections whereby section manage

  10. Effects of resource management regimes on project schedule

    NARCIS (Netherlands)

    Al-Jibouri, Saad H.S.

    2002-01-01

    This paper deals with the problem of resource scheduling within given resource constraints on a sectionalised construction project. A computer model has been developed which realistically simulates the progress of projects. A project has been selected and divided into sections whereby section

  11. Software Schedules Missions, Aids Project Management

    Science.gov (United States)

    2008-01-01

    NASA missions require advanced planning, scheduling, and management, and the Space Agency has worked extensively to develop the programs and software suites necessary to facilitate these complex missions. These enormously intricate undertakings have hundreds of active components that need constant management and monitoring. It is no surprise, then, that the software developed for these tasks is often applicable in other high-stress, complex environments, like in government or industrial settings. NASA work over the past few years has resulted in a handful of new scheduling, knowledge-management, and research tools developed under contract with one of NASA s partners. These tools have the unique responsibility of supporting NASA missions, but they are also finding uses outside of the Space Program.

  12. The development of KMRR schedule and progress control system (KSPCS) for the master schedule of KMRR project

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Woong; Lee, Tae Joon; Kim, Joon Yun; Cho, Yun Ho; Hah, Jong Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-07-01

    This report was to development the computerized schedule and progress control system for the master schedule of KMRR project with ARTEMIS 7000/386 CM (Ver. 7.4.2.) based on project management theory (PERT/CPM, PDM, and S-curve). This system has been efficiently used for KMRR master schedule and will be utilized for the detail scheduling of KMRR project. (Author) 23 refs., 26 figs., 52 tabs.

  13. Software Project Scheduling Management by Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Dinesh B. Hanchate

    2014-12-01

    Full Text Available PSO (Particle Swarm Optimization is, like GA, a heuristic global optimization method based on swarm intelligence. In this paper, we present a particle swarm optimization algorithm to solve software project scheduling problem. PSO itself inherits very efficient local search method to find the near optimal and best-known solutions for all instances given as inputs required for SPSM (Software Project Scheduling Management. At last, this paper imparts PSO and research situation with SPSM. The effect of PSO parameter on project cost and time is studied and some better results in terms of minimum SCE (Software Cost Estimation and time as compared to GA and ACO are obtained.

  14. Simulator for Optimization of Software Project Cost and Schedule

    Directory of Open Access Journals (Sweden)

    P. K. Suri

    2008-01-01

    Full Text Available Each phase of the software design consumes some resources and hence has cost associated with it. In most of the cases cost will vary to some extent with the amount of time consumed by the design of each phase .The total cost of project, which is aggregate of the activities costs will also depends upon the project duration, can be cut down to some extent. The aim is always to strike a balance between the cost and time and to obtain an optimum software project schedule. An optimum minimum cost project schedule implies lowest possible cost and the associated time for the software project management. In this research an attempt has been made to solve the cost and schedule problem of software project using PERT network showing the details of the activities to be carried out for a software project development/management with the help of crashing, reducing software project duration at a minimum cost by locating a minimal cut in the duration of an activity of the original project design network. This minimal cut is then utilized to identify the project phases which should experience a duration modification in order to achieve the total software duration reduction. Crashing PERT networks can save a significant amount of money in crashing and overrun costs of a company. Even if there are no direct costs in the form of penalties for late completion of projects, there is likely to be intangible costs because of reputation damage.

  15. PROJECT SCHEDULING OPTIMIZATION IN ELECTRICAL POWER UTILITIES

    Directory of Open Access Journals (Sweden)

    Cleber Mira

    2015-08-01

    Full Text Available The problem of choosing from a set of projects which ones should be executed and whenthey should start, depending on several restrictions involving project costs, risks, limited resources, dependencies among projects, and aiming at different, even conflicting, goals is known as the project portfolio selection (PPS problem. We study a particular version of the PPS problem stemming from the operation of a real power generation company. It includes distinct categories of resources, intricate dependencies between projects, which are especially important for the management of power plants, and the prevention of risks. We present an algorithm based on the GRASP meta-heuristic for finding better results thanmanual solutions produced by specialists. The algorithm yielded solutions that decreased the risk by 47%, as measured by the company's standard methodology.

  16. Project Scheduling problem using metaheuristic algorithm

    Directory of Open Access Journals (Sweden)

    Amir Seyedan Anby

    2016-06-01

    Full Text Available In this paper we solve Time-Cost trade-off project, in a way that sees decision maker preferences and cares about resource restriction simultaneously. Cause of being a part of NP-hard questions we use a meta-initiative multi index genetic algorithm method for model making and solving it. This paper estimates completing project time watching both time and cost elements, also initiative SJS method is being used for resource attribution. In this order with caring aforementioned purposes we calculate project completing time, and decision maker could run to ideal answers by changing time and cost indexes importance. This question was coded in Matlab software and cause of being complicated it reaches to an ideal answer in acceptable time.

  17. Planning and Scheduling of Software Manufacturing Projects

    Science.gov (United States)

    1991-03-01

    component of the TG allows a tourist to query about the: 1. Local Tourist Attractions 2. Local Hotels The navigational (path finding) component of TG allows...Engineering Project Mangement System. Ph.D. Th., University of California at Santa Barbara, 1979. 138. Christopher Tong. "Toward an Engineering Science of

  18. A planning and scheduling system for the LHC project

    CERN Document Server

    Bachy, Gérard; Tarrant, M

    1995-01-01

    The purpose of this paper is to present modern ways to manage time, resources and progress in a large-scale project. Over the last ten years, new project management techniques and tools have appeared such as concurrent engineering, Continuous Acquisition Lifecycle Support (CALS) and Engineering Data Management System (EDMS). The world downturn of the early 90s influenced project management: increasing constraints on time and budget and more external direction on spending that, for example, requires sophisticated sub-contracting practises. However, the evolution of the software and hardware market makes project control tools cheaper and easier to use. All project groups want to have their scope of work considered as complete projects and to control them themselves. This has several consequences on project staff behaviour concerning project control, and has to be taken into account in every planning process designed today. The system described will be at the heart of the planning and scheduling procedures issue...

  19. Forecasting project schedule performance using probabilistic and deterministic models

    Directory of Open Access Journals (Sweden)

    S.A. Abdel Azeem

    2014-04-01

    Full Text Available Earned value management (EVM was originally developed for cost management and has not widely been used for forecasting project duration. In addition, EVM based formulas for cost or schedule forecasting are still deterministic and do not provide any information about the range of possible outcomes and the probability of meeting the project objectives. The objective of this paper is to develop three models to forecast the estimated duration at completion. Two of these models are deterministic; earned value (EV and earned schedule (ES models. The third model is a probabilistic model and developed based on Kalman filter algorithm and earned schedule management. Hence, the accuracies of the EV, ES and Kalman Filter Forecasting Model (KFFM through the different project periods will be assessed and compared with the other forecasting methods such as the Critical Path Method (CPM, which makes the time forecast at activity level by revising the actual reporting data for each activity at a certain data date. A case study project is used to validate the results of the three models. Hence, the best model is selected based on the lowest average percentage of error. The results showed that the KFFM developed in this study provides probabilistic prediction bounds of project duration at completion and can be applied through the different project periods with smaller errors than those observed in EV and ES forecasting models.

  20. VERTICAL LINEAR PROJECT SCHEDULING FOR HIGH-RISE BUILDINGS

    Directory of Open Access Journals (Sweden)

    İlker ÖZDEMİR

    1999-02-01

    Full Text Available In this paper, an application to high-rise buildings of VPM (Vertical Production Method and an example will be given which is composition of two distinct and preferable methods are CPM (Critical Path Method that is prefering against traditional Bar-Charts or schedules especially in big and costly investments and LOB (Line of Balance technique that is suitable for using in linear project planning. Thus, it could be expected that to show the way of the method to designer and manufacturer about subjects which are activity, priority and sequencing of high-rise project, speeds of activity and construction, completion times, to add or take out some terms to schedule at the state of project changing.

  1. The Use of Project Time Management Processes and the Schedule Performance of Construction Projects in Mexico

    Directory of Open Access Journals (Sweden)

    Rómel G. Solís-Carcaño

    2015-01-01

    Full Text Available Delays have been frequently reported as the cause of several conflicts that affect the different parties involved in construction projects. Project Time Management (PTM includes a number of planning and controlling processes that are recommended for complying with requirements related to project time. The study reported in this paper aimed at assessing the use of PTM processes and its relation with project schedule performance (i.e., timely completion. Seven PTM processes and seventy-seven tasks associated with them were identified from the literature that is globally relevant to project management. The study included the assessment of fourteen school construction projects executed by a public agency in the Yucatan Peninsula, Mexico. These projects were monitored during the construction phase in order to measure two different variables: the use of processes related to PTM (i.e., schedule planning and controlling processes and the project schedule performance. For each of these projects a Use Index was obtained for assessing the first variable, while the Schedule Performance Index and the Schedule Variance were computed to assess the second one. The results demonstrated there is statistical dependence between these two variables. Most of the projects that attained timely completion also made a greater use of the PTM processes.

  2. Genetic algorithm-based multi-objective model for scheduling of linear construction projects

    OpenAIRE

    Senouci, Ahmed B.; Al-Derham, H.R.

    2007-01-01

    This paper presents a genetic algorithm-based multi-objective optimization model for the scheduling of linear construction projects. The model allows construction planners to generate and evaluate optimal/near-optimal construction scheduling plans that minimize both project time and cost. The computations in the present model are organized in three major modules. A scheduling module that develops practical schedules for linear construction projects. A cost module that computes the project's c...

  3. Application of Project Scheduling in Agriculture (Case Study: Mechanized Greenhouses Construction Project

    Directory of Open Access Journals (Sweden)

    Nasim Monjezi

    2012-02-01

    Full Text Available PERT is an acronym for Project Evaluation and Review Technique. It provides a method of modeling, simulating and solving a wide range of simplex large-scale system problems. In this paper, project scheduling in agriculture, for mechanized greenhouses construction in the Khuzestan province of Iran, is carried out by PERT method. The operation of allocating resources to activities was carried out by means of breaking the basic activities of the project into smaller ones. Network models are increasingly powerful tool for modeling, scheduling, planning, controlling, and analyzing of agricultural projects. The generated PERT network model is a powerful tool to help manager who could able to make optimum decision.

  4. Optimum Production Control and Workforce Scheduling of Machining Project

    Science.gov (United States)

    Lan, Tian-Syung; Lo, Chih-Yao; Hou, Cheng-I.

    Through the proposed model in this study, the production control with the consideration of workforce scheduling for advanced manufacturing systems becomes realistically and concretely solvable. This study not only meditates the concept of balancing machine productivity and human ability into the objective, but also implements Calculus of Variations to optimize the profit for a deterministic production quantity. In addition, the optimum solutions of dynamic productivity control and workforce scheduling are comprehensively provided. Moreover, the decision criteria for selecting the optimum solution and the sensitivity analysis of the critical variables are fully discussed. This study definitely contributes the applicable strategy to control the productivity and workforce in manufacturing and provides the valuable tool to conclusively optimize the profit of a machining project for operations research in today`s manufacturing industry with profound insight.

  5. Stochastic project networks temporal analysis, scheduling and cost minimization

    CERN Document Server

    Neumann, Klaus

    1990-01-01

    Project planning, scheduling, and control are regularly used in business and the service sector of an economy to accomplish outcomes with limited resources under critical time constraints. To aid in solving these problems, network-based planning methods have been developed that now exist in a wide variety of forms, cf. Elmaghraby (1977) and Moder et al. (1983). The so-called "classical" project networks, which are used in the network techniques CPM and PERT and which represent acyclic weighted directed graphs, are able to describe only projects whose evolution in time is uniquely specified in advance. Here every event of the project is realized exactly once during a single project execution and it is not possible to return to activities previously carried out (that is, no feedback is permitted). Many practical projects, however, do not meet those conditions. Consider, for example, a production process where some parts produced by a machine may be poorly manufactured. If an inspection shows that a part does no...

  6. IMPROVING PROJECT SCHEDULE ESTIMATES USING HISTORICAL DATA AND SIMULATION

    Directory of Open Access Journals (Sweden)

    P.H. Meyer

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Many projects are not completed on time or within the original budget. This is caused by uncertainty in project variables as well as the occurrence of risk events. A study was done to determine ways of measuring the risk in development projects executed by a mining company in South Africa. The main objective of the study was to determine whether historical project data would provide a more accurate means of estimating the total project duration. Original estimates and actual completion times for tasks of a number of projects were analysed and compared. The results of the study indicated that a more accurate total duration for a project could be obtained by making use of historical project data. The accuracy of estimates could be improved further by building a comprehensive project schedule database within a specific industry.

    AFRIKAANSE OPSOMMING: Verskeie projekte word nie binne die oorspronklike skedule of begroting voltooi nie. Dit word dikwels veroorsaak deur onsekerheid oor projekveranderlikes en die voorkoms van risiko’s. 'n Studie is gedoen om 'n metode te ontwikkel om risiko te meet vir ontwikkelingsprojekte van 'n mynmaatskappy in Suid Afrika. Die hoofdoel van die studie was om te bepaal of historiese projekdata gebruik kon word om 'n akkurater tydsduur vir 'n projek te beraam. Die geraamde tydsduur van take vir 'n aantal projekte is ontleed en vergelyk met die werklike tydsduur. Die resultate van die studie het getoon dat 'n akkurater totale tydsduur vir die projek verkry kon word deur gebruik te maak van historiese projekdata. Die akkuraatheid kan verder verbeter word deur 'n databasis van projekskedules vir 'n bepaalde industrie te ontwikkel en by datum te hou.

  7. Fuzzy Optimization of Construction Engineering Project Schedule Based on Critical Chain Management

    OpenAIRE

    Liu, Jianbing; Ren, Hong; Junshu DU

    2013-01-01

    Critical chain management was the very important theory innovation in the development of construction project schedule management field in recent years. Compared with the traditional methods of construction project schedule management, the methods of critical chain management considered resource constraints into construction project schedule management, the construction project cycle was shortened and the efficiency was enhanced by using the dynamic thinking and circulation pattern to manage ...

  8. The development of stochastic process modeling through risk analysis derived from scheduling of NPP project

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Ho; Roh, Myung Sub [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2013-10-15

    There are so many different factors to consider when constructing a nuclear power plant successfully from planning to decommissioning. According to PMBOK, all projects have nine domains from a holistic project management perspective. They are equally important to all projects, however, this study focuses mostly on the processes required to manage timely completion of the project and conduct risk management. The overall objective of this study is to let you know what the risk analysis derived from scheduling of NPP project is, and understand how to implement the stochastic process modeling through risk management. Building the Nuclear Power Plant is required a great deal of time and fundamental knowledge related to all engineering. That means that integrated project scheduling management with so many activities is necessary and very important. Simulation techniques for scheduling of NPP project using Open Plan program, Crystal Ball program, and Minitab program can be useful tools for designing optimal schedule planning. Thus far, Open Plan and Monte Carlo programs have been used to calculate the critical path for scheduling network analysis. And also, Minitab program has been applied to monitor the scheduling risk. This approach to stochastic modeling through risk analysis of project activities is very useful for optimizing the schedules of activities using Critical Path Method and managing the scheduling control of NPP project. This study has shown new approach to optimal scheduling of NPP project, however, this does not consider the characteristic of activities according to the NPP site conditions. Hence, this study needs more research considering those factors.

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

    Directory of Open Access Journals (Sweden)

    Stanimirović Ivan

    2009-01-01

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

  10. Pre-emptive resource-constrained multimode project scheduling using genetic algorithm: A dynamic forward approach

    Directory of Open Access Journals (Sweden)

    Aidin Delgoshaei

    2016-09-01

    Full Text Available Purpose: The issue resource over-allocating is a big concern for project engineers in the process of scheduling project activities. Resource over-allocating drawback is frequently seen after scheduling of a project in practice which causes a schedule to be useless. Modifying an over-allocated schedule is very complicated and needs a lot of efforts and time. In this paper, a new and fast tracking method is proposed to schedule large scale projects which can help project engineers to schedule the project rapidly and with more confidence. Design/methodology/approach: In this article, a forward approach for maximizing net present value (NPV in multi-mode resource constrained project scheduling problem while assuming discounted positive cash flows (MRCPSP-DCF is proposed. The progress payment method is used and all resources are considered as pre-emptible. The proposed approach maximizes NPV using unscheduled resources through resource calendar in forward mode. For this purpose, a Genetic Algorithm is applied to solve. Findings: The findings show that the proposed method is an effective way to maximize NPV in MRCPSP-DCF problems while activity splitting is allowed. The proposed algorithm is very fast and can schedule experimental cases with 1000 variables and 100 resources in few seconds. The results are then compared with branch and bound method and simulated annealing algorithm and it is found the proposed genetic algorithm can provide results with better quality. Then algorithm is then applied for scheduling a hospital in practice. Originality/value: The method can be used alone or as a macro in Microsoft Office Project® Software to schedule MRCPSP-DCF problems or to modify resource over-allocated activities after scheduling a project. This can help project engineers to schedule project activities rapidly with more accuracy in practice.

  11. Magnitude of Construction Cost and Schedule Overruns in Public Work Projects

    Directory of Open Access Journals (Sweden)

    Pramen P. Shrestha

    2013-01-01

    Full Text Available This study analyzed 363 Clark County Department of Public Works (CCDPW projects to determine construction cost and schedule overruns in various types and sizes of the projects. The sample projects were constructed from 1991 to 2008, with a total construction cost of $1.85 billion, equivalent to 2012 cost. A one-factor ANOVA test was conducted to determine whether construction cost and schedule overruns significantly varied based on types and sizes of the projects. The study showed that large, long-duration projects had significantly higher cost and schedule overruns than smaller, short-duration projects.

  12. The Difficulty in Following Project Schedule as a Key Project Management Challenge: Family Firm Perspective

    Directory of Open Access Journals (Sweden)

    Joanna SADKOWSKA

    2016-12-01

    Full Text Available The problem of how to manage projects successfully has been gaining growing interest for the last decades. The aforementioned is mainly caused by the fact that project management offers a wide range of methods and tools which, when properly used, can stimulate long-term growth of businesses. As a consequence it offers a particular development opportunity for family enterprises which, due to their specificity, have to overcome many difficulties. The primary objective of this paper is to examine whether family enterprises perceive, and to what extent, the factor of following project schedule as a difficulty in the area of project management. 154 Polish family firms representing different sectors were surveyed. The results of regression analysis show that family firms with global range of business activities, on the contrary to those with local or regional ones, do not find the factor of following project schedule as a difficulty. This results manly from the tools employed and the maturity level they have reached in project management. The findings support the current discussion on the specificity and uniqueness of family businesses in relationship to the knowledge area of project management. It also contributes to filling the gap on understanding the functioning of family firms in the emerging economies of Eastern Europe.

  13. The Theory of Constraints Applied to Project Scheduling: The Critical Chain Concept Defined.

    Science.gov (United States)

    1992-09-01

    developed by Dr. Eliyahu M. Goldratt has been successfully applied in many manufacturing settings. Researchers are now beginning to apply Theory of...is operations scheduling’s analogue in the project management environment - the resource constrained project scheduling problem. Eliyahu Goldratt , an...Scheduling: An Introduction to the Mathematics of the Job-Shop. New York: John Wiley and Sons, 1982. 11. Goldratt , Eliyahu M. The Haystack Syndrome

  14. A New Algorithm for Resource Constraint Project Scheduling Problem Based on Multi-Agent Systems

    Institute of Scientific and Technical Information of China (English)

    何曙光; 齐二石; 李钢

    2003-01-01

    The resource constrained project scheduling problem (RCPSP) and a decision-making model based on multi-agent systems (MAS) and general equilibrium marketing are proposed. An algorithm leading to the resource allocation decision involved in RCPSP has also been developed. And this algorithm can be used in the multi-project scheduling field as well.Finally, an illustration is given.

  15. Magnitude of Construction Cost and Schedule Overruns in Public Work Projects

    OpenAIRE

    Pramen P. Shrestha; Burns, Leslie A.; Shields, David R.

    2013-01-01

    This study analyzed 363 Clark County Department of Public Works (CCDPW) projects to determine construction cost and schedule overruns in various types and sizes of the projects. The sample projects were constructed from 1991 to 2008, with a total construction cost of $1.85 billion, equivalent to 2012 cost. A one-factor ANOVA test was conducted to determine whether construction cost and schedule overruns significantly varied based on types and sizes of the projects. The study showed that lar...

  16. Project scheduling method with time using MRP system – A case study: Construction project in Libya

    Directory of Open Access Journals (Sweden)

    Abdallah Ali Imetieg

    2015-04-01

    Full Text Available Materials Requirements and Planning (MRP is a system of production planning and inventory control, which is used to manage manufacturing processes. Most MRP systems are software-based and are used to ensure that the materials are available for production, that the products are available for delivery to customers, that the lowest possible material and product level is maintained in store, as well as to plan delivery schedules and purchasing activities. Upon completion of scheduling, begins the process of follow-up, which includes the achievement of the project goals in terms of quantity, quality and costs in accordance with deadlines. MRP system was applied to project of 5000 housing units in Solug area, which is close to Benghazi city, Libya, with the aim to provide necessary cash flow to pay dues on time without delay to all involved project sub-contractors and material suppliers, to ensure the smooth flow of operations, as well as to diminish costs by reduction of temporary storages and rented areas. There is a correlation between time and cost of each activity. If the required time is shorter than the scheduled time of the certain activity, it would demand more resources, which further leads to the increase in direct costs of the given activity. Therefore, the output of MRP is important since commands are issued through planning in order to launch the suggested orders with the required quantities and within the limited time period.

  17. Static scheduling in consideration of resource categories in collaborative product development project

    Directory of Open Access Journals (Sweden)

    Yingzi Li

    2015-10-01

    Full Text Available In collaborative product development project plan phase, a reasonable allocation plan can shorten project duration. Static scheduling is a useful way to obtain the allocation result. Matching degree and resource categories are introduced into the standard model of multi-mode resource-constrained project scheduling problem to reflect the resource characteristics including three aspects: (1 human resource is different from technology resource, (2 different technology resources will influence project duration, and (3 technology resource quantities also influence duration. Aimed at two static scheduling models, simple genetic algorithm and two-layer parthenogenetic algorithm are designed. Finally, a case study was presented to validate the method.

  18. Real-time and dynamic schedule optimization of construction projects on the basis of lean construction

    Institute of Scientific and Technical Information of China (English)

    QI Shen-jun; DING Lie-yun; LUO Han-bin; DONG Xiao-yan

    2007-01-01

    Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random; however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.

  19. Distributed Plug-and-Play Planning and Scheduling System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Planning and scheduling (P&S) is an essential task for managing current and future NASA missions. P&S systems are used in many areas of spacecraft operations...

  20. Integration of Tactical Departure Scheduling and Traffic Flow Management Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the ATM Select topic area of Integrated Arrival, Departure and Surface (IADS) planning, this proposal addresses Tactical Departure Scheduling (TDS), which is a...

  1. Control by Exception for Tactical Departure Scheduling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tactical Departure Scheduling (TDS) is a common activity in Air Traffic Control (ATC) in the National Airspace System (NAS) that requires significant coordination...

  2. Project scheduling: A multi-objective evolutionary algorithm that optimizes the effectiveness of human resources and the project makespan

    Science.gov (United States)

    Yannibelli, Virginia; Amandi, Analía

    2013-01-01

    In this article, the project scheduling problem is addressed in order to assist project managers at the early stage of scheduling. Thus, as part of the problem, two priority optimization objectives for managers at that stage are considered. One of these objectives is to assign the most effective set of human resources to each project activity. The effectiveness of a human resource is considered to depend on its work context. The other objective is to minimize the project makespan. To solve the problem, a multi-objective evolutionary algorithm is proposed. This algorithm designs feasible schedules for a given project and evaluates the designed schedules in relation to each objective. The algorithm generates an approximation to the Pareto set as a solution to the problem. The computational experiments carried out on nine different instance sets are reported.

  3. A Multiagent Evolutionary Algorithm for the Resource-Constrained Project Portfolio Selection and Scheduling Problem

    Directory of Open Access Journals (Sweden)

    Yongyi Shou

    2014-01-01

    Full Text Available A multiagent evolutionary algorithm is proposed to solve the resource-constrained project portfolio selection and scheduling problem. The proposed algorithm has a dual level structure. In the upper level a set of agents make decisions to select appropriate project portfolios. Each agent selects its project portfolio independently. The neighborhood competition operator and self-learning operator are designed to improve the agent’s energy, that is, the portfolio profit. In the lower level the selected projects are scheduled simultaneously and completion times are computed to estimate the expected portfolio profit. A priority rule-based heuristic is used by each agent to solve the multiproject scheduling problem. A set of instances were generated systematically from the widely used Patterson set. Computational experiments confirmed that the proposed evolutionary algorithm is effective for the resource-constrained project portfolio selection and scheduling problem.

  4. A fuzzy pert approach to evaluate plant construction project scheduling risk under uncertain resources capacity

    Directory of Open Access Journals (Sweden)

    Hsian Jong Hsiau

    2009-07-01

    Full Text Available A plant construction project always involves lots of activities. Precise information about the activities duration is unfortunately unavailable due to the uncertain resources capacity. The fuzzy program evaluation and review technique (PERT has been widely applied to solve the fuzzy project scheduling problem. This paper presents an extended fuzzy PERT approach with four major improvement aspects to support the construction project scheduling management: 1 Evaluate operation fuzzy times based on available working volumes, resources quantity and fuzzy capacity of resources, 2 Adopting a maximal alpha_i-level cut method to compare the fuzzy precedent activities times to determine the reasonable earliest starting times of each activity, 3 Using fuzzy algebra method instead of fuzzy subtraction method to compute the fuzzy latest starting times and 4 Developing a project scheduling risk index (PSRI to assist the decision maker to evaluate the project scheduling risk. Simulations experiments are conducted and demonstrated satisfactory results.

  5. A visual representation system for the scheduling and management of projects

    NARCIS (Netherlands)

    Pollalis, S.N.

    1992-01-01

    A VISUAL SCHEDULING AND MANAGEMENT SYSTEM (VSMS) This work proposes a new system for the visual representation of projects that displays the quantities of work, resources and cost. This new system, called Visual Scheduling and Management System, has a built-in hierarchical system to provide differen

  6. A visual representation system for the scheduling and management of projects

    NARCIS (Netherlands)

    Pollalis, S.N.

    1992-01-01

    A VISUAL SCHEDULING AND MANAGEMENT SYSTEM (VSMS) This work proposes a new system for the visual representation of projects that displays the quantities of work, resources and cost. This new system, called Visual Scheduling and Management System, has a built-in hierarchical system to provide differen

  7. A visual representation system for the scheduling and management of projects

    NARCIS (Netherlands)

    Pollalis, S.N.

    1992-01-01

    A VISUAL SCHEDULING AND MANAGEMENT SYSTEM (VSMS) This work proposes a new system for the visual representation of projects that displays the quantities of work, resources and cost. This new system, called Visual Scheduling and Management System, has a built-in hierarchical system to provide

  8. Criticality of Schedule Constraints – Classification and Identification for Project Management

    Directory of Open Access Journals (Sweden)

    Qui T. Nguyen

    2014-01-01

    Full Text Available In construction scheduling, constraints among activities are vital as they govern the schedule solution. Understanding their criticality is essential for better schedule management. This paper presents a systematic method to classify and identify the criticality of schedule constraints for the schedule management from the constraint perspective. In terms of criticality, schedule constraints can be grouped into four types: project-critical, activity-critical, sequence-critical and non-critical. Project-critical constraints are those which govern start/finish time of critical activities and the project end time. Activity-critical constraints define the start/finish time of non-critical activities, and sequence-critical constraints are those whose existence affect the start/finish time of some activities or the project end time. Constraints belonging to any of these groups are vital to a schedule as they cannot be removed from the constraint collection. Non-critical constraints, on the other hand, do not govern either start/finish time of any activity or the project end time. Accordingly, non-critical constraints are redundant and can be removed from the constraint collection without causing any change to the schedule solution. The method proposed was applied to a illustrative case example based on the construction of the main entrance of a nursing house for further interpretation. The proposed classification scheme could shed light on a more in-depth understanding of the nature of criticality and the role of constraints in a schedule, and thus better schedule management may be achieved.

  9. Project management a systems approach to planning, scheduling, and controlling

    CERN Document Server

    Kerzner, Harold R

    2013-01-01

    The bestselling project management text for students and professionals-now updated and expanded This Eleventh Edition of the bestselling ""bible"" of project management maintains the streamlined approach of the prior editions and moves the content even closer to PMI''s Project Management Body of Knowledge (PMBOK). New content has been added to this edition on measuring project management ROI, value to the organization and to customers, and much more. The capstone ""super"" case on the ""Iridium Project"" has been maintained, covering all aspects of project management. Increased use of sideba

  10. Simulated Annealing Genetic Algorithm Based Schedule Risk Management of IT Outsourcing Project

    Directory of Open Access Journals (Sweden)

    Fuqiang Lu

    2017-01-01

    Full Text Available IT outsourcing is an effective way to enhance the core competitiveness for many enterprises. But the schedule risk of IT outsourcing project may cause enormous economic loss to enterprise. In this paper, the Distributed Decision Making (DDM theory and the principal-agent theory are used to build a model for schedule risk management of IT outsourcing project. In addition, a hybrid algorithm combining simulated annealing (SA and genetic algorithm (GA is designed, namely, simulated annealing genetic algorithm (SAGA. The effect of the proposed model on the schedule risk management problem is analyzed in the simulation experiment. Meanwhile, the simulation results of the three algorithms GA, SA, and SAGA show that SAGA is the most superior one to the other two algorithms in terms of stability and convergence. Consequently, this paper provides the scientific quantitative proposal for the decision maker who needs to manage the schedule risk of IT outsourcing project.

  11. Fuzzy Optimization of Construction Engineering Project Schedule Based on Critical Chain Management

    Directory of Open Access Journals (Sweden)

    Jianbing LIU

    2013-07-01

    Full Text Available Critical chain management was the very important theory innovation in the development of construction project schedule management field in recent years. Compared with the traditional methods of construction project schedule management, the methods of critical chain management considered resource constraints into construction project schedule management, the construction project cycle was shortened and the efficiency was enhanced by using the dynamic thinking and circulation pattern to manage whole project. In view of the progress of critical chain management of the article, fuzzy theory  was used to calculate and optimize the buffer zone sizes with the determination of the buffer size of  the existing resources in certain critical chain management so as to shorten the cycle..

  12. A Framework for Augmenting 4D Visualization of Construction Projects with Scheduling Uncertainties

    NARCIS (Netherlands)

    Vahdatikhaki, Faridaddin; Mawlana, Mohammed

    2017-01-01

    Along with the advent of Building Information Modeling (BIM) came the rising popularity of visualizing not only the product of a project but also the underlying activities leading to such products. For this purpose, the schedule of a project is coupled with its 3D model to visualize how different co

  13. Analyzing Integrated Cost-Schedule Risk for Complex Product Systems R&D Projects

    Directory of Open Access Journals (Sweden)

    Zhe Xu

    2014-01-01

    Full Text Available The vast majority of the research efforts in project risk management tend to assess cost risk and schedule risk independently. However, project cost and time are related in reality and the relationship between them should be analyzed directly. We propose an integrated cost and schedule risk assessment model for complex product systems R&D projects. Graphical evaluation review technique (GERT, Monte Carlo simulation, and probability distribution theory are utilized to establish the model. In addition, statistical analysis and regression analysis techniques are employed to analyze simulation outputs. Finally, a complex product systems R&D project as an example is modeled by the proposed approach and the simulation outputs are analyzed to illustrate the effectiveness of the risk assessment model. It seems that integrating cost and schedule risk assessment can provide more reliable risk estimation results.

  14. Squaring the Project Management Circle: Updating the Cost, Schedule, and Performance Methodology

    Science.gov (United States)

    2016-04-30

    measure execution. This paper suggests that the cost, schedule, and performance paradigm, while still effective as a measure of managing programs, needs...acquisition and its relationship to the measures of cost, schedule, and performance—the project management circle (see Figure 1). Rather than use the... management circle. The circle recognizes the interrelationships, necessary equilibrium, and the influencing and balancing effects that these three

  15. A Hardware-Accelerated Fast Adaptive Vortex-Based Flow Simulation Software Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Scientific Research has recently developed a Lagrangian vortex-boundary element method for the grid-free simulation of unsteady incompressible...

  16. Dependency Test: Portraying Pearson's Correlation Coefficient Targeting Activities in Project Scheduling

    Directory of Open Access Journals (Sweden)

    Jana Shafi

    2016-09-01

    Full Text Available In this paper, we discuss project scheduling with conflicting activity-resources. Several project activities require same resources but, may be scheduled with the certain lapse of time resulting in repeatedly using the same kind of resources for executing dissimilar activities. Due to the frequent usage of same resources multiple times, expenditure become more expensive and project duration extends. The problem is to find out such kind of activities which are developing implicit relations amid them. , we proposed a solution by introducing TVs (Transparent view of Scheduling model. First, we analyze and enlists activities according to required resources, categorize them and then we segregate dependent and independent activities by indicating a value. Performing Dependency test on activities by using Pearson's Correlation Coefficient (PCC to calculate the rate of relations among the ordered activities for similar resources. By using this model we can reschedule activities to avoid confusion and disordering of resources without consumption of time and capital.

  17. Complete fuzzy scheduling and fuzzy earned value management in construction projects

    Institute of Scientific and Technical Information of China (English)

    José Luís PONZ-TIENDA; Eugenio PELLICER; Víctor YEPES

    2012-01-01

    This paper aims to present a comprehensive proposal for project scheduling and control by applying fuzzy eamed value.It goes a step further than the existing literature:in the formulation of the fuzzy earned value we consider not only its duration,but also cost and production,and alternatives in the scheduling between the earliest and latest times.The mathematical model is implemented in a prototypical construction project with all the estimated values taken as fuzzy numbers.Our findings suggest that different possible schedules and the fuzzy arithmetic provide more objective results in uncertain environments than the traditional methodology.The proposed model allows for controlling the vagueness of the environment through the adjustment of the a-cut,adapting it to the specific circumstances of the project.

  18. Project Management Patterns to Prevent Schedule Delay Caused by Requirement Elicitation

    Science.gov (United States)

    Hori, Shozo; Nakatani, Takako; Katamine, Keiichi; Ubayashi, Naoyasu; Hashimoto, Masaaki

    We propose PM (Project Management) patterns to prevent schedule delays caused by changes in requirements on empirical studies. Changes or late elicitation of requirements during the design, coding and test processes are one of the most serious risks, which may delay project schedules. However, changes and late elicitation of requirements are usually accepted during development processes. Therefore, the PM methods for preventing schedule delays caused by changes and late elicitation of requirements during development processes are an important area of study. In this study, we examined the actual conditions of various projects which succeeded in preventing schedule delays resulting from changes and late elicitation of requirements during development processes. We were able to extract various typical PM techniques for preventing these schedule delays. The techniques, known as “PM patterns”, were also applied to other projects. The patterns were arranged on a two-dimensional framework. We discuss a framework of PM patterns aimed at solving the problems caused by changes in requirements.

  19. Solving Resource-constrained Multiple Project Scheduling Problem Using Timed Colored Petri Nets

    Institute of Scientific and Technical Information of China (English)

    WU Yu; ZHUANG Xin-cun; SONG Guo-hui; XU Xiao-dong; LI Cong-xin

    2009-01-01

    To solve the resource-constrained multiple project scheduling problem (RCMPSP) more effectively, a method based on timed colored Petri net (TCPN) was proposed. In this methodology, firstly a novel mapping mechanism between traditional network diagram such as CPM (critical path method)/PERT (program evaluation and review technique) and TCPN was presented. Then a primary TCPN (PTCPN) for solving RCMPSP was modeled based on the proposed mapping mechanism. Meanwhile, the object PTCPN was used to simulate the multiple projects scheduling and to find the approximately optimal value of RCMPSP. Finally, the performance of the proposed approach for solving RCMPSP was validated by executing a mould manufacturing example.

  20. Robust Proactive Project Scheduling Model for the Stochastic Discrete Time/Cost Trade-Off Problem

    Directory of Open Access Journals (Sweden)

    Hongbo Li

    2015-01-01

    Full Text Available We study the project budget version of the stochastic discrete time/cost trade-off problem (SDTCTP-B from the viewpoint of the robustness in the scheduling. Given the project budget and a set of activity execution modes, each with uncertain activity time and cost, the objective of the SDTCTP-B is to minimize the expected project makespan by determining each activity’s mode and starting time. By modeling the activity time and cost using interval numbers, we propose a proactive project scheduling model for the SDTCTP-B based on robust optimization theory. Our model can generate robust baseline schedules that enable a freely adjustable level of robustness. We convert our model into its robust counterpart using a form of the mixed-integer programming model. Extensive experiments are performed on a large number of randomly generated networks to validate our model. Moreover, simulation is used to investigate the trade-off between the advantages and the disadvantages of our robust proactive project scheduling model.

  1. CARMENES: management of a schedule-driven project

    Science.gov (United States)

    García-Vargas, M. L.; Caballero, J.; Pérez-Calpena, A.; Amado, Pedro; Seifert, Walter; Azzaro, Marco; Mandel, Holger; Quirrenbach, Andreas; Ribas, Ignasi; Reiners, Ansgar; Guenther, Eike; Gesa, Lluís.; Galadí, David; Aceituno, Jesús

    2016-08-01

    CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is an instrument consistent in two ultra-stable high resolution (R 82,000) spectrographs covering simultaneously the visible (0.5 - 1.0μm) and near-IR (1.0 - 1.7μm) ranges to provide high-accuracy radial-velocity measurements (˜1 m/s) thanks to the long-term stability. CARMENES was the initiative of a consortium of eleven German and Spanish institutions. CARMENES has been built for the 3.5m telescope at the Centro Astronómico Hipano- Alemán (CAHA), Calar Alto Observatory (Almería, Spain) and is currently in operation. CAHA is jointly operated by the Max-Planck-Society (MPG) and the Spanish National Research Council (CSIC). The project received the green light in October 2010 and in February 2013 passed a Final Design Review. Six months later, the MPG and CSIC, the observatory's owners, made an independent evaluation concluding that CARMENES had to be ready for operations at the end of 2015. Since then, fulfilling the calendar was the driver of all project decisions. Moreover, the observatory's survival was linked to the instrument's success: should the instrument fail, the observatory would be closed. On the contrary, the instrument's success would give unique capabilities to the Observatory for Big Science. Such a challenge became to be our private Olympic Games: we had to be on time. This decision definitively impacted on the project dynamics, there was no room for a delay. The deadline, December 31st, 2015, was controlled by a strict tracking of the critical path; calendar deviations were corrected with risky decisions while fast tracking or even crashing methods were applied. The management scenario was far from optimum: most key people in the project shared their time with other duties; the observatory funding cuts; the budget was tight and distributed among the 11 partner centers with their own different rules, etc. Despite

  2. Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

    Institute of Scientific and Technical Information of China (English)

    Liu Yanqiong; Chen Yingwu

    2006-01-01

    When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the ln(schedule) and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the ln-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the ln-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.

  3. An Adaptive Large Neighborhood Search Algorithm for the Resource-constrained Project Scheduling Problem

    DEFF Research Database (Denmark)

    Muller, Laurent Flindt

    2009-01-01

    We present an application of an Adaptive Large Neighborhood Search (ALNS) algorithm to the Resource-constrained Project Scheduling Problem (RCPSP). The ALNS framework was first proposed by Pisinger and Røpke [19] and can be described as a large neighborhood search algorithm with an adaptive layer...

  4. Optimal Scheduling of Railway Track Possessions in Large-Scale Projects with Multiple Construction Works

    DEFF Research Database (Denmark)

    Li, Rui; Roberti, Roberto

    2017-01-01

    This paper addresses the railway track possession scheduling problem (RTPSP), where a large-scale railway infrastructure project consisting of multiple construction works is to be planned. The RTPSP is to determine when to perform the construction works and in which track possessions while satisf...

  5. Fiber Laser Coherent Lidar for Wake-Vortex Hazard Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a 1.5um fiber-optic pulsed coherent lidar as a highly effective sensor sub-system for airborne wake-vortex hazard detection. The proposed design is based...

  6. Rapid Estimation of Aircraft Performance Models using Differential Vortex Panel Method and Extended Kalman Filter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The problem of estimating the aerodynamic models for flight control of damaged aircraft using an innovative differential vortex lattice method tightly coupled with...

  7. An Optical Wake Vortex Detection System for Super-Density Airport Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OSI proposes to develop a wake vortex detection system including a group of double-ended and single-ended optical scintillometers properly deployed in the airfield...

  8. Fiber Laser Coherent Lidar for Wake-Vortex Hazard Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a 1.5um fiber-optic pulsed coherent lidar as a highly effective sensor sub-system for airborne wake-vortex hazard detection. The proposed design is based...

  9. Rapid Estimation of Aircraft Performance Models using Differential Vortex Panel Method and Extended Kalman Filter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Estimation of aerodynamic models for the control of damaged aircraft using an innovative differential vortex lattice method tightly coupled with an extended Kalman...

  10. Next Generation Fiber Coherent Lidar System for Wake Vortex Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SibellOptics proposes to develop an eye-safe, long-range, compact, versatile, all-fiber wind LIDAR system for wake vortex measurement and other wind measurement...

  11. Simultaneous planning of the project scheduling and material procurement problem under the presence of multiple suppliers

    Science.gov (United States)

    Tabrizi, Babak H.; Farid Ghaderi, Seyed

    2016-09-01

    Simultaneous planning of project scheduling and material procurement can improve the project execution costs. Hence, the issue has been addressed here by a mixed-integer programming model. The proposed model facilitates the procurement decisions by accounting for a number of suppliers offering a distinctive discount formula from which to purchase the required materials. It is aimed at developing schedules with the best net present value regarding the obtained benefit and costs of the project execution. A genetic algorithm is applied to deal with the problem, in addition to a modified version equipped with a variable neighbourhood search. The underlying factors of the solution methods are calibrated by the Taguchi method to obtain robust solutions. The performance of the aforementioned methods is compared for different problem sizes, in which the utilized local search proved efficient. Finally, a sensitivity analysis is carried out to check the effect of inflation on the objective function value.

  12. The Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem

    Directory of Open Access Journals (Sweden)

    Denis Pinha

    2016-11-01

    Full Text Available This paper presents the formulation and solution of the Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem. The focus of the proposed method is not on finding a single optimal solution, instead on presenting multiple feasible solutions, with cost and duration information to the project manager. The motivation for developing such an approach is due in part to practical situations where the definition of optimal changes on a regular basis. The proposed approach empowers the project manager to determine what is optimal, on a given day, under the current constraints, such as, change of priorities, lack of skilled worker. The proposed method utilizes a simulation approach to determine feasible solutions, under the current constraints. Resources can be non-consumable, consumable, or doubly constrained. The paper also presents a real-life case study dealing with scheduling of ship repair activities.

  13. A model for scheduling projects under the condition of inflation and under penalty and reward arrangements

    Directory of Open Access Journals (Sweden)

    J.K. Jolayemi

    2014-01-01

    Full Text Available A zero-one mixed integer linear programming model is developed for the scheduling of projects under the condition of inflation and under penalty and reward arrangements. The effects of inflation on time-cost trade-off curves are illustrated and a modified approach to time-cost trade-off analysis presented. Numerical examples are given to illustrate the model and its properties. The examples show that misleading schedules and inaccurate project-cost estimates will be produced if the inflation factor is neglected in an environment of high inflation. They also show that award of penalty or bonus is a catalyst for early completion of a project, just as it can be expected.

  14. Project Planning And Scheduling Using PERT And CPM Techniques With Linear Programming Case Study

    Directory of Open Access Journals (Sweden)

    Wallace Agyei

    2015-08-01

    Full Text Available Abstract Completing a project on time and within budget is not an easy task. Project planning and scheduling plays a central role in predicting both the time and cost aspects of a project. This study is aimed at finding trade-off between the cost and minimum expected time that will be required to complete the building project. The data on the cost and duration of activities involved were obtained Angel Estates and Construction Ltd. a construction company based in Ashanti region Ghana. Both critical path method CPM and project evaluation and review technique PERT were used for the analysis. The activities underwent crashing of both the time and cost using linear programming this paved way for the determination of critical path. Further analysis revealed that the shortest possible time for the completion of the analyzed building project is 40 days instead of the expected duration of 79 days. This means that through proper scheduling of activities the expected completion time was reduced by 39 days. The additional cost associated with the reduction in timing is GH1887.22 which increases the initial expected cost required to complete the project from GH57156.35 to GH59043.57.

  15. Solving a novel multi-skilled project scheduling model by scatter search

    Directory of Open Access Journals (Sweden)

    Kazemipoor, H.

    2013-05-01

    Full Text Available A multi-skilled project scheduling problem (MSPSP has generally been presented to schedule information technology projects in deterministic conditions. The contribution of this model is to consider the resources, called staff members. These members are regarded as valuable, renewable, and discrete resources with different multiple skills. The different skills of staff members, as well as the project networks activity requirement of different skills, cause this problem to become a special type of multi-mode resource-constrained project scheduling problem (MM-RCPSP, with a huge number of modes. Taking into account the importance of this issue and the few studies performed on this problem, a novel mathematical model for the MSPSP is presented. Since the complexity of this problem is NP-hard, an efficient scatter search (SS algorithm is developed to solve such a difficult problem. This proposed SS is capable of generating optimised solutions in small sizes, and the excellent solutions in large sizes are compared with the solutions reported by a proposed Tabu search (TS algorithm.

  16. An open source software project for obstetrical procedure scheduling and occupancy analysis.

    Science.gov (United States)

    Isken, Mark W; Ward, Timothy J; Littig, Steven J

    2011-03-01

    Increases in the rate of births via cesarean section and induced labor have led to challenging scheduling and capacity planning problems for hospital inpatient obstetrical units. We present occupancy and patient scheduling models to help address these challenges. These patient flow models can be used to explore the relationship between procedure scheduling practices and the resulting occupancy on inpatient obstetrical units such as labor and delivery and postpartum. The models capture numerous important characteristics of inpatient obstetrical patient flow such as time of day and day of week dependent arrivals and length of stay, multiple patient types and clinical interventions, and multiple patient care units with inter-unit patient transfers. We have used these models in several projects at different hospitals involving design of procedure scheduling templates and analysis of inpatient obstetrical capacity. In the development of these models, we made heavy use of open source software tools and have released the entire project as a free and open source model and software toolkit.

  17. Army Corps of Engineers: Factors Contributing to Cost Increases and Schedule Delays in the Olmsted Locks and Dam Project

    Science.gov (United States)

    2017-02-01

    and Dam Project The following information appears as interactive content in figure 3 when viewed electronically . • 1985: Lower Ohio River...ARMY CORPS OF ENGINEERS Factors Contributing to Cost Increases and Schedule Delays in the Olmsted Locks and Dam Project ...Contributing to Cost Increases and Schedule Delays in the Olmsted Locks and Dam Project What GAO Found Reports by the U.S. Army Corps of Engineers

  18. Solving the Resource Constrained Project Scheduling Problem to Minimize the Financial Failure Risk

    Directory of Open Access Journals (Sweden)

    Zhi Jie Chen

    2012-04-01

    Full Text Available In practice, a project usually involves cash in- and out-flows associated with each activity. This paper aims to minimize the payment failure risk during the project execution for the resource-constrained project scheduling problem (RCPSP. In such models, the money-time value, which is the product of the net cash in-flow and the time length from the completion time of each activity to the project deadline, provides a financial evaluation of project cash availability. The cash availability of a project schedule is defined as the sum of these money-time values associated with all activities, which is mathematically equivalent to the minimization objective of total weighted completion time. This paper presents four memetic algorithms (MAs which differ in the construction of initial population and restart strategy, and a double variable neighborhood search algorithm for solving the RCPSP problem. An experiment is conducted to evaluate the performance of these algorithms based on the same number of solutions calculated using ProGen generated benchmark instances. The results indicate that the MAs with regret biased sampling rule to generate initial and restart populations outperforms the other algorithms in terms of solution quality.

  19. A Study on Project Planning Using the Deterministic and Probabilistic Models by Network Scheduling Techniques

    Directory of Open Access Journals (Sweden)

    Rama.S

    2017-03-01

    Full Text Available Project planning is the important task in many areas like construction, resource allocation and many. A sequence of activities has to be performed to complete one task. Each activity has its unique processing time and all together to identify the critical activities which affect the completion of the project. In this paper the probabilistic and deterministic models to determine the project completion time and also the critical activities are considered. A case study on building construction project has been performed to demonstrate the application of the above said models. The two project scheduling namely PERT and CPM are used to determine numerically the different types of floating times of each activity and hence determined the critical path which plays an important role in the project completion time. Also a linear programing model has been developed to reduce the project completion time which optimize the resource allocation. To apply these techniques numerically the primary data from a housing project company in a metropolitan city has been taken, the network diagram of the activities involved in the building construction project has been drawn and the results are tabulated.

  20. Branch and Bound Algorithms for Resource Constrained Project Scheduling Problem Subject to Nonrenewable Resources with Prescheduled Procurement

    Directory of Open Access Journals (Sweden)

    A. Shirzadeh Chaleshtarti

    2014-01-01

    Full Text Available A lot of projects in real life are subject to some kinds of nonrenewable resources that are not exactly similar to the type defined in the project scheduling literature. The difference stems from the fact that, in those projects, contrary to the common assumption in the project scheduling literature, nonrenewable resources are not available in full amount at the beginning of the project, but they are procured along the project horizon. In this paper, we study this different type of nonrenewable resources. To that end, we extend the resource constrained project scheduling problem (RCPSP by this resource type (RCPSP-NR and customize four basic branch and bound algorithms of RCPSP for it, including precedence tree, extension alternatives, minimal delaying alternatives, and minimal forbidden sets. Several bounding and fathoming rules are introduced to the algorithms to shorten the enumeration process. We perform comprehensive experimental analysis using the four customized algorithms and also CPLEX solver.

  1. Solving resource availability cost problem in project scheduling by pseudo particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    Jianjun Qi; Bo Guo; Hongtao Lei; Tao Zhang

    2014-01-01

    This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations among the activities which require some kinds of renewable resources. We predigest the process of sol-ving the resource availability cost problem (RACP) by using start time of each activity to code the schedule. Then, a novel heuris-tic algorithm is proposed to make the process of looking for the best solution efficiently. And then pseudo particle swarm optimiza-tion (PPSO) combined with PSO and path relinking procedure is presented to solve the RACP. Final y, comparative computational experiments are designed and the computational results show that the proposed method is very effective to solve RACP.

  2. Project Scheduling Using Hybrid Genetic Algorithm with Fuzzy Logic Controller in SCM Environment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In supply chain management (SCM) environment, we consider a resource-constrained project scheduling problem (rcPSP) model as one of advanced scheduling problems considered by a constraint programming technique. We develop a hybrid genetic algorithm (hGA) with a fuzzy logic controller (FLC) to solve the rcPSP which is the well known NP-hard problem. This new approach is based on the design of genetic operators with FLC through initializing the serial method which is superior for a large rcPSP scale. For solving these rcPSP problems, we first demonstrate that our hGA with FLC (flc-hGA) yields better results than several heuristic procedures presented in the literature. We have revealed a fact that flc-hGA has the evolutionary behaviors of average fitness better than hGA without FLC.

  3. Recent trends in solving the deterministic resource constrained Project Scheduling Problem

    DEFF Research Database (Denmark)

    Karam, Ahmed; Lazarova-Molnar, Sanja

    2013-01-01

    , a number of new and promising meta-heuristic approaches for solving the RCPSP problem have emerged. In this paper, we provide a detailed review of the most recent approaches for solving the RCPSP that have been proposed in literature. In particular, we present a comparison, classification and analysis......, based on a number of relevant metrics. Extensive numerical results based on well-known benchmark problem instance sets of size J30, J60 and J120 from Project Scheduling Problem Library (PSPLIB), as well as comparisons among state-of-the-art hybrid meta-heuristic algorithms demonstrate the effectiveness...

  4. A Branch and Bound Algorithm for Project Scheduling Problem with Spatial Resource Constraints

    Directory of Open Access Journals (Sweden)

    Shicheng Hu

    2015-01-01

    Full Text Available With respect to the block assembly schedule in a shipbuilding enterprise, a spatial resource constrained project scheduling problem (SRCPSP is proposed, which aims to minimize the makespan of a project under the constraints of the availability of a two-dimensional spatial resource and the precedence relationship between tasks. In order to solve SRCPSP to the optimum, a branch and bound algorithm (BB is developed. For the BB-SRCPSP, first, an implicitly enumerative branch scheme is presented. Secondly, a precedence based lower bound, as well as an effective dominance rule, is employed for pruning. Next, a heuristic based algorithm is used to decide the order of a node to be selected for expansion such that the efficiency of the algorithm is further improved. In addition, a maximal space based arrangement is applied to the configuration of the areas required each day in an available area. Finally, the simulation experiment is conducted to illustrate the effectiveness of the BB-SRCPSP.

  5. SOLVING RESOURCE-CONSTRAINED PROJECT SCHEDULING PROBLEMS WITH BI-CRITERIA HEURISTIC SEARCH TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    M Kamrul AHSAN; De-bi TSAO

    2003-01-01

    In this paper we formulate a bi-criteria search strategy of a heuristic learning algorithm for solving multiple resource-constrained project scheduling problems. The heuristic solves problems in two phases. In the pre-processing phase, the algorithm estimates distance between a state and the goal state and measures complexity of problem instances. In the search phase, the algorithm uses estimates of the pre-processing phase to further estimate distances to the goal state. The search continues in a stepwise generation of a series of intermediate states through search path evaluation process with backtracking. Developments of intermediate states are exclusively based on a bi-criteria new state selection technique where we consider resource utilization and duration estimate to the goal state. We also propose a variable weighting technique based on initial problem complexity measures. Introducing this technique allows the algorithm to efficiently solve complex project scheduling problems. A numerical example illustrates the algorithm and performance is evaluated by extensive experimentation with various problem parameters. Computational results indicate significance of the algorithm in terms of solution quality and computational performance.

  6. Piecewise Linear Model for Multiskilled Workforce Scheduling Problems considering Learning Effect and Project Quality

    Directory of Open Access Journals (Sweden)

    Shujin Qin

    2016-01-01

    Full Text Available Workforce scheduling is an important and common task for projects with high labour intensities. It becomes particularly complex when employees have multiple skills and the employees’ productivity changes along with their learning of knowledge according to the tasks they are assigned to. Till now, in this context, only little work has considered the minimum quality limit of tasks and the quality learning effect. In this research, the workforce scheduling model is developed for assigning tasks to multiskilled workforce by considering learning of knowledge and requirements of project quality. By using piecewise linearization to learning curve, the mixed 0-1 nonlinear programming model (MNLP is transformed into a mixed 0-1 linear programming model (MLP. After that, the MLP model is further improved by taking account of the upper bound of employees’ experiences accumulation, and the stable performance of mature employees. Computational experiments are provided using randomly generated instances based on the investigation of a software company. The results demonstrate that the proposed MLPs can precisely approach the original MNLP model but can be calculated in much less time.

  7. Relevance and Applicability of Multi-objective Resource Constrained Project Scheduling Problem: Review Article

    Directory of Open Access Journals (Sweden)

    V. Oladokun

    2011-12-01

    Full Text Available Resource-Constrained Project Scheduling Problem (RCPSP is a Non Polynomial (NP - Hard optimization problem that considers how to assign activities to available resources in order to meet predefined objectives. The problem is usually characterized by precedence relationship between activities with limited capacity of renewable resources. In an environment where resources are limited, projects still have to be finished on time, within the approved budget and in accordance with the preset specifications. Inherently, these tend to make RCPSP, a multi-objective problem. However, it has been treated as a single objective problem with project makespan often recognized as the most relevant objective. As a result of not understanding the multi-objective dimension of some projects, where these objectives need to be simultaneously considered, distraction and conflict of interest have ultimately lead to abandoned or totally failed projects. The aim of this article is to holistically review the relevance and applicability of multi-objective performance dimension of RCPSP in an environment where optimal use of limited resources is important.

  8. Project scheduling with resources constraints: application in the equipment production for the oil industry; Scheduling de projetos com restricao de recursos: aplicacao na producao de equipamentos para a industria de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Carolina A.O.; Ferreira Filho, Virgilio J.M. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)

    2008-07-01

    One of the essential steps in the main scope Project Management is the Time Management made by the planning and control of the project schedule. In this work is presented the resource constrained scheduling problem beyond its mathematical formulation and a review of papers about this issue. In sequence is presented a practical example of this model considering a simplified model of an engineering project schedule of oil production equipment. The results obtained with the model application are shown and the conclusions about the work with resource constrained scheduling problems. (author)

  9. A Priority Rule-Based Heuristic for Resource Investment Project Scheduling Problem with Discounted Cash Flows and Tardiness Penalties

    Directory of Open Access Journals (Sweden)

    Amir Abbas Najafi

    2009-01-01

    Full Text Available Resource investment problem with discounted cash flows (RIPDCFs is a class of project scheduling problem. In RIPDCF, the availability levels of the resources are considered decision variables, and the goal is to find a schedule such that the net present value of the project cash flows optimizes. In this paper, we consider a new RIPDCF in which tardiness of project is permitted with defined penalty. We mathematically formulated the problem and developed a heuristic method to solve it. The results of the performance analysis of the proposed method show an effective solution approach to the problem.

  10. Solving a mixed-integer linear programming model for a multi-skilled project scheduling problem by simulated annealing

    Directory of Open Access Journals (Sweden)

    H Kazemipoor

    2012-04-01

    Full Text Available A multi-skilled project scheduling problem (MSPSP has been generally presented to schedule a project with staff members as resources. Each activity in project network requires different skills and also staff members have different skills, too. This causes the MSPSP becomes a special type of a multi-mode resource-constrained project scheduling problem (MM-RCPSP with a huge number of modes. Given the importance of this issue, in this paper, a mixed integer linear programming for the MSPSP is presented. Due to the complexity of the problem, a meta-heuristic algorithm is proposed in order to find near optimal solutions. To validate performance of the algorithm, results are compared against exact solutions solved by the LINGO solver. The results are promising and show that optimal or near-optimal solutions are derived for small instances and good solutions for larger instances in reasonable time.

  11. A generalized network flow model for the multi-mode resource-constrained project scheduling problem with discounted cash flows

    Science.gov (United States)

    Chen, Miawjane; Yan, Shangyao; Wang, Sin-Siang; Liu, Chiu-Lan

    2015-02-01

    An effective project schedule is essential for enterprises to increase their efficiency of project execution, to maximize profit, and to minimize wastage of resources. Heuristic algorithms have been developed to efficiently solve the complicated multi-mode resource-constrained project scheduling problem with discounted cash flows (MRCPSPDCF) that characterize real problems. However, the solutions obtained in past studies have been approximate and are difficult to evaluate in terms of optimality. In this study, a generalized network flow model, embedded in a time-precedence network, is proposed to formulate the MRCPSPDCF with the payment at activity completion times. Mathematically, the model is formulated as an integer network flow problem with side constraints, which can be efficiently solved for optimality, using existing mathematical programming software. To evaluate the model performance, numerical tests are performed. The test results indicate that the model could be a useful planning tool for project scheduling in the real world.

  12. Final Report on DOE Project entitled Dynamic Optimized Advanced Scheduling of Bandwidth Demands for Large-Scale Science Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ramamurthy, Byravamurthy [University of Nebraska-Lincoln

    2014-05-05

    In this project, developed scheduling frameworks for dynamic bandwidth demands for large-scale science applications. In particular, we developed scheduling algorithms for dynamic bandwidth demands in this project. Apart from theoretical approaches such as Integer Linear Programming, Tabu Search and Genetic Algorithm heuristics, we have utilized practical data from ESnet OSCARS project (from our DOE lab partners) to conduct realistic simulations of our approaches. We have disseminated our work through conference paper presentations and journal papers and a book chapter. In this project we addressed the problem of scheduling of lightpaths over optical wavelength division multiplexed (WDM) networks. We published several conference papers and journal papers on this topic. We also addressed the problems of joint allocation of computing, storage and networking resources in Grid/Cloud networks and proposed energy-efficient mechanisms for operatin optical WDM networks.

  13. Risk Level Assessment in Construction Projects Using the Schedule Performance Index

    Directory of Open Access Journals (Sweden)

    Roberto Barbosa dos Santos

    2016-01-01

    Full Text Available Construction projects are risky in both physical implementation and management. The characteristics of the risk reinforce the necessity of efficient management to increase the chances of success without commitment to its goals. This study explores the correlation of delay and the schedule performance index (SPI to evaluate the risk of a construction project completed with time overruns. The hypothesis that the SPI of projects with a delay is distinct from those projects without a delay is assumed. A database with 19 elements was used to test this hypothesis and to calculate limit values to the SPI. Therefore, the risk of delay will be small when the observed SPI is greater than the superior limit and large when the SPI is below the inferior limit. The simplicity involved in the calculation of these values showed an advantage in comparison with other methods of risk evaluation. Another strong point observed is that any company can determine the value of risk by considering its own history and support decisions like doing corrective actions.

  14. Vortex rings

    Energy Technology Data Exchange (ETDEWEB)

    Akhmetov, D.G. [Lavrentiev Institute of Hydrodynamics, Novosibirsk (Russian Federation)

    2009-07-01

    This book presents a comprehensive coverage of the wide field of vortex rings. The book presents the results of systematic experimental investigations, theoretical foundation, as well as the practical applications of vortex rings, such as the extinction of fires at gushing gas and oil wells. All the basic properties of vortex rings as well as their hydrodynamic structures are presented. Special attention is paid to the formation and motion of turbulent vortex rings. (orig.)

  15. Vulcanized Vortex

    CERN Document Server

    Cho, Inyong

    2008-01-01

    We investigate vortex configurations with the "vulcanization" term introduced for renormalization of $\\phi_\\star^4$ theory in canonical $\\theta$-deformed noncommutativity. In the small-$\\theta$ limit, we perform numerical calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted.

  16. Explore the Construction Project Schedule Management Measures%建筑工程进度管理措施研究

    Institute of Scientific and Technical Information of China (English)

    蒋立

    2014-01-01

    With the rapid development of social economy, construction industry is facing the fierce market competition. Construction project schedule is a very important indicator to measure the comprehensive ability of the state-owned enterp-rises, so in the construction engineering, effective measures must be taken to improve the level of construction project schedule management and ensure the project completed on schedule.%随着社会经济的快速发展,建筑行业面临着激烈的市场竞争。建筑工程进度是对企业的综合能力进行衡量的一项非常重要的指标,所以在建筑工程中,必须采取有效措施来提高建筑工程进度管理水平,保证工程如期完成。

  17. A hybrid electromagnetism-like algorithm for a multi-mode resource-constrained project scheduling problem

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Sadeghi

    2013-08-01

    Full Text Available In this paper, two different sub-problems are considered to solve a resource constrained project scheduling problem (RCPSP, namely i assignment of modes to tasks and ii scheduling of these tasks in order to minimize the makespan of the project. The modified electromagnetism-like algorithm deals with the first problem to create an assignment of modes to activities. This list is used to generate a project schedule. When a new assignment is made, it is necessary to fix all mode dependent requirements of the project activities and to generate a random schedule with the serial SGS method. A local search will optimize the sequence of the activities. Also in this paper, a new penalty function has been proposed for solutions which are infeasible with respect to non-renewable resources. Performance of the proposed algorithm has been compared with the best algorithms published so far on the basis of CPU time and number of generated schedules stopping criteria. Reported results indicate excellent performance of the algorithm.

  18. Incorporating High-Speed, Optimizing, Interleaving, Configurable/Composable Scheduling into NASA's EUROPA Planning Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced, robust, autonomous planning systems have not focused on the scheduling decisions made by the planner. And high quality, optimizing schedulers have rarely...

  19. Scheduling Multi-Mode Projects under Uncertainty to Optimize Cash Flows: A Monte Carlo Ant Colony System Approach

    Institute of Scientific and Technical Information of China (English)

    Wei-Neng Chen; Jun Zhang

    2012-01-01

    Project scheduling under uncertainty is a challenging field of research that has attracted increasing attention.While most existing studies only consider the single-mode project scheduling problem under uncertainty,this paper aims to deal with a more realistic model called the stochastic multi-mode resource constrained project scheduling problem with discounted cash flows (S-MRCPSPDCF).In the model,activity durations and costs are given by random variables.The objective is to find an optimal baseline schedule so that the expected net present value (NPV) of cash flows is maximized.To solve the problem,an ant colony system (ACS) based approach is designed.The algorithm dispatches a group of ants to build baseline schedules iteratively using pheromones and an expected discounted cost (EDC) heuristic.Since it is impossible to evaluate the expected NPV directly due to the presence of random variables,the algorithm adopts the Monte Carlo (MC)simulation technique.As the ACS algorithm only uses the best-so-far solution to update pheromone values,it is found that a rough simulation with a small number of random scenarios is enough for evaluation.Thus the computational cost is reduced.Experimental results on 33 instances demonstrate the effectiveness of the proposed model and the ACS approach.

  20. Memetic algorithm for multi-mode resource-constrained project scheduling problems

    Institute of Scientific and Technical Information of China (English)

    Shixin Liu; Di Chen; Yifan Wang

    2014-01-01

    A memetic algorithm (MA) for a multi-mode resource-constrained project scheduling problem (MRCPSP) is pro-posed. We use a new fitness function and two very effective lo-cal search procedures in the proposed MA. The fitness function makes use of a mechanism cal ed “strategic oscil ation” to make the search process have a higher probability to visit solutions around a“feasible boundary”. One of the local search procedures aims at improving the lower bound of project makespan to be less than a known upper bound, and another aims at improving a solution of an MRCPSP instance accepting infeasible solutions based on the new fitness function in the search process. A de-tailed computational experiment is set up using instances from the problem instance library PSPLIB. Computational results show that the proposed MA is very competitive with the state-of-the-art algorithms. The MA obtains improved solutions for one instance of set J30.

  1. School Construction Scheduling.

    Science.gov (United States)

    Delaney, J. B.

    1983-01-01

    Explains that favorable market and working conditions influence the scheduling of school construction projects. Facility planners, architects, and contractors are advised to develop a realistic time schedule for the entire project. (MLF)

  2. Multiobjective Resource-Constrained Project Scheduling with a Time-Varying Number of Tasks

    Directory of Open Access Journals (Sweden)

    Manuel Blanco Abello

    2014-01-01

    Full Text Available In resource-constrained project scheduling (RCPS problems, ongoing tasks are restricted to utilizing a fixed number of resources. This paper investigates a dynamic version of the RCPS problem where the number of tasks varies in time. Our previous work investigated a technique called mapping of task IDs for centroid-based approach with random immigrants (McBAR that was used to solve the dynamic problem. However, the solution-searching ability of McBAR was investigated over only a few instances of the dynamic problem. As a consequence, only a small number of characteristics of McBAR, under the dynamics of the RCPS problem, were found. Further, only a few techniques were compared to McBAR with respect to its solution-searching ability for solving the dynamic problem. In this paper, (a the significance of the subalgorithms of McBAR is investigated by comparing McBAR to several other techniques; and (b the scope of investigation in the previous work is extended. In particular, McBAR is compared to a technique called, Estimation Distribution Algorithm (EDA. As with McBAR, EDA is applied to solve the dynamic problem, an application that is unique in the literature.

  3. Status Report on the Development of Micro-Scheduling Software for the Advanced Outage Control Center Project

    Energy Technology Data Exchange (ETDEWEB)

    Germain, Shawn St. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thomas, Kenneth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Farris, Ronald [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    The long-term viability of existing nuclear power plants (NPPs) in the United States (U.S.) is dependent upon a number of factors, including maintaining high capacity factors, maintaining nuclear safety, and reducing operating costs, particularly those associated with refueling outages. Refueling outages typically take 20-30 days, and for existing light water NPPs in the U.S., the reactor cannot be in operation during the outage. Furthermore, given that many NPPs generate between $1-1.5 million/day in revenue when in operation, there is considerable interest in shortening the length of refueling outages. Yet, refueling outages are highly complex operations, involving multiple concurrent and dependent activities that are difficult to coordinate. Finding ways to improve refueling outage performance while maintaining nuclear safety has proven to be difficult. The Advanced Outage Control Center project is a research and development (R&D) demonstration activity under the Light Water Reactor Sustainability (LWRS) Program. LWRS is a R&D program which works with industry R&D programs to establish technical foundations for the licensing and managing of long-term, safe, and economical operation of current NPPs. The Advanced Outage Control Center project has the goal of improving the management of commercial NPP refueling outages. To accomplish this goal, this INL R&D project is developing an advanced outage control center (OCC) that is specifically designed to maximize the usefulness of communication and collaboration technologies for outage coordination and problem resolution activities. This report describes specific recent efforts to develop a capability called outage Micro-Scheduling. Micro-Scheduling is the ability to allocate and schedule outage support task resources on a sub-hour basis. Micro-Scheduling is the real-time fine-tuning of the outage schedule to react to the actual progress of the primary outage activities to ensure that support task resources are

  4. Tube Map Interface for a Coupled Scheduling and Diagnostics System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the concept of a tube map display as a means to effectively integrate schedule timeline information and fault diagnosis data into a single high value...

  5. The Design and Optimization of an Integrated Arrival/Departure Scheduler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Automation, Inc. (IAI) proposes the design and validation of a dynamic integrated arrival/departure scheduler. In contrast to current approaches, we...

  6. On the Construction Project Schedule Control%浅析建筑工程项目进度控制

    Institute of Scientific and Technical Information of China (English)

    刘子永; 李蕴澎

    2014-01-01

    本文通过对建设工程进度控制内涵、目标的阐述,详细分析了影响建设工程进度的各种因素,在此基础上对进度控制的组织、技术、经济、合同等具体的控制措施进行了非常详尽的分析,针对建设工程实施阶段进度控制的主要任务做出了概括总结,在实施中取得了良好的成效。%Based on elaborating the content and goals of construction schedule control, this paper analyzes various factors that affect the construction schedule, on this basis to analyze specific control measures of schedule control in organization, technology, economy, contracts, etc., summarizes main task of schedule control in project implementation, and achieves good results in the implementation.

  7. Multimode resource-constrained multiple project scheduling problem under fuzzy random environment and its application to a large scale hydropower construction project.

    Science.gov (United States)

    Xu, Jiuping; Feng, Cuiying

    2014-01-01

    This paper presents an extension of the multimode resource-constrained project scheduling problem for a large scale construction project where multiple parallel projects and a fuzzy random environment are considered. By taking into account the most typical goals in project management, a cost/weighted makespan/quality trade-off optimization model is constructed. To deal with the uncertainties, a hybrid crisp approach is used to transform the fuzzy random parameters into fuzzy variables that are subsequently defuzzified using an expected value operator with an optimistic-pessimistic index. Then a combinatorial-priority-based hybrid particle swarm optimization algorithm is developed to solve the proposed model, where the combinatorial particle swarm optimization and priority-based particle swarm optimization are designed to assign modes to activities and to schedule activities, respectively. Finally, the results and analysis of a practical example at a large scale hydropower construction project are presented to demonstrate the practicality and efficiency of the proposed model and optimization method.

  8. Schedule Risk Event Driven Methodology (SREDM): FY13 Army Studies Program Project Findings

    Science.gov (United States)

    2015-01-01

    acquisition, schedule, risk, assessment, analysis, 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF... IOTE - Initial Operational Test and Evaluation IPT - Integrated Product Team IRL - Integration Readiness Level KT - Key Technology LCB...Verification Testing (PVT) • Initial Operational Test and Evaluation ( IOT &E) 13 • Initial Operational Capability (IOC) • Full Rate Production (FRP

  9. DISCO An HPSG-based NLP System and its Application for Appointment Scheduling (Project Note)

    CERN Document Server

    Uszkoreit, H; Busemann, S; Diagne, A K; Hinkelman, E A; Kasper, W; Kiefer, B; Krieger, H U; Netter, K; Neumann, G; Oepen, S; Spackman, S P; Uszkoreit, Hans; Backofen, Rolf; Busemann, Stephan; Diagne, Abdel Kader; Hinkelman, Elizabeth A.; Kasper, Walter; Kiefer, Bernd; Krieger, Hans-Ulrich; Netter, Klaus; Neumann, Guenter; Oepen, Stephan; Spackman, Stephen P.

    1994-01-01

    The natural language system DISCO is described. It combines o a powerful and flexible grammar development system; o linguistic competence for German including morphology, syntax and semantics; o new methods for linguistic performance modelling on the basis of high-level competence grammars; o new methods for modelling multi-agent dialogue competence; o an interesting sample application for appointment scheduling and calendar management.

  10. Needs analysis and project schedule for the Los Alamos National Laboratory (LANL) Health Physics Analysis Laboratory (HPAL) upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rhea, T.A.; Rucker, T.L. [Science Applications International Corp., Oak Ridge, TN (United States); Stafford, M.W. [NUS Corp., Aiken, SC (US)

    1990-09-28

    This report is a needs assessment and project schedule for the Health Physics Analysis Laboratory (HPAL) upgrade project at Los Alamos National Laboratory (LANL). After reviewing current and projected HPAL operations, two custom-developed laboratory information management systems (LIMS) for similar facilities were reviewed; four commercially available LIMS products were also evaluated. This project is motivated by new regulations for radiation protection and training and by increased emphasis on quality assurance (QA). HPAL data are used to: protect the health of radiation workers; document contamination levels for transportation of radioactive materials and for release of materials to the public for uncontrolled use; and verify compliance with environmental emission regulations. Phase 1 of the HPAL upgrade project concentrates on four types of counting instruments which support in excess of 90% of the sample workload at the existing central laboratories. Phase 2 is a refinement phase and also integrates summary-level databases on the central Health, Safety, and Environment (HSE) VAX. Phase 3 incorporates additional instrument types and integrates satellite laboratories into the HPAL LIMS. Phase 1 will be a multi-year, multimillion dollar project. The temptation to approach the upgrade of the HPAL program in a piece meal fashion should be avoided. This is a major project, with clearly-defined goals and priorities, and should be approached as such. Major programmatic and operational impacts will be felt throughout HSE as a result of this upgrade, so effective coordination with key customer contacts will be critical.

  11. Vortex methods

    Energy Technology Data Exchange (ETDEWEB)

    Chorin, A.J. [California Univ., Berkeley, CA (United States). Dept. of Mathematics]|[Lawrence Berkeley Lab., CA (United States)

    1993-06-01

    Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.

  12. 工程进度款审核控制研究%The Study on Auditing and Control of the Project Schedule Fund

    Institute of Scientific and Technical Information of China (English)

    费安清

    2015-01-01

    Auditing and payment of the project schedule fund relates to the vital interests of the contractor and the con⁃tract letting party. For the contractor, the project schedule fund is the capital guarantee of construction;for the contract let⁃ting party, they can use fund rationally and effectively if they could perform the auditing and paying work of the project schedule fund properly. The project schedule fund is closely related to the project schedule and construction quality, it is in favor of ensuring the project schedule and engineering quality if we do it well. From the perspectives of preparation work, auditing method, auditing notice and auditing experience and etc., the paper discusses how to manage and control the project schedule effectively ,thus providing reference for peers.%工程进度款的审核和支付涉及到承包人和发包人的切身利益。对于承包人,工程进度款是工程施工的资金保障;对于发包人,做好进度款的审核与支付,有利于合理有效地利用资金。工程进度款与工程施工进度和施工质量密切相关,因此要做好进度款的审核和支付工作,这有利于保障施工进度和施工质量。本文从进度款审核的准备工作、审核方法、审核注意事项和审核的体会等方面论述了如何做好进度款的审核工作,为同业提供参考。

  13. Developing a Mathematical Model for Scheduling and Determining Success Probability of Research Projects Considering Complex-Fuzzy Networks

    Directory of Open Access Journals (Sweden)

    Gholamreza Norouzi

    2015-01-01

    Full Text Available In project management context, time management is one of the most important factors affecting project success. This paper proposes a new method to solve research project scheduling problems (RPSP containing Fuzzy Graphical Evaluation and Review Technique (FGERT networks. Through the deliverables of this method, a proper estimation of project completion time (PCT and success probability can be achieved. So algorithms were developed to cover all features of the problem based on three main parameters “duration, occurrence probability, and success probability.” These developed algorithms were known as PR-FGERT (Parallel and Reversible-Fuzzy GERT networks. The main provided framework includes simplifying the network of project and taking regular steps to determine PCT and success probability. Simplifications include (1 equivalent making of parallel and series branches in fuzzy network considering the concepts of probabilistic nodes, (2 equivalent making of delay or reversible-to-itself branches and impact of changing the parameters of time and probability based on removing related branches, (3 equivalent making of simple and complex loops, and (4 an algorithm that was provided to resolve no-loop fuzzy network, after equivalent making. Finally, the performance of models was compared with existing methods. The results showed proper and real performance of models in comparison with existing methods.

  14. Brownian vortexes

    Science.gov (United States)

    Sun, Bo; Lin, Jiayi; Darby, Ellis; Grosberg, Alexander Y.; Grier, David G.

    2009-07-01

    Mechanical equilibrium at zero temperature does not necessarily imply thermodynamic equilibrium at finite temperature for a particle confined by a static but nonconservative force field. Instead, the diffusing particle can enter into a steady state characterized by toroidal circulation in the probability flux, which we call a Brownian vortex. The circulatory bias in the particle’s thermally driven trajectory is not simply a deterministic response to the solenoidal component of the force but rather reflects interplay between advection and diffusion in which thermal fluctuations extract work from the nonconservative force field. As an example of this previously unrecognized class of stochastic heat engines, we consider a colloidal sphere diffusing in a conventional optical tweezer. We demonstrate both theoretically and experimentally that nonconservative optical forces bias the particle’s fluctuations into toroidal vortexes whose circulation can reverse direction with temperature or laser power.

  15. Stratospheric Aerosol and Gas Experiment, SAGE III on ISS, An Earth Science Mission on the International Space Station, Schedule Risk Analysis, A Project Perspective

    Science.gov (United States)

    Bonine, Lauren

    2015-01-01

    The presentation provides insight into the schedule risk analysis process used by the Stratospheric Aerosol and Gas Experiment III on the International Space Station Project. The presentation focuses on the schedule risk analysis process highlighting the methods for identification of risk inputs, the inclusion of generic risks identified outside the traditional continuous risk management process, and the development of tailored analysis products used to improve risk informed decision making.

  16. Vortex transmutation.

    Science.gov (United States)

    Ferrando, Albert; Zacarés, Mario; García-March, Miguel-Angel; Monsoriu, Juan A; de Córdoba, Pedro Fernández

    2005-09-16

    Using group theory arguments and numerical simulations, we demonstrate the possibility of changing the vorticity or topological charge of an individual vortex by means of the action of a system possessing a discrete rotational symmetry of finite order. We establish on theoretical grounds a "transmutation pass" determining the conditions for this phenomenon to occur and numerically analyze it in the context of two-dimensional optical lattices. An analogous approach is applicable to the problems of Bose-Einstein condensates in periodic potentials.

  17. Discussion on important factors affecting project schedule of EPC project%总承包模式下影响工程进度的因素分析

    Institute of Scientific and Technical Information of China (English)

    曹宁

    2011-01-01

    For the EPC projects, the owner' s original risk is transferred to EPC contractor after signing of EPC contract. Therefore, it is very critical to avoid inconsistency between engineering design, procurement and construction, minimize design changes resulting from failure in design and procurement, reduce project costs and shorten the project schedule. The design change, equipment & material delivery, etc will have a direct impact on project construction schedule. The impact of engineering design and procurement of EPC contract on project schedule is studied based upon years' experience in EPC project construction management. Recommendations for improvement of relations between engineering design and procurement and relations between equipment & material arrival status and construction sequence are proposed so as to bring the advantages of integrated project engineering design, procurement and construction into full play. The engineering design should be optimally coordinated with procurement and construction activities to minimize the impact of engineering design and procurement on construction. As the result, the schedule risk of EPC contractor is minimized and project objectives are met.%对于总承包管理项目,在总承包合同签订后,业主原有的风险转移,由总承包商承担。如何避免设计和采购、施工脱节,减少由于设计、采购失误引起的变更,降低项目成本,缩短工期成为关键问题。设计变更、设备材料到货等因素对项目施工进度的影响最为直接。结合多年来参与总承包项目施工管理实践活动中的体会,从现场施工管理角度,分析了总承包管理模式下的设计、采购问题对项目进度的影响,并就设计与施工的关系和设备材料到货状态与施工顺序的关系等提出了改进措施和建议,以发挥总承包作为设计、采购、施工一个有机整体的特点。通过加强设计与采购、施工的互动,将设

  18. Construction scheduled delay risk assessment by using combined AHP-RII methodology for an international NPP project

    Energy Technology Data Exchange (ETDEWEB)

    Hossen, Mufazal Muhammed; Kang, Sun Koo; Kim, Jong Hyun [KEPCO International Nuclear Graduate School (KINGS), Ulsan (Korea, Republic of)

    2015-04-15

    In this study, Nuclear Power Plant (NPP) construction schedule delay risk assessment methodology is developed and the construction delay risk is assessed for turnkey international NPP projects. Three levels of delay factors were selected through literature review and discussions with nuclear industry experts. A questionnaire survey was conducted on the basis of an analytic hierarchy process (AHP) and Relative Importance Index (RII) methods and the schedule delay risk is assessed qualitatively and quantitatively by severity and frequency of occurrence of delay factors. This study assigns four main delay factors to the first level: main contractor, utility, regulatory authority, and financial and country factor. The second and the third levels are designed with 12 sub-factors and 32 sub-sub-factors, respectively. This study finds the top five most important sub-sub-factors, which are as follows: policy changes, political instability and public intervention; uncompromising regulatory criteria and licensing documents conflicting with existing regulations; robust design document review procedures; redesign due to errors in design and design changes; and worldwide shortage of qualified and experienced nuclear specific equipment manufacturers. The proposed combined AHP-RII methodology is capable of assessing delay risk effectively and efficiently. Decision makers can apply risk informed decision making to avoid unexpected construction delays of NPPs.

  19. Automated Scheduling Via Artificial Intelligence

    Science.gov (United States)

    Biefeld, Eric W.; Cooper, Lynne P.

    1991-01-01

    Artificial-intelligence software that automates scheduling developed in Operations Mission Planner (OMP) research project. Software used in both generation of new schedules and modification of existing schedules in view of changes in tasks and/or available resources. Approach based on iterative refinement. Although project focused upon scheduling of operations of scientific instruments and other equipment aboard spacecraft, also applicable to such terrestrial problems as scheduling production in factory.

  20. Fiscal Year 2011 Afghanistan Infrastructure Fund Projects Are Behind Schedule and Lack Adequate Sustainment Plans

    Science.gov (United States)

    2012-07-30

    EWG Executive Working Group GAO Government Accountability Office IWG Infrastructure Working Group JPC Joint Program Committee JPDT Joint Project...Joint Program Committee ( JPC ), the U.S. Embassy’s Infrastructure Working Group (IWG), the U.S. Embassy’s Executive working Group (EWG), the Commander of...State, and USAID data and information, and applicable legislation. Notes: RCs/RPs = DOD Regional Commands/State Regional Platforms; JPC = Joint

  1. 关键链项目进度控制技术综合分析研究%Analysis on Critical Chain Project Comprehensive Schedule Control Method

    Institute of Scientific and Technical Information of China (English)

    李俊亭

    2015-01-01

    Critical chain project management(CCPM)is an important breakthrough in the development of project management, but critical chain project schedule controlling technology based on buffer mechanism is not comprehensive enough,and lacks of important control sector,and has no association with traditional project schedule control technology and so on. This paper analyzes the fundamental of CCPM schedule control method and traditional project schedule control technology. Based on buffer time management it proposes buffer time consumption ratio,buffer consumption & critical chain completion ratio,and critical chain project schedule control technology based on earned value. Based on resource management it puts forward three principles for critical chain project schedule control with CCPM characteristics. As a whole,this paper brings forward a comprehensive critical chain project schedule control technology,and provides a foundation for critical chain project control system.%关键链项目管理是现代项目管理理论的一个重要突破,但是基于缓冲机制的关键链项目进度控制技术还不够全面、存在部分控制环节缺失、未能与传统项目进度控制技术融合等问题.通过分析关键链项目进度控制基础和传统的项目进度控制技术,基于缓冲时间管理提出缓冲区消耗比例、缓冲区消耗与关键链完成比率和关键链挣值进度控制技术;基于资源管理提出具有关键链项目特色的3个进度控制准则,为系统研究关键链项目进度控制体系奠定了基础.

  2. Prediction and optimization methods for electric vehicle charging schedules in the EDISON project

    DEFF Research Database (Denmark)

    Aabrandt, Andreas; Andersen, Peter Bach; Pedersen, Anders Bro;

    2012-01-01

    project has been launched to investigate various areas relevant to electric vehicle integration. As part of EDISON an electric vehicle aggregator has been developed to demonstrate smart charging of electric vehicles. The emphasis of this paper is the mathematical methods on which the EDISON aggregator......Smart charging, where the charging of an electric vehicle battery is delayed or advanced in time based on energy costs, grid capacity or renewable contents, has a great potential for increasing the value of the electric vehicle to the owner, the grid and society as a whole. The Danish EDISON...

  3. 海心沙工程进度款的管控方法%Manage and Control Method of Haixinsha Project Schedule Fund

    Institute of Scientific and Technical Information of China (English)

    王冬梅; 唐辉; 刘子铭

    2011-01-01

    在简述海心沙工程及其进度款类别特征的基础上,分析该工程如何对工程进度款进行科学、有效的管理和控制,并具体介绍该工程"预先测算、先行支付、分类控制、决算修正"的工程进度款支付方法。%Resumes the Haixinsha project and the class features of its schedule fund,analyzes and sums up how to manage and control the project schedule fund effectively,and introduces the payment method about schedule fund with"beforehand calculation,payment in advance,classified control,final accounts amend".

  4. Vortex Flow Correlation

    Science.gov (United States)

    1981-01-01

    j . 1978. 93. Grabowski , W.J.; "Solutions of the Navier-Stokes Equations for Vortex Breakdown," NASA CR...including foreign nations. This technical report has been reviewed and is approved for publication. LAWRENCE W. ROGERS Q LOWELL C. KEEL, Major, USAF Project...or’ a w U - a LU LU U- LU C - J ’di 2 2 C LU I- 4 S Ua * - w x 2 40 20 I- 2 LU W S ~ 00 * U. 4 I- 𔃾 LU a 4 U 4 2 C C LU 4 a 4a 2 I- 4 a 3 9

  5. Dewey Decimal Classification Online Project: Evaluation of a Library Schedule and Index Integrated into the Subject Searching Capabilities of an Online Catalog. Final Report.

    Science.gov (United States)

    Markey, Karen; Demeyer, Anh N.

    In this research project, subject terms from the Dewey Decimal Classification (DDC) Schedules and Relative Index were incorporated into an online catalog as searcher's tools for subject access, browsing, and display. Four features of the DDC were employed to help searchers browse for and match their own subject terms with the online catalog's…

  6. Construction of the Project Schedule Management%工程项目进度管理建设初探

    Institute of Scientific and Technical Information of China (English)

    袁洁

    2011-01-01

    工程项目建设进度受诸多因素影响,这就要求工程项目管理人员在事先对影响进度的各种因素进行全面调查研究,预测、评估这些因素对工程建设进度产生的影响,并编制可行的进度计划。采取各种赶工措施使工程建设项目及早竣工,尽快发挥工程建设投资的经济效益。本文所提及的仅仅是一些定性分析,也是个人一种认识,其中还有许多问题有待深入探讨和研究。%The project construction schedule affected by many factors,which requires project management personnel in advance of the various factors that affect the progress of a comprehensive research,forecasting,assessment of these factors on the impact of the construction progress and the progress of preparation of a viable plan.Take various measures to make up the works of construction projects completed as early as possible,as soon as possible to play the economic benefits of investment in construction.This paper mentioned only some of the qualitative analysis,but also an understanding person,of which there are many issues to be further explored and examined.

  7. Analysis of Vortex Line Cutting and Reconnection by a Blade

    Science.gov (United States)

    Saunders, Curtis; Marshall, Jeffrey

    2015-11-01

    The essence of vortex reconnection involves the cutting of vortex lines originating from one region and reconnecting to vortex lines originating from another region via the diffusion-regulated annihilation of vorticity. Vortex cutting by a blade is a special case of the more general class of vortex reconnection problems, with an important difference being that vorticity is generated at the reconnection site. In this study, a series of Navier-Stokes simulations of orthogonal vortex cutting by a blade with different values of vortex strength are reported. The three phases of vortex reconnection identified in the literature are found to have counterparts for the vortex cutting problem. However numerous differences between the mechanics of vortex cutting and reconnection within each phase are discussed. In addition, comparisons are made between the temporal changes of the maximum and minimum components of vorticity for vortices of differing strength but still within the vortex cutting regime. The vortex cutting results are also compared with predictions of a simple analytical model that incorporates the key elements of a stretched vorticity field interacting with a solid surface, which is representative of the vortex cutting mechanism near the blade leading edge. Funded by National Science Foundation project DGE-1144388.

  8. NASA Schedule Management Handbook

    Science.gov (United States)

    2011-01-01

    The purpose of schedule management is to provide the framework for time-phasing, resource planning, coordination, and communicating the necessary tasks within a work effort. The intent is to improve schedule management by providing recommended concepts, processes, and techniques used within the Agency and private industry. The intended function of this handbook is two-fold: first, to provide guidance for meeting the scheduling requirements contained in NPR 7120.5, NASA Space Flight Program and Project Management Requirements, NPR 7120.7, NASA Information Technology and Institutional Infrastructure Program and Project Requirements, NPR 7120.8, NASA Research and Technology Program and Project Management Requirements, and NPD 1000.5, Policy for NASA Acquisition. The second function is to describe the schedule management approach and the recommended best practices for carrying out this project control function. With regards to the above project management requirements documents, it should be noted that those space flight projects previously established and approved under the guidance of prior versions of NPR 7120.5 will continue to comply with those requirements until project completion has been achieved. This handbook will be updated as needed, to enhance efficient and effective schedule management across the Agency. It is acknowledged that most, if not all, external organizations participating in NASA programs/projects will have their own internal schedule management documents. Issues that arise from conflicting schedule guidance will be resolved on a case by case basis as contracts and partnering relationships are established. It is also acknowledged and understood that all projects are not the same and may require different levels of schedule visibility, scrutiny and control. Project type, value, and complexity are factors that typically dictate which schedule management practices should be employed.

  9. Rotor Wake Vortex Definition Using 3C-PIV Measurements: Corrected for Vortex Orientation

    Science.gov (United States)

    Burley, Casey L.; Brooks, Thomas F.; vanderWall, Berend; Richard, Hughues Richard; Raffel, Markus; Beaumier, Philippe; Delrieux, Yves; Lim, Joon W.; Yu, Yung H.; Tung, Chee

    2003-01-01

    Three-component (3-C) particle image velocimetry (PIV) measurements, within the wake across a rotor disk plane, are used to determine wake vortex definitions important for BVI (Blade Vortex Interaction) and broadband noise prediction. This study is part of the HART II test program conducted using a 40 percent scale BO-105 helicopter main rotor in the German-Dutch Wind Tunnel (DNW). In this paper, measurements are presented of the wake vortex field over the advancing side of the rotor operating at a typical descent landing condition. The orientations of the vortex (tube) axes are found to have non-zero tilt angles with respect to the chosen PIV measurement cut planes, often on the order of 45 degrees. Methods for determining the orientation of the vortex axis and reorienting the measured PIV velocity maps (by rotation/projection) are presented. One method utilizes the vortex core axial velocity component, the other utilizes the swirl velocity components. Key vortex parameters such as vortex core size, strength, and core velocity distribution characteristics are determined from the reoriented PIV velocity maps. The results are compared with those determined from velocity maps that are not corrected for orientation. Knowledge of magnitudes and directions of the vortex axial and swirl velocity components as a function of streamwise location provide a basis for insight into the vortex evolution.

  10. 双湖新城项目施工进度管理研究%Research on Construction Schedule Management of Shuanghu New Town Project

    Institute of Scientific and Technical Information of China (English)

    胡迎心

    2015-01-01

    With the increasing size and complexity of the construction project, the construction process becomes more complex.How to rea-sonably control the project schedule and achieve the best balance between duration, cost and quality becomes the extremely important target for construction management.With the 1# building of Shuanghu New Town project as an example, the schedule control of construction phase was taken as a research object.On the basis of actual project situation and the construction plan, we determine the construction peri-od and design the project schedule plan;at last we optimize the time limit for the project, all these will be adopted to realize the schedule goal.%随着建设项目的规模和难度不断加大,其施工过程也更加复杂,如何合理地控制项目进度,实现工期、成本和质量三者之间的最佳平衡,已为施工管理中一项极为重要的目标。本文以双湖新城三区1#楼为例,将该工程施工阶段的进度计划作为研究对象,依据工程现状和施工方案确定施工工期并设计项目进度计划方案,最后运用网络计划技术对工期进行优化,确保实现既定的工期目标。

  11. Schedule Control in the Management of Waste Heat Power Projects%余热电站项目管理中的进度控制

    Institute of Scientific and Technical Information of China (English)

    曹良金

    2016-01-01

    The differences in construction and management of waste heat power projects and conventional thermal power projects are compared. Schedule management and control points in the management of waste heat power projects are mainly analyzed and summarized.%比较了余热电站与常规火力发电项目建设与管理的不同之处,着重就余热电站项目管理中进度管理及控制要点做了分析与总结。

  12. Integration of Building Information Modeling and Critical Path Method Schedules to Simulate the Impact of Temperature and Humidity at the Project Level

    Directory of Open Access Journals (Sweden)

    Yongwei Shan

    2014-07-01

    Full Text Available Steel construction activities are often undertaken in an environment with limited climate control. Both hot and cold temperatures can physically and psychologically affect construction workers, thus decreasing their productivity. Temperature and humidity are two factors that constantly exert forces on workers and influence their performance and efficiency. Previous studies have established a relationship between labor productivity and temperature and humidity. This research is built on the existing body of knowledge and develops a framework of integrating building information modeling (BIM with a lower level critical path method (CPM schedule to simulate the overall impact of temperature and humidity on a healthcare facility’s structural steel installation project in terms of total man hours required to build the project. This research effort utilized historical weather data of four cities across the U.S., with each city having workable seasons year-round and conducted a baseline assessment to test if various project starting dates and locations could significantly impact the project’s schedule performance. It was found that both varied project start dates and locations can significantly contribute to the difference in the man hours required to build the model project and that the project start date and location can have an interaction effect. This study contributes to the overall body of knowledge by providing a framework that can help practitioners better understand the overall impact of a productivity influencing factor at a project level, in order to facilitate better decision making.

  13. Fractional vortex Hilbert's Hotel

    CERN Document Server

    Gbur, Greg

    2015-01-01

    We demonstrate how the unusual mathematics of transfinite numbers, in particular a nearly perfect realization of Hilbert's famous hotel paradox, manifests in the propagation of light through fractional vortex plates. It is shown how a fractional vortex plate can be used, in principle, to create any number of "open rooms," i.e. topological charges, simultaneously. Fractional vortex plates are therefore demonstrated to create a singularity of topological charge, in which the vortex state is completely undefined and in fact arbitrary.

  14. An Efficient Genetic Agorithm for Solving the Multi-Mode Resource-Constrained Project Scheduling Problem Based on Random Key Representation

    Directory of Open Access Journals (Sweden)

    Mohammad Hassan Sebt

    2015-11-01

    Full Text Available In this paper, a new genetic algorithm (GA is presented for solving the multi-mode resource-constrained project scheduling problem (MRCPSP with minimization of project makespan as the objective subject to resource and precedence constraints. A random key and the related mode list (ML representation scheme are used as encoding schemes and the multi-mode serial schedule generation scheme (MSSGS is considered as the decoding procedure. In this paper, a simple, efficient fitness function is proposed which has better performance compared to the other fitness functions in the literature. Defining a new mutation operator for ML is the other contribution of the current study. Comparing the results of the proposed GA with other approaches using the well-known benchmark sets in PSPLIB validates the effectiveness of the proposed algorithm to solve the MRCPSP.

  15. Sadovskii vortex in strain

    Science.gov (United States)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2014-11-01

    A Sadovskii vortex is a patch of fluid with uniform vorticity surrounded by a vortex sheet. Using a boundary element type method, we investigate the steady states of this flow in an incompressible, inviscid straining flow. Outside the vortex, the fluid is irrotational. In the limiting case where the entire circulation is due to the vortex patch, this is a patch vortex (Moore & Saffman, Aircraft wake turbulence and its detection 1971). In the other limiting case, where all the circulation is due to the vortex sheet, this is a hollow vortex (Llewellyn Smith and Crowdy, J. Fluid Mech. 691, 2012). This flow has two governing nondimensional parameters, relating the strengths of the straining field, vortex sheet, and patch vorticity. We study the relationship between these two parameters, and examine the shape of the resulting vortices. We also work towards a bifurcation diagram of the steady states of the Sadovskii vortex in an attempt to understand the connection between vortex sheet and vortex patch desingularizations of the point vortex. Support from NSF-CMMI-0970113.

  16. 工程项目进度管理及控制探讨%On Engineering Project Schedule Management and Control

    Institute of Scientific and Technical Information of China (English)

    熊文彬

    2013-01-01

    Progress management is very important for engineering project management, which can fully reflect the implementation condition of the project. Doing a good job in the construction phase of the project progress control management to ensure the performance of the contract, the construction enterprise project completed on schedule plays a decisive role in use. This paper makes a deep analysis on the factors affecting the project schedule management, and specific management measures are put forward according to the related influencing factors. Project schedule control, cost control and quality control are the three core elements of project management, which spread in each other. It is an important measure to ensure the construction projects completed on schedule, scientific arrangement of resources and saving the cost for the project investment.%工程项目进度管理是工程项目管理的一项极为重要的工作,其能全面反映项目的实施情况。做好施工阶段的项目进度控制管理对保证施工企业履行合同、工程项目按期竣工投入使用发挥着决定性作用。文章对工程项目进度管理的影响因素进行了深入分析,并对影响其的相关因素提出了具体的管理措施。工程项目进度控制、成本控制、质量控制,是项目管理三个核心内容,相铺相成。它是确保施工工程项目按期完成,科学安排资源投入、节约工程成本投资的重要举措。

  17. On the Schedule Control of Large Metallurgical Construction Engineering Projects%大型冶金建设工程项目进度控制研究

    Institute of Scientific and Technical Information of China (English)

    孙忠林

    2015-01-01

    It has important practical significance for improving the metallurgical construction quality level and controlling construction investment to research the schedule control of large metallurgical construction engineering projects.%研究大型冶金建设工程项目进度控制对提高冶金建设质量水平、控制建设投资具有重要的现实意义。

  18. Streamwise Vortex Interaction with a Horseshoe Vortex

    Institute of Scientific and Technical Information of China (English)

    Piotr Doerffer; Pawel Flaszynski; Franco Magagnato

    2003-01-01

    Flow control in turbomachinery is very difficult because of the complexity of its fully 3-D flow structure. The authors propose to introduce streamwise vortices into the control of internal flows. A simple configuration of vortices was investigated in order to better understand the flow control methods by means of streamwise vortices.The research presented here concerns streamwise vortex interaction with a horseshoe vortex. The effects of such an interaction are significantly dependent on the relative location of the streamwise vortex in respect to the leading edge of the profile. The streamwise vortex is induced by an air jet. The horseshoe vortex is generated by the leading edge of a symmetric profile. Such a configuration gives possibility to investigate the interaction of these two vortices alone. The presented analysis is based on numerical simulations by means of N-S compressible solver with a two-equation turbulence model.

  19. Vortex mechanism in hydrocyclones

    Institute of Scientific and Technical Information of China (English)

    徐继润; 刘正宁; 邢军; 李新跃; 黄慧; 徐海燕; 罗茜

    2001-01-01

    On the basis of analyzing the vortex characteristics, a new mechanism of the vortex formation in hydrocyclones is developed. The main concept of the mechanism is that the vortex flow in a hydrocyclone is resulted from the overlapping of container rotation and hole leakage. The model is then used to explain the compound distribution of free vortex and forced vortex, predict the similarity of tangential velocity at different input pressures, and make count of the principle of small hydrocyclone with lower cut-size than large one. Meanwhile a new possible approach to a large hydro-cyclone with lower cut-size by minimizing or eliminating the air core is discussed briefly.

  20. Flexible Software for Flexible Scheduling

    Science.gov (United States)

    Economou, Frossie; Jenness, Tim; Tilanus, Remo P. J.; Hirst, Paul; Adamson, Andy J.; Rippa, Mathew; Delorey, Kynan K.; Isaak, Kate G.

    The JAC Observation Management Project (OMP) provides software for the James Clerk Maxwell (JCMT) and the United Kingdom Infrared (UKIRT) telescopes that manages the life-cycle of flexibly scheduled observations. Its aim is to increase observatory efficiency under flexible (queue) scheduled observing, without depriving the principal investigator (PI) of the flexibility associated with classical scheduling.

  1. Microscale vortex laser with controlled topological charge

    Science.gov (United States)

    Wang, Xing-Yuan; Chen, Hua-Zhou; Li, Ying; Li, Bo; Ma, Ren-Min

    2016-12-01

    A microscale vortex laser is a new type of coherent light source with small footprint that can directly generate vector vortex beams. However, a microscale laser with controlled topological charge, which is crucial for virtually any of its application, is still unrevealed. Here we present a microscale vortex laser with controlled topological charge. The vortex laser eigenmode was synthesized in a metamaterial engineered non-Hermitian micro-ring cavity system at exceptional point. We also show that the vortex laser cavity can operate at exceptional point stably to lase under optical pumping. The microscale vortex laser with controlled topological charge can serve as a unique and general building block for next-generation photonic integrated circuits and coherent vortex beam sources. The method we used here can be employed to generate lasing eigenmode with other complex functionalities. Project supported by the “Youth 1000 Talent Plan” Fund, Ministry of Education of China (Grant No. 201421) and the National Natural Science Foundation of China (Grant Nos. 11574012 and 61521004).

  2. Depicting Vortex Stretching and Vortex Relaxing Mechanisms

    Institute of Scientific and Technical Information of China (English)

    符松; 李启兵; 王明皓

    2003-01-01

    Different from many existing studies on the paranetrization of vortices, we investigate the effectiveness of two new parameters for identifying the vortex stretching and vortex relaxing mechanisms. These parameters are invariants and identify three-dimensional flow structures only, i.e. they diminish in two-dimensional flows. This is also unlike the existing vortex identification approaches which deliver information in two-dimensional flows. The present proposals have been successfully applied to identify the stretching and relaxing vortices in compressible mixing layers and natural convection flows.

  3. On the Project Schedule Management Based on BIM-4D Technology%基于BIM-4D技术的项目进度管理研究

    Institute of Scientific and Technical Information of China (English)

    易兵; 田北平; 钟华

    2015-01-01

    With the growing complexity of building project, the difficulty of project management has increased. As the main content of construction management, traditional schedule management model is difficult to apply. This article will introduce BIM-4D technology schedule management mode, the development of this technology is based on building information model. Through the comparison and analysis, the applicability and superiority of schedule management mode under BIM-4D technology are demonstrated.%随着建筑工程项目的日益复杂性,导致项目管理的难度增加,传统进度管理作为施工管理的主要内容,模式变的难以适用,本文将引入在以建筑信息化模型(Build Information Model)为基础上发展起来的BIM-4D技术的进度管理模式,通过对比分析,来论证在BIM-4D技术下的进度管理模式的适用性和优越性。

  4. Refinery scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcus V.; Fraga, Eder T. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Shah, Nilay [Imperial College, London (United Kingdom)

    2004-07-01

    This work addresses the refinery scheduling problem using mathematical programming techniques. The solution adopted was to decompose the entire refinery model into a crude oil scheduling and a product scheduling problem. The envelope for the crude oil scheduling problem is composed of a terminal, a pipeline and the crude area of a refinery, including the crude distillation units. The solution method adopted includes a decomposition technique based on the topology of the system. The envelope for the product scheduling comprises all tanks, process units and products found in a refinery. Once crude scheduling decisions are Also available the product scheduling is solved using a rolling horizon algorithm. All models were tested with real data from PETROBRAS' REFAP refinery, located in Canoas, Southern Brazil. (author)

  5. 基于BOM的项目看板进度预警模型研究%BOM-based Project Schedule Early-warning Model with Kanban Management

    Institute of Scientific and Technical Information of China (English)

    杜百岗; 郭顺生; 孙利波

    2013-01-01

    针对水泥装备制造企业项目进度难以控制的问题,结合企业实际和BOM(bill of material)的层次,建立了多级看板管理进度预警模型.通过典型工序的看板控制及对工序、部件、产品和项目进度预警策略,实现了进度的分级监控和预警.实际应用表明,该模型能满足对项目进度预警的要求.%A multi-stage kanban management model of project schedule early-warning was developed for the project schedule control difficulty in cement equipment manufacturing enterprise.The classification monitoring and early-warning were realized by kanban control for typical process as well as early-warning strategy for processes,parts,products and project progress,which are based on the level of BOM.The practical application in enterprise was accomplished successfully in demonstrating the effectiveness of the model.

  6. A Practical and Robust Execution Time-Frame Procedure for the Multi-Mode Resource-Constrained Project Scheduling Problem with Minimal and Maximal Time Lags

    Directory of Open Access Journals (Sweden)

    Angela Hsiang-Ling Chen

    2016-09-01

    Full Text Available Modeling and optimizing organizational processes, such as the one represented by the Resource-Constrained Project Scheduling Problem (RCPSP, improve outcomes. Based on assumptions and simplification, this model tackles the allocation of resources so that organizations can continue to generate profits and reinvest in future growth. Nonetheless, despite all of the research dedicated to solving the RCPSP and its multi-mode variations, there is no standardized procedure that can guide project management practitioners in their scheduling tasks. This is mainly because many of the proposed approaches are either based on unrealistic/oversimplified scenarios or they propose solution procedures not easily applicable or even feasible in real-life situations. In this study, we solve a more true-to-life and complex model, Multimode RCPSP with minimal and maximal time lags (MRCPSP/max. The complexity of the model solved is presented, and the practicality of the proposed approach is justified depending on only information that is available for every project regardless of its industrial context. The results confirm that it is possible to determine a robust makespan and to calculate an execution time-frame with gaps lower than 11% between their lower and upper bounds. In addition, in many instances, the solved lower bound obtained was equal to the best-known optimum.

  7. 改进的PERT网络在项目进度控制中的应用%APPLICATION OF IMPROVED PERT NETWORK IN PROJECT SCHEDULE CONTROL

    Institute of Scientific and Technical Information of China (English)

    唐华; 李慧民; 魏芳

    2011-01-01

    In order to reduce the project schedule risk, improved PERT network is proposed to control the project schedule. For the lack of classical PERT method, the probability distribution and parameters of important processes are determined using Mohr method. However, other processes that are still subject to beta distribution, at the same time, parameter estimation methods and calculations of process expectation and variance have been improved. To fully consider the schedule impact caused by non-critical path, MATLAB simulation method is used to simulate the process. Finally, make the improved PERT network apply into specific project, establish the corresponding procedures using MATLAB method in order to obtain the completion probability in prescribed period.%为了减小项目进度风险,提出了基于改进的PERT网络进度控制方法。针对经典PERT方法的不足,用莫尔法来确定重要工序的概率分布和参数,其他的工序仍认为近似服从beta分布,且在参数估计方法和工序期望、方差的计算上都有所改进。为了充分考虑非关键线路对项目工期的影响,应用MATLAB仿真的方法进行模拟。最后将改进后的PERT网络应用到具体的工程项目中,应用MATLAB编制相应的程序,得到了在规定丁期内的完工概率。

  8. 基于网络图的软件项目进度计划编制%Schedule Planning of Software Project Based on Network Chart

    Institute of Scientific and Technical Information of China (English)

    任永昌; 邢涛; 刘大成

    2011-01-01

    Well-developed, concise and accurate software project schedule planning is the key to successful software development. The current schedule planning mainly uses manual methods, draw up slow, lack of scientific characteristics and so on, the article bases on the network chart, the use of work breakdown structures, program evaluation and review technique, critical path method, gantt chart and other technical studies. It illustrates preparatory work firstly, including the definition of activities, activity sequencing, drawing the network chart, gives time parameters derived formula, including estimation the activity time, estimation the project cycle, calculation activity time, and describes preparation process by examples. The results show that the method of software project scheduling planning has high practical value.%制订周密、简洁和精确的软件项目进度计划,是软件项目开发成功的关键.针对当前进度计划主要采用手工方法,编制速度慢、缺乏科学性等特点,基于网络图,运用工作分解结构、计划评审技术、关键路径法、甘特图等技术对其进行研究.说明了前期准备工作,包括定义活动、活动排序、绘制网络图;给出了推导时间参数公式,包括活动时间估计、项目周期估计、活动时间计算;并通过实例阐述了编制过程.结果表明,该方法对软件项目进度计划编制具有较高的实用价值.

  9. Distributed scheduling

    OpenAIRE

    Toptal, Ayşegül

    1999-01-01

    Ankara : Department of Industrial Engineering and the Institute of Engineering and Science of Bilkent Univ., 1999. Thesis (Master's) -- Bilkent University, 1999. Includes bibliographical references. Distributed Scheduling (DS) is a new paradigm that enables the local decisionmakers make their own schedules by considering local objectives and constraints within the boundaries and the overall objective of the whole system. Local schedules from different parts of the system are...

  10. Personnel scheduling

    OpenAIRE

    Vanden Berghe, Greet

    2012-01-01

    Personnel scheduling can become a particularly difficult optimisation problem due to human factors. And yet: people working in healthcare, transportation and other round the clock service regimes perform their duties based on a schedule that was often manually constructed. The unrewarding manual scheduling task deserves more attention from the timetabling community so as to support computation of fair and good quality results. The present abstract touches upon a set of particular characterist...

  11. Final Results from A Pilot Project to Investigate Wake Vortex Patterns and Weather Patterns at the Atlantic City Airport by the Richard Stockton College of NJ and the FAA

    Science.gov (United States)

    Trout, Joseph; Manson, J. Russell; King, David; Decicco, Nicolas; Prince, Alyssa; di Mercurio, Alexis; Rios, Manual

    2017-01-01

    Wake Vortex Turbulence is the turbulence generated by an aircraft in flight. This turbulence is created by vortices at the tips of the wing that may decay slowly and persist for several minutes after creation. These vortices and turbulence are hazardous to other aircraft in the vicinity. The strength, formation and lifetime of the turbulence and vortices are effected by many things including the weather. Here we present the final results of the pilot project to investigation of low level wind fields generated by the Weather Research and Forecasting Model and an analysis of historical data. The findings from the historical data and the data simulations were used as inputs for the computational fluid dynamics model (OpenFoam) to show that the vortices could be simulated using OpenFoam. Presented here are the updated results from a research grant, ``A Pilot Project to Investigate Wake Vortex Patterns and Weather Patterns at the Atlantic City Airport by the Stockton University and the FAA''.

  12. Location-based Scheduling

    DEFF Research Database (Denmark)

    Andersson, Niclas; Christensen, Knud

    The coordination of activities and resources in order to establish an effective production flow is central to the management of construction projects. The traditional technique for coordination of activities and resources in construction projects is the CPM-scheduling, which has been the predomin......The coordination of activities and resources in order to establish an effective production flow is central to the management of construction projects. The traditional technique for coordination of activities and resources in construction projects is the CPM-scheduling, which has been...... the predominant scheduling method since it was introduced in the late 1950s. Over the years, CPM has proven to be a very powerful technique for planning, scheduling and controlling projects, which among other things is indicated by the development of a large number of CPM-based software applications available...... on the market. However, CPM is primarily an activity based method that takes the activity as the unit of focus and there is criticism raised, specifically in the case of construction projects, on the method for deficient management of construction work and continuous flow of resources. To seek solutions...

  13. Cryptanalysis of Vortex

    DEFF Research Database (Denmark)

    Aumasson, Jean-Philippe; Dunkelman, Orr; Mendel, Florian;

    2009-01-01

    Vortex is a hash function that was first presented at ISC'2008, then submitted to the NIST SHA-3 competition after some modifications. This paper describes several attacks on both versions of Vortex, including collisions, second preimages, preimages, and distinguishers. Our attacks exploit flaws ...

  14. Aerodynamically shaped vortex generators

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Velte, Clara Marika; Øye, Stig;

    2016-01-01

    An aerodynamically shaped vortex generator has been proposed, manufactured and tested in a wind tunnel. The effect on the overall performance when applied on a thick airfoil is an increased lift to drag ratio compared with standard vortex generators. Copyright © 2015 John Wiley & Sons, Ltd....

  15. Vortex cutting in superconductors

    Science.gov (United States)

    Glatz, A.; Vlasko-Vlasov, V. K.; Kwok, W. K.; Crabtree, G. W.

    2016-08-01

    Vortex cutting and reconnection is an intriguing and still-unsolved problem central to many areas of classical and quantum physics, including hydrodynamics, astrophysics, and superconductivity. Here, we describe a comprehensive investigation of the crossing of magnetic vortices in superconductors using time dependent Ginsburg-Landau modeling. Within a macroscopic volume, we simulate initial magnetization of an anisotropic high temperature superconductor followed by subsequent remagnetization with perpendicular magnetic fields, creating the crossing of the initial and newly generated vortices. The time resolved evolution of vortex lines as they approach each other, contort, locally conjoin, and detach, elucidates the fine details of the vortex-crossing scenario under practical situations with many interacting vortices in the presence of weak pinning. Our simulations also reveal left-handed helical vortex instabilities that accompany the remagnetization process and participate in the vortex crossing events.

  16. 软件项目进度风险的定量分析方法%Quantitative Risk Analysis of Software Project Schedule Management

    Institute of Scientific and Technical Information of China (English)

    何剑虹; 白晓颖; 胡林平

    2011-01-01

    Project delay is still a common phenomenon in software development,which may affect seriously in software quality and cost, even result in project failure Risk control is thus essential for project schedule management. The paper analyzed the quantitative approaches for schedule risk analysis and management. It surveyed and compared the three typical models of software project management, including PERT/CPM, Critical Chain/Buffer Management, Event Chain Methodology. Among them,the Event Chain is a newly proposed model and risk analysis method from 2004. It introduces the event model into traditional models of activities, which captures the basic characteristics of risk occurrence and propagation. It represents a new viewpoint with a separated and dedicated risk model, and promotes a innovative approach for quantitative risk analysis.%软件项目超期仍然是业界的一个普遍现象,进度延期可能直接导致项目质量下降、费用超支甚至失败,因此项目执行过程中对于进度的风险控制至关重要.从定量分析的角度探讨项目进度管理的风险管理方法,并对3种主要的进度管理方法和模型--PERT/CPM方法、关键链方法、事件链方法--进行了调研和对比.其中,事件链是近年来新提出的一种针对风险事件进行建模和分析的方法,为进一步研究有效的进度风险管理控制方法和技术提供了新的思路和视角.

  17. Scheduling Supercomputers.

    Science.gov (United States)

    1983-02-01

    no task is scheduled with overlap. Let numpi be the total number of preemptions and idle slots of size at most to that are introduced. We see that if...no usable block remains on Qm-*, then numpi < m-k. Otherwise, numpi ! m-k-1. If j>n when this procedure terminates, then all tasks have been scheduled

  18. Analysis of the Application of Schedule Management in the Management of Construction Project%进度管理在建筑工程管理中的应用分析

    Institute of Scientific and Technical Information of China (English)

    郭军

    2014-01-01

    The paper discussed the influence of schedule ma-nagement on the construction project management and related initiatives to strengthen the progress management in project management of buildings, so as to analyze the application of schedule management in management of construction project.%本文针对进度管理,对建筑工程管理的重要影响、加强建设工程管理中的进度管理相关举措展开探讨,从而分析研究进度管理在建筑工程管理中的应用。

  19. An optical vortex coronagraph

    Science.gov (United States)

    Palacios, David M.

    2005-08-01

    An optical vortex may be characterized as a dark core of destructive interference in a beam of spatially coherent light. This dark core may be used as a filter to attenuate a coherent beam of light so an incoherent background signal may be detected. Applications of such a filter include: eye and sensor protection, forward-scattered light measurement, and the detection of extra-solar planets. Optical vortices may be created by passing a beam of light through a vortex diffractive optical element, which is a plate of glass etched with a spiral pattern, such that the thickness of the glass increases in the azimuthal direction. An optical vortex coronagraph may be constructed by placing a vortex diffractive optical element near the image plane of a telescope. An optical vortex coronagraph opens a dark window in the glare of a distant star so nearby terrestrial sized planets and exo-zodiacal dust may be detected. An optical vortex coronagraph may hold several advantages over other techniques presently being developed for high contrast imaging, such as lower aberration sensitivity and multi-wavelength operation. In this manuscript, I will discuss the aberration sensitivity of an optical vortex coronagraph and the key advantages it may hold over other coronagraph architectures. I will also provide numerical simulations demonstrating high contrast imaging in the presence of low-order static aberrations.

  20. Fast Josephson vortex

    Energy Technology Data Exchange (ETDEWEB)

    Malishevskii, A.S.; Silin, V.P.; Uryupin, S.A

    2002-12-30

    For the magnetically coupled waveguide and long Josephson junction we gave the analytic description of two separate velocity domains where the free motion of traveling vortex (2{pi}-kink) exists. The role of the mutual influence of waveguide and long Josephson junction is discussed. It is shown the possibility of the fast vortex motion with the velocity much larger than Swihart velocity of Josephson junction and close to the speed of light in the waveguide. The excitation of motion of such fast Josephson vortex is described.

  1. Development of a multi-objective scheduling system for offshore projects based on hybrid non-dominated sorting genetic algorithm

    Directory of Open Access Journals (Sweden)

    Jinghua Li

    2015-03-01

    Full Text Available In order to enhance the efficiency of offshore companies, a multi-objective scheduling system based on hybrid non-dominated sorting genetic algorithm was proposed. An optimized model for multi-objective and multi-execution mode was constructed under the condition of taking time, cost, and resource into account, and then the mathematical model for the same was established. Moreover, the key techniques of the proposed system were elaborated, and the flowchart was designed. Aiming at the weaknesses of non-dominated sorting genetic algorithm which is short for non-dominated sorting genetic algorithm-II in the facet of local search and computational efficiency, Pareto-dominated simulated annealing algorithm was applied in search global solution. Finally, by simulation examples and industrial application, the robustness and outperformance of the improved algorithm were verified.

  2. Vortex flow hysteresis

    Science.gov (United States)

    Cunningham, A. M., Jr.

    1986-01-01

    An experimental study was conducted to quantify the hysteresis associated with various vortex flow transition points and to determine the effect of planform geometry. The transition points observed consisted of the appearance (or disappearance) of trailing edge vortex burst and the transition to (or from) flat plate or totally separated flows. Flow visualization with smoke injected into the vortices was used to identify the transitions on a series of semi-span models tested in a low speed tunnel. The planforms tested included simple deltas (55 deg to 80 deg sweep), cranked wings with varying tip panel sweep and dihedral, and a straked wing. High speed movies at 1000 frames per second were made of the vortex flow visualization in order to better understand the dynamics of vortex flow, burst and transition.

  3. Modeling gasodynamic vortex cooling

    Science.gov (United States)

    Allahverdyan, A. E.; Fauve, S.

    2017-08-01

    We aim at studying gasodynamic vortex cooling in an analytically solvable, thermodynamically consistent model that can explain limitations on the cooling efficiency. To this end, we study an angular plus radial flow between two (coaxial) rotating permeable cylinders. Full account is taken of compressibility, viscosity, and heat conductivity. For a weak inward radial flow the model qualitatively describes the vortex cooling effect, in terms of both temperature and the decrease of the stagnation enthalpy, seen in short uniflow vortex (Ranque) tubes. The cooling does not result from external work and its efficiency is defined as the ratio of the lowest temperature reached adiabatically (for the given pressure gradient) to the lowest temperature actually reached. We show that for the vortex cooling the efficiency is strictly smaller than 1, but in another configuration with an outward radial flow, we find that the efficiency can be larger than 1. This is related to both the geometry and the finite heat conductivity.

  4. Vector Lattice Vortex Solitons

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Dong; YE Fang-Wei; DONG Liang-Wei; LI Yong-Ping

    2005-01-01

    @@ Two-dimensional vector vortex solitons in harmonic optical lattices are investigated. The stability properties of such solitons are closely connected to the lattice depth Vo. For small Vo, vector vortex solitons with the total zero-angular momentum are more stable than those with the total nonzero-angular momentum, while for large Vo, this case is inversed. If Vo is large enough, both the types of such solitons are stable.

  5. Research on the Construction Project Cost and Schedule Control from the Perspective of BIM Model%BIM模型视角下建设项目成本与进度控制研究

    Institute of Scientific and Technical Information of China (English)

    李静; 杜润泽

    2016-01-01

    Schedule and cost control is important in all stages of the construction project. Building information modeling (BIM) provides a comparatively complete solution for effective project cost and schedule control, and can realize the seamless integration of project participants. Through construction simulation, this article uses comprehensive progress rate curve for schedule control, and uses the method of earned value to evaluate the various cost parameters of the project, in order to realize schedule and cost control. Empirical research of the schedule and cost control of a project is carried out using BIM to implement the visualization simulation of the project schedule and cost control.%施工建设项目各个阶段都要关注进度与成本控制。建筑信息模型BIM为有效项目成本与进度控制提供了较为完备的解决方案,实现了项目参与各方的无缝集成。本文通过对项目施工模拟实现,利用综合进展率曲线进行进展控制,利用挣得值法对项目各个成本参数进行评估,以此来实现以进度与成本控制。以利用BIM对某项目进度成本控制进行实证研究,实现项目进度的可视化模拟与成本控制。

  6. Buoyant Norbury's vortex rings

    Science.gov (United States)

    Blyth, Mark; Rodriguez-Rodriguez, Javier; Salman, Hayder

    2014-11-01

    Norbury's vortices are a one-parameter family of axisymmetric vortex rings that are exact solutions to the Euler equations. Due to their relative simplicity, they are extensively used to model the behavior of real vortex rings found in experiments and in Nature. In this work, we extend the original formulation of the problem to include buoyancy effects for the case where the fluid that lies within the vortex has a different density to that of the ambient. In this modified formulation, buoyancy effects enter the problem through the baroclinic term of the vorticity equation. This permits an efficient numerical solution of the governing equation of motion in terms of a vortex contour method that tracks the evolution of the boundary of the vortex. Finally, we compare our numerical results with the theoretical analysis of the short-time evolution of a buoyant vortex. Funded by the Spanish Ministry of Economy and Competitiveness through grant DPI2011-28356-C03-02 and by the London Mathematical Society.

  7. Kelvin Waves and Dynamic Knots on Perturbative Helical Vortex Lines

    CERN Document Server

    Kou, Su-Peng

    2016-01-01

    Vortex lines are one-dimensional extended objects in three-dimensional superfluids. Vortex lines have many interesting properties, including Kelvin waves, exotic statistics, and possible entanglement. In this paper, an emergent "quantum world" is explored by projecting helical vortex lines. A one-dimensional quantum Fermionic model is developed to effectively describe the local fluctuations of helical vortex lines. The elementary excitations are knots with half winding-number that obey emergent quantum mechanics. The Biot-Savart equation, and its Kelvin wave solutions on helical vortex lines become Schrodinger equation, and the wave functions of probability waves for finding knots, respectively. This work shows an alternative approach to simulating quantum many-body physics based on classical systems.

  8. Controlling vortex motion and vortex kinetic friction

    Science.gov (United States)

    Nori, Franco; Savel'ev, Sergey

    2006-05-01

    We summarize some recent results of vortex motion control and vortex kinetic friction. (1) We describe a device [J.E. Villegas, S. Savel'ev, F. Nori, E.M. Gonzalez, J.V. Anguita, R. Garcìa, J.L. Vicent, Science 302 (2003) 1188] that can easily control the motion of flux quanta in a Niobium superconducting film on an array of nanoscale triangular magnets. Even though the input ac current has zero average, the resulting net motion of the vortices can be directed along either one direction, the opposite direction, or producing zero net motion. We also consider layered strongly anisotropic superconductors, with no fixed spatial asymmetry, and show [S. Savel'ev, F. Nori, Nature Materials 1 (2002) 179] how, with asymmetric drives, the ac motion of Josephson and/or pancake vortices can provide a net dc vortex current. (2) In analogy with the standard macroscopic friction, we present [A. Maeda, Y. Inoue, H. Kitano, S. Savel'ev, S. Okayasu, I. Tsukada, F. Nori , Phys. Rev. Lett. 94 (2005) 077001] a comparative study of the friction force felt by vortices in superconductors and charge density waves.

  9. Environmental surveillance master sampling schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, L.E.

    1996-02-01

    Environmental surveillance of the Hanford Site and surrounding areas is conducted by the Pacific Northwest National Laboratory (PNNL) for the US Department of Energy (DOE). This document contains the planned 1996 schedules for routine collection of samples for the Surface Environmental Surveillance Project (SESP), Drinking Water Project, and Ground-Water Surveillance Project.

  10. Design and Implementation of the Schedule Management System for Software Projects%软件项目进度管理系统的设计与实现

    Institute of Scientific and Technical Information of China (English)

    姚辉

    2015-01-01

    With a focus on the software project schedule management, the paper proposes dynamic manage-ment for different stages and for each module in the stage. The system is developed by ASP.NET 3.5, C # and the Ajax technology. SQL Server 2005 is database management Server of this project. According to each role and dif-ferent operations of the Web, this system can divide roles and authorities dynamically.%本文以软件项目进度管理为研究的中心议题,提出动态管理某个项目中的各个阶段和阶段中的各个模块。结合前沿的Ajax技术,该系统使用业界流行的ASP.NET 3.5+ C#进行整合开发,并且数据库服务器管理的后台数据使用SQL Server 2005。系统中进行的Web操作各异,基于每个角色的不同,动态实现了各角色权限的严格划分。

  11. Demodulation for multi vortex beams based on composite diffraction hologram

    Science.gov (United States)

    Zhang, Weibin; Li, Yingchun; Sun, Tengfen; Shao, Wei; Zhu, Fuquan; Wang, YingYing

    2016-12-01

    While projecting a Gaussian beam onto the spatial light modulator (SLM) which has loaded a composite hologram, several vortex beams can be generated at one time. On the contrary, while projecting the corresponding vortex beam onto the hologram, the Gaussian beam can be restored, realizing the demodulation of vortex beam. In traditional optical communication systems, a hologram can only demodulate one incident vortex beam. In this paper, a vortex beam demodulation method based on composite diffraction hologram is proposed, which can demodulate several incident vortex beams with only one hologram. An experimental system is set up in this paper which achieves the generation, transmission and demodulation experiments of vortex beams with 64QAM-OFDM signals. After a series of offline processing on the demodulated Gaussian beam, constellation and bit error rates (BER) of each subcarrier for OFDM signals are acquired. The experimental results show that good system performance can be achieved with this method as the BERs of all subcarriers are under the FEC threshold.

  12. 多目标资源受限项目鲁棒调度研究%Research on Multi-Objective Robust Resource-Constrained Project Scheduling

    Institute of Scientific and Technical Information of China (English)

    庞南生; 孟俊姣

    2012-01-01

    由于资源受限项目调度属于NP-hard问题,传统的RCPSP主要集中于工期最短单一目标的基本同题研究,而忽略了项目调度对鲁棒性筹多目标属性特征的要求.本文以经典的串行进度生成机制为基础,引入了衡量项目稳定性的鲁棒性要素,创建了项目鲁棒调度串行生成机制(RSSGS),提出了项目鲁棒性的测度新指标,构建了优化鲁棒结构的工期最短和鲁棒性最大的双目标优化模型,并结合分层优化原理,设计了改进的SA算法.最后,采用算例验证了该模型的可行性和合理性.%The resource-constrained project scheduling problem is a NP-hard problem, but the traditional RCPSP still focuses on the single objective of makespan minimization and ignores the requirements of the multi-objective feature, such as, robustness. In this paper, based on the classical serial schedule generation scheme, a factor measuring the stability of activity is introduced and robust SSGS is put forward; with the proposition of a robust measure index, a bi-objective optimal model aimed at makespan minimization and robustness maximization is developed; and combined with the hierarchical optimization principle, an improved SA algorithm is presented. Finally, the results of the numerical example show that the model is feasible.

  13. On the construction safety and project schedule control%浅析施工安全与项目进度控制

    Institute of Scientific and Technical Information of China (English)

    李天平

    2015-01-01

    建筑施工中安全工作和施工的进度控制是团队的工作,不是个人的工作,安全工作和进度控制是复杂的系统化工程。企业的领导和公司的全体人员要加强安全工作和进度控制工作,要不断提高安全意识,要认真贯彻执行国家有关部门的各项规章制度,根据施工现场的现实情况要客观地工作,减少施工现场的事故发生。对于施工进度的控制也要按照国家有关部门的规定认真执行。%Progress of the construction work and construction safety control is a team work, not individual work, security work and schedule control is a complex systematic project. Business leaders and all the staff's work to strengthen the security and progress control work to continuously improve safety awareness, we should conscientiously implement the rules and regulations of national authorities, according to the construction site of the reality of the situation objectively,to reduce construction site the accident occurred. Should conscientiously implement the construction schedule for the control of national authorities in accordance with the provisions.

  14. Reconnection of superfluid vortex bundles.

    Science.gov (United States)

    Alamri, Sultan Z; Youd, Anthony J; Barenghi, Carlo F

    2008-11-21

    Using the vortex filament model and the Gross-Pitaevskii nonlinear Schroedinger equation, we show that bundles of quantized vortex lines in He II are structurally robust and can reconnect with each other maintaining their identity. We discuss vortex stretching in superfluid turbulence and show that, during the bundle reconnection process, kelvin waves of large amplitude are generated, in agreement with the finding that helicity is produced by nearly singular vortex interactions in classical Euler flows.

  15. Nano magnetic vortex wall guide

    Directory of Open Access Journals (Sweden)

    H. Y. Yuan

    2015-11-01

    Full Text Available A concept of nano magnetic vortex wall guide is introduced. Two architectures are proposed. The first one is properly designed superlattices while the other one is bilayer nanostrips. The concept is verified by micromagnetic simulations. Both guides can prevent the vortex core in a magnetic vortex wall from colliding with sample surface so that the information stored in the vortex core can be preserved during its transportation from one location to another one through the guides.

  16. Vortex Characterization for Engineering Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jankun-Kelly, M; Thompson, D S; Jiang, M; Shannahan, B; Machiraju, R

    2008-01-30

    Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the vortex topology identification component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that illustrate the strengths and weaknesses of our approach.

  17. Jet vortex methods

    CERN Document Server

    Holm, Darryl D

    2015-01-01

    Vortex blob methods are typically characterized by a regularization length scale, below which the the dynamics are trivial for isolated blobs. In this article we will find that the dynamics need not be trivial if one is willing to consider distributional derivatives of Dirac delta functionals as valid vorticity distributions. More specifically, a new singular vortex theory is presented for regularised Euler fluid equations of ideal incompressible flow in the plane. We determine the conditions under which such regularised Euler fluid equations may admit vorticity singularities which are stronger than delta functions, e.g., derivatives of delta functions. We also characterise the Hamiltonian dynamics of the higher-order singular vortices. Applications to the design of numerical meth- ods similar to vortex blob methods are also discussed. Such findings shed light onto the rich dynamics which occur below the regularization length scale and enlighten our perspective on the multiscale aspects of regularized fluid m...

  18. Vortex tube optimization theory

    Energy Technology Data Exchange (ETDEWEB)

    Lewins, Jeffery [Cambridge Univ., Magdalene Coll., Cambridge (United Kingdom); Bejan, Adrian [Duke Univ., Dept. of Mechanical Engineering and Materials Science, Durham, NC (United States)

    1999-11-01

    The Ranque-Hilsch vortex tube splits a single high pressure stream of gas into cold and warm streams. Simple models for the vortex tube combined with regenerative precooling are given from which an optimisation can be undertaken. Two such optimisations are needed: the first shows that at any given cut or fraction of the cold stream, the best refrigerative load, allowing for the temperature lift, is nearly half the maximum loading that would result in no lift. The second optimisation shows that the optimum cut is an equal division of the vortex streams between hot and cold. Bounds are obtainable within this theory for the performance of the system for a given gas and pressure ratio. (Author)

  19. Magnetic vortex racetrack memory

    Science.gov (United States)

    Geng, Liwei D.; Jin, Yongmei M.

    2017-02-01

    We report a new type of racetrack memory based on current-controlled movement of magnetic vortices in magnetic nanowires with rectangular cross-section and weak perpendicular anisotropy. Data are stored through the core polarity of vortices and each vortex carries a data bit. Besides high density, non-volatility, fast data access, and low power as offered by domain wall racetrack memory, magnetic vortex racetrack memory has additional advantages of no need for constrictions to define data bits, changeable information density, adjustable current magnitude for data propagation, and versatile means of ultrafast vortex core switching. By using micromagnetic simulations, current-controlled motion of magnetic vortices in cobalt nanowire is demonstrated for racetrack memory applications.

  20. Three-dimensional vortex structures under breaking waves

    OpenAIRE

    WATANABE Yasunori; Saeki, Hiroshi; Hosking, Roger J.

    2005-01-01

    The large-scale vortex structures under spilling and plunging breakers are investigated, using a fully three-dimensional large-eddy simulation (LES). When an overturning jet projecting from the crest in a breaking wave rebounds from the water surface ahead, the vorticity becomes unstable in a saddle region of strain between the rebounding jet and a primary spanwise vortex, resulting in spanwise undulations of the vorticity. The undulations are amplified on a braid in this saddle region, leadi...

  1. Gantt Chart Drawing Software Design of Project Schedule Management%项目进度管理Gantt图绘制软件设计

    Institute of Scientific and Technical Information of China (English)

    郑丽娟; 任永昌

    2013-01-01

      进度计划在项目管理中处于重要地位,是有条不紊地开展项目工作的基础,是项目成功的关键。针对计划制定过程中CPM计算复杂及Gantt难于绘制的问题,文中设计了自动完成软件。首先,进行基础理论研究,包括Gantt图表示和关键路径法及时间计算公式;然后,进行数据库设计,包括概念结构设计和逻辑结构设计;最后,进行详细设计,用盒图设计时间计算过程,用问题分析图设计Gantt图绘制过程。 Gantt图自动绘制软件,对加强项目管理、提高项目成功率具有重要意义。%The schedule planning with an important position in project management,is the basis of carrying out project work in an orderly manner,is the key to the success of project. Design the auto-complete software for the problem of calculation complexity on CPM and difficult to draw Gantt in the planning process. First,research basic theories,including the Gantt chart representation,critical path method and time formula. Then,design database,including the concept structural design and logical structure design. Finally,carry out the detailed design,calculate process with the block diagram design time,design Gantt chart drawing process with the problem analysis diagram. Gantt chart drawing software automatically has a great significance for strengthening project management and improving project success rate.

  2. Dynamics of Vortex Cavitation

    NARCIS (Netherlands)

    Pennings, P.C.

    2016-01-01

    This thesis describes the mechanisms with which tip vortex cavitation is responsible for broadband pressure fluctuations on ship propellers. Hypotheses for these are described in detail by Bosschers (2009). Validation is provided by three main cavitation-tunnel experiments, one on a model propeller

  3. Study on schedule control and management of construction project underthe information technology%信息科技下建筑工程项目进度控制管理研究

    Institute of Scientific and Technical Information of China (English)

    陈恩善

    2016-01-01

    Construction project schedule control is an important work of construction project management. However,there are many factors impacted the project schedule,so the construction project schedule management and control is very important.This paper takes the construction project of Z College as an example,the problems are analyzed in the construction progress.The corresponding control measures are put forward.%建筑工程项目进度控制是建筑工程项目管理的重要工作.但是由于影响工程项目进度的因素较多,因此对于建筑工程项目的进度管理与控制是非常关键的.本文以Z学院实验楼建设工程项目为例,对其建设进度中出现的问题展开研究,提出了相应的进度控制措施.

  4. Passive Wake Vortex Control

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J M

    2001-10-18

    The collapse of the Soviet Union and ending of the Cold War brought about many significant changes in military submarine operations. The enemies that the US Navy faces today and in the future will not likely be superpowers armed with nuclear submarines, but rather smaller, rogue nations employing cheaper diesel/electric submarines with advanced air-independent propulsion systems. Unlike Cold War submarine operations, which occurred in deep-water environments, future submarine conflicts are anticipated to occur in shallow, littoral regions that are complex and noisy. Consequently, non-acoustic signatures will become increasingly important and the submarine stealth technology designed for deep-water operations may not be effective in these environments. One such non-acoustic signature is the surface detection of a submarine's trailing vortex wake. If a submarine runs in a slightly buoyant condition, its diving planes must be inclined at a negative angle of attack to generate sufficient downforce, which keeps the submarine from rising to the surface. As a result, the diving planes produce a pair of counter-rotating trailing vortices that propagate to the water surface. In previous deep-water operations, this was not an issue since the submarines could dive deep enough so that the vortex pair became incoherent before it reached the water surface. However, in shallow, littoral environments, submarines do not have the option of diving deep and, hence, the vortex pair can rise to the surface and leave a distinct signature that might be detectable by synthetic aperture radar. Such detection would jeopardize not only the mission of the submarine, but also the lives of military personnel on board. There has been another attempt to solve this problem and reduce the intensity of trailing vortices in the wakes of military submarines. The research of Quackenbush et al. over the past few years has been directed towards an idea called ''vortex leveraging

  5. A parabolized stability analysis of a trailing vortex wake

    Science.gov (United States)

    Edstrand, Adam; Schmid, Peter; Taira, Kunihiko; Cattafesta, Louis

    2016-11-01

    To aid in understanding how best to control a trailing vortex, we perform a parabolized stability analysis on a flow past a wing at a chord-based Reynolds number of 1000. At the upstream position, the wake instability branch dominates, with only a single vortex instability present in the spectrum. With downstream progression, the growth rate of the wake instability decays, but remains unstable 10 chords downstream. With the wake mode being unstable so far downstream, these results imply that the excitation of the wake instability, despite the varying base flow, will continue to see growth and potentially disrupt the trailing vortex. Conversely, the vortex instability in its formative region rapidly decays to the stable half-plane, then at 11 chords downstream becomes unstable again. We hypothesized the renewed instability growth far downstream is developing as a result of vortex instabilities, however the excitation of these instabilities proves to be challenging in the vortex far field. From these results, control near the two-dimensional wake behind the airfoil may better interfere with the trailing vortex formation; however, to determine the optimal disturbances, an adjoint analysis is required and is included in the future work of the project. ONR Grants N00014-10-1-0832 and N00014-15-1-2403.

  6. Reactive scheduling algorithm for multiple mould and die projects based on optimized resource flow constraints%基于优化资源流约束的模具多项目反应调度算法

    Institute of Scientific and Technical Information of China (English)

    张沙清; 陈新度; 陈庆新; 陈新

    2011-01-01

    This paper proposed a reactive scheduling algorithm based on optimized resource flow constraints, which was used to repair multiple mould and die projects baseline schedule that suffer from multiple tasks taking long time than planning during projects execution. Firstly, a baseline schedule minimizing weighted sum duration of projects was built with priority rules based particle swarm optimization and a resource flow network was built and optimized for the baseline schedule with heuristic algorithm. By combining critical chain technology and resource flow network, the baseline schedule was improved by setting proper time buffers. Then, a heuristic reactive scheduling model with the optimization object of minimizing the disruptions cost when tasks starting time changed during projects execution was constructed and priority rules based particle swarm optimization was used to solve it. Finally, the feasibility and reliability of the above reactive algorithm were analyzed by simulations and the results show that this algorithm could effectively solve dynamic scheduling problems for multiple mould and die projects with multiple tasks duration enlarging.%针对模具多项目执行过程中由于任务拖期而导致的调度计划变更,提出了一种基于优化的资源流约束的反应调度算法.首先利用基于优先规则的微粒群算法构建一个项目加权工期之和最小的初始调度计划,采用启发式算法建立并优化初始调度计划的资源流网络,并将关键链技术与资源流网络相结合,对初始调度计划进行合理的时间缓冲设置.然后建立了以调度计划扰动费用最小为优化目标的反应调度模型,并用基于优先规则的微粒群算法进行求解.最后,通过仿真计算分析了算法的可行性与可靠性,结果表明该反应调度算法在模具多项目动态调度中具有一定的应用价值.

  7. The GBT Dynamic Scheduling System: A New Scheduling Paradigm

    Science.gov (United States)

    O'Neil, K.; Balser, D.; Bignell, C.; Clark, M.; Condon, J.; McCarty, M.; Marganian, P.; Shelton, A.; Braatz, J.; Harnett, J.; Maddalena, R.; Mello, M.; Sessoms, E.

    2009-09-01

    The Robert C. Byrd Green Bank Telescope (GBT) is implementing a new Dynamic Scheduling System (DSS) designed to maximize the observing efficiency of the telescope while ensuring that none of the flexibility and ease of use of the GBT is harmed and that the data quality of observations is not adversely affected. To accomplish this, the GBT DSS is implementing a dynamic scheduling system which schedules observers, rather than running scripts. The DSS works by breaking each project into one or more sessions which have associated observing criteria such as RA, Dec, and frequency. Potential observers may also enter dates when members of their team will not be available for either on-site or remote observing. The scheduling algorithm uses those data, along with the predicted weather, to determine the most efficient schedule for the GBT. The DSS provides all observers at least 24 hours notice of their upcoming observing. In the uncommon (DSS project, including the ranking and scheduling algorithms for the sessions, the scheduling probabilities generation, the web framework for the system, and an overview of the results from the beta testing which were held from June - September, 2008.

  8. Hanford Site Environmental Surveillance Master Sampling Schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2000-01-27

    This document contains the CY2000 schedules for the routine collection of samples for the Surface Environmental Surveillance Project (SESP) and Drinking Water Monitoring Project. Each section includes sampling locations, sample types, and analyses to be performed.

  9. 浅析水利水电工程施工进度计划的控制%Analysis of the Control of Water Resources and Hydropower Project Construction Schedule

    Institute of Scientific and Technical Information of China (English)

    何达军

    2014-01-01

    施工进度计划控制贯穿于整个水利水电施工项目施工过程。因此,如何进行有效可行的进度计划控制就显得非常重要。本文针对水利水电工程施工进度计划的控制,对其进行了一些探讨。%The construction schedule control throughout the whole project construction process of water conservancy and hydropower construction. Therefore, how to carry out effective feasible schedule control is very important. This article bases on the control of water resources and hydropower engineering construction schedule and discusses some of them.

  10. The shock-vortex interaction patterns affected by vortex flow regime and vortex models

    Science.gov (United States)

    Chang, Keun-Shik; Barik, Hrushikesh; Chang, Se-Myong

    2009-08-01

    We have used a third-order essentially non-oscillatory method to obtain numerical shadowgraphs for investigation of shock-vortex interaction patterns. To search different interaction patterns, we have tested two vortex models (the composite vortex model and the Taylor vortex model) and as many as 47 parametric data sets. By shock-vortex interaction, the impinging shock is deformed to a S-shape with leading and lagging parts of the shock. The vortex flow is locally accelerated by the leading shock and locally decelerated by the lagging shock, having a severely elongated vortex core with two vertices. When the leading shock escapes the vortex, implosion effect creates a high pressure in the vertex area where the flow had been most expanded. This compressed region spreads in time with two frontal waves, an induced expansion wave and an induced compression wave. They are subsonic waves when the shock-vortex interaction is weak but become supersonic waves for strong interactions. Under a intermediate interaction, however, an induced shock wave is first developed where flow speed is supersonic but is dissipated where the incoming flow is subsonic. We have identified three different interaction patterns that depend on the vortex flow regime characterized by the shock-vortex interaction.

  11. Schedule Management of Construction Projects Based on Last Planner System%基于最后计划者系统的工程项目进度计划管理

    Institute of Scientific and Technical Information of China (English)

    金峻炎

    2013-01-01

    为了使工程项目进度计划更具有可操作性以及对进度的可控性,在编制项目进度计划过程中引入基于精益思想TFV理论的最后计划者系统。通过该系统的项目主计划、前瞻计划以及周计划的编制与实施,将进度计划的编制从传统的“推式”系统转变为“拉式”系统,可以实现项目计划的动态跟踪与管理。基于案例比较分析,证实该方法可以提高项目进度计划的有效性和可操作性。%Last planner system (LPS) is a kind of schedule management of project based TFV theory of lean thinking, which can enhance the operability and controllability of the project schedule. Based on the master schedule, look-ahead schedule and weekly work plan, LPS transfers the traditional"push"system into"pull"sys-tem for schedule management and realizes the dynamic tracking and management of the schedule. The new tech-nology can improve the effectiveness and operability by comparison between traditional method and LPS based on the case study.

  12. Experimental study of periodic flow effects on spanwise vortex

    Science.gov (United States)

    Garcia Molina, Cruz Daniel; Lopez Sanchez, Erick Javier; Ruiz Chavarria, Gerardo; Medina Ovando, Abraham

    2014-11-01

    We present an experimental study about the spanwise vortex produced in a flow going out of a channel in shallow waters. This vortex travels in front of the dipole. The velocity field measurement was done using the PIV technique, and DPIVsoft (https://www.irphe.fr/ ~meunier/) was used for data processing. In this case the flow has a periodic forcing to simulate ocean tides. The experiment was conducted in a channel with variable width and the measurements were made using three different values of the aspect ratio width-depth. We present results of the position, circulation of this spanwise vortex and the flow inversion effect. The change of flow direction modify the intensity of the vortex, but it does not destroy it. The vertical components of the velocity field contributes particle transport. G. Ruiz Chavarria, E. J. Lopez Sanchez and C. D. Garcia Molina acknowledge DGAPA-UNAM by support under project IN 116312 (Vorticidad y ondas no lineales en fluidos).

  13. Multi-project Scheduling Problems with Human Resources: A Case Study%多项目人力资源调度实证研究

    Institute of Scientific and Technical Information of China (English)

    付芳; 周泓

    2011-01-01

    We construct a mixed integer linear programming model to better understand human resource management issues associated with apartment overhaul projects. The model deals with multi-scheduling problems because all staffs employed in each project have different skill sets and exceed minimum job requirements for their positions. Multi-project and limited resource environments are considered as constraints to the proposed model. Moreover, we categorize process multiple execution modes based on resource requirements. The purpose of the model is to minimize total costs and increase direct ratios of activity duration. First, we employ the column generation procedure to decompose a research problem into a master program and many sub-problems in order to simplify computation effectively. A multiple pricing strategy is adopted to optimize cost minimization via innumerous interactions of sub-problems. Second, we develop a heuristic algorithm to cope with the complexity of sub-problems by treating the activity list as a code and serial generation scheme. The priority rule based heuristic algorithm provides initial solutions. We seek further improvements in our solution via genetic algorithm that employs two-tournament selection, regular two-point crossover and neighbor swapping mutation. Lastly, applying our model and algorithm to managing human resources of apartment overhaul projects can considerably reduce total costs and deliver projects on time. Decision makers can use our proposed model to help implement apartment overhaul projects.%针对某公寓大修项目,建立有关人力资源约束下的多项目进度管理问题混合整数规划模型.其中考虑了多种约束,如项目对人员能力、水平的不同要求,而人员又具有多种能力及水平;目标为满足约束的条件下总成本最小化,其中包含按时间计资的工资,和福利等的固定费用.为了简化计算,采用列生成法把复杂的多项目模型分解为一个主问题和多

  14. Simulations of vortex generators

    Science.gov (United States)

    Koumoutsakos, P.

    1995-01-01

    We are interested in the study, via direct numerical simulations, of active vortex generators. Vortex generators may be used to modify the inner part of the boundary layer or to control separation thus enhancing the performance and maneuverability of aerodynamic configurations. We consider generators that consist of a surface cavity elongated in the stream direction and partially covered with a moving lid that at rest lies flush with the boundary. Streamwise vorticity is generated and ejected due to the oscillatory motion of the lid. The present simulations complement relevant experimental investigations of active vortex generators at NASA Ames and Stanford University (Saddoughi, 1994, and Jacobson and Reynolds, 1993). Jacobson and Reynolds (1993) used a piezoelectric device in water, allowing for small amplitude high frequency oscillations. They placed the lid asymmetrically on the cavity and observed a strong outward velocity at the small gap of the cavity. Saddoughi used a larger mechanically driven device in air to investigate this flow and he observed a jet emerging from the wide gap of the configuration, contrary to the findings of Jacobson and Reynolds. Our task is to simulate the flows generated by these devices and to conduct a parametric study that would help us elucidate the physical mechanisms present in the flow. Conventional computational schemes encounter difficulties when simulating flows around complex configurations undergoing arbitrary motions. Here we present a formulation that achieves this task on a purely Lagrangian frame by extending the formulation presented by Koumoutsakos, Leonard and Pepin (1994). The viscous effects are taken into account by modifying the strength of the particles, whereas fast multipole schemes employing hundreds of thousands of particles allow for high resolution simulations. The results of the present simulations would help us assess some of the effects of three-dimensionality in experiments and investigate the role

  15. PRACTICAL IMPLICATIONS OF LOCATION-BASED SCHEDULING

    DEFF Research Database (Denmark)

    Andersson, Niclas; Christensen, Knud

    2007-01-01

    The traditional method for planning, scheduling and controlling activities and resources in construction projects is the CPM-scheduling, which has been the predominant scheduling method since its introduction in the late 1950s. Over the years, CPM has proven to be a very powerful technique...... for planning, scheduling and controlling projects. However, criticism has been raised on the CPM method, specifically in the case of construction projects, for deficient management of construction work and discontinuous flow of resources. Alternative scheduling techniques, often called repetitive or linear...... that will be used in this study. LBS is a scheduling method that rests upon the theories of line-of-balance and which uses the graphic representation of a flowline chart. As such, LBS is adapted for planning and management of workflows and, thus, may provide a solution to the identified shortcomings of CPM. Even...

  16. Multiply Phased Traveling BPS Vortex

    CERN Document Server

    Kimm, Kyoungtae; Cho, Y M

    2016-01-01

    We present the multiply phased current carrying vortex solutions in the U(1) gauge theory coupled to an $(N+1)$-component SU(N+1) scalar multiplet in the Bogomolny limit. Our vortex solutions correspond to the static vortex dressed with traveling waves along the axis of symmetry. What is notable in our vortex solutions is that the frequencies of traveling waves in each component of the scalar field can have different values. The energy of the static vortex is proportional to the topological charge of $CP^N$ model in the BPS limit, and the multiple phase of the vortex supplies additional energy contribution which is proportional to the Noether charge associated to the remaining symmetry.

  17. 基于现金流均衡目标的多模式项目调度问题研究%Multi-mode Project Scheduling Problems with Cash Flow Balanced Objectives

    Institute of Scientific and Technical Information of China (English)

    何正文; 刘人境; 徐渝

    2011-01-01

    A contractor needs to spend capital on project-related resources before receiving payment from customers for services delivered at each milestone. However, contractors have varying capital availabilities when implementing different projects. Thus,balancing cash inflows and outflows throughout the project life cycle is critical to project success for contractors.This paper studies multi-mode project scheduling problems with the goal of balancing cash inflows and outflows. We use the event-based method to represent a contractor's project schedule in the activity-on-node mode, and distribute project expenses to their beginning and ending activities. The objective of this exercise is to minimize the gap of a contractor's cumulative capital flows given the constraint of a fixed project deadline.We define two groups of decision variables in order to determine the modes of performing activities and the actual delivery date of events. A0-1 programming model is established to address cash flow problems. A simulated annealing heuristic algorithm with two nested loops is developed to solve cash flow problems. These two nested loops include inner and outer loops. The inner loop searches for a desirable vector of an event's completion time under a given activity's performing mode. The outer loop seeks the desirable vector of an event's completion time established by the inner loop. The simulation results show desirable solutions for cash problems in inner and outer loops. A contracted superhighway construction project is used as a case study to illustrate the use of our proposed simulated algorithm. This project is able to develop a satisfactory schedule. We compare the developed schedule with the actual schedule regarding key cash flow parameters, including project deadline, payment proportion, advance payment proportion, deposit rate of security payment, and objective function values.A contractor can maximize its cumulative capital gap by reducing the procrastination of

  18. Vortex cores and vortex motion in superconductors with anisotropic Fermi surfaces

    Science.gov (United States)

    Galvis, J. A.; Herrera, E.; Guillamón, I.; Vieira, S.; Suderow, H.

    2017-02-01

    Explaning static and dynamic properties of the vortex lattice in anisotropic superconductors requires a careful characterization of vortex cores. The vortex core contains Andreev bound states whose spatial extension depends on the anisotropy of the electronic band-structure and superconducting gap. This might have an impact on the anisotropy of the superconducting properties and on vortex dynamics. Here we briefly summarize basic concepts to understand anisotropic vortex cores and review vortex core imaging experiments. We further discuss moving vortex lattices and the influence of vortex core shape in vortex motion. We find vortex motion in highly tilted magnetic fields. We associate vortex motion to the vortex entry barrier and the screening currents at the surface. We find preferential vortex motion along the main axis of the vortex lattice. After travelling integers of the intervortex distance, we find that vortices move more slowly due to the washboard potential of the vortex lattice.

  19. The Research of Project Schedule Plan and Control on UPS Design in Nuclear Island of Z Nuclear Power Plant%Z核电站核岛UPS设备设计进度计划及控制研究

    Institute of Scientific and Technical Information of China (English)

    林建

    2012-01-01

    采用工作分解结构分解了Z核电站核岛UPS设备设计项目,并用关键路径法编制了该项目进度,结合项目特点,基于PDCA控制流程对项目实施进度控制,确保项目顺利实施.%This paper uses work breakdown structure to break down the UPS design project in nuclear island of Z nuclear power plant, uses critical path method to build the schedule of the project, combined with the characteristics of the project, based on the PDCA control flow, controls the progress of project implementation and ensures the smooth implementation of the project.

  20. 用赢得值法进行测绘项目进度和费用控制%Mapping the Project Schedule and Cost Control with the Earned Value Management

    Institute of Scientific and Technical Information of China (English)

    吴玉忱; 王敬华

    2016-01-01

    基于工程项目管理理论,主要探讨了用赢得值法进行测绘项目进度和费用控制的方法,对测绘工程项目进行有效管理,从而实现项目目标,提高项目管理水平。%In this paper, based on the theory of project management, mainly discusses using earned value management to control the schedule and cost of Surveying and mapping project, effective management of Surveying and mapping engineering project, in order to achieve the project objectives, improve the level of project management.

  1. Environmental surveillance master sampling schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, L.E.

    1997-01-01

    Environmental surveillance of the Hanford Site and surrounding areas is conducted by the Pacific Northwest National Laboratory (PNNL)(a) for the US Department of Energy (DOE). This document contains the planned 1997 schedules for routine collection of samples for the Surface Environmental Surveillance Project (SESP) and Drinking Water Monitoring Project. In addition, Section 3.0, Biota, also reflects a rotating collection schedule identifying the year a specific sample is scheduled for collection. The purpose of these monitoring projects is to evaluate levels of radioactive and nonradioactive pollutants in the Hanford environs, as required in DOE Order 5400.1, General Environmental Protection Program, and DOE Order 5400.5, Radiation Protection of the Public and the Environment. The sampling methods will be the same as those described in the Environmental Monitoring Plan, US Department of Energy, Richland Operations Office, DOE/RL91-50, Rev. 1, US Department of Energy, Richland, Washington.

  2. 施工项目质量进度安全管理措施研究%Study on Quality,Schedule and Safety Management Measures of Construction Projects

    Institute of Scientific and Technical Information of China (English)

    曹志刚; 刘江伟; 姜晴

    2012-01-01

      Ensuring the safe quality,smooth forwarding schedule and safety construction of construction projects,pursuing maximum profit are management purposes of construction enterprises.According to the actual situation of the construction site and combining the characteristics of construction projects,studying on the quality,schedule and safety management measures and application of construction projects,in order to as far as possible prevent principles are regarded main; engineering quality,schedule and safety controlling be changed from after checked to before and during construction controlling,projects quality checking was changed to work quality,schedule,and semi finished products directly checked; requiring as far as possible shorten work a period under the premise of the assurance quality and safety,cost controlling at lowest.%  保证项目施工质量、施工进度、施工安全和利润最大化是施工企业的管理目的。根据施工现场实际情况并结合施工项目特点,对施工项目质量、进度、安全管理措施及其应用进行了研究,尽量做到以预防为主,把工程质量、进度、安全控制从事后检查转向事前控制、事中控制,从对工程质量的检查转向对工作质量的检查,对工序质量的检查,对中间产品的质量检查;要求在保证质量和安全的前提下,尽量缩短工期,进而将成本控制在最低。

  3. A generalization of vortex lines

    CERN Document Server

    Fecko, Marian

    2016-01-01

    Helmholtz theorem states that, in ideal fluid, vortex lines move with the fluid. Another Helmholtz theorem adds that strength of a vortex tube is constant along the tube. The lines may be regarded as integral surfaces of an 1-dimensional integrable distribution (given by the vorticity 2-form). In general setting of theory of integral invariants, due to Poincare and Cartan, one can find $d$-dimensional integrable distribution whose integral surfaces show both properties of vortex lines: they move with (abstract) fluid and, for appropriate generalization of vortex tube, strength of the latter is constant along the tube.

  4. Experimental benchmark and code validation for airfoils equipped with passive vortex generators

    DEFF Research Database (Denmark)

    Baldacchino, D.; Manolesos, M.; Ferreira, Célia Maria Dias;

    2016-01-01

    Experimental results and complimentary computations for airfoils with vortex generators are compared in this paper, as part of an effort within the AVATAR project to develop tools for wind turbine blade control devices. Measurements from two airfoils equipped with passive vortex generators, a 30%...

  5. Analysis of the importance of schedule management in construction project management%进度管理在建筑工程管理中的重要性分析

    Institute of Scientific and Technical Information of China (English)

    霍德广

    2015-01-01

    对整个建筑施工过程中的进度进行一个良好的规划与管理,是保证建设各方利益实现、建筑项目按期完工的重要保障。本文通过建筑工程中施工进度控制的概述和工程进度管理在建筑工程管理中的重要性以及解决建筑工程进度管理问题的措施进行简要分析。%the progress of the whole building construction process, a good planning and management is to ensure that the construction of the interests of al parties to realize the important guarantee, construction project completed on schedule. In this paper, through the overview of construction engineering construction progress control and the importance of the construction schedule management in construction project management and the measures to solve the problem of construction project schedule management is briefly analyzed.

  6. 基于挣值法的项目进度-成本管理决策模型研究%Decision-making Model for Project Schedule-Cost Management Based on Earned Value Method 

    Institute of Scientific and Technical Information of China (English)

    黄慧君; 常澜潇; 娄海艳

    2012-01-01

    Earned value management is a very important and effective method in monitoring project schedule and cost. This method is mainly used for analyzing schedule, cost variance and forecasting the unperfect project duration and cost. Combining with management reserve, it proposes a quantitative decision - making model based on earned value method and the improved model. This can help project manager to take proper action to correct schedule and cost variance.%挣值法作为一种先进的项目管理方法,在国际上已被普遍应用于项目进度-成本的综合控制.在挣值法及其改进方法的基础上,结合管理储备的思想,提出了定量化的决策模型和调整成本优化模型,进一步辅助项目经理采取合适的进度-成本纠偏措施.

  7. 园林工程项目施工进度管理研究%Study on Construction Schedule Management of Landscape Engineering Project

    Institute of Scientific and Technical Information of China (English)

    樊松丽; 李梅

    2013-01-01

    分析园林工程施工特点,总结施工进度影响因素,提出园林工程施工进度管理目标和内容,指出为保证施工进度管理目标顺利实现,必须做好事前计划、事中控制、事后补救,采取有效的进度管理方法。%This paper analysed the construction characteristics of landscape engineering ,construction progress influencing factors were summarized.Target and content of construction schedule management were proposed.In order to ensure the realization of construction schedule management goals , schedule plan must be made beforehand and controlled during the matter and help after the mat -ter.Relevant schedule management method should be taken.

  8. Aircraft Wake Vortex Deformation in Turbulent Atmosphere

    OpenAIRE

    Hennemann, Ingo; Holzaepfel, Frank

    2007-01-01

    Large-scale distortion of aircraft wake vortices appears to play a crucial role for aircraft safety during approach and landing. Vortex distortion is investigated based on large eddy simulations of wake vortex evolution in a turbulent atmosphere. A vortex identification method is developed that can be adapted to the vortex scales of interest. Based on the identified vortex center tracks, a statistics of vortex curvature radii is established. This statistics constitutes the basis for understan...

  9. CMS Planning and Scheduling System

    CERN Document Server

    Kotamaki, M

    1998-01-01

    The paper describes the procedures and the system to build and maintain the schedules needed to manage time, resources, and progress of the CMS project. The system is based on the decomposition of the project into work packages, which can be each considered as a complete project with its own structure. The system promotes the distribution of the decision making and responsibilities to lower levels in the organisation by providing a state-of-the-art system to formalise the external commitments of the work packages without limiting their ability to modify their internal schedules to best meet their commitments. The system lets the project management focus on the interfaces between the work packages and alerts the management immediately if a conflict arises. The proposed system simplifies the planning and management process and eliminates the need for a large, centralised project management system.

  10. Vortex-Surface Interactions: Vortex Dynamics and Instabilities

    Science.gov (United States)

    2015-10-16

    a) Main vortex structures developing on a typical submarine hull; (b) Schematic illustrating a horseshoe vortex at a wing-body junction of a " Rood ...secondary vortices. Firstly, looking at Figure 7, showing only the secondary vortices being visualized by our technique , we see that a tongue of secondary

  11. Evolution of optical vortex distributions in stochastic vortex fields

    CSIR Research Space (South Africa)

    Roux, FS

    2011-01-01

    Full Text Available dipole,? Opt. Commun. 236, 433?440 (2004). [23] Dana, I. and Freund, I., ?Vortex-lattice wave fields,? Opt. Commun. . [24] Jenkins, R., Banerji, J., and Davies, A., ?The generation of optical vortices and shape preserving vortex arrays in hollow...

  12. Schedule Matters: Understanding the Relationship between Schedule Delays and Costs on Overruns

    Science.gov (United States)

    Majerowicz, Walt; Shinn, Stephen A.

    2016-01-01

    This paper examines the relationship between schedule delays and cost overruns on complex projects. It is generally accepted by many project practitioners that cost overruns are directly related to schedule delays. But what does "directly related to" actually mean? Some reasons or root causes for schedule delays and associated cost overruns are obvious, if only in hindsight. For example, unrealistic estimates, supply chain difficulties, insufficient schedule margin, technical problems, scope changes, or the occurrence of risk events can negatively impact schedule performance. Other factors driving schedule delays and cost overruns may be less obvious and more difficult to quantify. Examples of these less obvious factors include project complexity, flawed estimating assumptions, over-optimism, political factors, "black swan" events, or even poor leadership and communication. Indeed, is it even possible the schedule itself could be a source of delay and subsequent cost overrun? Through literature review, surveys of project practitioners, and the authors' own experience on NASA programs and projects, the authors will categorize and examine the various factors affecting the relationship between project schedule delays and cost growth. The authors will also propose some ideas for organizations to consider to help create an awareness of the factors which could cause or influence schedule delays and associated cost growth on complex projects.

  13. 试论工程进度控制管理及影响进度问题研究%Research on Schedule Management and Problems Influencing on the Progress of the Project Control

    Institute of Scientific and Technical Information of China (English)

    刘康康

    2014-01-01

    建筑工程的管理工作随着建筑业的发展越来越受到重视。在工程项目管理工作中,对工程进度的控制与管理是其中重要的内容之一。为使工程能够按时完工,相关负责人员对工程进度的监控管理工作就必须做到位,对影响工程进度的因素要及时进行排除。%The construction project management work is more and more valued with the development of construction industry. In the engineering project management, the control and mana-gement of the project schedule is one of the important content. In order to make the project to be completed on time, the monitoring and management of the progress that the relevant personnel is responsible for must be completed wel and the factors lagging the project schedule should be ruled out in time.

  14. The GBT Dynamic Scheduling System

    Science.gov (United States)

    McCarty, M. T.; Balser, D. S.; Braatz, J.; Clark, M. H.; Condon, J.; Creager, R. E.; Maddalena, R. J.; Marganian, P.; O'Neil, K.; Sessoms, E.; Shelton, A. L.

    2012-09-01

    The Robert C. Byrd Green Bank Telescope (GBT) Dynamic Scheduling System (DSS), in use since September, 2009, was designed to maximize observing efficiency while preserving telescope flexibility and data quality without creating undue adversity for the observers. Using observing criteria; observer availability and qualifications for remote observing; three-dimensional weather forecasts; and telescope state, the DSS software optimally schedules observers 24 to 48 hours in advance for a telescope that has a wide-range of capabilities and a geographical location with variable weather patterns. The DSS project was closed October 28, 2011 and will now enter a continuing maintenance and enhancement phase. Recent improvements include a new resource calendar for incorporating telescope maintenance activities, a sensitivity calculator that leverages the scheduling algorithms to facilitate consistent tools for proposal preparation, improved support for monitoring observations, scheduling of high frequency continuum and spectral line observations for both sparse and fully sampled array receivers, and additional session parameters for observations having special requirements.

  15. Scheduling the Secondary School.

    Science.gov (United States)

    Dempsey, Richard A.; Traverso, Henry P.

    This "how-to-do-it" manual on the intricacies of school scheduling offers both technical information and common sense advice about the process of secondary school scheduling. The first of six chapters provides an overview of scheduling; chapter 2 examines specific considerations for scheduling; chapter 3 surveys the scheduling models and their…

  16. 基于SD的船舶敏捷制造项目进度管理模型研究%The Schedule Management Model of Ship Agile Manufacturing Project Based on System Dynamics

    Institute of Scientific and Technical Information of China (English)

    杨兴林; 韩凯

    2013-01-01

    针对传统项目管理方法的不足,提出利用系统动力学方法来研究船舶敏捷制造项目的进度管理问题.通过传统项目管理方法与系统动力学方法的比较,证明利用系统动力学研究船舶敏捷制造项目进度管理的可行性和必要性,然后确定建模边界,构建因果关系图,对其中的反馈关系进行详细分析,得到四种反馈回路,进而对系统做进一步分析,建立船舶敏捷制造项目进度管理系统的系统动力学模型,最后通过实例仿真对模型进行有效性验证.%According to the deficiency of the traditional methods of project management,this paper presents researching schedule management of ship agile manufacturing project by using system dynamics method.The system dynamics method is introduced and the characteristics of ship agile manufacturing project is analyzed,then the cause mapping of schedule management system of ship agile manufacturing project is set up.By analyzing the cause mapping,the system dynamics model of schedule management system of ship agile manufacturing project is established.Finally,model validation is made through the simulation of an example.

  17. Solitary vortexes in magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Vainshtein, S.I.

    1985-12-01

    Stationary configurations in magnetohydrodynamics are investigated for the following two particular cases: (1) there is no motion, which corresponds to a state of magnetostatic equilibrium; and (2) the magnetic field intensity becomes zero, i.e., hydrodynamic vortexes are involved. It is shown that in certain cases the line-of-force topology must be sufficiently simple in order before a stationary or equilibrium state can be achieved. It is also shown that in the two-dimensional case, the magnetic surfaces of an equilibrium configuration represent coaxial cylindrical surfaces. 12 references.

  18. Robustness of a coherence vortex.

    Science.gov (United States)

    Alves, Cleberson R; Jesus-Silva, Alcenisio J; Fonseca, Eduardo J S

    2016-09-20

    We study, experimentally and theoretically, the behavior of a coherence vortex after its transmission through obstacles. Notably, we find that such a vortex survives and preserves its effective topological charge. Despite suffering changes on the modulus of the coherence function, these changes disappear during propagation.

  19. Vortex duality in higher dimensions

    NARCIS (Netherlands)

    Beekman, Aron Jonathan

    2011-01-01

    A dynamic vortex line traces out a world sheet in spacetime. This thesis shows that the information of all its dynamic behaviour is completely contained in the world sheet. Furthermore a mathematical framework for order–disorder phase transitions in terms of the proliferation of such vortex world sh

  20. Application of Total Quality Management Idea in Project Design Schedule Management%全面质量管理思想在项目设计进度管理中的应用

    Institute of Scientific and Technical Information of China (English)

    王皓

    2013-01-01

      在EPR三代核电项目,参与中外联合设计团队设计进度管理过程中,应用全面质量管理的思想来策划、组织设计进度管理体系,以达到优化进度计划管理系统,持续增加顾客满意度的目的。其中重点关注基于全面管理思想8项基本原则,其在项目设计进度管理中的实际应用,以达到工程经验反馈的目的。%  In the EPR project, in the design schedule management progress of joint design organization, with application of total quality management idea in planning and organize the design schedule management system, for the target of optimizing the schedule management system and increase the satisfaction of the client. Of all the work, the text focus more on 8 basic criterions of total quality management idea, which have been used to tutor the actual project work, to achieve the target of experience feed back.

  1. Lift enhancement by trapped vortex

    Science.gov (United States)

    Rossow, Vernon J.

    1992-01-01

    The viewgraphs and discussion of lift enhancement by trapped vortex are provided. Efforts are continuously being made to find simple ways to convert wings of aircraft from an efficient cruise configuration to one that develops the high lift needed during landing and takeoff. The high-lift configurations studied here consist of conventional airfoils with a trapped vortex over the upper surface. The vortex is trapped by one or two vertical fences that serve as barriers to the oncoming stream and as reflection planes for the vortex and the sink that form a separation bubble on top of the airfoil. Since the full three-dimensional unsteady flow problem over the wing of an aircraft is so complicated that it is hard to get an understanding of the principles that govern the vortex trapping process, the analysis is restricted here to the flow field illustrated in the first slide. It is assumed that the flow field between the two end plates approximates a streamwise strip of the flow over a wing. The flow between the endplates and about the airfoil consists of a spanwise vortex located between the suction orifices in the endplates. The spanwise fence or spoiler located near the nose of the airfoil serves to form a separated flow region and a shear layer. The vorticity in the shear layer is concentrated into the vortex by withdrawal of fluid at the suction orifices. As the strength of the vortex increases with time, it eventually dominates the flow in the separated region so that a shear or vertical layer is no longer shed from the tip of the fence. At that point, the vortex strength is fixed and its location is such that all of the velocity contributions at its center sum to zero thereby making it an equilibrium point for the vortex. The results of a theoretical analysis of such an idealized flow field are described.

  2. Superfluid Vortex Cooler

    Science.gov (United States)

    Tanaeva, I. A.; Lindemann, U.; Jiang, N.; de Waele, A. T. A. M.; Thummes, G.

    2004-06-01

    A superfluid vortex cooler (SVC) is a combination of a fountain pump and a vortex cooler. The working fluid in the SVC is 4He at a temperature below the lambda line. The cooler has no moving parts, is gravity independent, and hardly requires any additional infrastructure. At saturated vapour pressure the SVC is capable of reaching a temperature as low as 0.75 K. At pressures close to the melting pressure the temperature can be brought down to 0.65 K. As the SVC operates only below the lambda line, it has to be precooled e.g. by a liquid-helium bath or a cryocooler. As a first step of our research we have carried out a number of experiments, using a liquid-helium bath as a precooler for the SVC. In this arrangement we have reached temperatures below 1 K with 3.5 mW heating power supplied to the fountain part of the SVC at 1.4 K. The next step was combining the SVC with a pulse tube refrigerator (PTR), developed at the University of Giessen. It is a two-stage G-M type refrigerator with 3He as a working fluid that reached a lowest temperature of 1.27 K. In this contribution we report on the results of the SVC tests in liquid helium and the progress in the integration of the SVC with the PTR.

  3. Regimes of flow past a vortex generator

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Okulov, V.L.; Naumov, I.V.

    2012-01-01

    A complete parametric investigation of the development of multi-vortex regimes in a wake past simple vortex generator has been carried out. It is established that the vortex structure in the wake is much more complicated than a simple monopole tip vortex. The vortices were studied by stereoscopic...

  4. Vectorial rotating vortex Hankel laser beams

    Science.gov (United States)

    Kotlyar, Victor V.; Kovalev, Alexey A.; Soifer, Victor A.

    2016-09-01

    We propose a generalization of spherical waves in the form of linearly polarized beams with embedded optical vortices. The source of these beams is an infinitely narrow light ring with an infinitely small radius. These vectorial beams are obtained based on scalar Hankel beams discovered by the authors recently. We have derived explicit relations for complex amplitudes of all six components of vectorial vortex Hankel beams. A closed analytical expression for the axial projection of the orbital angular momentum density in far field has been obtained. We also showed that the intensity distribution of the electric vector rotates by 90 degrees upon the beam propagation in near field.

  5. Point vortex dynamics: A classical mathematics playground

    DEFF Research Database (Denmark)

    Aref, Hassan

    2007-01-01

    The idealization of a two-dimensional, ideal flow as a collection of point vortices embedded in otherwise irrotational flow yields a surprisingly large number of mathematical insights and connects to a large number of areas of classical mathematics. Several examples are given including...... the integrability of the three-vortex problem, the interplay of relative equilibria of identical vortices and the roots of certain polynomials, addition formulas for the cotangent and the Weierstrass zeta function, projective geometry, and other topics. The hope and intent of the article is to garner further...

  6. Crew Scheduling for Netherlands Railways: "destination: customer"

    NARCIS (Netherlands)

    L.G. Kroon (Leo); M. Fischetti (Matteo)

    2000-01-01

    textabstract: In this paper we describe the use of a set covering model with additional constraints for scheduling train drivers and conductors for the Dutch railway operator NS Reizigers. The schedules were generated according to new rules originating from the project "Destination: Customer"

  7. Scheduling Algorithm for Complex Product Development

    Institute of Scientific and Technical Information of China (English)

    LIUMin; ZHANGLong; WUCheng

    2004-01-01

    This paper describes the Complex product development project scheduling problem (CPDPSP) with a great number of activities, complicated resource, precedence and calendar constraints. By the conversion of precedence constraint relations, the CPDPSP is simplified. Then, according to the predictive control principle, we propose a new scheduling algorithm Based on prediction (BoP-procedure). In order to get the problem characteristics coming from resource status and precedence constraints of the scheduling problem at the scheduling time, a sub-project is constructed on the basis of a sub-AoN (Activity on node) graph of the project. Then, we use the modified GDH-procedure to solve the sub-project scheduling problem and to obtain the maximum feasible active subset for determining the activity group which satisfies resource, precedence and calendar constraints and has the highest scheduling priority at the scheduling time. Additionaily, we make a great number of numerical computations and compare the performance of BoP-procedure algorithm with those of other scheduling algorithms. Computation results show that the BoP-procedure algorithm is more suitable for the CPDPSP. At last, we discuss briefly future research work in the CPDPSP.

  8. Some discussions on Arctic vortex

    Institute of Scientific and Technical Information of China (English)

    Li Hai; Sun Lantao; Wu Huiding; Li Xiang

    2006-01-01

    The Arctic vortex is a persistent large-scale cyclonic circulation in the middle and upper troposphere and the stratosphere. Its activity and variation control the semi-permanent active centers of Pan-Arctic and the short-time cyclone activity in the subarctic areas. Its strength variation, which directly relates to the atmosphere, ocean, sea ice and ecosystem of the Arctic, can affect the lower atmospheric circulation, the weather of subarctic area and even the weather of middle latitude areas. The 2003 Chinese Second Arctic Research Expedition experienced the transition of the stratosphereic circulation from a warm anticyclone to a cold cyclone during the ending period of Arctic summertime, a typical establishing process of the polar vortex circulation. The impact of the polar vortex variation on the low-level circulation has been investigated by some scientists through studying the coupling mechanisms of the stratosphere and troposphere. The impact of the Stratospheric Sudden Warming (SFW) events on the polar vortex variation was drawing people's great attention in the fifties of the last century. The Arctic Oscillation (AO) , relating to the variation of the Arctic vortex, has been used to study the impact of the Arctic vortex on climate change. The recent Arctic vortex studies are simply reviewed and some discussions on the Arctic vertex are given in the paper. Some different views and questions are also discussed.

  9. Motion of a helical vortex

    CERN Document Server

    Fuentes, Oscar Velasco

    2015-01-01

    We study the motion of a single helical vortex in an unbounded, inviscid, incompressible fluid. The vortex is an infinite tube whose centerline is a helix and whose cross section is a circle of small radius (compared to the radius of curvature) where the vorticity is uniform and parallel to the centerline. Ever since Joukowsky (1912) deduced that this vortex translates and rotates steadily without change of form, numerous attempts have been made to compute these self-induced velocities. Here we use Hardin's (1982) solution for the velocity field to find new expressions for the vortex's linear and angular velocities. Our results, verified by numerically computing the Helmholtz integral and the Rosenhead-Moore approximation to the Biot-Savart law, are more accurate than previous results over the whole range of values of the vortex pitch and cross-section. We then use the new formulas to study the advection of passive particles near the vortex; we find that the vortex's motion and capacity to transport fluid dep...

  10. Bathtub vortex induced by instability

    Science.gov (United States)

    Mizushima, Jiro; Abe, Kazuki; Yokoyama, Naoto

    2014-10-01

    The driving mechanism and the swirl direction of the bathtub vortex are investigated by the linear stability analysis of the no-vortex flow as well as numerical simulations. We find that only systems having plane symmetries with respect to vertical planes deserve research for the swirl direction. The bathtub vortex appearing in a vessel with a rectangular cross section having a drain hole at the center of the bottom is proved to be induced by instability when the flow rate exceeds a threshold. The Coriolis force is capable of determining the swirl direction to be cyclonic.

  11. Dynamic signatures of driven vortex motion.

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, G. W.; Kwok, W. K.; Lopez, D.; Olsson, R. J.; Paulius, L. M.; Petrean, A. M.; Safar, H.

    1999-09-16

    We probe the dynamic nature of driven vortex motion in superconductors with a new type of transport experiment. An inhomogeneous Lorentz driving force is applied to the sample, inducing vortex velocity gradients that distinguish the hydrodynamic motion of the vortex liquid from the elastic and-plastic motion of the vortex solid. We observe elastic depinning of the vortex lattice at the critical current, and shear induced plastic slip of the lattice at high Lorentz force gradients.

  12. Simulations of a single vortex ring using an unbounded, regularized particle-mesh based vortex method

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Spietz, Henrik J.; Walther, Jens Honore

    2014-01-01

    In resent work we have developed a new FFT based Poisson solver, which uses regularized Greens functions to obtain arbitrary high order convergence to the unbounded Poisson equation. The high order Poisson solver has been implemented in an unbounded particle-mesh based vortex method which uses a re......-meshing of the vortex particles to ensure the convergence of the method. Furthermore, we use a re-projection of the vorticity field to include the constraint of a divergence-free stream function which is essential for the underlying Helmholtz decomposition and ensures a divergence free vorticity field. The high order...... with the principal axis of the strain rate tensor. We find that the dynamics of the enstrophy density is dominated by the local flow deformation and axis of rotation, which is used to infer some concrete tendencies related to the topology of the vorticity field....

  13. Vortex electronis and squids

    CERN Document Server

    2003-01-01

    Understanding the nature of vortices in high-Tc superconductors is a crucial subject for research on superconductive electronics, especially for superconducting interference devices (SQUIDs), it is also a fundamental problem in condensed-matter physics. Recent technological progress in methods for both direct and indirect observation of vortices, e.g. scanning SQUID, terahertz imaging, and microwave excitation, has led to new insights into vortex physics, the dynamic behavior of vortices in junctions and related questions of noise. This book presents the current status of research activity and provides new information on the applications of SQUIDs, including magnetocardiography, immunoassays, and laser-SQUID microscopes, all of which are close to being commercially available.

  14. Entangled vector vortex beams

    Science.gov (United States)

    D'Ambrosio, Vincenzo; Carvacho, Gonzalo; Graffitti, Francesco; Vitelli, Chiara; Piccirillo, Bruno; Marrucci, Lorenzo; Sciarrino, Fabio

    2016-09-01

    Light beams having a vectorial field structure, or polarization, that varies over the transverse profile and a central optical singularity are called vector vortex (VV) beams and may exhibit specific properties such as focusing into "light needles" or rotation invariance. VV beams have already found applications in areas ranging from microscopy to metrology, optical trapping, nano-optics, and quantum communication. Individual photons in such beams exhibit a form of single-particle quantum entanglement between different degrees of freedom. On the other hand, the quantum states of two photons can be also entangled with each other. Here, we combine these two concepts and demonstrate the generation of quantum entanglement between two photons that are both in VV states: a form of entanglement between two complex vectorial fields. This result may lead to quantum-enhanced applications of VV beams as well as to quantum information protocols fully exploiting the vectorial features of light.

  15. Vortex loops and Majoranas

    Energy Technology Data Exchange (ETDEWEB)

    Chesi, Stefano [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Jaffe, Arthur [Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Basel, Basel (Switzerland); Institute for Theoretical Physics, ETH Zürich, Zürich (Switzerland); Loss, Daniel [CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Basel, Basel (Switzerland); Pedrocchi, Fabio L. [Department of Physics, University of Basel, Basel (Switzerland)

    2013-11-15

    We investigate the role that vortex loops play in characterizing eigenstates of interacting Majoranas. We give some general results and then focus on ladder Hamiltonian examples as a test of further ideas. Two methods yield exact results: (i) A mapping of certain spin Hamiltonians to quartic interactions of Majoranas shows that the spectra of these two examples coincide. (ii) In cases with reflection-symmetric Hamiltonians, we use reflection positivity for Majoranas to characterize vortices in the ground states. Two additional methods suggest wider applicability of these results: (iii) Numerical evidence suggests similar behavior for certain systems without reflection symmetry. (iv) A perturbative analysis also suggests similar behavior without the assumption of reflection symmetry.

  16. Vortex cores and vortex motion in superconductors with anisotropic Fermi surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Galvis, J.A. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Departamento de Ciencias Naturales, Facultad de ingeniería y Ciencias Básicas, Universidad Central, Bogotá (Colombia); National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Herrera, E.; Guillamón, I.; Vieira, S. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Unidad Asociada de Altos Campos Magnéticos y Bajas Temperaturas, UAM, CSIC, Madrid (Spain); Suderow, H., E-mail: hermann.suderow@uam.es [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Unidad Asociada de Altos Campos Magnéticos y Bajas Temperaturas, UAM, CSIC, Madrid (Spain)

    2017-02-15

    Highlights: • The observation of vortex cores is reviewed, with emphasis in new experiments. • Vortex cores are follow superconducting gap and Fermi surface shapes. • The vortex core shape influences vortex dynamics. - Abstract: Explaning static and dynamic properties of the vortex lattice in anisotropic superconductors requires a careful characterization of vortex cores. The vortex core contains Andreev bound states whose spatial extension depends on the anisotropy of the electronic band-structure and superconducting gap. This might have an impact on the anisotropy of the superconducting properties and on vortex dynamics. Here we briefly summarize basic concepts to understand anisotropic vortex cores and review vortex core imaging experiments. We further discuss moving vortex lattices and the influence of vortex core shape in vortex motion. We find vortex motion in highly tilted magnetic fields. We associate vortex motion to the vortex entry barrier and the screening currents at the surface. We find preferential vortex motion along the main axis of the vortex lattice. After travelling integers of the intervortex distance, we find that vortices move more slowly due to the washboard potential of the vortex lattice.

  17. Home Appliance Load Scheduling with SEMIAH

    DEFF Research Database (Denmark)

    Jacobsen, Rune Hylsberg; Ghasem Azar, Armin; Zhang, Qi

    2015-01-01

    The European research project SEMIAH aims at designing a scalable infrastructure for residential demand response. This paper presents the progress towards a centralized load scheduling algorithm for controlling home appliances taking power grid constraints and satisfaction of consumers into account....

  18. Scheduling By Using Fuzzy Logic in Manufacturing

    Directory of Open Access Journals (Sweden)

    Miss. Ashwini. A. Mate

    2014-07-01

    Full Text Available This paper represents the scheduling process in furniture manufacturing unit. It gives the fuzzy logic application in flexible manufacturing system. Flexible manufacturing systems are production system in furniture manufacturing unit. FMS consist of same multipurpose numerically controlled machines. Here in this project the scheduling has been done in FMS by using fuzzy logic tool in Matlab software. The fuzzy logic based scheduling model in this paper will deals with the job and best alternative route selection with multi-criteria of machine. Here two criteria for job and sequencing and routing with rules. This model is applicable to the scheduling of any manufacturing industry.

  19. List scheduling revisited

    NARCIS (Netherlands)

    Schutten, Johannes M.J.

    1996-01-01

    We consider the problem of scheduling n jobs on m identical parallel machines to minimize a regular cost function. The standard list scheduling algorithm converts a list into a feasible schedule by focusing on the job start times. We prove that list schedules are dominant for this type of problem.

  20. A scheduling model for astronomy

    Science.gov (United States)

    Solar, M.; Michelon, P.; Avarias, J.; Garces, M.

    2016-04-01

    Astronomical scheduling problem has several external conditions that change dynamically at any time during observations, like weather condition (humidity, temperature, wind speed, opacity, etc.), and target visibility conditions (target over the horizon, Sun/Moon blocking the target). Therefore, a dynamic re-scheduling is needed. An astronomical project will be scheduled as one or more Scheduling Blocks (SBs) as an atomic unit of astronomical observations. We propose a mixed integer linear programming (MILP) solution to select the best SBs, favors SBs with high scientific values, and thus maximizing the quantity of completed observation projects. The data content of Atacama Large Millimeter/Submillimeter Array (ALMA) projects of cycle 0 and cycle 1 were analyzed, and a synthetic set of tests of the real instances was created. Two configurations, one of 5000 SBs in a 3 months season and another 10,000 SBs a 6 months season were created. These instances were evaluated with excellent results. Through the testing it is showed that the MILP proposal has optimal solutions.

  1. A Coupled Probabilistic Wake Vortex and Aircraft Response Prediction Model

    Science.gov (United States)

    Gloudemans, Thijs; Van Lochem, Sander; Ras, Eelco; Malissa, Joel; Ahmad, Nashat N.; Lewis, Timothy A.

    2016-01-01

    Wake vortex spacing standards along with weather and runway occupancy time, restrict terminal area throughput and impose major constraints on the overall capacity and efficiency of the National Airspace System (NAS). For more than two decades, the National Aeronautics and Space Administration (NASA) has been conducting research on characterizing wake vortex behavior in order to develop fast-time wake transport and decay prediction models. It is expected that the models can be used in the systems level design of advanced air traffic management (ATM) concepts that safely increase the capacity of the NAS. It is also envisioned that at a later stage of maturity, these models could potentially be used operationally, in groundbased spacing and scheduling systems as well as on the flight deck.

  2. Vortex state in ferromagnetic nanoparticles

    Science.gov (United States)

    Betto, Davide; Coey, J. M. D.

    2014-05-01

    The evolution of the magnetic state of a soft ferromagnetic nanoparticle with its size is usually thought to be from superparamagnetic single domain to blocked single domain to a blocked multidomain structure. Néel pointed out that a vortex configuration produces practically no stray field at the cost of an increase in the exchange energy, of the order of RJS2lnR /c, where JS2 is the bond energy, R is the particle radius, and c is of the order of the exchange length. A vortex structure is energetically cheaper than single domain when the radius is greater than a certain value. The correct sequence should include a vortex configuration between the single domain and the multidomain states. The critical size is calculated for spherical particles of four important materials (nickel, magnetite, permalloy, and iron) both numerically and analytically. A vortex state is favored in materials with high magnetisation.

  3. Particle-vortex symmetric liquid

    CERN Document Server

    Mulligan, Michael

    2016-01-01

    We introduce an effective theory with manifest particle-vortex symmetry for disordered thin films undergoing a magnetic field-tuned superconductor-insulator transition. The theory may enable one to access both the critical properties of the strong-disorder limit, which has recently been confirmed [Breznay et al., PNAS 113, 280 (2016)] to exhibit particle-vortex symmetric electrical response, and the metallic phase discovered earlier [Mason and Kapitulnik, Phys. Rev. Lett. 82, 5341 (1999)] in less disordered samples. Within the effective theory, the Cooper-pair and field-induced vortex degrees of freedom are simultaneously incorporated into an electrically-neutral Dirac fermion minimally coupled to an (emergent) Chern-Simons gauge field. A derivation of the theory follows upon mapping the superconductor-insulator transition to the integer quantum Hall plateau transition and the subsequent use of Son's particle-hole symmetric composite Fermi liquid. Remarkably, particle-vortex symmetric response does not requir...

  4. Vortex migration in protoplanetary discs

    Directory of Open Access Journals (Sweden)

    Papaloizou John C. B.

    2013-04-01

    Full Text Available Vortices embedded in protoplanetary discs can act as obstacles to the unperturbed disc flow. The resulting velocity perturbations propagate away from the vortex in the form of density waves that transport angular momentum. Any asymmetry between the inner and the outer density wave means that the region around the vortex has to change its angular momentum. We find that this leads to orbital migration of the vortex. Asymmetric waves always arise except in the case of a disc with constant pressure, for isothermal as well as non-isothermal discs. Depending on the size and strength of the vortex, the resulting migration time scales can be as short as a few thousand orbits.

  5. Based on Markov Chain in the IT project schedule control and management%基于马尔科夫链在IT项目进度中的控制管理

    Institute of Scientific and Technical Information of China (English)

    龚雯; 胡家福

    2013-01-01

    In the IT project development process,IT project management is increasingly concerned by people, so many IT companies are active in management of the project into the progress of development activities, on the development of effective management.This paper uses Markov chain models and methods for IT project network diagrams and schedule management to predict,in the import and use of IT projects Markov model en-ables managers to more easily manage the project and make it better forecasting manpower savings and cost.%在IT项目的开发过程中,IT项目管理日益受到人们的关注,各个IT企业都在积极将项目管理引入到开发活动的进度当中,对开发实行有效的管理。本文运用马尔可夫链模型和网络图方法进行IT项目进度管理并进行预测,在IT项目中导入并使用马尔可夫模型使管理者们更加容易对项目进行管理以及预测使之更好的节约人力以及成本。

  6. Dynamic Fractional Resource Scheduling vs. Batch Scheduling

    CERN Document Server

    Casanova, Henri; Vivien, Frédéric

    2011-01-01

    We propose a novel job scheduling approach for homogeneous cluster computing platforms. Its key feature is the use of virtual machine technology to share fractional node resources in a precise and controlled manner. Other VM-based scheduling approaches have focused primarily on technical issues or on extensions to existing batch scheduling systems, while we take a more aggressive approach and seek to find heuristics that maximize an objective metric correlated with job performance. We derive absolute performance bounds and develop algorithms for the online, non-clairvoyant version of our scheduling problem. We further evaluate these algorithms in simulation against both synthetic and real-world HPC workloads and compare our algorithms to standard batch scheduling approaches. We find that our approach improves over batch scheduling by orders of magnitude in terms of job stretch, while leading to comparable or better resource utilization. Our results demonstrate that virtualization technology coupled with light...

  7. New omega vortex identification method

    Science.gov (United States)

    Liu, ChaoQun; Wang, YiQian; Yang, Yong; Duan, ZhiWei

    2016-08-01

    A new vortex identification criterion called Ω-method is proposed based on the ideas that vorticity overtakes deformation in vortex. The comparison with other vortex identification methods like Q-criterion and λ 2-method is conducted and the advantages of the new method can be summarized as follows: (1) the method is able to capture vortex well and very easy to perform; (2) the physical meaning of Ω is clear while the interpretations of iso-surface values of Q and λ 2 chosen to visualize vortices are obscure; (3) being different from Q and λ 2 iso-surface visualization which requires wildly various thresholds to capture the vortex structure properly, Ω is pretty universal and does not need much adjustment in different cases and the iso-surfaces of Ω=0.52 can always capture the vortices properly in all the cases at different time steps, which we investigated; (4) both strong and weak vortices can be captured well simultaneously while improper Q and λ 2 threshold may lead to strong vortex capture while weak vortices are lost or weak vortices are captured but strong vortices are smeared; (5) Ω=0.52 is a quantity to approximately define the vortex boundary. Note that, to calculate Ω, the length and velocity must be used in the non-dimensional form. From our direct numerical simulation, it is found that the vorticity direction is very different from the vortex rotation direction in general 3-D vortical flow, the Helmholtz velocity decomposition is reviewed and vorticity is proposed to be further decomposed to vortical vorticity and non-vortical vorticity.

  8. BIM-BASED SCHEDULING OF CONSTRUCTION

    DEFF Research Database (Denmark)

    Andersson, Niclas; Büchmann-Slorup, Rolf

    2010-01-01

    overlap of the design and construction processes. Consequently, the overall scheduling is primarily based on intuition and personal experiences, rather than well founded figures of the specific project. Finally, the overall schedule is comprehensive and complex, and consequently, difficult to overview......The potential of BIM is generally recognized in the construction industry, but the practical application of BIM for management purposes is, however, still limited among contractors. The objective of this study is to review the current scheduling process of construction in light of BIM...... and communicate. Scheduling on the detailed level, on the other hand, follows a stipulated approach to scheduling, i.e. the Last Planner System (LPS), which is characterized by involvement of all actors in the construction phase. Thus, the major challenge when implementing BIM-based scheduling is to improve...

  9. BIM-BASED SCHEDULING OF CONSTRUCTION

    DEFF Research Database (Denmark)

    Andersson, Niclas; Büchmann-Slorup, Rolf

    2010-01-01

    The potential of BIM is generally recognized in the construction industry, but the practical application of BIM for management purposes is, however, still limited among contractors. The objective of this study is to review the current scheduling process of construction in light of BIM...... overlap of the design and construction processes. Consequently, the overall scheduling is primarily based on intuition and personal experiences, rather than well founded figures of the specific project. Finally, the overall schedule is comprehensive and complex, and consequently, difficult to overview...... and communicate. Scheduling on the detailed level, on the other hand, follows a stipulated approach to scheduling, i.e. the Last Planner System (LPS), which is characterized by involvement of all actors in the construction phase. Thus, the major challenge when implementing BIM-based scheduling is to improve...

  10. Formation number for vortex dipoles

    Science.gov (United States)

    Sadri, Vahid; Krueger, Paul S.

    2016-11-01

    This investigation considers the axisymmetric formation of two opposite sign concentric vortex rings from jet ejection between concentric cylinders. This arrangement is similar to planar flow in that the vortex rings will travel together when the gap between the cylinders is small, similar to a vortex dipole, but it has the advantage that the vortex motion is less constrained than the planar case (vortex stretching and vortex line curvature is allowed). The flow was simulated numerically at a jet Reynolds number of 1,000 (based on ΔR and the jet velocity), jet pulse length-to-gap ratio (L / ΔR) in the range 10-20, and gap-to-outer radius ratio (ΔR /Ro) in the range 0.01-0.1. Small gap ratios were chosen for comparison with 2D results. In contrast with 2D results, the closely paired vortices in this study exhibited pinch-off from the generating flow and finite formation numbers. The more complex flow evolution afforded by the axisymmetric model and its influence on the pinch-off process will be discussed. This material is based on work supported by the National Science Foundation under Grant No. 1133876 and SMU. This supports are gratefully acknowledged.

  11. Vortex migration in protoplanetary disks

    CERN Document Server

    Paardekooper, S -J; Papaloizou, J C B

    2010-01-01

    We consider the radial migration of vortices in two-dimensional isothermal gaseous disks. We find that a vortex core, orbiting at the local gas velocity, induces velocity perturbations that propagate away from the vortex as density waves. The resulting spiral wave pattern is reminiscent of an embedded planet. There are two main causes for asymmetries in these wakes: geometrical effects tend to favor the outer wave, while a radial vortensity gradient leads to an asymmetric vortex core, which favors the wave at the side that has the lowest density. In the case of asymmetric waves, which we always find except for a disk of constant pressure, there is a net exchange of angular momentum between the vortex and the surrounding disk, which leads to orbital migration of the vortex. Numerical hydrodynamical simulations show that this migration can be very rapid, on a time scale of a few thousand orbits, for vortices with a size comparable to the scale height of the disk. We discuss the possible effects of vortex migrat...

  12. Schedule Uncertainty Control: A Literature Review

    Science.gov (United States)

    Jun-yan, Liu

    Risk control on project schedule is one of the focus problems in the academic circle and the practical area all the time. Lots of research about risk control on project schedule have been fulfilled and many achievements have appeared in recent several decades. The literature on the techniques of schedule uncertainty control was reviewed. A summary analysis on those chievements is presented such as CPM, PERT, MC, BBN, and so on and in light of that summary analysis a deep discussion in terms of advantages and disadvantages of existing research has been analyzed, so that researchers can continue to refine their research.

  13. Optical Vortex Solitons in Parametric Wave Mixing

    CERN Document Server

    Alexander, T J; Buryak, A V; Sammut, R A; Alexander, Tristram J.; Kivshar, Yuri S.; Buryak, Alexander V.; Sammut, Rowland A.

    2000-01-01

    We analyze two-component spatial optical vortex solitons supported by degenerate three- or four-wave mixing in a nonlinear bulk medium. We study two distinct cases of such solitons, namely, parametric vortex solitons due to phase-matched second-harmonic generation in a optical medium with competing quadratic and cubic nonlinear response, and vortex solitons in the presence of third-harmonic generation in a cubic medium. We find, analytically and numerically, the structure of two-component vortex solitons, and also investigate modulational instability of their plane-wave background. In particular, we predict and analyze in detail novel types of vortex solitons, a `halo-vortex', consisting of a two-component vortex core surrounded by a bright ring of its harmonic field, and a `ring-vortex' soliton which is a vortex in a harmonic field that guides a bright localized ring-like mode of a fundamental frequency field.

  14. Achromatic Vector Vortex Waveplates for Coronagraphy Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Diffractive waveplates are optical components made of thin films of anisotropic materials by modulating their optical axis orientation in the plane of the waveplate....

  15. Achromatic Vector Vortex Waveplates for Coronagraphy Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Using small aperture telescopes for detecting exoplanets could have a significant impact on astronomy and other imaging and space communication systems. In this new...

  16. 基于缓冲区和挣值分析的项目成本与进度风险预警%A Method of Risk Warning for Project Cost and Schedule Based on Buffer and Earned Value Analysis

    Institute of Scientific and Technical Information of China (English)

    李南; 戴育雷; 杨莉

    2015-01-01

    为弥补挣值分析法不具有对项目成本与进度风险量进行测评的缺陷,在挣值分析法的基础上,提出了运用缓冲区定期监测项目成本与进度风险动态变化的定量方法。该方法定义了项目成本与时间的动态缓冲区,用于表示项目成本与工期在受控范围内的变化量,并运用蒙特卡罗仿真法获取动态缓冲区尺寸;在此基础上,结合挣值分析指标,构建了项目成本与进度风险动态预警指标,对预警指标值的范围进行划分与说明。并以某弹体分系统中尾段子系统初样研制项目为例演示了该方法的使用过程,表明该方法具有良好的有效性与可操作性。%This paper proposes a quantitative method of regular monitoring the dynamic change of project cost and schedule risk using buffer based earned value analysis method to against the defect of the earned value analysis method which does not evaluate project cost and schedule risk. The dynamic buffers of project cost and time are defined,which indicates the variable amount of project cost and duration in the controlled range,and monte carlo simulation is applied to obtain the dynamic buffers size. Based on them,combined with the earned value analysis indexes,the indexes of dynamic risk warning for project cost and schedule are made and the dynamic warning value ranges are divided and explained. Finally,the application process of the proposed method is illustrated by a case study of tail subsystem in a missile system. This proves the method effective and maneuverable.

  17. Environmental surveillance master sampling schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, L.E.

    1995-02-01

    Environmental surveillance of the Hanford Site and surrounding areas is conducted by the Pacific Northwest Laboratory (PNL) for the U.S. Department of Energy (DOE). This document contains the planned 1994 schedules for routine collection of samples for the Surface Environmental Surveillance Project (SESP), Drinking Water Project, and Ground-Water Surveillance Project. Samples are routinely collected for the SESP and analyzed to determine the quality of air, surface water, soil, sediment, wildlife, vegetation, foodstuffs, and farm products at Hanford Site and surrounding communities. The responsibility for monitoring onsite drinking water falls outside the scope of the SESP. PNL conducts the drinking water monitoring project concurrent with the SESP to promote efficiency and consistency, utilize expertise developed over the years, and reduce costs associated with management, procedure development, data management, quality control, and reporting. The ground-water sampling schedule identifies ground-water sampling .events used by PNL for environmental surveillance of the Hanford Site. Sampling is indicated as annual, semi-annual, quarterly, or monthly in the sampling schedule. Some samples are collected and analyzed as part of ground-water monitoring and characterization programs at Hanford (e.g. Resources Conservation and Recovery Act (RCRA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), or Operational). The number of samples planned by other programs are identified in the sampling schedule by a number in the analysis column and a project designation in the Cosample column. Well sampling events may be merged to avoid redundancy in cases where sampling is planned by both-environmental surveillance and another program.

  18. Resource-Driven Scheduling Implementation in Malaysian Construction Industry

    Directory of Open Access Journals (Sweden)

    Aftab Hameed Memon

    2011-07-01

    Full Text Available Resource-driven scheduling techniques focus on resource. Their objective is to schedule activities so that a project dead line is met using predefined resource availability limits. This paper reports about the status of resource-driven scheduling implementation in Malaysian construction industry. An investigation Survey was conducted to determine the level of resource-driven scheduling and factors affecting the concerned implementation. Construction Firm registered under G7 (A Class, G6 (B class and G5 (C class were used in investigation. Data was analyzed by Statistical package SPSS to find the means and rank. Average index method was adapted to for the level of features of resource scheduling implementation and barrier to resource-driven scheduling. It is significant 59.65% firms are implementing resource-driven scheduling as partial. Also methods of project scheduling and resource options adopted were investigated. A Significant majority of construction firms (approximately 65% adopt Microsoft project for scheduling. Study showed that the features of resource scheduling are being implemented at Medium Level. Lack of understanding / awareness of concepts, lack of genuine commitment, lack of coordination of key personnel and Lack of coordination of constructors consultants were found major factors that affect resource-driven scheduling. While, expensive to prepare is most contributing factor, no enforcement on schedules from authority, difficult to prepare and hurdles by personnel/authorities were found as major constraints in implementing resource driven scheduling.

  19. NSGA-Ⅱ based fuzzy multi-object product development project scheduling approach%基于NSGA-Ⅱ的模糊多目标产品开发项目调度

    Institute of Scientific and Technical Information of China (English)

    张连营; 查鸿

    2013-01-01

    针对具有模糊持续时间的产品开发项目工期-成本均衡调度问题,进一步考虑了模糊环境下决策者风险偏好(可接受风险水平与乐观指数)对工期-成本均衡的影响,并运用NSGA-Ⅱ算法,结合项目实例,对该问题进行了求解和分析.研究表明,通过调整决策者的可接受风险水平或乐观指数,可以获得一系列不同的Pareto解,以便决策者从中选择其偏好的调度方案.%Aiming at the time and cost tradeoff problem in product development project scheduling with fuzzy durations, this paper considered the effect of decision -makers' risk preference on time and cost tradeoff in fuzzy environment further, and it introduced NSGA- Ⅱ to solve the problem in project example. The results show that by means of adjusting the values of risk acceptance level and optimism index, different Pareto sets are obtained, from which the decision can choose the preferred scheduling alternative.

  20. Application of Improved PERT in Schedule Mmanagement of Large and Complex Project%改进的计划评审技术在大型复杂项目进度管理中的应用

    Institute of Scientific and Technical Information of China (English)

    金勇

    2012-01-01

    To settle the issue on schedule management in large complex project, this paper establishes the PERT BN model where the program evaluation and review technique (PERT) improved based on Bayesian network (BN) is applied for analysis, control and optimization of project schedule. This paper gives out the fundamental definition of PERT BN and details of inclusive nodes, oriented edges and conditional probability. The PERT BN case study is implemented based on the experimental network diagram of R & D project for certain model. Finally, it takes the model as the example to analyze the impacts of external factors such as people, cost and technology to the process duration and the impacts of changed total project duration changes to the demanded resources.%针对大型复杂项目进度管理中存在的问题,提出了PERT BN模型,其基于贝叶斯网络(BN)而改进的PERT,用于项目进度分析、控制及优化.给出了PERT BN的基本定义,并详述了其包含的节点、有向边和条件概率.然后,以某型号研制项目实验网络图为例,建立起对应的PERT BN模型实例.最后,以模型实例为基础,分析了人、成本和技术等外界因素对工序持续时间的影响,以及总工期变化时对资源的需求变化情况.

  1. Project Multi-objective Scheduling Optimization Based on Set Pair Analysis and NSGA-II%基于集对分析与 NSGA -II 的工程项目多目标优化

    Institute of Scientific and Technical Information of China (English)

    翟瑞; 张云宁; 陈国伟; 赵迎亮

    2015-01-01

    工程项目进度、成本和质量三者是对立统一的,工程项目的多目标优化着重于求解三者的和谐统一。以工程项目施工过程中的进度、成本和质量水平阈值为约束条件,运用集对分析法为建筑工程多目标优化问题的处理构建了柔性的建模框架;利用NSGA-II算法求解多目标优化模型,得到多目标优化的Pareto最优解集;通过实际算例验证了该算法在解决工程项目多目标优化问题中的可行性和有效性。%The three main objectives of the project are schedule , cost, and quality, which are the unity of opposites .The op-timization of the multi-objectives of the project focuses on seeking the harmony of the three of them .Constrained by the thresh-old level of the project schedule , cost and quality , a flexible modeling framework was constructed for the construction of multi -objective optimization problem by set pair analysis method .Then NSGA-II algorithm was used to solve the model of multi objec-tive optimization in order to get multi -objective optimization of Pareto optimal solution set .Finally, a practical example was giv-en to verify the feasibility and effectiveness of the algorithm in solving multi -objective optimization project problems .

  2. Stratospheric polar vortex splits and displacements in the high-top CMIP5 climate models

    Science.gov (United States)

    Seviour, William J. M.; Gray, Lesley J.; Mitchell, Daniel M.

    2016-02-01

    Sudden stratospheric warming (SSW) events can occur as either a split or a displacement of the stratospheric polar vortex. Recent observational studies have come to different conclusions about the relative impacts of these two types of SSW upon surface climate. A clearer understanding of their tropospheric impact would be beneficial for medium-range weather forecasts and could improve understanding of the physical mechanism for stratosphere-troposphere coupling. Here we perform the first multimodel comparison of stratospheric polar vortex splits and displacements, analyzing 13 stratosphere-resolving models from the fifth Coupled Model Intercomparison Project (CMIP5) ensemble. We find a wide range of biases among models in both the mean state of the vortex and the frequency of vortex splits and displacements, although these biases are closely related. Consistent with observational results, almost all models show vortex splits to occur barotropically throughout the depth of the stratosphere, while vortex displacements are more baroclinic. Vortex splits show a slightly stronger North Atlantic surface signal in the month following onset. However, the most significant difference in the surface response is that vortex displacements show stronger negative pressure anomalies over Siberia. This region is shown to be colocated with differences in tropopause height, suggestive of a localized response to lower stratospheric potential vorticity anomalies.

  3. Improved Quantum Genetic Algorithm for the Resource Constrained Multi-Project Scheduling Problem with Transfer Times%转移资源受限多项目调度的改进量子遗传算法

    Institute of Scientific and Technical Information of China (English)

    郭云涛; 陈志; 白思俊

    2014-01-01

    Traditional resource constrained multi-project scheduling problem do not consider the resource transfer times within or between projects,an improved quantum genetic algorithm is presented to solve the resource constrained multi-project scheduling problem with transfer times.The modified parallel schedule generation scheme is used to construct project schedules.An angle-based coding method is devised which can represent both task and resource transfer priority values,each chromosome can be converted into two chains of random key representation to increase the diversity of the population.The quantum rotation gate and quantum non-gate operations are given,meanwhile the chaotic mutation is introduced to avoid the premature.An example is designed and the proposed algorithm with priority rules algorithm,the common genetic algorithm are all tested on the problem.The experimental results show that:the improved quantum genetic algorithm can effectively solve the resource constrained multi-project scheduling problem with transfer times,and the solution quality and time are better than common genetic algorithm.%传统的资源受限多项目调度问题没有考虑资源在项目内部以及项目之间的转移时间,针对考虑了资源转移的多项目调度问题提出了一种改进的量子遗传算法。算法采用改进的并行进度生成机制,结合多项目任务优先权以及资源转移优先权设计了基于角度的编码方法,该编码能够转换成双链随机键编码,增加了种群的多样性,给出了量子旋转门以及随机组合量子非门算子,同时将混沌变异引入量子遗传算法中,避免了早熟现象。设计了相应的算例,并将本文算法与各种优先规则和普通遗传算法的求解效果进行了比较。实验表明:改进的量子遗传算法能够有效地求解转移资源受限多项目调度问题,并且求解质量和时间均优于普通遗传算法。

  4. Runway Scheduling Using Generalized Dynamic Programming

    Science.gov (United States)

    Montoya, Justin; Wood, Zachary; Rathinam, Sivakumar

    2011-01-01

    A generalized dynamic programming method for finding a set of pareto optimal solutions for a runway scheduling problem is introduced. The algorithm generates a set of runway fight sequences that are optimal for both runway throughput and delay. Realistic time-based operational constraints are considered, including miles-in-trail separation, runway crossings, and wake vortex separation. The authors also model divergent runway takeoff operations to allow for reduced wake vortex separation. A modeled Dallas/Fort Worth International airport and three baseline heuristics are used to illustrate preliminary benefits of using the generalized dynamic programming method. Simulated traffic levels ranged from 10 aircraft to 30 aircraft with each test case spanning 15 minutes. The optimal solution shows a 40-70 percent decrease in the expected delay per aircraft over the baseline schedulers. Computational results suggest that the algorithm is promising for real-time application with an average computation time of 4.5 seconds. For even faster computation times, two heuristics are developed. As compared to the optimal, the heuristics are within 5% of the expected delay per aircraft and 1% of the expected number of runway operations per hour ad can be 100x faster.

  5. Project Schedule Management of Power Transmission and Transformation Project——Based on the Critical Chain Theory%输变电工程项目进度管理——基于关键链理论

    Institute of Scientific and Technical Information of China (English)

    王倩

    2015-01-01

    In the management of power transmission and transformation project, project schedule management is one of the most important parts. Currently, methods frequently applied in the schedule management of power transmission and transformation project include Gantt chart,CPM,earned value management,S curve, PERT and etc..However, we often come across all kinds of problems when applying these methods in power transmission and transformation project, for instance, the project safety time is lost or the duration program is too long. To solve the problems mentioned above ,this paper introduces the Critical Chain theory to optimize the schedule management of power transmission and transformation project. The advantage of the Critical Chain theory is that it can start from the whole project, giving full consideration to the project's human power, material resource and financial resource, and additionally, it can meanwhile consider the sequence constraint of activities and the resource constraint between the activities as well. By taking 500kV power transmission and transformation project as an example to conduct the empirical analysis, it shows that this theory can effectively solve the resource conflict in the construction of power transmission and transformation project, therefore it can both improve the work efficiency and reduce the cost at the same time.%项目进度管理是输变电项目管理中最重要的一个环节,目前常用于输变电工程项目进度管理的方法包括甘特图法、关键路径法、挣得值法、S曲线比较法和计划评审技术法等,然而在输变电工程项目中采用这些方法时,存在项目安全时间丢失、工期计划过长等问题.为解决上述问题,本文引入关键链理论来对输变电项目进度管理进行优化处理,关键链理论的优势是它可以从工程的整体出发,充分考虑项目的人、物和财等资源,并考虑项目活动的前后约束和活动间的资源约束.以500kV输变

  6. Geographic Information Systems in Evaluation and Visualization of Construction Schedule

    CERN Document Server

    Bansal, V K

    2008-01-01

    Commercially available scheduling tools such as Primavera and Microsoft Project fail to provide information pertaining to the spatial aspects of construction project. A methodology using geographical information systems (GIS) is developed to represent spatial aspects of the construction progress graphically by synchronizing it with construction schedule. The spatial aspects are depicted by 3D model developed in AutoCAD and construction schedule is generated using Microsoft Excel. Spatial and scheduling information are linked together into the GIS environment (ArcGIS). The GIS-based system developed in this study may help in better understanding the schedule along with its spatial aspects.

  7. Immunization Schedules for Adults

    Science.gov (United States)

    ... Everyone: Easy-to-read Schedules Infants and Children Preteens and Teens Adults Display Immunization Schedules and Quiz ... file Microsoft Word file Microsoft Excel file Audio/Video file Apple Quicktime file RealPlayer file Text file ...

  8. Instant Childhood Immunization Schedule

    Science.gov (United States)

    ... Everyone: Easy-to-read Schedules Infants and Children Preteens and Teens Adults Display Immunization Schedules and Quiz ... file Microsoft Word file Microsoft Excel file Audio/Video file Apple Quicktime file RealPlayer file Text file ...

  9. Resource-Driven Scheduling Implementation in Malaysian Construction Industry

    OpenAIRE

    Aftab Hameed Memon; Rosli Mohammad Zin

    2011-01-01

    Resource-driven scheduling techniques focus on resource. Their objective is to schedule activities so that a project dead line is met using predefined resource availability limits. This paper reports about the status of resource-driven scheduling implementation in Malaysian construction industry. An investigation Survey was conducted to determine the level of resource-driven scheduling and factors affecting the concerned implementation. Construction Firm registered under G7 (A Class), G6 (B c...

  10. Reinforcement learning in scheduling

    Science.gov (United States)

    Dietterich, Tom G.; Ok, Dokyeong; Zhang, Wei; Tadepalli, Prasad

    1994-01-01

    The goal of this research is to apply reinforcement learning methods to real-world problems like scheduling. In this preliminary paper, we show that learning to solve scheduling problems such as the Space Shuttle Payload Processing and the Automatic Guided Vehicle (AGV) scheduling can be usefully studied in the reinforcement learning framework. We discuss some of the special challenges posed by the scheduling domain to these methods and propose some possible solutions we plan to implement.

  11. Small hydro and river renaturation - A vortex for energy; Kleinwasserkraft und Renaturierung. Wirbeln fuer Energie

    Energy Technology Data Exchange (ETDEWEB)

    Niederhaeusern, A.

    2009-07-01

    This short article takes a look at a novel form of producing low-head hydropower The so-called water-vortex power stations are small-size, low-tech installations which operate with very low differences in height and are also said to be fish-friendly. A first Swiss installation in Schoeftland, Switzerland, is described. The installation, which was realised in combination with the renaturation of the river Suhre, uses vortex technology developed in Austria. Further projects involving larger versions of the vortex power station are mentioned.

  12. Scheduling with Time Lags

    NARCIS (Netherlands)

    X. Zhang (Xiandong)

    2010-01-01

    textabstractScheduling is essential when activities need to be allocated to scarce resources over time. Motivated by the problem of scheduling barges along container terminals in the Port of Rotterdam, this thesis designs and analyzes algorithms for various on-line and off-line scheduling problems

  13. Parallel scheduling algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Dekel, E.; Sahni, S.

    1983-01-01

    Parallel algorithms are given for scheduling problems such as scheduling to minimize the number of tardy jobs, job sequencing with deadlines, scheduling to minimize earliness and tardiness penalties, channel assignment, and minimizing the mean finish time. The shared memory model of parallel computers is used to obtain fast algorithms. 26 references.

  14. 挣时管理:一种基于挣值的项目进度绩效评价方法%Earned time:a new optimal method of project schedule performance evaluation based on earned value

    Institute of Scientific and Technical Information of China (English)

    郭文静; 周晓宏

    2014-01-01

    The Earned Value Management methodology is a very important and systematic technique that evaluates project performance.This paper studies the disadvantages and limitations of traditional earned value method while evaluating the project Schedule Performance from the application point of view based on the introduction of the traditional earned value management method,and puts forward a performance evaluation method called Earned Time method.It corrects the deviation from traditional earned value method when evaluating the project Schedule Performance,and all the information needed comes form the traditional earned value management.%挣值管理方法是现代项目管理中评价项目绩效的一个非常重要的系统方法。本文在对传统挣值管理方法简要介绍基础上,从实际应用角度就传统挣值管理方法在项目进度绩效评价方面存在的不足和局限进行分析,提出了一种基于时间进度的进度绩效评价方法-挣时分析法。该方法能够改进传统挣值法在进度评价方面的偏差,而且该方法所有信息都来自传统挣值分析,不需要增加额外的信息。

  15. Study on Optimization and Simulation of DSM Project Schedule Based on Activities Overlapping%基于活动重叠的 DSM 项目进度优化与仿真

    Institute of Scientific and Technical Information of China (English)

    张春生; 严广乐

    2013-01-01

      Overlapping between project activities can shorten project schedule , but it can result in a rework risk. Therefore, the paper first adopts the design structure matrix (DSM), proposes activities advancing overlapping factor DSM and activities crashing overlapping factor DSM , combines rework risk DSM, aiming to completely de-scribe the effect of activities overlapping on rework .Finally, the author presents a hybrid particle swarm algorithm for schedule optimization based on activities overlapping .The calculation proves that the method can not only reduce the duration of projects, but also provide decision-makers with a new perspective in properly choosing activities overlapping .%  项目活动之间的重叠虽然可以缩短项目工期,但又存在返工风险。为此,本文采用设计结构矩阵(DSM),提出活动超前重叠因子矩阵和活动赶工重叠因子矩阵,结合返工风险矩阵,完整地描述了项目活动的重叠及其对返工的影响。提出了基于活动重叠的混合粒子群项目进度优化方法。通过案例计算表明,该法可以有效缩短项目工期,同时为项目决策者合理选择活动重叠量提供了新思路。

  16. AN OPTIMISED TASK-PERSONNEL MATCHING METHOD SUPPORTING SOFTWARE PROJECT RESOURCES SCHEDULING%一种支持软件项目资源调度的任务人员优化匹配方法

    Institute of Scientific and Technical Information of China (English)

    吴安琪; 谢利子; 肖俊超

    2011-01-01

    依赖主观判断和个人经验的任务人员分配方法具有不稳定性和不可靠性,直接导致较低的人力资源利用效率.已有的资源调度方法对人力资源的复杂性和能力差异性考虑不足.提出了一种支持软件项目资源调度的任务人员优化匹配方法.方法将心理学与软件项目管理进行结合,通过挖掘人力资源的性格能力属性,综合技术能力属性,对任务人员的匹配过程进行优化.工具和实验表明,方法可为项目管理人员进行任务分配时提供有效的决策支持.%The task-personnel assignment method depending on subjective judgment and individual experiences is instable and unreliable,which directly leads to low staffing efficiency. Existing resource scheduling methods do not pay enough attention to the complexity and capability diversity of human resources. An optimised task-personnel matching method supporting software project resource scheduling is proposed in this paper. The method combines software project management with psychology,and optimises task-personnel matching process by mining the character capabilities property in HR resource as well as integrating the skill capabilities property. The prototype tool and internal experiment indicate that the method can offer effective decision support to project managers on task assignments.

  17. Vortex Laser at Exceptional Point

    CERN Document Server

    Wang, Xing-Yuan; Li, Ying; Li, Bo; Ma, Ren-Min

    2016-01-01

    The optical vortices carrying orbital angular momentum (OAM) are commonly generated by modulating the available conventional light beam. This article shows that a micro-laser operates at the exceptional point (EP) of the non-Hermitian quantum system can directly emit vortex laser with well-defined OAM at will. Two gratings (the refractive index modulation and along azimuthal direction and the grating protruding from the micro-ring cavity) modulate the eigenmode of a micro-ring cavity to be a vortex laser mode. The phase-matching condition ensures that we can tune the OAM of the vortex beam to be arbitrary orders by changing the grating protruding from the micro-ring cavity while the system is kept at EP. The results are obtained by analytical analysis and confirmed by 3D full wave simulations.

  18. Scheduling lessons learned from the Autonomous Power System

    Science.gov (United States)

    Ringer, Mark J.

    1992-01-01

    The Autonomous Power System (APS) project at NASA LeRC is designed to demonstrate the applications of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution systems. The project consists of three elements: the Autonomous Power Expert System (APEX) for Fault Diagnosis, Isolation, and Recovery (FDIR); the Autonomous Intelligent Power Scheduler (AIPS) to efficiently assign activities start times and resources; and power hardware (Brassboard) to emulate a space-based power system. The AIPS scheduler was tested within the APS system. This scheduler is able to efficiently assign available power to the requesting activities and share this information with other software agents within the APS system in order to implement the generated schedule. The AIPS scheduler is also able to cooperatively recover from fault situations by rescheduling the affected loads on the Brassboard in conjunction with the APEX FDIR system. AIPS served as a learning tool and an initial scheduling testbed for the integration of FDIR and automated scheduling systems. Many lessons were learned from the AIPS scheduler and are now being integrated into a new scheduler called SCRAP (Scheduler for Continuous Resource Allocation and Planning). This paper will service three purposes: an overview of the AIPS implementation, lessons learned from the AIPS scheduler, and a brief section on how these lessons are being applied to the new SCRAP scheduler.

  19. A Experimental Study of Viscous Vortex Rings.

    Science.gov (United States)

    Dziedzic, Mauricio

    Motivated by the role played by vortex rings in the process of turbulent mixing, the work is focused on the problem of stability and viscous decay of a single vortex ring. A new classification is proposed for vortex rings which is based on extensive hot-wire measurements of velocity in the ring core and wake and flow visualization. Vortex rings can be classified as laminar, wavy, turbulence-producing, and turbulent. Prediction of vortex ring type is shown to be possible based on the vortex ring Reynolds number. Linear growth rates of ring diameter with time are observed for all types of vortex rings, with different growth rates occurring for laminar and turbulent vortex rings. Data on the viscous decay of vortex rings are used to provide experimental confirmation of the accuracy of Saffman's equation for the velocity of propagation of a vortex ring. Experimental data indicate that instability of the vortex ring strongly depends on the mode of generation and can be delayed by properly adjusting the generation parameters. A systematic review of the literature on vortex-ring interactions is presented in the form of an appendix, which helps identify areas in which further research may be fruitful.

  20. Longitudinal Plasmoid in High-Speed Vortex Gas Flow Created by Capacity HF Discharge

    Science.gov (United States)

    2010-10-28

    instrumentation will be used in this Project to study plasma and gas flow parameters, including new shadow device with excimer KrF laser, MW...vortex decay (attenuation) by HF plasma. The additional experiments with small helium jet injection prove the conclusion about vortex attenuation by a...equilibrium HF plasma. Plasma and airflow parameters are measured by different diagnostic instrumentation including shadow optical device with excimer

  1. Fractional vortex dipole phase filter

    Science.gov (United States)

    Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam

    2014-10-01

    In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.

  2. Vortex ice in nanostructured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Libal, Andras J [Los Alamos National Laboratory

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  3. Generation of nonlinear vortex precursors

    CERN Document Server

    Chen, Yue-Yue; Liu, Chengpu

    2016-01-01

    We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex har- monics are generated in the transmitted field due to ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provide a straightforward way of measuring precursors. By the virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical informa- tion and communication fields where controllable loss, large information-carrying capacity and high speed communication are required.

  4. Software Multi-project Scheduling Genetic Algorithms Based on a Time-line Model%基于时间轴的软件多项目任务调度遗传算法

    Institute of Scientific and Technical Information of China (English)

    肖菁; 吴洲

    2012-01-01

    合理的调度可以在很大程度上提高人力资源在软件项目开发中的利用率.在研究了现有的任务调度算法的基础上,考虑了软件开发任务的可拆分特性,结合员工的技能水平与项目经验对任务调度的影响,定义了基于时间轴的多项目并行调度模型.该模型将任务按时间单元进行拆分,并且提出员工学习模式,用以动态改变员工的技能水平和项目经验,从而提高员工分配的灵活性,使得满足约束下的成本开销最小化,其中包含员工薪水和超时任务的开销.模型分解后,利用遗传算法求解,由于模型中约束条件众多,因此遗传算法中增加了各种启发式来提高算法性能.通过仿真实例验证了模型和算法的有效性.%Reasonable scheduling can greatly improve the utilization of the human resources in the process of software project development. Based on the research of current task scheduling algorithms, taking the separable of software development tasks, employee's skills and project experience into consideration, the multi-project concurrent scheduling model based on time-line which splits the tasks by time unit was defined to minimize the cost that includes the employees' salaries and the penalties of overtime. At the same time,in order to improve the flexibility of assignment of employees , the model also proposes that the employees' skills and experience can be improved by training and working on some tasks. Since the model contains many conditions,genetic algorithm with some heuristics is used to implement the model. The effectiveness of this model and algorithm is verified by the simulation results.

  5. Hanford Site Environmental Surveillance Master Sampling Schedule, January 2001

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2001-01-08

    This document contains the CY 2001 schedules for the routine collection of samples for the Surface Environmental Surveillance Project (SESP) and Drinking Water Monitoring Project. Each section includes sampling locations, sample types, and analyses to be performed.

  6. Melting of heterogeneous vortex matter: The vortex `nanoliquid'

    Indian Academy of Sciences (India)

    S S Banerjee; S Goldberg; Y Myasoedov; M Rappaport; E Zeldov; A Soibel; F de la Cruz; C J van der Beek; M Konczykowski; T Tamegai; V Vinokur

    2006-01-01

    Disorder and porosity are parameters that strongly influence the physical behavior of materials, including their mechanical, electrical, magnetic and optical properties. Vortices in superconductors can provide important insight into the effects of disorder because their size is comparable to characteristic sizes of nanofabricated structures. Here we present experimental evidence for a novel form of vortex matter that consists of inter-connected nanodroplets of vortex liquid caged in the pores of a solid vortex structure, like a liquid permeated into a nanoporous solid skeleton. Our nanoporous skeleton is formed by vortices pinned by correlated disorder created by high-energy heavy ion irradiation. By sweeping the applied magnetic field, the number of vortices in the nanodroplets is varied continuously from a few to several hundred. Upon cooling, the caged nanodroplets freeze into ordered nanocrystals through either a first-order or a continuous transition, whereas at high temperatures a uniform liquid phase is formed upon delocalization-induced melt- ing of the solid skeleton. This new vortex nanoliquid displays unique properties and symmetries that are distinct from both solid and liquid phases.

  7. Geographic Information Systems in Evaluation and Visualization of Construction Schedule

    OpenAIRE

    Bansal, V. K.; Pal, Mahesh

    2008-01-01

    Commercially available scheduling tools such as Primavera and Microsoft Project fail to provide information pertaining to the spatial aspects of construction project. A methodology using geographical information systems (GIS) is developed to represent spatial aspects of the construction progress graphically by synchronizing it with construction schedule. The spatial aspects are depicted by 3D model developed in AutoCAD and construction schedule is generated using Microsoft Excel. Spatial and ...

  8. DSN Scheduling Engine

    Science.gov (United States)

    Clement, Bradley; Johnston, Mark; Wax, Allan; Chouinard, Caroline

    2008-01-01

    The DSN (Deep Space Network) Scheduling Engine targets all space missions that use DSN services. It allows clients to issue scheduling, conflict identification, conflict resolution, and status requests in XML over a Java Message Service interface. The scheduling requests may include new requirements that represent a set of tracks to be scheduled under some constraints. This program uses a heuristic local search to schedule a variety of schedule requirements, and is being infused into the Service Scheduling Assembly, a mixed-initiative scheduling application. The engine resolves conflicting schedules of resource allocation according to a range of existing and possible requirement specifications, including optional antennas; start of track and track duration ranges; periodic tracks; locks on track start, duration, and allocated antenna; MSPA (multiple spacecraft per aperture); arraying/VLBI (very long baseline interferometry)/delta DOR (differential one-way ranging); continuous tracks; segmented tracks; gap-to-track ratio; and override or block-out of requirements. The scheduling models now include conflict identification for SOA(start of activity), BOT (beginning of track), RFI (radio frequency interference), and equipment constraints. This software will search through all possible allocations while providing a best-effort solution at any time. The engine reschedules to accommodate individual emergency tracks in 0.2 second, and emergency antenna downtime in 0.2 second. The software handles doubling of one mission's track requests over one week (to 42 total) in 2.7 seconds. Further tests will be performed in the context of actual schedules.

  9. Propagation of Airy Gaussian vortex beams in uniaxial crystals

    Science.gov (United States)

    Weihao, Yu; Ruihuang, Zhao; Fu, Deng; Jiayao, Huang; Chidao, Chen; Xiangbo, Yang; Yanping, Zhao; Dongmei, Deng

    2016-04-01

    The propagation dynamics of the Airy Gaussian vortex beams in uniaxial crystals orthogonal to the optical axis has been investigated analytically and numerically. The propagation expression of the beams has been obtained. The propagation features of the Airy Gaussian vortex beams are shown with changes of the distribution factor and the ratio of the extraordinary refractive index to the ordinary refractive index. The correlations between the ratio and the maximum intensity value during the propagation, and its appearing distance have been investigated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374108, 11374107, 10904041, and 11547212), the Foundation of Cultivating Outstanding Young Scholars of Guangdong Province, China, the CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, the National Training Program of Innovation and Entrepreneurship for Undergraduates (Grant No. 2015093), and the Science and Technology Projects of Guangdong Province, China (Grant No. 2013B031800011).

  10. Advanced Reactors Transition Program Resource Loaded Schedule

    Energy Technology Data Exchange (ETDEWEB)

    GANTT, D.A.

    2000-01-12

    The Advanced Reactors Transition (ART) Resource Loaded Schedule (RLS) provides a cost and schedule baseline for managing the project elements within the ART Program. The Fast Flux Test Facility (FETF) activities are delineated through the end of FY 2000, assuming continued standby. The Nuclear Energy (NE) Legacies and Plutonium Recycle Test Reactor (PRTR) activities are delineated through the end of the deactivation process. This revision reflects the 19 Oct 1999 baseline.

  11. Advanced Reactors Transition Program Resource Loaded Schedule

    Energy Technology Data Exchange (ETDEWEB)

    BOWEN, W.W.

    1999-11-08

    The Advanced Reactors Transition (ART) Resource Loaded Schedule (RLS) provides a cost and schedule baseline for managing the project elements within the ART Program. The Fast Flux Test Facility (FFTF) activities are delineated through the end of FY 2000, assuming continued standby. The Nuclear Energy (NE) Legacies and Plutonium Recycle Test Reactor (PRTR) activities are delineated through the end of the deactivation process. This document reflects the 1 Oct 1999 baseline.

  12. Backreaction of excitations on a vortex

    CERN Document Server

    Arodz, H; Arodz, Henryk; Hadasz, Leszek

    1997-01-01

    Excitations of a vortex are usually considered in a linear approximation neglecting their backreaction on the vortex. In the present paper we investigate backreaction of Proca type excitations on a straightlinear vortex in the Abelian Higgs model. We propose exact Ansatz for fields of the excited vortex. From initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the backreaction corrections. Their approximate solutions are found in the cases of plane wave and wave packet type excitations. We find that the excited vortex radiates vector field and that the Higgs field has a very broad oscillating component.

  13. Aircraft Wake Vortex Measurements at Denver International Airport

    Science.gov (United States)

    Dougherty, Robert P.; Wang, Frank Y.; Booth, Earl R.; Watts, Michael E.; Fenichel, Neil; D'Errico, Robert E.

    2004-01-01

    Airport capacity is constrained, in part, by spacing requirements associated with the wake vortex hazard. NASA's Wake Vortex Avoidance Project has a goal to establish the feasibility of reducing this spacing while maintaining safety. Passive acoustic phased array sensors, if shown to have operational potential, may aid in this effort by detecting and tracking the vortices. During August/September 2003, NASA and the USDOT sponsored a wake acoustics test at the Denver International Airport. The central instrument of the test was a large microphone phased array. This paper describes the test in general terms and gives an overview of the array hardware. It outlines one of the analysis techniques that is being applied to the data and gives sample results. The technique is able to clearly resolve the wake vortices of landing aircraft and measure their separation, height, and sinking rate. These observations permit an indirect estimate of the vortex circulation. The array also provides visualization of the vortex evolution, including the Crow instability.

  14. Particle-vortex symmetric liquid

    Science.gov (United States)

    Mulligan, Michael

    2017-01-01

    We introduce an effective theory with manifest particle-vortex symmetry for disordered thin films undergoing a magnetic field-tuned superconductor-insulator transition. The theory may enable one to access both the critical properties of the strong-disorder limit, which has recently been confirmed by Breznay et al. [Proc. Natl. Acad. Sci. USA 113, 280 (2016), 10.1073/pnas.1522435113] to exhibit particle-vortex symmetric electrical response, and the nearby metallic phase discovered earlier by Mason and Kapitulnik [Phys. Rev. Lett. 82, 5341 (1999), 10.1103/PhysRevLett.82.5341] in less disordered samples. Within the effective theory, the Cooper-pair and field-induced vortex degrees of freedom are simultaneously incorporated into an electrically neutral Dirac fermion minimally coupled to a (emergent) Chern-Simons gauge field. A derivation of the theory follows upon mapping the superconductor-insulator transition to the integer quantum Hall plateau transition and the subsequent use of Son's particle-hole symmetric composite Fermi liquid. Remarkably, particle-vortex symmetric response does not require the introduction of disorder; rather, it results when the Dirac fermions exhibit vanishing Hall effect. The theory predicts approximately equal (diagonal) thermopower and Nernst signal with a deviation parameterized by the measured electrical Hall response at the symmetric point.

  15. Anatomy of a Bathtub Vortex

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Bohr, Tomas; Stenum, Bjarne

    2003-01-01

    We present experiments and theory for the "bathtub vortex," which forms when a fluid drains out of a rotating cylindrical container through a small drain hole. The fast down-flow is found to be confined to a narrow and rapidly rotating "drainpipe" from the free surface down to the drain hole. Sur...

  16. Merger of Long Vortex Filaments

    CERN Document Server

    Khandekar, Akshay

    2012-01-01

    This fluid dynamics video demonstrates the merger of long vortex filaments is shown experimentally. Two counter-rotating vortices are generated using in a tank with very high aspect ratio. PIV demonstrates the merger of the vortices within a single orbit.

  17. Thermal inhomogeneities in vortex tubes

    Science.gov (United States)

    Lemesh, N. I.; Senchuk, L. A.

    An experimental study of the effect of the temperature of the inlet gas on the temperature difference between the hot and cold streams discharged from a Ranque-Hilsch vortex tube is described. The experimental results are presented in graphical form. It is that the temperature difference increases with the temperature of the entering gas.

  18. Instability of vortex pair leapfrogging

    DEFF Research Database (Denmark)

    Tophøj, Laust; Aref, Hassan

    2013-01-01

    pairs fly off to infinity, and a "walkabout" mode, where the vortices depart from leapfrogging but still remain within a finite distance of one another. We show numerically that this transition is more gradual, a result that we relate to earlier investigations of chaotic scattering of vortex pairs [L...

  19. 150 Years of vortex dynamics

    DEFF Research Database (Denmark)

    Aref, Hassan

    2010-01-01

    An IUTAM symposium with the title of this paper was held on October 12-16, 2008, in Lyngby and Copenhagen, Denmark, to mark the sesquicentennial of publication of Helmholtz's seminal paper on vortex dynamics. This volume contains the proceedings of the Symposium. The present paper provides...

  20. Improved MLWDF scheduler for LTE downlink transmission

    Science.gov (United States)

    Obinna Nnamani, Christantus; Anioke, Chidera Linda; Ikechukwu Ani, Cosmas

    2016-11-01

    In long-term evolution (LTE) downlink transmission, modified least weighted delay first (MLWDF) scheduler is a quality of service (QoS) aware scheduling scheme for real-time (RT) services. Nevertheless, MLWDF performs below optimal among the trade-off between strict delay and loss restraints of RT and non-RT traffic flows, respectively. This is further worsened with the implementation of hybrid automatic retransmission request (HARQ). As these restraints grow unabated with increasing number of user demands, the performance of MLWDF further reduces. In order to ameliorate this situation, there is a need to directly incorporate the variations in user demands and HARQ implementation as parameters to the MLWDF scheduler. In this work, an improvement to the MLWDF scheduler is proposed. The improvement entails adding two novel parameters that characterise user demand and HARQ implementation. The scheduler was tested using varying three classes of service in QoS class identifiers (QCIs) table standardised by Third Generation Partnership Project for LTE network to characterise different services. It was also tested on the basis of packet prioritisation. The proposed scheduler was simulated with LTE-SIM simulator and compared with the MLWDF and proportional fairness schedulers. In terms of delay, throughput and packet loss ratio; the proposed scheduler increased overall system performance.

  1. Chaos in body-vortex interactions

    DEFF Research Database (Denmark)

    Pedersen, Johan Rønby; Aref, Hassan

    2010-01-01

    The model of body–vortex interactions, where the fluid flow is planar, ideal and unbounded, and the vortex is a point vortex, is studied. The body may have a constant circulation around it. The governing equations for the general case of a freely moving body of arbitrary shape and mass density...... of a circle is integrable. As the body is made slightly elliptic, a chaotic region grows from an unstable relative equilibrium of the circle-vortex case. The case of a cylindrical body of any shape moving in fluid otherwise at rest is also integrable. A second transition to chaos arises from the limit between...... and an arbitrary number of point vortices are presented. The case of a body and a single vortex is then investigated numerically in detail. In this paper, the body is a homogeneous, elliptical cylinder. For large body–vortex separations, the system behaves much like a vortex pair regardless of body shape. The case...

  2. Projeto Seis Sigma para a implementação de software de programação Six Sigma project for scheduling software implementation

    Directory of Open Access Journals (Sweden)

    Rogério Cerávolo Calia

    2005-12-01

    Full Text Available O artigo visa analisar a eficácia organizacional da metodologia Seis Sigma na gestão de projetos para a redução de atrasos e redução de estoques na manufatura, por meio da implementação de um software com algoritmos da Teoria das Restrições. Inicialmente, é apresentada uma revisão bibliográfica sobre a gestão de projetos na perspectiva da gestão da mudança organizacional nos processos de negócios. Em seguida, são revistos os conceitos sobre a metodologia Seis Sigma para a gestão de projetos e sobre os algoritmos da Teoria das Restrições. Então, são descritos os estudos de caso em dois projetos de implementação do software da Teoria das Restrições, sendo que apenas uma das implementações utilizou-se da metodologia Seis Sigma para a gestão do projeto. Na análise dos resultados, busca-se compreender os motivos de o projeto com a metodologia Seis Sigma ter reduzido inventário três vezes mais rápido do que o projeto sem o Seis Sigma.The article aims to analyze the organizational effectiveness of the Six Sigma methodology for project management to reduce delays and to reduce inventory in manufacture, by the implementation of software with Theory of Constraints algorithms. Initially, the article presents a bibliographic revision on project management and its impact on the organizational change management for improving business processes. Then, the article revises the concepts about the Six Sigma methodology for project management and about the Theory of Constraints algorithms. It follows, the case studies descriptions on two implementation projects of the Theory of Constraints software, in which only one of these implementations adopted the Six Sigma methodology in the project management. In the results analyzes, the article discusses the reasons why the project with the Six Sigma methodology was three times faster than the other project.

  3. Environmental surveillance master sampling schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, L.E.

    1994-02-01

    This document contains the planned 1994 schedules for routine collection of samples for the Surface Environmental Surveillance Project (SESP), Drinking Water Project, and Ground-Water Surveillance Project. Samples are routinely collected for the SESP and analyzed to determine the quality of air, surface water, soil, sediment, wildlife, vegetation, foodstuffs, and farm products at Hanford Site and surrounding communities. The responsibility for monitoring the onsite drinking water falls outside the scope of the SESP. The Hanford Environmental Health Foundation is responsible for monitoring the nonradiological parameters as defined in the National Drinking Water Standards while PNL conducts the radiological monitoring of the onsite drinking water. PNL conducts the drinking water monitoring project concurrent with the SESP to promote efficiency and consistency, utilize the expertise developed over the years, and reduce costs associated with management, procedure development, data management, quality control and reporting. The ground-water sampling schedule identifies ground-water sampling events used by PNL for environmental surveillance of the Hanford Site.

  4. Routing and scheduling problems

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander

    be that the objects routed have an availability time window and a delivery time window or that locations on the path have a service time window. When routing moving transportation objects such as vehicles and vessels schedules are made in connection with the routing. Such schedules represent the time for the presence...... to a destination on a predefined network, the routing and scheduling of vessels in a liner shipping network given a demand forecast to be covered, the routing of manpower and vehicles transporting disabled passengers in an airport and the vehicle routing with time windows where one version studied includes edge...... of a connection between two locations. This could be an urban bus schedule where busses are routed and this routing creates a bus schedule which the passengers between locations use. In this thesis various routing and scheduling problems will be presented. The topics covered will be routing from an origin...

  5. LDRD Report: Scheduling Irregular Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Boman, Erik G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    This LDRD project was a campus exec fellowship to fund (in part) Donald Nguyen’s PhD research at UT-Austin. His work has focused on parallel programming models, and scheduling irregular algorithms on shared-memory systems using the Galois framework. Galois provides a simple but powerful way for users and applications to automatically obtain good parallel performance using certain supported data containers. The naïve user can write serial code, while advanced users can optimize performance by advanced features, such as specifying the scheduling policy. Galois was used to parallelize two sparse matrix reordering schemes: RCM and Sloan. Such reordering is important in high-performance computing to obtain better data locality and thus reduce run times.

  6. A survey of planning and scheduling research at the NASA Ames Research Center

    Science.gov (United States)

    Zweben, Monte

    1989-01-01

    NASA Ames Research Center has a diverse program in planning and scheduling. Some research projects as well as some applications are highlighted. Topics addressed include machine learning techniques, action representations and constraint-based scheduling systems. The applications discussed are planetary rovers, Hubble Space Telescope scheduling, and Pioneer Venus orbit scheduling.

  7. Factor structure of the Positive and Negative Affect Schedule (PANAS in adult women with fibromyalgia from Southern Spain: the al-Ándalus project

    Directory of Open Access Journals (Sweden)

    Fernando Estévez-López

    2016-03-01

    Full Text Available Background: Fibromyalgia is a syndrome characterized by the presence of widespread chronic pain. People with fibromyalgia report lower levels of Positive Affect and higher levels of Negative Affect than non-fibromyalgia peers. The Positive and Negative Affect Schedule (PANAS–a widely used questionnaire to assess two core domains of affect; namely ‘Positive Affect’ and ‘Negative Affect’ –has a controversial factor structure varying across studies. The internal structure of a measurement instrument has an impact on the meaning and validity of its score. Therefore, the aim of the present study was to assess the structural construct validity of the PANAS in adult women with fibromyalgia. Methods: This population-based cross-sectional study included 442 adult women with fibromyalgia (age: 51.3 ± 7.4 years old from Andalusia (Southern Spain. Confirmatory factor analyses were conducted to test the factor structure of the PANAS. Results: A structure with two correlated factors (Positive Affect and Negative Affect obtained the best fit; S-B χ2 = 288.49, df = 155, p < .001; RMSEA = .04; 90% CI of RMSEA = (.036, .052; the best fit SRMR = .05; CFI = .96; CAIC = −810.66, respectively. Conclusions: The present study demonstrates that both Positive Affect and Negative Affect are core dimensions of affect in adult women with fibromyalgia. A structure with two correlated factors of the PANAS emerged from our sample of women with fibromyalgia from Andalusia (Southern Spain. In this model, the amount of variance shared by Positive Affect and Negative Affect was small. Therefore, our findings support to use and interpret the Positive Affect and Negative Affect subscales of the PANAS as separate factors that are associated but distinctive as well.

  8. Two vortex-blob regularization models for vortex sheet motion

    Science.gov (United States)

    Sohn, Sung-Ik

    2014-04-01

    Evolving vortex sheets generally form singularities in finite time. The vortex blob model is an approach to regularize the vortex sheet motion and evolve past singularity formation. In this paper, we thoroughly compare two such regularizations: the Krasny-type model and the Beale-Majda model. It is found from a linear stability analysis that both models have exponentially decaying growth rates for high wavenumbers, but the Beale-Majda model has a faster decaying rate than the Krasny model. The Beale-Majda model thus gives a stronger regularization to the solution. We apply the blob models to the two example problems: a periodic vortex sheet and an elliptically loaded wing. The numerical results show that the solutions of the two models are similar in large and small scales, but are fairly different in intermediate scales. The sheet of the Beale-Majda model has more spiral turns than the Krasny-type model for the same value of the regularization parameter δ. We give numerical evidences that the solutions of the two models agree for an increasing amount of spiral turns and tend to converge to the same limit as δ is decreased. The inner spiral turns of the blob models behave differently with the outer turns and satisfy a self-similar form. We also examine irregular motions of the sheet at late times and find that the irregular motions shrink as δ is decreased. This fact suggests a convergence of the blob solution to the weak solution of infinite regular spiral turns.

  9. Vortex tube reconnection at Re = 104

    Science.gov (United States)

    van Rees, Wim M.; Hussain, Fazle; Koumoutsakos, Petros

    2012-07-01

    We present simulations of the long-time dynamics of two anti-parallel vortex tubes with and without initial axial flow, at Reynolds number Re = Γ/ν = 104. Simulations were performed in a periodic domain with a remeshed vortex method using 785 × 106 particles. We quantify the vortex dynamics of the primary vortex reconnection that leads to the formation of elliptical rings with axial flow and report for the first time a subsequent collision of these rings. In the absence of initial axial flow, a -5/3 slope of the energy spectrum is observed during the first reconnection of the tubes. The resulting elliptical vortex rings experience a coiling of their vortex lines imparting an axial flow inside their cores. These rings eventually collide, exhibiting a -7/3 slope of the energy spectrum. Studies of vortex reconnection with an initial axial flow exhibit also the -7/3 slope during the initial collision as well as in the subsequent collision of the ensuing elliptical vortex rings. We quantify the detailed vortex dynamics of these collisions and examine the role of axial flow in the breakup of vortex structures.

  10. Influence of mesoscale topography on vortex intensity

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effect of mesoscale topography on multi-vortex self-organization is investigated numerically in this paper using a barotropic primitive equation model with topographic term. In the initial field there are one DeMaria major vortex with the maximum wind radius rm of 80 km at the center of the computational domain, and four meso-β vortices in the vicinity of rm to the east of the major vortex center.When there is no topography present, the initial vortices self-organize into a quasi-final state flow pattern, I.e. A quasi-axisymmetric vortex whose intensity is close to that of the initial major vortex. However, when a mesoscale topography is incorporated, the spatial scale of the quasi-final state vortex reduces, and the relative vorticity at the center of the vortex and the local maximum wind speed remarkably increase. The possible mechanism for the enhancement of the quasi-final state vortex might be that the negative relative vorticity lump,generated above the mesoscale topography because of the constraint of absolute vorticity conservation, squeezes the center of positive vorticity towards the mountain slope area, and thus reduces the spatial range of the major vortex. Meanwhile, because the total kinetic energy is basically conservative, the squeezing directly leads to the concentration of the energy in a smaller area, I.e. The strengthening of the vortex.

  11. Routine environmental monitoring schedule, calendar year 1997

    Energy Technology Data Exchange (ETDEWEB)

    Markes, B.M., Westinghouse Hanford

    1996-12-10

    This document provides the Environmental Restorations Contractor (ERC) and the Project Hanford Management Contractor.(PHMC) a schedule in accordance with the WHC-CM-7-5, Environmental Compliance` and BHI- EE-02, Environmental Requirements, of monitoring and sampling routines for the Near-Field Monitoring (NFM) program during calendar year (CY) 1997. Every attempt will be made to consistently follow this schedule; any deviation from this schedule will be documented by an internal memorandum (DSI) explaining the reason for the deviation. The DSI will be issued by the scheduled performing organization and directed to Near-Field Monitoring. The survey frequencies for particular sites are determined by the technical judgment of Near- Field Monitoring and may depend on the site history, radiological status, use, and general conditions. Additional surveys may be requested at irregular frequencies if conditions warrant. All radioactive wastes sites are scheduled to be surveyed at least annually. Any newly discovered wastes sites not documented by this schedule will be included in the revised schedule for CY 1998. The outside perimeter road surveys of 200 East and West Area and the rail survey from the 300 Area to Columbia Center will be performed in the year 2000 per agreement with Department of Energy. Richland Field Office. This schedule does not discuss staffing needs, nor does it list the monitoring equipment to be used in completing specific routines. Personnel performing routines to meet this schedule shall communicate any need for assistance in completing these routines to Radiological Control management and Near-Field Monitoring. After each routine survey is completed, a copy of the survey record, maps, and data sheets will be forwarded to Near-Field Monitoring. These routine surveys will not be considered complete until this documentation is received. At the end of each month, the ERC and PHMC radiological control organizations shall forward a copy of the Routine

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

    Directory of Open Access Journals (Sweden)

    Gh. Assadipour

    2012-01-01

    Full Text Available

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

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

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

  13. 应用P3软件加强工程进度控制%Application of P3 software to strengthen project schedule control

    Institute of Scientific and Technical Information of China (English)

    华洪; 舒景樟

    2003-01-01

    通过对上海外高桥电厂二期工程(2台进口900 MW超临界燃煤机组)中P3(Primavera Project Plan-ner)软件的实际应用,论述了在大型火电站工程中使用P3软件加强进度管理的情况,并结合实际应用,阐述了应用P3软件进行计划编制和动态控制的-些体会和应用前景.

  14. Widening the Schedulability Hierarchical Scheduling Systems

    DEFF Research Database (Denmark)

    Boudjadar, Jalil; David, Alexandre; Kim, Jin Hyun

    2014-01-01

    the supply of resources in each component. We specifically investigate two different techniques to widen the set of provably schedulable systems: 1) a new supplier model; 2) restricting the potential task offsets. We also provide a way to estimate the minimum resource supply (budget) that a component...

  15. Interval Scheduling: A Survey

    NARCIS (Netherlands)

    Kolen, A.W.J.; Lenstra, J.K.; Papadimitriou, C.H.; Spieksma, F.C.R.

    2007-01-01

    In interval scheduling, not only the processing times of the jobs but also their starting times are given. This article surveys the area of interval scheduling and presents proofs of results that have been known within the community for some time. We first review the complexity and approximability o

  16. Scheduling: Seven Period Day

    Science.gov (United States)

    Williamson, Ronald

    2010-01-01

    Driven by stable or declining financial resources many school districts are considering the costs and benefits of a seven-period day. While there is limited evidence that any particular scheduling model has a greater impact on student learning than any other, it is clear that the school schedule is a tool that can significantly impact teacher…

  17. Vortex scattering by step topography

    Science.gov (United States)

    Hinds, A. K.; Johnson, E. R.; McDonald, N. R.

    The scattering at a rectilinear step change in depth of a shallow-water vortex pair consisting of two patches of equal but opposite-signed vorticity is studied. Using the constants of motion, an explicit relationship is derived relating the angle of incidence to the refracted angle after crossing. A pair colliding with a step from deep water crosses the escarpment and subsequently propagates in shallow water refracted towards the normal to the escarpment. A pair colliding with a step from shallow water either crosses and propagates in deep water refracted away from the normal or, does not cross the step and is instead totally internally reflected by the escarpment. For large depth changes, numerical computations show that the coherence of the vortex pair is lost on encountering the escarpment.

  18. Perturbations of vortex ring pairs

    CERN Document Server

    Gubser, Steven S; Parikh, Sarthak

    2015-01-01

    We study pairs of co-axial vortex rings starting from the action for a classical bosonic string in a three-form background. We complete earlier work on the phase diagram of classical orbits by explicitly considering the case where the circulations of the two vortex rings are equal and opposite. We then go on to study perturbations, focusing on cases where the relevant four-dimensional transfer matrix splits into two-dimensional blocks. When the circulations of the rings have the same sign, instabilities are mostly limited to wavelengths smaller than a dynamically generated length scale at which single-ring instabilities occur. When the circulations have the opposite sign, larger wavelength instabilities can occur.

  19. Collisions of Vortex Filament Pairs

    Science.gov (United States)

    Banica, Valeria; Faou, Erwan; Miot, Evelyne

    2014-12-01

    We consider the problem of collisions of vortex filaments for a model introduced by Klein et al. (J Fluid Mech 288:201-248, 1995) and Zakharov (Sov Phys Usp 31(7):672-674, 1988, Lect. Notes Phys 536:369-385, 1999) to describe the interaction of almost parallel vortex filaments in three-dimensional fluids. Since the results of Crow (AIAA J 8:2172-2179, 1970) examples of collisions are searched as perturbations of antiparallel translating pairs of filaments, with initial perturbations related to the unstable mode of the linearized problem; most results are numerical calculations. In this article, we first consider a related model for the evolution of pairs of filaments, and we display another type of initial perturbation leading to collision in finite time. Moreover, we give numerical evidence that it also leads to collision through the initial model. We finally study the self-similar solutions of the model.

  20. Divergence of optical vortex beams

    CERN Document Server

    Reddy, Salla Gangi; Prabhakar, Shashi; Anwar, Ali; Banerji, J; Singh, R P

    2015-01-01

    We show, both theoretically and experimentally, that the propagation of optical vortices in free space can be analysed by using the width ($w(z)$) of the host Gaussian beam and the inner and outer radii of the vortex beam at the source plane ($z=0$) as defined in \\textit{Optics Letters \\textbf{39,} 4364-4367 (2014)}. We also studied the divergence of vortex beams, considered as the rate of change of inner or outer radius with the propagation distance, and found that it varies with the order in the same way as that of the inner and outer radii at zero propagation distance. These results may be useful in designing optical fibers for orbital angular momentum modes that play a crucial role in quantum communication.

  1. 基于时间片段的多IT项目人力资源调度问题求解%Time slice based solution for human resource scheduling problem of multiple IT projects

    Institute of Scientific and Technical Information of China (English)

    芦鹏宇; 孙文俊; 井瑞

    2012-01-01

    针对多个IT项目的人力资源调度问题,根据其在时间和人员方面的特殊要求,可以将项目的演进时间划分为相等的时间片段,然后根据特定时间片段内的活动与可选人员之间的关系,建立相应的人员调度方案搜索树.将所有时间片段内的搜索树按顺序连接后,可以得到总的方案树,并列出所有的方案,然后根据不同方案下得到的平均提前完工率和提前完工率方差,找到最优解.又为该搜索算法添加了启发规则,使搜索空间急剧收缩,极大提高了搜索效率.基于该算法的特殊性,可以将其用于求解许多具有与上述问题类似条件的资源调度问题.本研究通过实例发现,根据运算中的特殊规律,该算法还具有进一步提取启发规则的潜力.%This paper deals with the human resource scheduling problem of multiple IT projects. According to its specific requirements on time and personnel, the duration of the whole development process can be divided into equal-length time slices. Based on the relations among activities and personnel in a certain time slice, the search tree of personnel scheduling solutions can be constructed. By connecting all the search trees sequentially from all the time slices, the solution tree for the whole problem can be generated and all the solutions can be listed. Then, based on the average of advanced completion rate and the variance of advanced completion rate, the optimal solution can be found. By adding heuristic rules to this algorithm, the searching space can contract rapidly, and the searching efficiency can be enhanced greatly. In view of the particularities of this algorithm, it can be applied to many generalized resource scheduling problems that possess similar conditions with the problem described above. After applying this algorithm to a mock example, some regular patterns emerged, showing the potential that further heuristic rules can be extracted.

  2. Dust vortex flows in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, P.K

    2002-12-30

    Coherent nonlinear structures in the form of dust vortex flows have been observed in unmagnetized laboratory dusty plasmas. Our objective here is show that the dynamics of such dust vortices is governed by a modified Navier-Stokes equation (MNSE) and that the stationary solutions of the MNSE can be represented as monopolar as well as a row of identical Stuart and a row of counter-rotating vortices.

  3. Experimental characteristics of vortex heaters

    Science.gov (United States)

    Piralishvili, Sh. A.; Novikov, N. N.

    The performance of a Ranque-Hilsch vortex tube is investigated experimentally for the case where the tube operates as a heater, with the mass of the heated gas remaining constant. The results obtained indicate that energy separation zones with sufficiently high (50 percent) relative heating effects can be achieved for a gas flow ratio of unity. A nomogram is presented for calculating the relative and absolute heating effects as a function of the tube geometry.

  4. Prediction and Control of Vortex Dominated and Vortex-wake Flows

    Science.gov (United States)

    Kandil, Osama

    1996-01-01

    This report describes the activities and accomplishments under this research grant, including a list of publications and dissertations, produced in the field of prediction and control of vortex dominated and vortex wake flows.

  5. Scheduling for Responsive Grids

    CERN Document Server

    Germain-Renaud, C; Moscicki,JT; Texier, R

    2008-01-01

    Grids are facing the challenge of seamless integration of the Grid power into everyday use. One critical component for this integration is responsiveness, the capacity to support on-demand computing and interactivity. Grid scheduling is involved at two levels in order to provide responsiveness: the policy level and the implementation level. The main contributions of this paper are as follows. First, we present a detailed analysis of the performance of the EGEE Grid with respect to responsiveness. Second, we examine two user-level schedulers located between the general scheduling layer and the application layer. These are the DIANE (distributed analysis environment) framework, a general-purpose overlay system, and a specialized, embedded scheduler for gPTM3D, an interactive medical image analysis application. Finally, we define and demonstrate a virtualization scheme, which achieves guaranteed turnaround time, schedulability analysis, and provides the basis for differentiated services. Both methods target a br...

  6. An Analysis of Construction Cost and Schedule Performance

    Science.gov (United States)

    2008-03-01

    paradigm to develop project success measures. Griffith, Gibson, Hamilton, Tortora , and Wilson (1999 categorized projects by their cost, schedule, and...E., Hamilton, M. R., Tortora , A. L., & Wilson, C. T. (1999). Project success index for capital facility construction projects. Journal of

  7. Birth and evolution of an optical vortex

    CERN Document Server

    Vallone, Giuseppe; D'Ambrosio, Vincenzo; Marrucci, Lorenzo; Sciarrino, Fabio; Villoresi, Paolo

    2016-01-01

    When a phase singularity is suddenly imprinted on the axis of an ordinary Gaussian beam, an optical vortex appears and starts to grow radially, by effect of diffraction. This radial growth and the subsequent evolution of the optical vortex under focusing or imaging can be well described in general within the recently introduced theory of circular beams, which generalize the hypergeometric-Gaussian beams and which obey novel kinds of ABCD rules. Here, we investigate experimentally these vortex propagation phenomena and test the validity of circular-beam theory. Moreover, we analyze the difference in radial structure between the newly generated optical vortex and the vortex obtained in the image plane, where perfect imaging would lead to complete closure of the vortex core.

  8. Topology of Vortex-Wing Interaction

    Science.gov (United States)

    McKenna, Chris; Rockwell, Donald

    2016-11-01

    Aircraft flying together in an echelon or V formation experience aerodynamic advantages. Impingement of the tip vortex from the leader (upstream) wing on the follower wing can yield an increase of lift to drag ratio. This enhancement is known to depend on the location of vortex impingement on the follower wing. Particle image velocimetry is employed to determine streamline topology in successive crossflow planes, which characterize the streamwise evolution of the vortex structure along the chord of the follower wing and into its wake. Different modes of vortex-follower wing interaction are created by varying both the spanwise and vertical locations of the leader wing. These modes are defined by differences in the number and locations of critical points of the flow topology, and involve bifurcation, attenuation, and mutual induction. The bifurcation and attenuation modes decrease the strength of the tip vortex from the follower wing. In contrast, the mutual induction mode increases the strength of the follower tip vortex. AFOSR.

  9. Vortex rings impinging on permeable boundaries

    Science.gov (United States)

    Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen

    2015-01-01

    Experiments with vortex rings impinging permeable and solid boundaries are presented in order to investigate the influence of permeability. Utilizing Particle Image Velocimetry, we compared the behaviour of a vortex ring impinging four different reticulated foams (with permeability k ˜ 26 - 85 × 10-8 m2) and a solid boundary. Results show how permeability affects the stretching phenomena of the vortex ring and the formation and evolution of the secondary vortex ring with opposite sign. Moreover, permeability also affects the macroscopic no-slip boundary condition found on the solid boundary, turning it into an apparent slip boundary condition for the most permeable boundary. The apparent slip-boundary condition and the flux exchange between the ambient fluid and the foam are jointly responsible for both the modified formation of the secondary vortex and changes on the vortex ring diameter increase.

  10. Vortex dynamics in nonrelativistic Abelian Higgs model

    Directory of Open Access Journals (Sweden)

    A.A. Kozhevnikov

    2015-11-01

    Full Text Available The dynamics of the gauge vortex with arbitrary form of a contour is considered in the framework of the nonrelativistic Abelian Higgs model, including the possibility of the gauge field interaction with the fermion asymmetric background. The equations for the time derivatives of the curvature and the torsion of the vortex contour generalizing the Betchov–Da Rios equations in hydrodynamics, are obtained. They are applied to study the conservation of helicity of the gauge field forming the vortex, twist, and writhe numbers of the vortex contour. It is shown that the conservation of helicity is broken when both terms in the equation of the vortex motion are present, the first due to the exchange of excitations of the phase and modulus of the scalar field and the second one due to the coupling of the gauge field forming the vortex, with the fermion asymmetric background.

  11. An axisymmetric steady state vortex ring model

    CERN Document Server

    Wang, Ruo-Qian

    2016-01-01

    Based on the solution of Atanasiu et al. (2004), a theoretical model for axisymmetric vortex flows is derived in the present study by solving the vorticity transport equation for an inviscid, incompressible fluid in cylindrical coordinates. The model can describe a variety of axisymmetric flows with particular boundary conditions at a moderately high Reynolds number. This paper shows one example: a high Reynolds number laminar vortex ring. The model can represent a family of vortex rings by specifying the modulus function using a Rayleigh distribution function. The characteristics of this vortex ring family are illustrated by numerical methods. For verification, the model results compare well with the recent direct numerical simulations (DNS) in terms of the vorticity distribution and streamline patterns, cross-sectional areas of the vortex core and bubble, and radial vorticity distribution through the vortex center. Most importantly, the asymmetry and elliptical outline of the vorticity profile are well capt...

  12. Magnetism near Vortex Cores of Cuprate Superconductors

    Science.gov (United States)

    Lee, J. C.; Prudchenko, K.; Launspach, B.; Ruiz, E. J.; Boekema, C.

    2005-03-01

    We examined muon-spin-resonance (μSR) vortex data of Bi2212, Tl2223, and YBCO to search for antiferromagnetism (AF) near the vortex cores. [1] Field distributions were obtained from μSR data using Maximum-Entropy analysis. The grainboundary and vortex signals were fitted by Gaussian and Lorentzian curves, the latter suggestive of extra AF ordering. Narrow Gaussians fit the grainboundary signals well, independent of temperature. For T B17 (2003) 3436.

  13. Astronomical demonstration of an optical vortex coronagraph.

    Science.gov (United States)

    Swartzlander, Grover A; Ford, Erin L; Abdul-Malik, Rukiah S; Close, Laird M; Peters, Mary A; Palacios, David M; Wilson, Daniel W

    2008-07-07

    Using an optical vortex coronagraph and simple adaptive optics techniques, we have made the first convincing demonstration of an optical vortex coronagraph that is coupled to a star gazing telescope. We suppressed by 97% the primary star of a resolvable binary system, Cor Caroli. The stars had an angular separation of 1.9lambda/D at our imaging camera. The secondary star suffered no suppression from the vortex lens.

  14. Guidelines of Decommissioning Schedule Establishment

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jae Yong; Yun, Taesik; Kim, Younggook; Kim, Hee-Geun [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    Decommissioning has recently become an issue highlighted in Korea due to the Permanent Shutdown (PS) of Kori-1 plant. Since Korea Hydro and Nuclear Power (KHNP) Company decided the PS of Kori-1 instead of further continued operation, Kori-1 will be the first decommissioning plant of the commercial reactors in Korea. Korean regulatory authority demands Initial Decommissioning Plan (IDP) for all the plants in operation and under construction. In addition, decommissioning should be considered for the completion of the life cycle of NPPs. To date, Korea has no experience regarding decommissioning of the commercial reactor and a lot of uncertainties will be expected due to its site-specific factors. However, optimized decommissioning process schedule must be indispensable in the safety and economic efficiency of the project. Differed from USA, Korea has no experience and know-hows of the operation and site management for decommissioning. Hence, in Korea, establishment of decommissioning schedule has to give more weight to safety than precedent cases. More economical and rational schedule will be composed by collecting and analyzing the experience data and site-specific data and information as the decommissioning progresses. In a long-range outlook, KHNP having capability of NPP decommissioning will try to decommissioning business in Korea and foreign countries.

  15. VTX HyHeat Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this project Orbital Technologies Corporation (ORBITEC) will utilize its unique vortex propulsion technology to develop a high-capacity heating system to heat...

  16. The quasi-vortex-lattice method for wings with edge vortex separation

    Science.gov (United States)

    Pao, J. L.; Lan, E.

    1980-01-01

    The aerodynamic characteristics of wings with leading-edge vortex separation were predicted using a method based on a flow model with free vortex elements which are allowed to merge into a concentrated core. The calculated pressure distribution is more accurate than that predicted by methods with discrete vortex filaments alone. In addition, the computer time is reduced approximately by half.

  17. Recent Advances in Study of Oceanic Vortex

    Institute of Scientific and Technical Information of China (English)

    FU Gang; LI Li; LIU Qinyu

    2002-01-01

    In this paper, the recent advances in the study of oceanic vortex are outlined. Firstly, the previous studies on oceanic vortex are reviewed. Secondly, some prominent features of oceanic vortex in the Gulf Stream, the Kuroshio, the South China Sea and the Japan Sea regions are depicted based upon the observations and numerical modeling results. Generally, the lifetime of these oceanic vortices ranges from several weeks to several months, and their horizontal scales vary from tens of kilometers to hundreds of kilometers. Their vertical scales are on the order of thousands of meters. Finally, some theoretical studies, mainly on the splitting of a cyclonic vortex and the merging of anticyclonic vortices, are introduced.

  18. Effects of Block Scheduling

    Directory of Open Access Journals (Sweden)

    William R. Veal

    1999-09-01

    Full Text Available This study examined the effects of a tri-schedule on the academic achievement of students in a high school. The tri-schedule consists of traditional, 4x4 block, and hybrid schedules running at the same time in the same high school. Effectiveness of the schedules was determined from the state mandated test of basic skills in reading, language, and mathematics. Students who were in a particular schedule their freshman year were tested at the beginning of their sophomore year. A statistical ANCOVA test was performed using the schedule types as independent variables and cognitive skill index and GPA as covariates. For reading and language, there was no statistically significant difference in test results. There was a statistical difference mathematics-computation. Block mathematics is an ideal format for obtaining more credits in mathematics, but the block format does little for mathematics achievement and conceptual understanding. The results have content specific implications for schools, administrations, and school boards who are considering block scheduling adoption.

  19. Estimating exponential scheduling preferences

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Börjesson, Maria; Engelson, Leonid

    2015-01-01

    Different assumptions about travelers' scheduling preferences yield different measures of the cost of travel time variability. Only few forms of scheduling preferences provide non-trivial measures which are additive over links in transport networks where link travel times are arbitrarily...... of car drivers' route and mode choice under uncertain travel times. Our analysis exposes some important methodological issues related to complex non-linear scheduling models: One issue is identifying the point in time where the marginal utility of being at the destination becomes larger than the marginal...

  20. Optimizing Department of Defense Acquisition Development Test and Evaluation Scheduling

    Science.gov (United States)

    2015-06-01

    Technique PMO program management office R&D research and development RCPSP resource-constrained project scheduling problem SME subject matter...Program Management Office ( PMO ) test personnel develop test schedules manually using time estimates and heuristic subject matter expert (SME) advice...on several SMEs and PMO test personnel to develop the initial test schedule for any new acquisition. This is used to establish an initial plan for

  1. The shop floor scheduling game

    NARCIS (Netherlands)

    Riezebos, Jan; Slomp, Jannes

    1995-01-01

    The aim of the shop floor scheduling game is getting participants acquainted with: - developing robust planning and scheduling procedures; - accepting orders under uncertainty and competition; - using information from cost accounting in scheduling; - creating an adequate communication structure

  2. Evolution of the vortex state in the BCS-BEC crossover of a quasi two-dimensional superfluid Fermi gas

    Science.gov (United States)

    Luo, Xuebing; Zhou, Kezhao; Zhang, Zhidong

    2016-11-01

    We use the path-integral formalism to investigate the vortex properties of a quasi-two dimensional (2D) Fermi superfluid system trapped in an optical lattice potential. Within the framework of mean-field theory, the cooper pair density, the atom number density, and the vortex core size are calculated from weakly interacting BCS regime to strongly coupled while weakly interacting BEC regime. Numerical results show that the atoms gradually penetrate into the vortex core as the system evolves from BEC to BCS regime. Meanwhile, the presence of the optical lattice allows us to analyze the vortex properties in the crossover from three-dimensional (3D) to 2D case. Furthermore, using a simple re-normalization procedure, we find that the two-body bound state exists only when the interaction is stronger than a critical one denoted by G c which is obtained as a function of the lattice potential’s parameter. Finally, we investigate the vortex core size and find that it grows with increasing interaction strength. In particular, by analyzing the behavior of the vortex core size in both BCS and BEC regimes, we find that the vortex core size behaves quite differently for positive and negative chemical potentials. Project supported by the National Natural Science Foundation of China (Grant Nos. 51331006, 51590883, and 11204321) and the Project of Chinese Academy of Sciences (Grant No. KJZD-EW-M05-3).

  3. Numerical study of asymmetrical modes in a vortex ring impacting a conical surface

    Science.gov (United States)

    Trejo Gutierrez, Jose Antonio; Lopez Sanchez, Erick Javier; Hernandez Zapata, Sergio; Ruiz Chavarria, Gerardo

    2016-11-01

    In this work we investigate the impact of an annular vortex on a conical surface when their symmetry axes are parallel but they do not coincide. For this purpose we solve the Navier-Stokes and continuity equations in cylindrical coordinates. We use a finite difference scheme for r and z coordinates whereas for the angular coordinate we use a Fourier spectral method. We study the development of asymmetrical modes when the vortex approaches the inner surface of the cone. The presence of the vortex ring induces the formation of a boundary layer which detaches and leads to the formation of a secondary vortex of opposite sign which moves away the cone. This secondary vortex also exhibits asymmetrical modes, which are attenuated as it moves. We present some results as the trajectories of the primary and the secondary vortices, their circulations as a function of time, the development of asymmetrical modes and the dependence of these properties on the Reynolds number and the distance between both symmetry axes. Finally we made a comparison of primary and secondary vortices with a free vortex. Authors acknowledge DGAPA-UNAM by support under project IN115315 "Ondas y estructuras coherentes en dinamica de fluidos".

  4. Rotating hot-wire investigation of the vortex responsible for blade-vortex interaction noise

    Science.gov (United States)

    Fontana, Richard Remo

    1988-01-01

    This distribution of the circumferential velocity of the vortex responsible for blade-vortex interaction noise was measured using a rotating hot-wire rake synchronously meshed with a model helicopter rotor at the blade passage frequency. Simultaneous far-field acoustic data and blade differential pressure measurements were obtained. Results show that the shape of the measured far-field acoustic blade-vortex interaction signature depends on the blade-vortex interaction geometry. The experimental results are compared with the Widnall-Wolf model for blade-vortex interaction noise.

  5. Vortex diffusion and vortex-line hysteresis in radial quantum turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Saluto, L., E-mail: lidia.saluto@unipa.it [DEIM, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Jou, D., E-mail: david.jou@uab.es [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Mongiovi, M.S., E-mail: m.stella.mongiovi@unipa.it [DEIM, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2014-05-01

    We study the influence of vortex diffusion on the evolution of inhomogeneous quantized vortex tangles. A simple hydrodynamical model to describe inhomogeneous counterflow superfluid turbulence is used. As an illustration, we obtain solutions for these effects in radial counterflow of helium II between two concentric cylinders at different temperatures. The vortex diffusion from the inner hotter cylinder to the outer colder cylinder increases the vortex length density everywhere as compared with the non-diffusive situation. The possibility of hysteresis in the vortex line density under cyclical variations of the heat flow is explored.

  6. ALGORITHM FOR SOLVING EXTREME SCHEDULING PROBLEMS

    OpenAIRE

    Gennady A. Berketov

    2015-01-01

    The article considers the original algorithmfor solving the generalized problem ofscheduling theory, based on the branch and bound method. Task schedulingperform works (operations) and restrictions on resources used often occur with scheduling discrete manufacturing operations, optimizing network implementationschedules of scientific, economic or technical projects. Tools to solve suchproblems are included in the decisionsupport system ACS in many businesses.The effectiveness of the proposed ...

  7. Resource constrained multi-project scheduling modeling under certainty and uncertainty duration%工期确定及可变工期下的受限资源多项目调度建模

    Institute of Scientific and Technical Information of China (English)

    胡文斌; 乐宇; 许龙; 王凯凯; 夏畅; 杜博; 宋伟

    2012-01-01

    针对不确定性工期问题的研究方法无法正确和清晰地描述工序状态变化、只能近似求解的现象,提出一种扩展Petri网建模方法,对工期确定和可变工期受限资源多项目调度问题进行建模。该方法将托肯分为逻辑托肯与资源托肯,托肯的转移分别表示任务的执行和资源的分配。通过对库所和变迁的分类以及对库所的赋时,将库所分为活动库所、资源库所、等待库所和终极库所,将变迁分为协调变迁、资源调度变迁和资源释放变迁。等待库所和活动库所通过协调变迁连接反映任务之间的时序关系,通过资源库所、资源调度变迁与资源释放变迁,反映任务之间对资源的竞争、占用和释放。对于可变工期问题,通过增加库所和变迁种类以及修改变迁触发规则来描述实际系统。采用PSPLIBlibrary中的实例对提出的建模方法进行模型求解成功率分析、模型求解适应度能力分析和对比性实验分析表明,所提方法比其他方法具有更好的求解能力和表现,并通过一个实际工程应用求解验证了建模方法的有效性。%Uncertain project duration method couldn't describe state changes in sequence accurately and explicitly, there was only approximate solution. In order to deal with this problem, a modeling method by extending Petri net was proposed. Scheduling problems in resource-constrained projects with definite duration and changeable duration were modeled. This method classified tokens into logic token and resource token, and token's transformation repre- sented the task execution as well as resource allocation respectively. Through classifying place, transitions and timed place, the places were divided into activity place, resource place, waiting place, and final place, and transitions were divided into coordination transition, resource scheduling transition and resource releasing transition. Through coor

  8. Hanford Site Environmental Surveillance Master Sampling Schedule

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2002-01-16

    Environmental surveillance of the Hanford Site and surrounding areas is conducted by Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE). Sampling is conducted to evaluate levels of radioactive and nonradioactive pollutants in the Hanford environs. The document contains the CY 2002 schedules for the routine collection of samples for the Surface Environmental Surveillance Project (SESP) and Drinking Water Monitoring Project.

  9. DMEPOS Fee Schedule

    Data.gov (United States)

    U.S. Department of Health & Human Services — The list contains the fee schedule amounts, floors, and ceilings for all procedure codes and payment category, jurisdication, and short description assigned to each...

  10. Estimating exponential scheduling preferences

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Börjesson, Maria; Engelson, Leonid

    time by maximising expected total utility over the day, their departure times are conditional on rates of utility derived at these locations. For forecasting and economic evaluation of planning alternatives, it is desirable to have simple forms of utility rates with few parameters. Several forms...... the travel time is random, Noland and Small (1995) suggested using expected utility theory to derive the reduced form of expected travel time cost that includes the cost of TTV. For the α-β-γ formulation of scheduling preferences and exponential or uniform distribution of travel time, Noland and Small (1995....... The purpose of this paper is to explore how well these scheduling preferences explain behaviour, compared to other possible scheduling models, and whether empirical estimation of the more complex exponential scheduling preferences is feasible. We use data from a stated preference survey conducted among car...

  11. CERN confirms LHC schedule

    CERN Multimedia

    2003-01-01

    The CERN Council held its 125th session on 20 June. Highlights of the meeting included confirmation that the LHC is on schedule for a 2007 start-up, and the announcement of a new organizational structure in 2004.

  12. Decentralized Ground Staff Scheduling

    DEFF Research Database (Denmark)

    Sørensen, M. D.; Clausen, Jens

    2002-01-01

    Typically, ground staff scheduling is centrally planned for each terminal in an airport. The advantage of this is that the staff is efficiently utilized, but a disadvantage is that staff spends considerable time walking between stands. In this paper a decentralized approach for ground staff...... scheduling is investigated. The airport terminal is divided into zones, where each zone consists of a set of stands geographically next to each other. Staff is assigned to work in only one zone and the staff scheduling is planned decentralized for each zone. The advantage of this approach is that the staff...... work in a smaller area of the terminal and thus spends less time walking between stands. When planning decentralized the allocation of stands to flights influences the staff scheduling since the workload in a zone depends on which flights are allocated to stands in the zone. Hence solving the problem...

  13. Clinical Laboratory Fee Schedule

    Data.gov (United States)

    U.S. Department of Health & Human Services — Outpatient clinical laboratory services are paid based on a fee schedule in accordance with Section 1833(h) of the Social Security Act. The clinical laboratory fee...

  14. Estimating exponential scheduling preferences

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Börjesson, Maria; Engelson, Leonid

    time by maximising expected total utility over the day, their departure times are conditional on rates of utility derived at these locations. For forecasting and economic evaluation of planning alternatives, it is desirable to have simple forms of utility rates with few parameters. Several forms...... the travel time is random, Noland and Small (1995) suggested using expected utility theory to derive the reduced form of expected travel time cost that includes the cost of TTV. For the α-β-γ formulation of scheduling preferences and exponential or uniform distribution of travel time, Noland and Small (1995....... The purpose of this paper is to explore how well these scheduling preferences explain behaviour, compared to other possible scheduling models, and whether empirical estimation of the more complex exponential scheduling preferences is feasible. We use data from a stated preference survey conducted among car...

  15. Fee Schedules - General Information

    Data.gov (United States)

    U.S. Department of Health & Human Services — A fee schedule is a complete listing of fees used by Medicare to pay doctors or other providers-suppliers. This comprehensive listing of fee maximums is used to...

  16. Physician Fee Schedule Search

    Data.gov (United States)

    U.S. Department of Health & Human Services — This website is designed to provide information on services covered by the Medicare Physician Fee Schedule (MPFS). It provides more than 10,000 physician services,...

  17. CMS Records Schedule

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CMS Records Schedule provides disposition authorizations approved by the National Archives and Records Administration (NARA) for CMS program-related records...

  18. Resource Minimization Job Scheduling

    Science.gov (United States)

    Chuzhoy, Julia; Codenotti, Paolo

    Given a set J of jobs, where each job j is associated with release date r j , deadline d j and processing time p j , our goal is to schedule all jobs using the minimum possible number of machines. Scheduling a job j requires selecting an interval of length p j between its release date and deadline, and assigning it to a machine, with the restriction that each machine executes at most one job at any given time. This is one of the basic settings in the resource-minimization job scheduling, and the classical randomized rounding technique of Raghavan and Thompson provides an O(logn/loglogn)-approximation for it. This result has been recently improved to an O(sqrt{log n})-approximation, and moreover an efficient algorithm for scheduling all jobs on O((OPT)^2) machines has been shown. We build on this prior work to obtain a constant factor approximation algorithm for the problem.

  19. PAR Loop Schedule Review

    Energy Technology Data Exchange (ETDEWEB)

    Schaffer, Jr.; W.F.

    1958-04-30

    The schedule for the installation of the PAR slurry loop experiment in the South Facility of the ORR has been reviewed and revised. The design, fabrications and Installation is approximately two weeks behind schedule at this time due to many factors; however, indications are that this time can be made up. Design is estimated to be 75% complete, fabrication 32% complete and installation 12% complete.

  20. Pinch-off of axisymmetric vortex pairs in the limit of vanishing vortex line curvature

    Science.gov (United States)

    Sadri, V.; Krueger, P. S.

    2016-07-01

    Pinch-off of axisymmetric vortex pairs generated by flow between concentric cylinders with radial separation ΔR was studied numerically and compared with planar vortex dipole behavior. The axisymmetric case approaches planar vortex dipole behavior in the limit of vanishing ΔR. The flow was simulated at a jet Reynolds number of 1000 (based on ΔR and the jet velocity), jet pulse length-to-gap ratio ( /L Δ R ) in the range 10-20, and gap-to-outer radius ratio ( /Δ R R o ) in the range 0.01-0.1. Contrary to investigations of strictly planar flows, vortex pinch-off was observed for all gap sizes investigated. This difference was attributed to the less constrained geometry considered, suggesting that even very small amounts of vortex line curvature and/or vortex stretching may disrupt the absence of pinch-off observed in strictly planar vortex dipoles.

  1. ATLAS construction schedule

    CERN Multimedia

    Kotamaki, M

    The goal during the last few months has been to freeze and baseline as much as possible the schedules of various ATLAS systems and activities. The main motivations for the re-baselining of the schedules have been the new LHC schedule aiming at first collisions in early 2006 and the encountered delays in civil engineering as well as in the production of some of the detectors. The process was started by first preparing a new installation schedule that takes into account all the new external constraints and the new ATLAS staging scenario. The installation schedule version 3 was approved in the March EB and it provides the Ready For Installation (RFI) milestones for each system, i.e. the date when the system should be available for the start of the installation. TCn is now interacting with the systems aiming at a more realistic and resource loaded version 4 before the end of the year. Using the new RFI milestones as driving dates a new summary schedule has been prepared, or is under preparation, for each system....

  2. Simulations of Active Vortex Generators

    Science.gov (United States)

    Mansour, N. N.; Koumoutsakos, P.; Merriam, Marshal (Technical Monitor)

    1996-01-01

    We are interested in the study, via numerical simulations, of active vortex generators. Vortex generators may be used to modify the inner part of the boundary layer or to control separation thus enhancing the performance and maneuverability of aerodynamic configurations. We consider generators that consist of a surface cavity elongated in the streamwise direction and partially covered with a moving lid that at rest lies flush with the boundary. Streamwise voracity is generated and ejected due to the oscillatory motion of the lid. The present simulations c Implement relevant experimental investigations of active vortex generators that have been conducted at NASA Ames Research Center and Stanford University. Jacobson and Reynolds used a piezoelectric device in water, allowing for small amplitude high frequency oscillations. They placed the lid asymmetrically on the cavity and observed a strong outward velocity at the small gap of the cavity. Saddoughi used a larger mechanically driven device in air to investigate this flow and observed a jet emerging from the wide gap of the configuration, contrary to the findings of Jacobson and Reynolds. More recently, Lachowiez and Wlezien are investigating the flow generated by an electro-mechanically driven lid to be used for assertion control in aerodynamic applications. We are simulating the flows generated by these devices and we are conducting a parametric study that would help us elucidate the physical mechanisms present in the flow. Conventional computational schemes encounter difficulties when simulating flows around complex configurations undergoing arbitrary motions. Here we present a formulation that achieves this task on a purely Lagrangian frame by extending the formulation presented by Koumoutsakos, Leonard and Pepin. The viscous effects are taken into account by modifying the strength of the particles, whereas fast multipole schemes employing hundreds of thousands ol'particle's allow for high resolution simulations

  3. Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes.

    Science.gov (United States)

    Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Néstor

    2012-10-20

    In this work, we introduce an alternative method of analysis in vortex metrology based on the application of the Fourier optics techniques. The first part of the procedure is conducted as is usual in vortex metrology for uniform in-plane displacement determination. On the basis of two recorded intensity speckled distributions, corresponding to two states of a diffuser coherently illuminated, we numerically generate an analytical signal from each recorded intensity pattern by using a version of the Riesz integral transform. Then, from each analytical signal, a two-dimensional pseudophase map is generated in which the vortices are located and characterized in terms of their topological charges and their core's structural properties. The second part of the procedure allows obtaining Young's interference fringes when Fourier transforming the light passing through a diffracting mask with multiple apertures at the locations of the homologous vortices. In fact, we use the Fourier transform as a mathematical operation to compute the far-field diffraction intensity pattern corresponding to the multiaperture set. Each aperture from the set is associated with a rectangular hole that coincides both in shape and size with a pixel from recorded images. We show that the fringe analysis can be conducted as in speckle photography in an extended range of displacement measurements. Effects related with speckled decorrelation are also considered. Our experimental results agree with those of speckle photography in the range in which both techniques are applicable.

  4. Delaying vortex breakdown by waves

    Science.gov (United States)

    Yao, M. F.; Jiang, L. B.; Wu, J. Z.; Ma, H. Y.; Pan, J. Y.

    1989-03-01

    The effect of spiral waves on delaying vortex breakdown in a tube is studied experimentally and theoretically. When a harmonic oscillation was imposed on one of guiding vanes in the tube, the breakdown was observed to be postponed appreciately. According to the generalized Lagrangian mean theory, proper forcing spiral waves may produce an additional streaming momentum, of which the effect is favorable and similar to an axial suction at downstream end. The delayed breakdown position is further predicted by using nonlinear wave theory. Qualitative agreement between theory and experiment is obtained, and experimental comparison of the effects due to forcing spiral wave and axial suction is made.

  5. Anatomy of a bathtub vortex.

    Science.gov (United States)

    Andersen, A; Bohr, T; Stenum, B; Rasmussen, J Juul; Lautrup, B

    2003-09-05

    We present experiments and theory for the "bathtub vortex," which forms when a fluid drains out of a rotating cylindrical container through a small drain hole. The fast down-flow is found to be confined to a narrow and rapidly rotating "drainpipe" from the free surface down to the drain hole. Surrounding this drainpipe is a region with slow upward flow generated by the Ekman layer at the bottom of the container. This flow structure leads us to a theoretical model similar to one obtained earlier by Lundgren [J. Fluid Mech. 155, 381 (1985)

  6. Formation of Ion Phase-Space Vortexes

    DEFF Research Database (Denmark)

    Pécseli, Hans; Trulsen, J.; Armstrong, R. J.

    1984-01-01

    The formation of ion phase space vortexes in the ion two stream region behind electrostatic ion acoustic shocks are observed in a laboratory experiment. A detailed analysis demonstrates that the evolution of such vortexes is associated with ion-ion beam instabilities and a nonlinear equation for ...

  7. Tight Focusing of Partially Coherent Vortex Beams

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Singh

    2012-01-01

    Full Text Available Tight focusing of partially polarized vortex beams has been studied. Compact form of the coherence matrix has been derived for polarized vortex beams. Effects of topological charge and polarization distribution of the incident beam on intensity distribution, degree of polarization, and coherence have been investigated.

  8. The linear stability of swirling vortex rings

    Science.gov (United States)

    Gargan-Shingles, C.; Rudman, M.; Ryan, K.

    2016-11-01

    The stability of vortex rings with an azimuthal component of velocity is investigated numerically for various combinations of ring wavenumber and swirl magnitude. The vortex rings are equilibrated from an initially Gaussian distribution of azimuthal vorticity and azimuthal velocity, at a circulation-based Reynolds number of 10 000, to a state in which the vortex core is qualitatively identical to that of the piston generated vortex rings. The instability modes of these rings can be characterised as Kelvin instability modes, analogous to instability modes observed for Gaussian and Batchelor vortex pairs. The shape of an amplified mode typically depends only on the azimuthal wavenumber at the centre of the vortex core and the magnitude of the corresponding velocity component. The wavenumber of a particular sinuous instability varies with radius from the vortex ring centre for rings of finite aspect ratio. Thicker rings spread the amplification over a wider range of wavenumbers for a particular resonant mode pair, while the growth rate and the azimuthal wavenumber corresponding to the peak growth both vary as a function of the wavenumber variation. Normalisation of the wavenumber and the growth rate by a measure of the wavenumber variation allows a coherent description of stability modes to be proposed, across the parameter space. These results provide a framework for predicting the development of resonant Kelvin instabilities on vortex rings with an induced component of swirling velocity.

  9. Ring vortex solitons in nonlocal nonlinear media

    DEFF Research Database (Denmark)

    Briedis, D.; Petersen, D.E.; Edmundson, D.;

    2005-01-01

    or higher charge fundamental vortices as well as higher order (multiple ring) vortex solitons. Our results pave the way for experimental observation of stable vortex rings in other nonlocal nonlinear systems including Bose-Einstein condensates with pronounced long-range interparticle interaction....

  10. An investigation of the vortex method

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, Jr., Duaine Wright [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    The vortex method is a numerical scheme for solving the vorticity transport equation. Chorin introduced modern vortex methods. The vortex method is a Lagrangian, grid free method which has less intrinsic diffusion than many grid schemes. It is adaptive in the sense that elements are needed only where the vorticity is non-zero. Our description of vortex methods begins with the point vortex method of Rosenhead for two dimensional inviscid flow, and builds upon it to eventually cover the case of three dimensional slightly viscous flow with boundaries. This section gives an introduction to the fundamentals of the vortex method. This is done in order to give a basic impression of the previous work and its line of development, as well as develop some notation and concepts which will be used later. The purpose here is not to give a full review of vortex methods or the contributions made by all the researchers in the field. Please refer to the excellent review papers in Sethian and Gustafson, chapters 1 Sethian, 2 Hald, 3 Sethian, 8 Chorin provide a solid introduction to vortex methods, including convergence theory, application in two dimensions and connection to statistical mechanics and polymers. Much of the information in this review is taken from those chapters, Chorin and Marsden and Batchelor, the chapters are also useful for their extensive bibliographies.

  11. Vortex attraction and the formation of sunspots

    Science.gov (United States)

    Parker, E. N.

    1992-01-01

    A downdraft vortex ring in a stratified atmosphere exhibits universal attraction for nearby vertical magnetic flux bundles. It is speculated that the magnetic fields emerging through the surface of the sun are individually encircled by one or more subsurface vortex rings, providing an important part of the observed clustering of magnetic fibrils to form pores and sunspots.

  12. Investigation of Wake-Vortex Aircraft Encounters

    Science.gov (United States)

    Smith, Sonya T.

    1999-01-01

    The National Aeronautics and Space Administration is addressing airport capacity enhancements during instrument meteorological conditions though the Terminal Area Productivity (TAP) program. The major goal of the TAP program is to develop the technology that will allow air traffic levels during instrument meteorological condition to approach those achieved during visual operations. The Reduced Spacing Operations (RSO) subelement of TAP at the NASA Langley Research Center (LaRC) will develop the Aircraft Vortex Spacing System (AVOSS). The purpose of the AVOSS is to integrate current and predicted weather conditions, wake vortex transport and decay knowledge, wake vortex sensor data, and operational definitions of acceptable strengths for vortex encounters to produce dynamic wake vortex separation criteria. The proposed research is in support of the wake vortex hazard definition component of the LaRC AVOSS development research. The research program described in the next section provided an analysis of the static test data and uses this data to evaluate the accuracy vortex/wake-encounter models. The accuracy of these models has not before been evaluated using experimental data. The research results also presented the first analysis of the forces and moments imparted on an airplane during a wake vortex encounter using actual flight test data.

  13. On a few Aspects of Vortex Motion

    Directory of Open Access Journals (Sweden)

    Prantik Sinha

    2013-08-01

    Full Text Available Intricacies of vortex motion have been drawing the attention of scientists for many years. A number of works both experimental and numerical have been conducted to understand the various features of vortex motion and its effects on drag, etc. In the present experimental work we have made an attempt to visualize the patterns of both Forced and Free vortex motion. Here colored die has been used to understand the profiles and an arrow shaped strip marks the difference between irrotational and rotational flow. In the Forced vortex motion it has been observed that the parabolic profile remains invariant with the flow rate (speed of paddle, height of the lowest point of the profile decreases with the increase in flow rate (paddle speed. In the Free Vortex motion observations, the hyperbolic profile doesn’t change with the change in flow rate. In this case, suction is created towards the centre where as in the case of Force vortex no such suction arises. With the reduction in the size of the orifice diameter, the profile becomes less steep for Free vortex. In this case the velocity profile in the core region is straight, as the radius increases the profile becomes rectangular hyperbola where as in the case of Forced vortex the velocity profile maintains its linear nature for the entire range of radii.

  14. The bathtub vortex in a rotating container

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Bohr, Tomas; Stenum, B.

    2006-01-01

    We study the time-independent free-surface flow which forms when a fluid drains out of a container, a so-called bathtub vortex. We focus on the bathtub vortex in a rotating container and describe the free-surface shape and the complex flow structure using photographs of the free surface, flow...

  15. EXPERIMENTAL AND NUMERICAL INVESTIGATION OF FREE SURFACE VORTEX

    Institute of Scientific and Technical Information of China (English)

    LI Hai-feng; CHEN Hong-xun; MA Zheng; ZHOU Yi

    2008-01-01

    An experimental model was set up to investigate the formation and evolution of the free surface vortex. A Particle Image Velocimetry (PIV) was used to measure the free surface vortex flow field at different development stages. Flow visualization was used to locate the vortex position and find its structure. Empirical formulas about the critical submergence and the whole field structure were obtained. It is found that the tangential velocity distribution is similar to that of the Rankine vortex and the radial velocity changes little in the vortex functional scope. Vortex starts from the free surface and gradually intensifies to air entrainment vortex. The vortex core moves during the formation and evolution of the free surface vortex. Based on the experimental model, the vortex position and structure were predicted by numerical simulation combined with a vortex model and compared with that of the experiments, which shows satisfactory agreement.

  16. Bifurcation and instability problems in vortex wakes

    Energy Technology Data Exchange (ETDEWEB)

    Aref, H [Center for Fluid Dynamics and Department of Physics, Technical University of Denmark, Kgs. Lyngby, DK-2800 (Denmark); Broens, M [Center for Fluid Dynamics and Department of Mathematics, Technical University of Denmark, Kgs. Lyngby, DK-2800 (Denmark); Stremler, M A [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2007-04-15

    A number of instability and bifurcation problems related to the dynamics of vortex wake flows are addressed using various analytical tools and approaches. We discuss the bifurcations of the streamline pattern behind a bluff body as a vortex wake is produced, a theory of the universal Strouhal-Reynolds number relation for vortex wakes, the bifurcation diagram for 'exotic' wake patterns behind an oscillating cylinder first determined experimentally by Williamson and Roshko, and the bifurcations in topology of the streamlines pattern in point vortex streets. The Hamiltonian dynamics of point vortices in a periodic strip is considered. The classical results of von Karman concerning the structure of the vortex street follow from the two-vortices-in-a-strip problem, while the stability results follow largely from a four-vortices-in-a-strip analysis. The three-vortices-in-a-strip problem is argued to be relevant to the wake behind an oscillating body.

  17. Bifurcation and instability problems in vortex wakes

    DEFF Research Database (Denmark)

    Aref, Hassan; Brøns, Morten; Stremler, Mark A.

    2007-01-01

    A number of instability and bifurcation problems related to the dynamics of vortex wake flows are addressed using various analytical tools and approaches. We discuss the bifurcations of the streamline pattern behind a bluff body as a vortex wake is produced, a theory of the universal Strouhal......-Reynolds number relation for vortex wakes, the bifurcation diagram for "exotic" wake patterns behind an oscillating cylinder first determined experimentally by Williamson & Roshko, and the bifurcations in topology of the streamlines pattern in point vortex streets. The Hamiltonian dynamics of point vortices...... in a periodic strip is considered. The classical results of von Kármán concerning the structure of the vortex street follow from the two-vortices-in-a-strip problem, while the stability results follow largely from a four-vortices-in-a-strip analysis. The three-vortices-in-a-strip problem is argued...

  18. 基于联合视角的项目支付问题及其模拟退火启发式算法%Joint Perspective Based Project Payment Scheduling Problem and Its Simulated Annealing Heuristic Algorithm

    Institute of Scientific and Technical Information of China (English)

    任世科; 何正文; 徐渝

    2012-01-01

    This paper involves the project payment scheduling problem from a joint perspective of two parties of contract. In this problem, payments are attached to events and the task is to arrange payment events, performing mode of activities, and occurrence time of events reasonably so as to maximize the joint revenue of the two parties and make them willing to accept the relative arrangement in the meantime. On the basis of the identification of the problem, the optimization model composed of two submodels is constructed. It. view of the strong NP-hardness of the problem, a simulated annealing heuristic algorithm which consists of two modules is developed. The algorithm is tested on a data set of standard instances generated randomly and the result shows that it is an efficient algorithm for the problem studied. Ultimately, an example is utilized to illustrate the significance of the study and the following conclusion is drawn: If the two parties of contract make decisions according to their own preference, they will get an outcome which is bad for both parties. However, if they take a cooperative attitude and coordinate with each other, they will obtain more profits from the project. The research in this paper can provide decision supports for the two parties of contract in the negotiation on project payment scheduling.%从合同双方的联合视角出发,研究项目支付进度问题。其中,支付与项目事件相联系,任务是合理地安排支付事件、活动执行模式及事件发生时间,以使合同双方的共同收益最大化并使二者都能接受相应的安排。在对问题进行界定的基础上,构建由两个子模型构成的优化模型。针对问题的强NP-hard属性,设计包含两个子模块的模拟退火启发式算法,并在随机生成的标准算例集合上对算法进行测试,结果表明,该算法是求解问题的有效算法。最后,用一个算例对研究进行说明,得到如下结论:如果合同双方均按自身

  19. Introduction to Vortex Lattice Theory

    Directory of Open Access Journals (Sweden)

    Santiago Pinzón

    2015-10-01

    Full Text Available Panel methods have been widely used in industry and are well established since the 1970s for aerodynamic analysis and computation. The Vortex Lattice Panel Method presented in this study comes across a sophisticated method that provides a quick solution time, allows rapid changes in geometry and suits well for aerodynamic analysis. The aerospace industry is highly competitive in design efficiency, and perhaps one of the most important factors on airplane design and engineering today is multidisciplinary optimization.  Any cost reduction method in the design cycle of a product becomes vital in the success of its outcome. The subsequent sections of this article will further explain in depth the theory behind the vortex lattice method, and the reason behind its selection as the method for aerodynamic analysis during preliminary design work and computation within the aerospace industry. This article is analytic in nature, and its main objective is to present a mathematical summary of this widely used computational method in aerodynamics.

  20. The VORTEX coronagraphic test bench

    CERN Document Server

    Jolivet, Aissa; Huby, Elsa; Absil, Olivier; Delacroix, Christian; Mawet, Dimitri; Surdej, Jean; Habraken, Serge

    2016-01-01

    In this paper, we present the infrared coronagraphic test bench of the University of Li\\`ege named VODCA (Vortex Optical Demonstrator for Coronagraphic Applications). The goal of the bench is to assess the performances of the Annular Groove Phase Masks (AGPMs) at near- to mid-infrared wavelengths. The AGPM is a subwavelength grating vortex coronagraph of charge two (SGVC2) made out of diamond. The bench is designed to be completely achromatic and will be composed of a super continuum laser source emitting in the near to mid-infrared, several parabolas, diaphragms and an infrared camera. This way, we will be able to test the different AGPMs in the M, L, K and H bands. Eventually, the bench will also allow the computation of the incident wavefront aberrations on the coronagraph. A reflective Lyot stop will send most of the stellar light to a second camera to perform low-order wavefront sensing. This second system coupled with a deformable mirror will allow the correction of the wavefront aberrations. We also ai...

  1. Vortex dynamics in $R^4$

    CERN Document Server

    Shashikanth, Banavara N

    2011-01-01

    The vortex dynamics of Euler's equations for a constant density fluid flow in $R^4$ is studied. Most of the paper focuses on singular Dirac delta distributions of the vorticity two-form $\\omega$ in $R^4$. These distributions are supported on two-dimensional surfaces termed {\\it membranes} and are the analogs of vortex filaments in $R^3$ and point vortices in $R^2$. The self-induced velocity field of a membrane is shown to be unbounded and is regularized using a local induction approximation (LIA). The regularized self-induced velocity field is then shown to be proportional to the mean curvature vector field of the membrane but rotated by 90 degrees in the plane of normals. Next, the Hamiltonian membrane model is presented. The symplectic structure for this model is derived from a general formula for vorticity distributions due to Marsden and Weinstein (1983). Finally, the dynamics of the four-form $\\omega \\wedge \\omega$ is examined. It is shown that Ertel's vorticity theorem in $R^3$, for the constant density...

  2. Vortex bursting and tracer transport of a counter-rotating vortex pair

    Science.gov (United States)

    Misaka, T.; Holzäpfel, F.; Hennemann, I.; Gerz, T.; Manhart, M.; Schwertfirm, F.

    2012-02-01

    Large-eddy simulations of a coherent counter-rotating vortex pair in different environments are performed. The environmental background is characterized by varying turbulence intensities and stable temperature stratifications. Turbulent exchange processes between the vortices, the vortex oval, and the environment, as well as the material redistribution processes along the vortex tubes are investigated employing passive tracers that are superimposed to the initial vortex flow field. It is revealed that the vortex bursting phenomenon, known from photos of aircraft contrails or smoke visualization, is caused by collisions of secondary vortical structures traveling along the vortex tube which expel material from the vortex but do not result in a sudden decay of circulation or an abrupt change of vortex core structure. In neutrally stratified and weakly turbulent conditions, vortex reconnection triggers traveling helical vorticity structures which is followed by their collision. A long-lived vortex ring links once again establishing stable double rings. Key phenomena observed in the simulations are supported by photographs of contrails. The vertical and lateral extents of the detrained passive tracer strongly depend on environmental conditions where the sensitivity of detrainment rates on initial tracer distributions appears to be low.

  3. The method to control the submarine horseshoe vortex by breaking the vortex core

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-hua; XIONG Ying; TU Cheng-xu

    2014-01-01

    The quality of the inflow across the propeller is closely related with the hydrodynamic performance and the noise characteristics of the propeller. For a submarine, with a horseshoe vortex generated at the junction of the main body and the appendages, the submarine wake is dominated by a kind of highly non-uniform flow field, which has an adverse effect on the performance of the submarine propeller. In order to control the horseshoe vortex and improve the quality of the submarine wake, the flow field around a submarine model is simulated by the detached eddies simulation (DES) method, and the vortex configuration is displayed using the second invariant of the velocity derivative tensor. The state and the transition process of the horseshoe vortex are analyzed, then a modified method to break the vortex core by a vortex baffle is proposed. The flow numerical simulation is carried out to study the effect of this method. Numerical simulations show that, with the breakdown of the vortex core, many unstable vortices are shed and the energy of the horseshoe vortex is dissipated quickly, and the uniformity of the submarine wake is improved. The submarine wake test in a wind tunnel has verified the effect of the method to control the horseshoe vortex. The vortex baffle can improve the wake uniformity in cases of high Reynolds numbers as well, and it does not have adverse effects on the maneuverability and the speed ability of the submarine.

  4. The Effect of Mounting Vortex Generators on the DTU 10MW Reference Wind Turbine Blade

    DEFF Research Database (Denmark)

    Skrzypinski, Witold Robert; Gaunaa, Mac; Bak, Christian

    2014-01-01

    The aim of the current work is to analyze possible advantages of mounting Vortex Generators (VG's) on a wind turbine blade. Specifically, the project aims at investigating at which radial sections of the DTU 10 MW Reference Wind Turbine blade it is most beneficial to mount the VG's in order...

  5. Simulation of external flows using a hybrid particle mesh vortex method

    DEFF Research Database (Denmark)

    Spietz, Henrik; Hejlesen, Mads Mølholm; Walther, Jens Honore

    The long-term goal of this project is to develop and apply state-of-the-art simulation software to enable accurate prediction of fluid structure interaction, specifically vortex-induced-vibration and flutter of long-span suspension bridges to avoid error-prone structural designs. In the following...

  6. A Discussion on Application of P3 Project Scheduling Software in Large Power Plant Project%大型火电站工程建设应用P3进度管理的探讨

    Institute of Scientific and Technical Information of China (English)

    沈石楠

    2000-01-01

    介绍了大型火电站建设中应用Primavera,Project,Planner(P3项目进度管理软件)的优点、工程管理的模式和层次,详细介绍了3级进度计划的具体内容,根据上海电力建设公司的实际情况,应用P3软件编制了一个大型火电站2级进度计划,有4个图例.

  7. The robust schedule - a link to improved workflow

    DEFF Research Database (Denmark)

    Lindhard, Søren Munch; Wandahl, Søren

    2012-01-01

    In today’s construction, there is a paramount focus on time, and on the scheduling and control of time. Everything is organized with respect to time. The construction project has to be completed within a fixed and often tight deadline. Otherwise a daily penalty often has to be paid. This pins down...... the contractors, and forces them to rigorously adhere to the initial schedule. If delayed the work-pace or manpower has to be increased to observe the schedule. In an attempt to improve productivity, three independent site-mangers have been interviewed about time-scheduling. Their experiences and opinions have...... been analyzed and weaknesses in existing time scheduling have been found. The findings showed a negative side effect of keeping the schedule too tight as it becomes inflexible and cannot absorb variability in production. Flexibility is necessary because of the contractors’ interacting and dependent...

  8. Nonlinear ion acoustic waves scattered by vortexes

    Science.gov (United States)

    Ohno, Yuji; Yoshida, Zensho

    2016-09-01

    The Kadomtsev-Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here, we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes 'scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are 'ambient' because they do not receive reciprocal reactions from the waves (i.e., the vortex equation is independent of the wave fields). This model describes a minimal departure from the integrable KP system. By the Painlevé test, we delineate how the vorticity term violates integrability, bringing about an essential three-dimensionality to the solutions. By numerical simulation, we show how the solitons are scattered by vortexes and become chaotic.

  9. A VORTEX MODEL OF A HELICOPTER ROTOR

    Directory of Open Access Journals (Sweden)

    Valentin BUTOESCU

    2009-06-01

    Full Text Available A vortex model of a helicopter rotor is presented. Each blade of the rotor has three degrees of freedom: flapping, lagging and feathering. The motions after each degree of freedom are also known for all blades. The blade is modelled as a thin vortex surface. The wakes are free fluid surfaces. A system of five equations are obtained: the first one is the integral equation of the lifting surface (rotor, the next three describe the wakes motion, and the last one relates the vortex strength on the wakes and the variation of vorticity on the rotor. A numerical solution of this system is presented. To avoid the singularities that can occur due to the complexity of vortex system, a desingularized model of the vortex core was adopted. A Mathcad worksheet containing the method has been written.The original contribution of the work. The calculation method of the motion of the wakes free vortex system, the development of the vortex cores in time and a new method to approximate the aerodynamic influence of remoted wake regions.

  10. Intelligent Agents for Scheduling Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The new exploration initiative, and the planned new antenna types to be developed in support of that initiative will increase the number and complexity of missions...

  11. Intelligent Agents for Scheduling Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — With the advent of the new exploration initiative, the number of customers and missions to be supported by the NASA Space Communications infrastructure will increase...

  12. An Iterated Local Search Algorithm for a Place Scheduling Problem

    Directory of Open Access Journals (Sweden)

    Shicheng Hu

    2013-01-01

    Full Text Available We study the place scheduling problem which has many application backgrounds in realities. For the block manufacturing project with special manufacturing platform requirements, we propose a place resource schedule problem. First, the mathematical model for the place resource schedule problem is given. On the basis of resource-constrained project scheduling problem and packing problem, we develop a hybrid heuristic method which combines priority rules and three-dimensional best fit algorithm, in which the priority rules determine the scheduling order and the three-dimensional best fit algorithm solves the placement. After this method is used to get an initial solution, the iterated local search is employed to get an improvement. Finally, we use a set of simulation data to demonstrate the steps of the proposed method and verify its feasibility.

  13. Dispatch Scheduling to Maximize Exoplanet Detection

    Science.gov (United States)

    Johnson, Samson; McCrady, Nate; MINERVA

    2016-01-01

    MINERVA is a dedicated exoplanet detection telescope array using radial velocity measurements of nearby stars to detect planets. MINERVA will be a completely robotic facility, with a goal of maximizing the number of exoplanets detected. MINERVA requires a unique application of queue scheduling due to its automated nature and the requirement of high cadence observations. A dispatch scheduling algorithm is employed to create a dynamic and flexible selector of targets to observe, in which stars are chosen by assigning values through a weighting function. I designed and have begun testing a simulation which implements the functions of a dispatch scheduler and records observations based on target selections through the same principles that will be used at the commissioned site. These results will be used in a larger simulation that incorporates weather, planet occurrence statistics, and stellar noise to test the planet detection capabilities of MINERVA. This will be used to heuristically determine an optimal observing strategy for the MINERVA project.

  14. Enabling Adaptive Grid Scheduling and Resource Management

    CERN Document Server

    Lazarevic, Aleksandar; Prnjat, Ognjen

    2007-01-01

    Wider adoption of the Grid concept has led to an increasing amount of federated computational, storage and visualisation resources being available to scientists and researchers. Distributed and heterogeneous nature of these resources renders most of the legacy cluster monitoring and management approaches inappropriate, and poses new challenges in workflow scheduling on such systems. Effective resource utilisation monitoring and highly granular yet adaptive measurements are prerequisites for a more efficient Grid scheduler. We present a suite of measurement applications able to monitor per-process resource utilisation, and a customisable tool for emulating observed utilisation models. We also outline our future work on a predictive and probabilistic Grid scheduler. The research is undertaken as part of UK e-Science EPSRC sponsored project SO-GRM (Self-Organising Grid Resource Management) in cooperation with BT.

  15. GIS-Based Simulation of Engineering Construction Schedule

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; ZHONG Denghua; HU Chengshun

    2005-01-01

    For its complexity, engineering construction schedule design is limited by various factors.Simulation-based engineering construction schedule takes critical path method (CPM) network as frame and calls complex cyclic operation network (CYCLONE) simulation model enclosed in advance for its simulation nodes. CYCLONE simulation model takes charge of simulating stochastic duration of activity and efficiency of resources, while CPM model performs project scheduling. This combination avoids the shortcomings of both models. Furthermore, geographic information system (GIS) technique is utilized to visualize the construction processes which are otherwise difficult to be understood by static results described. Application in practical project verifies the feasibility and advantage of the technique.

  16. Enhanced Software for Scheduling Space-Shuttle Processing

    Science.gov (United States)

    Barretta, Joseph A.; Johnson, Earl P.; Bierman, Rocky R.; Blanco, Juan; Boaz, Kathleen; Stotz, Lisa A.; Clark, Michael; Lebovitz, George; Lotti, Kenneth J.; Moody, James M.; Nguyen, Tony K.; Peterson, Kenneth A.; Sargent, Susan; Shaw, Karma; Stoner, Mack D.; Stowell, Deborah S.; Young, Daniel A.; Tulley, James H., Jr.

    2004-01-01

    The Ground Processing Scheduling System (GPSS) computer program is used to develop streamlined schedules for the inspection, repair, and refurbishment of space shuttles at Kennedy Space Center. A scheduling computer program is needed because space-shuttle processing is complex and it is frequently necessary to modify schedules to accommodate unanticipated events, unavailability of specialized personnel, unexpected delays, and the need to repair newly discovered defects. GPSS implements constraint-based scheduling algorithms and provides an interactive scheduling software environment. In response to inputs, GPSS can respond with schedules that are optimized in the sense that they contain minimal violations of constraints while supporting the most effective and efficient utilization of space-shuttle ground processing resources. The present version of GPSS is a product of re-engineering of a prototype version. While the prototype version proved to be valuable and versatile as a scheduling software tool during the first five years, it was characterized by design and algorithmic deficiencies that affected schedule revisions, query capability, task movement, report capability, and overall interface complexity. In addition, the lack of documentation gave rise to difficulties in maintenance and limited both enhanceability and portability. The goal of the GPSS re-engineering project was to upgrade the prototype into a flexible system that supports multiple- flow, multiple-site scheduling and that retains the strengths of the prototype while incorporating improvements in maintainability, enhanceability, and portability.

  17. Contrasting vortex-gyration dispersions for different lattice bases in one-dimensional magnetic vortex arrays

    Science.gov (United States)

    Han, Dong-Soo; Jeong, Han-Byeol; Kim, Sang-Koog

    2013-09-01

    We performed micromagnetic numerical and analytical calculations in studying the effects of change in the primitive unit cells of one-dimensional (1D) vortex arrays on collective vortex-gyration dispersion. As the primitive basis, we consider alternating constituent materials (NiMnSb vs. Permalloy) and alternating dimensions including constituent disk diameter and thickness. In the simplest case, that of one vortex-state disk of given dimensions and single material in the primitive cell, only a single branch of collective vortex-gyration dispersion appears. By contrast, two constituent disks' different alternating materials, thicknesses, and diameters yield characteristic two-branch dispersions, the band widths and gaps of which differ in each case. This work offers not only an efficient means of manipulating collective vortex-gyration band structures but also a foundation for the development of a rich variety of 1D or 2D magnonic crystals and their band structures based on dipolar-coupled-vortex arrays.

  18. Evaluation of travelling vortex speed by means of vortex tracking and dynamic mode decomposition

    Science.gov (United States)

    Hyhlík, Tomáš

    2016-06-01

    The article deals with the analysis of unsteady periodic flow field related to synthetic jet creation. The analyses are based on the data obtained using ANSYS Fluent solver. Numerical results are validated by hot wire anemometry data measured along the jet centerline. The speed of travelling vortex ring is evaluated by using vortex tracking method and by using dynamic mode decomposition method. Vortex identification is based on residual vorticity which allows identifying regions in the flow field where fluid particles perform the rotational motion. The regime of the synthetic jet with Re = 329 and S = 19.7 is chosen. Both the vortex tracking and the dynamic mode decomposition based vortex speed evaluation indicate an increase in the vortex speed close to the orifice and then decrease with maximum reaching almost one and half of orifice centerline velocity. The article contains extended version the article presented at the conference AEaNMiFMaE 2016.

  19. Phase diagrams of vortex matter with multi-scale inter-vortex interactions in layered superconductors

    Science.gov (United States)

    Meng, Qingyou; Varney, Christopher N.; Fangohr, Hans; Babaev, Egor

    2017-01-01

    It was recently proposed to use the stray magnetic fields of superconducting vortex lattices to trap ultracold atoms for building quantum emulators. This calls for new methods for engineering and manipulating of the vortex states. One of the possible routes utilizes type-1.5 superconducting layered systems with multi-scale inter-vortex interactions. In order to explore the possible vortex states that can be engineered, we present two phase diagrams of phenomenological vortex matter models with multi-scale inter-vortex interactions featuring several attractive and repulsive length scales. The phase diagrams exhibit a plethora of phases, including conventional 2D lattice phases, five stripe phases, dimer, trimer, and tetramer phases, void phases, and stable low-temperature disordered phases. The transitions between these states can be controlled by the value of an applied external field.

  20. Symmetry-constrained electron vortex propagation

    CERN Document Server

    Clark, L; Béché, A; Lubk, A; Verbeeck, J

    2016-01-01

    Electron vortex beams hold great promise for development in transmission electron microscopy, but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to focus on the interaction between geometrical symmetries, OAM and topology. We present multiple simulations, alongside experimental data to study the behaviour of a variety of electron vortex beams after interacting with apertures of different symmetries, and investigate the effect on their OAM and vortex structure, both in the far-field and under free-space propagation.

  1. Dynamic Optimization for Vortex Shedding Suppression

    Directory of Open Access Journals (Sweden)

    Bonis Ioannis

    2016-01-01

    Full Text Available Flows around structures exhibiting vortex shedding induce vibrations that can potentially damage the structure. A way to avoid it is to suppress vortex shedding by controlling the wake. Wake control of laminar flow behind a rotating cylinder is formulated herein as a dynamic optimization problem. Angular cylinder speed is the manipulated variable that is adjusted to suppress vortex shedding by minimizing lift coefficient variation. The optimal angular speed is assumed to be periodic like wake formation. The control problem is solved for different time horizons tH. The impact of tH to control is evaluated and the need for feedback is assessed.

  2. Vortex dynamics in ferromagnetic/superconducting bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Cieplak, M.Z.; Adamus, Z. [Polish Acad Sci, Inst Phys, PL-02668 Warsaw, (Poland); Konczykowski, M. [CEA, DSM, DRECAM, Lab Solides Irradies, Ecole Polytechnique, CNRS-UMR 7642, F-91128 Palaiseau (France); Zhu, L.Y.; Chien, C.L. [Johns Hopkins Univ, Dept Phys and Astron, Baltimore, MD 21218 (United States)

    2008-07-01

    The dependence of vortex dynamics on the geometry of magnetic domain pattern is studied in the superconducting/ferromagnetic bilayers, in which niobium is a superconductor, and Co/Pt multilayer with perpendicular magnetic anisotropy serves as a ferromagnetic layer. Magnetic domain patterns with different density of domains per surface area and different domain size, w, are obtained for Co/Pt with different thickness of Pt. The dense patterns of domains with the size comparable to the magnetic penetration depth (w {>=} {lambda}) produce large vortex pinning and smooth vortex penetration, while less dense patterns with larger domains (w {>=}{>=} {lambda}) enhance pinning less effectively and result in flux jumps during flux motion. (authors)

  3. The Influence of Low-frequency Oscillation Propagation of the Tibetan Plateau Vortex on Rainstorm Downstream

    Science.gov (United States)

    Xiao, Tiangui; Wang, Chao; La, Jia; Du, Jun; Zhang, Kairong

    2017-04-01

    disappearance during the basin rainstorm. A typical heavy rainstorm occurred in Sichuan was studied. In the horizontal direction,atmospheric disturbance energy transmit from the west Sichuan plateau to heavy rainfall areas in basin, that is indicating the low-frequency atmospheric disturbance energy transmission. In the vertical direction, the disturbance energy transfer to the downstream is probably the major reason caused this heavy rainstorm. The value of wave packet and disturbance energy indicates the difference stages of rainstorm. Key words: the tibetan plateau; plateau vortex; FLO; rainstorm; wave-packet Acknowledgements This study was supported by National Natural Science Foundation of China Fund Project (91337215, 41575066), National Key Basic Research Program (2013CB733206), Special Fund for Meteorological Research in the Public Interest (GYHY201406015), and Risk Assessment System of Significant Climate Events in Tibet (14H046).

  4. Theory of specific heat of vortex liquid of high T c superconductors

    Science.gov (United States)

    Bai, Chen; Chi, Cheng; Wang, Jiangfan

    2016-10-01

    Superconducting thermal fluctuation (STF) plays an important role in both thermodynamic and transport properties in the vortex liquid phase of high T c superconductors. It was widely observed in the vicinity of the critical transition temperature. In the framework of Ginzburg-Landau-Lawrence-Doniach theory in magnetic field, a self-consistent analysis of STF including all Landau levels is given. Besides that, we calculate the contribution of STF to specific heat in vortex liquid phase for high T c cuprate superconductors, and the fitting results are in good agreement with experimental data. Project supported by the National Natural Science Foundation of China (Grant No. 11274018).

  5. Superconducting Josephson vortex flow transistors

    CERN Document Server

    Tavares, P A C

    2002-01-01

    The work reported in this thesis focuses on the development of high-temperature superconducting Josephson vortex-flow transistors (JVFTs). The JVFT is a particular type of superconducting transistor, i.e. an electromagnetic device capable of delivering gain while keeping the control and output circuits electrically isolated. Devices were fabricated from (100) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta thin films grown by Pulsed Laser Deposition on 24 deg magnesium oxide and strontium titanate bicrystals. The design of the JVFTs was guided by numerical simulations and the devices were optimised for current gain. Improvements were made to the fabrication process in order to accurately pattern the small structures required. The devices exhibited current gains higher than 60 in liquid nitrogen. Gains measured at lower temperatures were significantly higher. As part of the work a data acquisition suite was developed for the characterisation of three-terminal devices and, in particular, of JVFTs.

  6. Vortex disruption by magnetohydrodynamic feedback

    CERN Document Server

    Mak, Julian; Hughes, D W

    2016-01-01

    In an electrically conducting fluid, vortices stretch out a weak, large-scale magnetic field to form strong current sheets on their edges. Associated with these current sheets are magnetic stresses, which are subsequently released through reconnection, leading to vortex disruption, and possibly even destruction. This disruption phenomenon is investigated here in the context of two-dimensional, homogeneous, incompressible magnetohydrodynamics. We derive a simple order of magnitude estimate for the magnetic stresses --- and thus the degree of disruption --- that depends on the strength of the background magnetic field (measured by the parameter $M$, a ratio between the Alfv\\'en speed and a typical flow speed) and on the magnetic diffusivity (measured by the magnetic Reynolds number $\\mbox{Rm}$). The resulting estimate suggests that significant disruption occurs when $M^{2}\\mbox{Rm} = O(1)$. To test our prediction, we analyse direct numerical simulations of vortices generated by the breakup of unstable shear flo...

  7. Project Success in Agile Development Software Projects

    Science.gov (United States)

    Farlik, John T.

    2016-01-01

    Project success has multiple definitions in the scholarly literature. Research has shown that some scholars and practitioners define project success as the completion of a project within schedule and within budget. Others consider a successful project as one in which the customer is satisfied with the product. This quantitative study was conducted…

  8. Project Success in Agile Development Software Projects

    Science.gov (United States)

    Farlik, John T.

    2016-01-01

    Project success has multiple definitions in the scholarly literature. Research has shown that some scholars and practitioners define project success as the completion of a project within schedule and within budget. Others consider a successful project as one in which the customer is satisfied with the product. This quantitative study was conducted…

  9. Vortex Dynamics in Anisotropic Superconductors

    Science.gov (United States)

    Steel, David Gordon

    Measurements of the ac screening response and resistance of superconducting Bi_2Sr _2CaCu_2O _8 (BSCCO) crystals have been used to probe the dynamics of the magnetic flux lines within the mixed state as a function of frequency, temperature, and applied dc field. For the particular range of temperature and magnetic field in which measurements were made, the systematic behavior of the observed dissipation peak in the screening response is consistent with electromagnetic skin size effects rather than a phase transition. According to microscopic theories of the interaction between the flux lines and a driving ac field, such a skin size effect is expected for the case when the vortex motion is diffusive in nature. However, diffusive motion is inconsistent with simple activation models that use a single value for the pinning energy (derived from direct measurement of the dc resistance). This contradiction suggests a distribution of pinning energies within the sample. Interlayer vortex decoupling has been directly observed as a function of temperature and applied magnetic field using electronic transport perpendicular to the layers in synthetic amorphous MoGe/Ge multilayer samples. Perpendicular transport has been shown to be a far more sensitive measure of the phase coupling between layers than in-plane properties. Below the decoupling temperature T_{D} the resistivity anisotropy collapses and striking nonlinearities appear in the perpendicular current-voltage behavior, which are not observed in parallel transport. A crossover in behavior is also observed at a field H _{x}, in accordance with theory. The data suggest the presence of a phase transition into a state with finite in-plane resistivity. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.).

  10. Cash flow balanced project scheduling optimization based on different payment conditions%基于不同支付条件的现金流均衡项目调度优化

    Institute of Scientific and Technical Information of China (English)

    何正文; 刘人境; 徐渝

    2011-01-01

    以现金流均衡为目标,研究不同支付条件下的项目调度问题.在对所研究问题进行界定的基础上,构建了基于里程碑事件支付条件的优化模型,并将其扩展为基于累计时间、累计挣值和累计费用等支付条件的优化模型;针对问题的强NP-hard属性,设计禁忌搜索启发式算法;在随机生成的标准算例集合上对算法进行测试,并与其他两种启发式算法进行比较;最后用一个算例对研究进行说明,比较分析支付条件对承包商现金流均衡目标的影响.研究结论如下:不同支付条件下的现金流均衡结果差异显著,随着支付次数、支付比例和项目截止日期的增大,承包商更易实现现金流出与流入的均衡.%Taking cash flow balance as the objective, this paper studies the project scheduling problem under different payment conditions. Based on the identification of the studied problem, the authors construct the optimization model under the milestone event payment condition and then extend it to the cumulative time, cumulative earned value, and cumulative expense payment conditions. Because of the strong NP-hardness of the problem, a tabu search heuristic algorithm is developed. The algorithm is tested and compared with other two heuristic algorithms on a data set generated randomly. Ultimately, an example is used to illustrate the method and the influences of the payment conditions on the objective of cash flow balance are analyzed. The conclusions are as follows; Payment conditions may exert an important influence on cash flow balance, and with the increase of payment number, payment proportion, and project deadline, it becomes easier for contractor to balance cash outflows and inflows.

  11. Polar night vortex breakdown and large-scale stirring in the southern stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Alvaro de la [Universidad Complutense de Madrid, Departamento de Geofisica y Meteorologia, Madrid (Spain); University of California, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA (United States); Mechoso, C.R. [University of California, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA (United States); Ide, K. [University of California, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA (United States); University of Maryland, Department of Atmospheric and Oceanic Science, Collage Park, MD (United States); Walterscheid, R. [The Aerospace Corporation, Space Sciences Department, Los Angeles, CA (United States); Schubert, G. [University of California, Department of Earth and Space Sciences, Institute of Geophysics and Planetary Physics, Los Angeles, CA (United States)

    2010-11-15

    The present paper examines the vortex breakdown and large-scale stirring during the final warming of the Southern Hemisphere stratosphere during the spring of 2005. A unique set of in situ observations collected by 27 superpressure balloons (SPBs) is used. The balloons, which were launched from McMurdo, Antarctica, by the Strateole/VORCORE project, drifted for several weeks on two different isopycnic levels in the lower stratosphere. We describe balloon trajectories and compare them with simulations obtained on the basis of the velocity field from the GEOS-5 and NCEP/NCAR reanalyses performed with and without VORCORE data. To gain insight on the mechanisms responsible for the horizontal transport of air inside and outside the well-isolated vortex we examine the balloon trajectories in the framework of the Lagrangian properties of the stratospheric flow. Coherent structures of the flow are visualized by computing finite-time Lyapunov exponents (FTLE). A combination of isentropic analysis and FTLE distributions reveals that air is stripped away from the vortex's interior as stable manifolds eventually cross the vortex's edge. It is shown that two SPBs escaped from the vortex within high potential vorticity tongues that developed in association with wave breaking at locations along the vortex's edge where forward and backward FTLE maxima approximately intersect. The trajectories of three SPBs flying as a group at the same isopycnic level are examined and their behavior is interpreted in reference to the FTLE field. These results support the concept of stable and unstable manifolds governing transport of air masses across the periphery of the stratospheric polar vortex. (orig.)

  12. CMS multicore scheduling strategy

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Calero Yzquierdo, Antonio [Madrid, CIEMAT; Hernandez, Jose [Madrid, CIEMAT; Holzman, Burt [Fermilab; Majewski, Krista [Fermilab; McCrea, Alison [UC, San Diego

    2014-01-01

    In the next years, processor architectures based on much larger numbers of cores will be most likely the model to continue 'Moore's Law' style throughput gains. This not only results in many more jobs in parallel running the LHC Run 1 era monolithic applications, but also the memory requirements of these processes push the workernode architectures to the limit. One solution is parallelizing the application itself, through forking and memory sharing or through threaded frameworks. CMS is following all of these approaches and has a comprehensive strategy to schedule multicore jobs on the GRID based on the glideinWMS submission infrastructure. The main component of the scheduling strategy, a pilot-based model with dynamic partitioning of resources that allows the transition to multicore or whole-node scheduling without disallowing the use of single-core jobs, is described. This contribution also presents the experiences made with the proposed multicore scheduling schema and gives an outlook of further developments working towards the restart of the LHC in 2015.

  13. Model Migration Schedules

    OpenAIRE

    1981-01-01

    This report draws on the fundamental regularity exhibited by age profiles of migration all over the world to develop a system of hypothetical model schedules that can be used in multiregional population analyses carried out in countries that lack adequate migration data.

  14. Personnel Scheduling in Laboratories

    NARCIS (Netherlands)

    Franses, Philip; Post, Gerhard; Burke, Edmund; De Causmaecker, Patrick

    2003-01-01

    We describe an assignment problem particular to the personnel scheduling of organisations such as laboratories. Here we have to assign tasks to employees. We focus on the situation where this assignment problem reduces to constructing maximal matchings in a set of interrelated bipartite graphs. We d

  15. Round Robin Schedules.

    Science.gov (United States)

    Iannone, Michael A.

    1983-01-01

    Presented is a computer program written in BASIC that covers round-robin schedules for team matches in competitions. The program was originally created to help teams in a tennis league play one match against every other team. Part of the creation of the program involved use of modulo arithmetic. (MP)

  16. Harmonious personnel scheduling

    NARCIS (Netherlands)

    Fijn van Draat, Laurens; Post, Gerhard; Veltman, Bart; Winkelhuijzen, Wessel

    2006-01-01

    The area of personnel scheduling is very broad. Here we focus on the ‘shift assignment problem’. Our aim is to discuss how ORTEC HARMONY handles this planning problem. In particular we go into the structure of the optimization engine in ORTEC HARMONY, which uses techniques from genetic algorithms, l

  17. Harmonious personnel scheduling

    NARCIS (Netherlands)

    Fijn van Draat, Laurens; Post, Gerhard F.; Veltman, Bart; Winkelhuijzen, Wessel

    2006-01-01

    The area of personnel scheduling is very broad. Here we focus on the ‘shift assignment problem’. Our aim is to discuss how ORTEC HARMONY handles this planning problem. In particular we go into the structure of the optimization engine in ORTEC HARMONY, which uses techniques from genetic algorithms,

  18. Prediction and control of vortex-dominated and vortex-wake flows

    Science.gov (United States)

    Kandil, Osama

    1993-01-01

    This progress report documents the accomplishments achieved in the period from December 1, 1992 until November 30, 1993. These accomplishments include publications, national and international presentations, NASA presentations, and the research group supported under this grant. Topics covered by documents incorporated into this progress report include: active control of asymmetric conical flow using spinning and rotary oscillation; supersonic vortex breakdown over a delta wing in transonic flow; shock-vortex interaction over a 65-degree delta wing in transonic flow; three dimensional supersonic vortex breakdown; numerical simulation and physical aspects of supersonic vortex breakdown; and prediction of asymmetric vortical flows around slender bodies using Navier-Stokes equations.

  19. Scattering of a vortex pair by a single quantum vortex in a Bose-Einstein condensate

    Science.gov (United States)

    Smirnov, L. A.; Smirnov, A. I.; Mironov, V. A.

    2016-01-01

    We analyze the scattering of vortex pairs (the particular case of 2D dark solitons) by a single quantum vortex in a Bose-Einstein condensate with repulsive interaction between atoms. For this purpose, an asymptotic theory describing the dynamics of such 2D soliton-like formations in an arbitrary smoothly nonuniform flow of a ultracold Bose gas is developed. Disregarding the radiation loss associated with acoustic wave emission, we demonstrate that vortex-antivortex pairs can be put in correspondence with quasiparticles, and their behavior can be described by canonical Hamilton equations. For these equations, we determine the integrals of motion that can be used to classify various regimes of scattering of vortex pairs by a single quantum vortex. Theoretical constructions are confirmed by numerical calculations performed directly in terms of the Gross-Pitaevskii equation. We propose a method for estimating the radiation loss in a collision of a soliton-like formation with a phase singularity. It is shown by direct numerical simulation that under certain conditions, the interaction of vortex pairs with a core of a single quantum vortex is accompanied by quite intense acoustic wave emission; as a result, the conditions for applicability of the asymptotic theory developed here are violated. In particular, it is visually demonstrated by a specific example how radiation losses lead to a transformation of a vortex-antivortex pair into a vortex-free 2D dark soliton (i.e., to the annihilation of phase singularities).

  20. Influence of Blood Inertia on Vortex Enhancement in the Wake of Plaque Deposited Arteries

    Directory of Open Access Journals (Sweden)

    Muhammad Anwar Solangi

    2011-04-01

    Full Text Available Flow of blood structure is presented in terms of stream line projections at different percentages of deposition against various Reynolds numbers. The impact of atherosclerosis is investigated on the vortex enhancement and intensity. The predicted results are computed in terms of stream function for quantifying the reattachment length and re-circulating flow rate of blood at various Reynolds numbers and different percentages of blockage. The results show that flow of blood is disturbs at the vicinity of blockage, especially in the down stream area that leads to the formation of vortexes. It is observed that the length of vortex increases along with the deposition levels as well as with increasing inertia .To solve the Navier-Stokes equations, together with the incompressibility constraints a semi-implicit time stepping procedure, namely Taylor- Galerkin/Pressure-correction finite element scheme has been employed.

  1. The Life of a Vortex Knot

    CERN Document Server

    Kleckner, Dustin; Irvine, William T M

    2013-01-01

    The idea that the knottedness (hydrodynamic Helicity) of a fluid flow is conserved has a long history in fluid mechanics. The quintessential example of a knotted flow is a knotted vortex filament, however, owing to experimental difficulties, it has not been possible until recently to directly generate knotted vortices in real fluids. Using 3D printed hydrofoils and high-speed laser scanning tomography, we generate vortex knots and links and measure their subsequent evolution. In both cases, we find that the vortices deform and stretch until a series of vortex reconnections occurs, eventually resulting several disjoint vortex rings. This article accompanies a fluid dynamics video entered into the Gallery of Fluid Motion at the 66th Annual Meeting of the APS Division of Fluid Dynamics.

  2. Vortex Shedding From a Flexible Hydrofoil

    OpenAIRE

    Dreyer, Matthieu; Farhat, Mohamed

    2011-01-01

    Video of vortex shedding in the wake of a Naca0009 hydrofoil made of polyoxymethylene type C (POM C). This video was submitted as part of the Gallery of Fluid Motion 2011 which is showcase of fluid dynamics videos.

  3. Free wake models for vortex methods

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, K. [Technical Univ. Berlin, Aerospace Inst. (Germany)

    1997-08-01

    The blade element method works fast and good. For some problems (rotor shapes or flow conditions) it could be better to use vortex methods. Different methods for calculating a wake geometry will be presented. (au)

  4. 'Optimal' vortex rings and aquatic propulsion mechanisms

    Science.gov (United States)

    Linden, Paul; Turner, Stewart

    2004-11-01

    Fish swim by flapping their tail and other fins. Other sea creatures, such as squid and salps, eject fluid intermittently as a jet. We discuss the fluid mechanics behind these propulsion mechanisms, and show that these animals produce optimal vortex rings, which give the maximum thrust for a given energy input. We show fish optimise both their steady swimming and their ability to accelerate and turn by producing an individual optimal ring with each flap of the tail or fin. Salps produce vortex rings directly by ejecting a volume of fluid through a rear orifice, and these are also optimal. An important implication of this paper is that the repetition of vortex production is not necessary for an individual vortex to have the `optimal' characteristics.

  5. Experiments with vortex rings in air

    Science.gov (United States)

    Hernández, R. H.; Cibert, B.; Béchet, C.

    2006-09-01

    We report quantitative experimental measurements of the instability of vortex rings generated in air. Vortex rings are created by pushing air through the circular orifice of a cylindrical cavity with a flat piston driven by a loudspeaker. Hot-wire anemometry provides accurate measurements of the velocity profile at all stages of the ring formation including stable and unstable rings. Flow visualization using a laser light sheet shows that the initially undisturbed vortex ring is progressively deformed in the azimuthal direction giving rise to a wavy azimuthal and periodic pattern in the circumference of the ring. The wavy pattern is steady, i.e., it does not rotate or translate during the ring's motion. However as the vortex motion progresses in the axial direction, the displaced portions of the ring are convected away from the initial undisturbed position and the wavy pattern grows with local Reynolds number.

  6. Development of gas pressure vortex regulator

    Science.gov (United States)

    Uss, A. Yu.; Chernyshyov, A. V.; Krylov, V. I.

    2017-08-01

    The present paper describes the applications of vortex regulators and the current state of the issue on the use and development of such devices. A patent review has been carried out. Automatic control systems using a vortex regulator are considered. Based on the analysis and preliminary numerical calculation of gas flow in the working cavity of the regulator, a new design of a vortex gas pressure regulator has been developed. An experimental sample of the device was made using additive technologies and a number of tests were carried out. The results of experimental studies confirmed the adequacy of the created mathematical model. Based on further numerical studies a new design of a vortex regulator with a distributed feed of the process control flow as well as with the regulated swirl of the supply and control process flows has been developed.

  7. Investigation of aircraft vortex wake structure

    Science.gov (United States)

    Baranov, N. A.; Turchak, L. I.

    2014-11-01

    In this work we analyze the mechanisms of formation of the vortex wake structure of aircraft with different wing shape in the plan flying close to or away from the underlying surface cleaned or released mechanization wing.

  8. Interaction and merging of vortex filaments

    Science.gov (United States)

    Liu, C. H.; Weston, R. P.; Ishii, K.; Ting, L.; Visintainer, J. A.

    1988-01-01

    The asymptotic solutions of Navier-Stokes equations for vortex filaments of finite strength with small effective vortical cores are summarized with special emphasis placed on the physical meaning and the practical limit to the applicability of the asymptotic solution. Finite-difference solutions of Navier-Stokes equations for the marging of the filament(s) are described with a focus on the development of the approximate boundary conditions for the computational domain. An efficiency study employing a model problem is used to assess the advantages of the present approximate boundary condition method over previously used techniques. Applications of the present method are presented for the motion and decay of a 3:1 elliptic vortex ring, and for the merging process of a pair of coaxial vortex rings. A numerical procedure for the problem of local merging of vortex filaments, which requires the asymptotic analysis as well as the numerical Navier-Stokes solver, is also presented.

  9. Class Schedules--Computer Loaded or Student Self-Scheduled?

    Science.gov (United States)

    Wall, Edward F.

    1979-01-01

    In the two-step process of student scheduling, the initial phase of course selection is the most important. At Chesterton High School in Indiana, student self-scheduling is preferred over computer loading. (Author/MLF)

  10. Applications of 2D helical vortex dynamics

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær

    2010-01-01

    In the paper, we show how the assumption of helical symmetry in the context of 2D helical vortices can be exploited to analyse and to model various cases of rotating flows. From theory, examples of three basic applications of 2D dynamics of helical vortices embedded in flows with helical symmetry...... of the vorticity field are addressed. These included some of the problems related to vortex breakdown, instability of far wakes behind rotors and vortex theory of ideal rotors....

  11. Structure of a Steady Bathtub Vortex

    Science.gov (United States)

    Andersen, Anders; Bøhling, Lasse; Fabre, David

    2010-11-01

    Bathtub vortex flows constitute an important class of concentrated vortex flows which are characterised by intense axial down-flow and stress free surface. We use direct numerical simulations to explore the flow structure of a steady bathtub vortex in a cylindrical tank with a central drain-hole. We find that the qualitative structure of the meridional flow does not depend on the radial Reynolds number, whereas we observe a weak overall rotation at low radial Reynolds number and a concentrated vortex above the drain-hole at high radial Reynolds number. We present a simple analytical model which shows the same qualitative dependence on the radial Reynolds number as the simulations and which compares favourably with the results for the radial velocity and the azimuthal velocity at the surface. Finally, we describe the height dependence of the radius of the vortex core and the maximum of the azimuthal velocity at high radial Reynolds number, and we show that the data on the radius of the vortex core and the maximum of the azimuthal velocity as functions of height collapse on single curves by appropriate scaling.

  12. Application of vortex method; Uzuho no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsukiji, T. [Ashikaga Inst. of Technology, Tochigi (Japan); Shimizu, S. [Hiroshima Univ., Hiroshima (Japan). Faculty of Engineering

    1995-07-15

    Basic jets such as two dimensional free jet, impact jet, axisymmetric circular free jet, and jet flowing out from a nozzle equipped with a collar at the outlet, as well as flow in such valves as disc valves, spool valves, and poppet valves are taken up to discuss their applications using the vortex method, and the results of studies made using vortex method on the analysis of jet and conditions inside valves are reported. The state of the development of large scale vortex structure in the shear layer can be simulated comparatively simply by using the vortex method. The effects of the radius and the lift of a valve on the fluid outlet angle of jet and on the discharge coefficient of orifice are analyzed. Although the shape of the spool valve near the throttle is very complicated, simplified models are used for numerical analysis. An example of calculated result in the case where the spool reciprocates is introduced. Actual vibrating phenomena can be simulated well by the vortex method for minute vibration of the poppet caused by the discharge of lump vortex. 17 refs., 16 figs., 1 tab.

  13. Boundary Layers in Laminar Vortex Flows.

    Science.gov (United States)

    Baker, Glenn Leslie

    A detailed experimental study of the flow in an intense, laminar, axisymmetric vortex has been conducted in the Purdue Tornado Vortex Simulator. The complicated nature of the flow in the boundary layer of laboratory vortices and presumably on that encountered in full-scale tornadoes has been examined. After completing a number of modifications to the existing facility to improve the quality of the flow in the simulator, hot-film anemometry was employed for making velocity-component and turbulence-intensity measurements of both the free-stream and boundary layer portions of the flow. The measurements represent the first experimental boundary layer investigation of a well-defined vortex flow to appear in the literature. These results were compared with recent theoretical work by Burggraf, Stewartson and Belcher (1971) and with an exact similarity solution for line-sink boundary layers developed by the author. A comparison is also made with the numerical simulation of Wilson (1981) in which the boundary conditions were matched to those of the present experimental investigation. Expressions for the vortex core radius, the maximum tangential velocity and the maximum pressure drop are given in terms of dimensionless modeling parameters. References. Burggraf, O. R., K. Stewartson and R. Belcher, Boundary layer. induced by a potential vortex. Phys. Fluids 14, 1821-1833 (1971). Wilson, T., M. S. thesis, Vortex Boundary Layer Dynamics, Univ. Calif. Davis (1981).

  14. Numerical Study of Mechanism of U-shaped Vortex Formation

    CERN Document Server

    Lu, Ping; Liu, Chaoqun

    2014-01-01

    This paper illustrates the mechanism of U-shaped vortex formation which is found both by experiment and DNS. The main goal of this paper is to explain how the U-shaped vortex is formed and further develops. According to the results obtained by our direct numerical simulation with high order accuracy, the U-shaped vortex is part of the coherent vortex structure and is actually the tertiary streamwise vortices induced by the secondary vortices. The new finding is quite different from existing theories which describe that the U-shaped vortex is newly formed as the head of young turbulence spot and finally break down to small pieces. In addition, we find that the U-shaped vortex has the same vorticity sign as the original {\\lambda}-shaped vortex tube legs and serves as a second neck to supply vorticity to the ringlike vortex when the original vortex tube is stretched and multiple rings are generated.

  15. Experimental Investigation of wing-tip vortex evolution in turbulence

    Science.gov (United States)

    Bailey, Sean; Ghimire, Hari

    2016-11-01

    Towing tank experiments were conducted to examine the evolution of a wing-tip vortex in grid-generated turbulence. Measurements using particle image velocimetry (PIV) were conducted of the velocity field generated by towing a semi-span symmetric wing oriented at 8 degree angle of attack. Turbulence of different kinetic energy and length scales was produced by simultaneously towing grids of different mesh sizes upstream of the wing. Results showed that wing-tip vortex wandering increased with the increase in turbulence kinetic energy, ultimately leading to spontaneous collapse of the vortex. During this process, a measurable diffusion of overall vortex circulation was observed, with the rate of diffusion leading to the collapse of the vortex dependent on the turbulence intensity. Interestingly, the radius of the vortex core remained largely unchanged during the diffusion process, Evidence suggests that the breakdown of vortex was enhanced by entrainment of fluid inside vortex core due to vortex stripping in presence of turbulence.

  16. Vortex sound in confined flows

    Science.gov (United States)

    Hofmans, Gerardus Carolus Johannus

    The interaction of vortex structures with the acoustic velocity field is prerequisite for the production or absorption of acoustic energy. When the source region in which this interaction occurs is much smaller than the wavelength of the acoustic wave, it is possible to neglect wave propagation in the source region itself. Such a source region is called 'compact' and it results in a simplified description of the acoustic source. We have restricted ourselves to compact source regions. Three relevant applications have been studied: speech modelling, damping of acoustic waves by means of diaphragms, and the prediction of flow-induced resonances in bifurcated pipe systems with T-shaped junctions. Experimental as well as numerical work has been carried out for rigid in vitro models of the vocal folds. It was found that it is possible to use a simplified quasi- steady model, which describes the boundary-layer flow in the glottis, to reasonably predict the separation point during a part of one cycle of the vocal-fold movement. This results in a reasonable prediction of the source of sound in voiced speech. Furthermore, it was found that the instability of the jet, that is formed downstream of the glottis, can be a significant source of broad-band sound. A diaphragm used as a constriction in a pipe is a common element in mufflers. This configuration is investigated theoretically, numerically, and experimentally. Results of the quasi-steady flow model and of the numerical calculations are in good agreement with results of experiments. Theory also correctly describes the limit of high frequencies. For the intermediate frequencies we found some deviation between theory and experiments, which is not yet fully understood. The flow through T-joints, with sharp edges, has been numerically investigated as a function of the acoustic amplitude, the Strouhal number, and the flow configuration. In the limit of low frequencies the acoustic source in a T-joint can be described by means

  17. Artificial intelligence for the CTA Observatory scheduler

    Science.gov (United States)

    Colomé, Josep; Colomer, Pau; Campreciós, Jordi; Coiffard, Thierry; de Oña, Emma; Pedaletti, Giovanna; Torres, Diego F.; Garcia-Piquer, Alvaro

    2014-08-01

    The Cherenkov Telescope Array (CTA) project will be the next generation ground-based very high energy gamma-ray instrument. The success of the precursor projects (i.e., HESS, MAGIC, VERITAS) motivated the construction of this large infrastructure that is included in the roadmap of the ESFRI projects since 2008. CTA is planned to start the construction phase in 2015 and will consist of two arrays of Cherenkov telescopes operated as a proposal-driven open observatory. Two sites are foreseen at the southern and northern hemispheres. The CTA observatory will handle several observation modes and will have to operate tens of telescopes with a highly efficient and reliable control. Thus, the CTA planning tool is a key element in the control layer for the optimization of the observatory time. The main purpose of the scheduler for CTA is the allocation of multiple tasks to one single array or to multiple sub-arrays of telescopes, while maximizing the scientific return of the facility and minimizing the operational costs. The scheduler considers long- and short-term varying conditions to optimize the prioritization of tasks. A short-term scheduler provides the system with the capability to adapt, in almost real-time, the selected task to the varying execution constraints (i.e., Targets of Opportunity, health or status of the system components, environment conditions). The scheduling procedure ensures that long-term planning decisions are correctly transferred to the short-term prioritization process for a suitable selection of the next task to execute on the array. In this contribution we present the constraints to CTA task scheduling that helped classifying it as a Flexible Job-Shop Problem case and finding its optimal solution based on Artificial Intelligence techniques. We describe the scheduler prototype that uses a Guarded Discrete Stochastic Neural Network (GDSN), for an easy representation of the possible long- and short-term planning solutions, and Constraint

  18. Toward an Autonomous Telescope Network: the TBT Scheduler

    Science.gov (United States)

    Racero, E.; Ibarra, A.; Ocaña, F.; de Lis, S. B.; Ponz, J. D.; Castillo, M.; Sánchez-Portal, M.

    2015-09-01

    Within the ESA SSA program, it is foreseen to deploy several robotic telescopes to provide surveillance and tracking services for hazardous objects. The TBT project will procure a validation platform for an autonomous optical observing system in a realistic scenario, consisting of two telescopes located in Spain and Australia, to collect representative test data for precursor SSA services. In this context, the planning and scheduling of the night consists of two software modules, the TBT Scheduler, that will allow the manual and autonomous planning of the night, and the control of the real-time response of the system, done by the RTS2 internal scheduler. The TBT Scheduler allocates tasks for both telescopes without human intervention. Every night it takes all the inputs needed and prepares the schedule following some predefined rules. The main purpose of the scheduler is the distribution of the time for follow-up of recently discovered targets and surveys. The TBT Scheduler considers the overall performance of the system, and combine follow-up with a priori survey strategies for both kind of objects. The strategy is defined according to the expected combined performance for both systems the upcoming night (weather, sky brightness, object accessibility and priority). Therefore, TBT Scheduler defines the global approach for the network and relies on the RTS2 internal scheduler for the final detailed distribution of tasks at each sensor.

  19. Job shop scheduling problem with late work criterion

    Science.gov (United States)

    Piroozfard, Hamed; Wong, Kuan Yew

    2015-05-01

    Scheduling is considered as a key task in many industries, such as project based scheduling, crew scheduling, flight scheduling, machine scheduling, etc. In the machine scheduling area, the job shop scheduling problems are considered to be important and highly complex, in which they are characterized as NP-hard. The job shop scheduling problems with late work criterion and non-preemptive jobs are addressed in this paper. Late work criterion is a fairly new objective function. It is a qualitative measure and concerns with late parts of the jobs, unlike classical objective functions that are quantitative measures. In this work, simulated annealing was presented to solve the scheduling problem. In addition, operation based representation was used to encode the solution, and a neighbourhood search structure was employed to search for the new solutions. The case studies are Lawrence instances that were taken from the Operations Research Library. Computational results of this probabilistic meta-heuristic algorithm were compared with a conventional genetic algorithm, and a conclusion was made based on the algorithm and problem.

  20. Revisiting conjugate schedules.

    Science.gov (United States)

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed.

  1. Multiprocessor scheduling with rejection

    Energy Technology Data Exchange (ETDEWEB)

    Bartal, Y. [Tel-Aviv Univ. (Israel); Leonardi, S.; Marchetti-Spaccamela, A. [Universita di Roma (Italy); Sgall, J. [Mathematical Inst., Zitna (Czechoslovakia)] [and others

    1996-12-31

    We consider a version of multiprocessor scheduling with the special feature that jobs may be rejected for a certain penalty. An instance of the problem is given by m identical parallel machines and a set of n jobs, each job characterized by a processing time and a penalty. In the on-line version the jobs arrive one by one and we have to schedule or reject a job before we have any information about future jobs. The objective is to minimize the makespan of the schedule for accepted jobs plus the sum of the penalties of rejected jobs. The main result is a 1 + {phi} {approx} 2.618 competitive algorithm for the on-line version of the problem, where 0 is the golden ratio. A matching lower bound shows that this is the best possible algorithm working for all m. For fixed m we give improved bounds, in particular for m = 2 we give an optimal {phi} {approx} 1.618 competitive algorithm. For the off-line problem we present a fully polynomial approximation scheme for fixed m and an approximation algorithm which runs in time O(n log n) for arbitrary m and guarantees 2 - 1/m approximation ratio.

  2. CMS Multicore Scheduling Strategy

    CERN Document Server

    Perez-Calero Yzquierdo, Antonio

    2014-01-01

    In the next years, processor architectures based on much larger numbers of cores will be most likely the model to continue Moores Law style throughput gains. This not only results in many more jobs in parallel running the LHC Run 1 era monolithic applications. Also the memory requirements of these processes push the workernode architectures to the limit. One solution is parallelizing the application itself, through forking and memory sharing or through threaded frameworks. CMS is following all of these approaches and has a comprehensive strategy to schedule multi-core jobs on the GRID based on the glideIn WMS submission infrastructure. We will present the individual components of the strategy, from special site specific queues used during provisioning of resources and implications to scheduling; to dynamic partitioning within a single pilot to allow to transition to multi-core or whole-node scheduling on site level without disallowing single-core jobs. In this presentation, we will present the experiences mad...

  3. Customer Appeasement Scheduling

    CERN Document Server

    Nikseresht, Mohammad R; Maheshwari, Anil

    2010-01-01

    Almost all of the current process scheduling algorithms which are used in modern operating systems (OS) have their roots in the classical scheduling paradigms which were developed during the 1970's. But modern computers have different types of software loads and user demands. We think it is important to run what the user wants at the current moment. A user can be a human, sitting in front of a desktop machine, or it can be another machine sending a request to a server through a network connection. We think that OS should become intelligent to distinguish between different processes and allocate resources, including CPU, to those processes which need them most. In this work, as a first step to make the OS aware of the current state of the system, we consider process dependencies and interprocess communications. We are developing a model, which considers the need to satisfy interactive users and other possible remote users or customers, by making scheduling decisions based on process dependencies and interproce...

  4. Scheduling a C-Section

    Science.gov (United States)

    ... Pregnancy > Labor & birth > Scheduling a c-section Scheduling a c-section E-mail to a friend Please fill in all fields. Please enter ... and develop before she’s born. Why can scheduling a c-section for non-medical reasons be a ...

  5. Flexible Scheduling: Making the Transition

    Science.gov (United States)

    Creighton, Peggy Milam

    2008-01-01

    Citing literature that supports the benefits of flexible scheduling on student achievement, the author exhorts readers to campaign for flexible scheduling in their library media centers. She suggests tips drawn from the work of Graziano (2002), McGregor (2006) and Stripling (1997) for making a smooth transition from fixed to flexible scheduling:…

  6. Probabilistic Bisimulation for Realistic Schedulers

    DEFF Research Database (Denmark)

    Eisentraut, Christian; Godskesen, Jens Christian; Hermanns, Holger

    2015-01-01

    . This holds in the classical context of arbitrary schedulers, but it has been argued that this class of schedulers is unrealistically powerful. This paper studies a strictly coarser notion of bisimilarity, which still enjoys these properties in the context of realistic subclasses of schedulers: Trace...

  7. Continuous Media Tasks Scheduling Algorithm

    Directory of Open Access Journals (Sweden)

    Myungryun Yoo

    2016-03-01

    Full Text Available In this paper the authors propose modified proportional share scheduling algorithm considering the characteristics of continuous media such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and decreases the number of context switching. Proposed scheduling algorithm is evaluated using several numerical tests under various conditions, especially overloaded situation.

  8. Effects of surface anisotropy on magnetic vortex core

    Energy Technology Data Exchange (ETDEWEB)

    Pylypovskyi, Oleksandr V., E-mail: engraver@univ.net.ua [Taras Shevchenko National University of Kiev, 01601 Kiev (Ukraine); Sheka, Denis D. [Taras Shevchenko National University of Kiev, 01601 Kiev (Ukraine); Kravchuk, Volodymyr P.; Gaididei, Yuri [Institute for Theoretical Physics, 03143 Kiev (Ukraine)

    2014-06-01

    The vortex core shape in the three dimensional Heisenberg magnet is essentially influenced by a surface anisotropy. We predict that depending of the surface anisotropy type there appears barrel- or pillow-shaped deformation of the vortex core along the magnet thickness. Our theoretical study is well confirmed by spin–lattice simulations. - Highlights: • The shape of magnetic vortex core is essentially influenced by SA (surface anisotropy). • We predict barrel- or pillow-shaped deformation of the vortex depending on SA. • The variational approach fully describes the vortex core deformation. • We performed spin–lattice simulations to detect SA influence on the vortex core.

  9. Effect of Dzyaloshinskii–Moriya interaction on magnetic vortex

    Directory of Open Access Journals (Sweden)

    Y. M. Luo

    2014-04-01

    Full Text Available The effect of the Dzyaloshinskii–Moriya (DM interaction on the vortex in magnetic microdisk was investigated by micro-magnetic simulation based on the Landau–Lifshitz–Gilbert equation. Our results show that the DM interaction modifies the size of the vortex core, and also induces an out-of-plane magnetization component at the edge and inside the disk. The DM interaction can destabilizes one vortex handedness, generate a bias field to the vortex core and couple the vortex polarity and chirality. This DM-interaction-induced coupling can therefore provide a new way to control vortex polarity and chirality.

  10. Sculptured 3D twister superlattices embedded with tunable vortex spirals.

    Science.gov (United States)

    Xavier, Jolly; Vyas, Sunil; Senthilkumaran, Paramasivam; Denz, Cornelia; Joseph, Joby

    2011-09-01

    We present diverse reconfigurable complex 3D twister vortex superlattice structures in a large area embedded with tunable vortex spirals as well as dark rings, threaded by vortex helices. We demonstrate these tunable complex chiral vortex superlattices by the superposition of relatively phase engineered plane waves. The generated complex 3D twister lattice vortex structures are computationally as well as experimentally analyzed using various tools to verify the presence of phase singularities. Our observation indicates the application-specific flexibility of our approach to tailor the transverse superlattice spatial irradiance profile of these longitudinally whirling vortex-cluster units and dark rings.

  11. Vortex loops entry into type-II superconductors

    CERN Document Server

    Samokhvalov, A V

    1996-01-01

    The magnetic field distribution, the magnetic flux, and the free energy of an Abrikosov vortex loop near a flat surface of type--II superconductors are calculated in the London approximation. The shape of such a vortex line is a semicircle of arbitrary radius. The interaction of the vortex half--ring and an external homogeneous magnetic field applied along the surface is studied. The magnitude of the energy barrier against the vortex expansion into superconductor is found. The possibilities of formation of an equilibrium vortex line determined by the structure of the applied magnetic field by creating the expanding vortex loops near the surface of type--II superconductor are discussed.

  12. S-CHART - SCHEDULING CHART PROGRAM

    Science.gov (United States)

    Klinkner, E. R.

    1994-01-01

    The Scheduling Chart Program (S-Chart) uses simple menu choices to produce high quality Gantt type scheduling and production time-line charts with minimal data entry requirements. The software produces high quality charts (20, 40, and 80 day options) in 10-20 minutes including start up, data entry, and printing. Reprints take less than one minute. Some of the more significant features are as follows: speed and ease of use with menu driven selections from start to finish, storage and catalogs of all data sets for rapid access and manipulation, compact program size to permit storage of dozens of data sets on the program disc, and creation of ASCII text files of graphs for rapid printing. The final product of the plot routine is an extended ASCII character file which shows the events scheduled and actual work dates. This file may be printed from the program, from DOS, or imported to a word processor for customizing. S-Chart is not intended to take the place of commercial scheduling/project management software. However, it is a simple, somewhat limited Gantt chart plotter and scheduling tracking program with an emphasis on straightforward data entry. There is no complex relationship building between the scheduled events. Dates are entered as dates, not as algebraic functions. All the files of S-Chart, except for the graph picture and the stand-alone executable, were written in 100% dBASE III compatible code. The executable code was created with CLIPPER and the graph picture files are written in ASCII code. S-Chart was implemented on an IBM PC series machine under DOS and requires 215k bytes of memory. The program was developed in 1988.

  13. Research on schedulers for astronomical observatories

    Science.gov (United States)

    Colome, Josep; Colomer, Pau; Guàrdia, Josep; Ribas, Ignasi; Campreciós, Jordi; Coiffard, Thierry; Gesa, Lluis; Martínez, Francesc; Rodler, Florian

    2012-09-01

    The main task of a scheduler applied to astronomical observatories is the time optimization of the facility and the maximization of the scientific return. Scheduling of astronomical observations is an example of the classical task allocation problem known as the job-shop problem (JSP), where N ideal tasks are assigned to M identical resources, while minimizing the total execution time. A problem of higher complexity, called the Flexible-JSP (FJSP), arises when the tasks can be executed by different resources, i.e. by different telescopes, and it focuses on determining a routing policy (i.e., which machine to assign for each operation) other than the traditional scheduling decisions (i.e., to determine the starting time of each operation). In most cases there is no single best approach to solve the planning system and, therefore, various mathematical algorithms (Genetic Algorithms, Ant Colony Optimization algorithms, Multi-Objective Evolutionary algorithms, etc.) are usually considered to adapt the application to the system configuration and task execution constraints. The scheduling time-cycle is also an important ingredient to determine the best approach. A shortterm scheduler, for instance, has to find a good solution with the minimum computation time, providing the system with the capability to adapt the selected task to varying execution constraints (i.e., environment conditions). We present in this contribution an analysis of the task allocation problem and the solutions currently in use at different astronomical facilities. We also describe the schedulers for three different projects (CTA, CARMENES and TJO) where the conclusions of this analysis are applied to develop a suitable routine.

  14. Multiply-interacting Vortex Streets

    CERN Document Server

    Oskouei, Babak G; Newton, Paul K

    2010-01-01

    We investigate the behavior of an infinite array of (reverse) von K'arm'an streets. Our primary motivation is to model the wake dynamics in large fish schools. We ignore the fish and focus on the dynamic interaction of multiple wakes where each wake is modeled as a reverse von K'arm'an street. There exist configurations where the infinite array of vortex streets is in relative equilibrium, that is, the streets move together with the same translational velocity. We examine the topology of the streamline patterns in a frame moving with the same translational velocity as the streets which lends insight into fluid transport through the mid-wake region. Fluid is advected along different paths depending on the distance separating two adjacent streets. Generally, when the distance between the streets is large enough, each street behaves as a single von K'arm'an street and fluid moves globally between two adjacent streets. When the streets get closer to each other, the number of streets that enter into partnership in...

  15. Effect of vortex generators on the power conversion performance and structural dynamic loads of the Mod-2 wind turbine

    Science.gov (United States)

    Sullivan, T. L.

    1984-01-01

    Applying vortex generators from 20 to 100 percent span of the Mod-2 rotor resulted in a projected increase in annual energy capture of 20 percent and reduced the wind speed at which rated power is reached by nearly 3 m/sec. Application of vortex generators from 20 to 70 percent span, the fixed portion of the Mod-2 rotor, resulted in a projected increase in annual energy capture of about half this. This improved performance came at the cost of a small increase in cyclic blade loads in below rated power conditions. Cyclic blade loads were found to correlate well with the change in wind speed during one rotor revolution.

  16. Visualization and Simulation in Scheduling

    Directory of Open Access Journals (Sweden)

    R. Čapek

    2008-01-01

    Full Text Available This paper deals with the representation of scheduling results and it introduces a new tool for visualization and simulation in time scheduling called VISIS. The purpose of this tool is to provide an environment for visualization, e.g. in production line scheduling. The simulation also proposes a way to simulate the influence of a schedule on a user defined system, e.g. for designing filters in digital signal processing. VISIS arises from representing scheduling results using the well-known Gantt chart. The application is implemented in the Matlab programming environment using Simulink and the Virtual Reality toolbox. 

  17. CPU Scheduling Algorithms: A Survey

    Directory of Open Access Journals (Sweden)

    Imran Qureshi

    2014-01-01

    Full Text Available Scheduling is the fundamental function of operating system. For scheduling, resources of system shared among processes which are going to be executed. CPU scheduling is a technique by which processes are allocating to the CPU for a specific time quantum. In this paper the review of different scheduling algorithms are perform with different parameters, such as running time, burst time and waiting times etc. The reviews algorithms are first come first serve, Shortest Job First, Round Robin, and Priority scheduling algorithm.

  18. Hanford Site Environmental Surveillance Master Sampling Schedule for Calendar Year 2011

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2011-01-21

    This document contains the calendar year 2011 schedule for the routine collection of samples for the Surface Environmental Surveillance Project and the Drinking Water Monitoring Project. Each section includes sampling locations, sampling frequencies, sample types, and analyses to be performed. In some cases, samples are scheduled on a rotating basis. If a sample will not be collected in 2011, the anticipated year for collection is provided. Maps showing approximate sampling locations are included for media scheduled for collection in 2011.

  19. Hanford Site Environmental Surveillance Master Sampling Schedule for Calendar Year 2011

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2011-01-21

    This document contains the calendar year 2011 schedule for the routine collection of samples for the Surface Environmental Surveillance Project and the Drinking Water Monitoring Project. Each section includes sampling locations, sampling frequencies, sample types, and analyses to be performed. In some cases, samples are scheduled on a rotating basis. If a sample will not be collected in 2011, the anticipated year for collection is provided. Maps showing approximate sampling locations are included for media scheduled for collection in 2011.

  20. Hanford Site Environmental Surveillance Master Sampling Schedule for Calendar Year 2007

    Energy Technology Data Exchange (ETDEWEB)

    Bisping, Lynn E.

    2007-01-31

    This document contains the calendar year 2007 schedule for the routine collection of samples for the Surface Environmental Surveillance Project and Drinking Water Monitoring Project. Each section includes sampling locations, sampling frequencies, sample types, and analyses to be performed. In some cases, samples are scheduled on a rotating basis and may not be collected in 2007 in which case the anticipated year for collection is provided. Maps showing approximate sampling locations are included for media scheduled for collection in 2007.

  1. Scheduling theory, algorithms, and systems

    CERN Document Server

    Pinedo, Michael L

    2016-01-01

    This new edition of the well-established text Scheduling: Theory, Algorithms, and Systems provides an up-to-date coverage of important theoretical models in the scheduling literature as well as important scheduling problems that appear in the real world. The accompanying website includes supplementary material in the form of slide-shows from industry as well as movies that show actual implementations of scheduling systems. The main structure of the book, as per previous editions, consists of three parts. The first part focuses on deterministic scheduling and the related combinatorial problems. The second part covers probabilistic scheduling models; in this part it is assumed that processing times and other problem data are random and not known in advance. The third part deals with scheduling in practice; it covers heuristics that are popular with practitioners and discusses system design and implementation issues. All three parts of this new edition have been revamped, streamlined, and extended. The reference...

  2. Operational waste volume projection

    Energy Technology Data Exchange (ETDEWEB)

    Koreski, G.M.

    1996-09-20

    Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement. Assumptions were current as of June 1996.

  3. Vortex-Based Aero- and Hydrodynamic Estimation

    Science.gov (United States)

    Hemati, Maziar Sam

    Flow control strategies often require knowledge of unmeasurable quantities, thus presenting a need to reconstruct flow states from measurable ones. In this thesis, the modeling, simulation, and estimator design aspects of flow reconstruction are considered. First, a vortex-based aero- and hydrodynamic estimation paradigm is developed to design a wake sensing algorithm for aircraft formation flight missions. The method assimilates wing distributed pressure measurements with a vortex-based wake model to better predict the state of the flow. The study compares Kalman-type algorithms with particle filtering algorithms, demonstrating that the vortex nonlinearities require particle filters to yield adequate performance. Furthermore, the observability structure of the wake is shown to have a negative impact on filter performance regardless of the algorithm applied. It is demonstrated that relative motions can alleviate the filter divergence issues associated with this observability structure. In addition to estimator development, the dissertation addresses the need for an efficient unsteady multi-body aerodynamics testbed for estimator and controller validation studies. A pure vortex particle implementation of a vortex panel-particle method is developed to satisfy this need. The numerical method is demonstrated on the impulsive startup of a flat plate as well as the impulsive startup of a multi-wing formation. It is clear, from these validation studies, that the method is able to accommodate the unsteady wake effects that arise in formation flight missions. Lastly, successful vortex-based estimation is highly dependent on the reliability of the low-order vortex model used in representing the flow of interest. The present treatise establishes a systematic framework for vortex model improvement, grounded in optimal control theory and the calculus of variations. By minimizing model predicted errors with respect to empirical data, the shortcomings of the baseline vortex model

  4. Vortex-based line beam optical tweezers

    Science.gov (United States)

    Cheng, Shubo; Tao, Shaohua

    2016-10-01

    A vortex-based line beam, which has a straight-line shape of intensity and possesses phase gradient along the line trajectory is developed and applied for optical manipulation in this paper. The intensity and phase distributions of the beam in the imaging plane of the Fourier transform are analytically studied. Simulation results show that the length of the line and phase gradient possessed by a vortex-based line beam are dependent on the topological charge and the azimuthal proportional constant. A superposition of multiple phase-only holograms with elliptical azimuthal phases can be used to generate an array of vortex-based line beams. Optical trapping with the vortex-based line beams has been implemented. Furthermore, the automatic transportation of microparticles along the line trajectory perpendicular to the optical axis is realized with an array of the beams. The generation method for the vortex-based line beam is simple. The beam would have potential applications in fields such as optical trapping, laser machining, and so on.

  5. Vortices and vortex lattices in quantum ferrofluids

    Science.gov (United States)

    Martin, A. M.; Marchant, N. G.; O’Dell, D. H. J.; Parker, N. G.

    2017-03-01

    The experimental realization of quantum-degenerate Bose gases made of atoms with sizeable magnetic dipole moments has created a new type of fluid, known as a quantum ferrofluid, which combines the extraordinary properties of superfluidity and ferrofluidity. A hallmark of superfluids is that they are constrained to rotate through vortices with quantized circulation. In quantum ferrofluids the long-range dipolar interactions add new ingredients by inducing magnetostriction and instabilities, and also affect the structural properties of vortices and vortex lattices. Here we give a review of the theory of vortices in dipolar Bose–Einstein condensates, exploring the interplay of magnetism with vorticity and contrasting this with the established behaviour in non-dipolar condensates. We cover single vortex solutions, including structure, energy and stability, vortex pairs, including interactions and dynamics, and also vortex lattices. Our discussion is founded on the mean-field theory provided by the dipolar Gross–Pitaevskii equation, ranging from analytic treatments based on the Thomas–Fermi (hydrodynamic) and variational approaches to full numerical simulations. Routes for generating vortices in dipolar condensates are discussed, with particular attention paid to rotating condensates, where surface instabilities drive the nucleation of vortices, and lead to the emergence of rich and varied vortex lattice structures. We also present an outlook, including potential extensions to degenerate Fermi gases, quantum Hall physics, toroidal systems and the Berezinskii–Kosterlitz–Thouless transition.

  6. Nonlinear ion acoustic waves scattered by vortexes

    CERN Document Server

    Ohno, Yuji

    2015-01-01

    The Kadomtsev--Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes `scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are `ambient' because they do not receive reciprocal reactions from the waves (i.e.,...

  7. An integrated scheduling and program management system

    Science.gov (United States)

    Porter, D.; Gibson, J. D.; Williams, G. G.

    2012-09-01

    An integrated scheduling and program management system is being developed for the MMT Observatory (MMTO), Arizona, USA. A systems engineering approach is used to combine existing and new relational databases, spreadsheets, file storage systems, and web-based user interfaces into a single unified system. An overview of software design, data management, user interfaces, and techniques for performance assessment is presented. Goals of this system include streamlined data management and an optimized user experience. The MMTO has over a dozen different telescope configurations, including three secondary mirrors and a wide range of observing instruments. Scheduling is complex for the varying telescope configurations, limited available observing time, and appropriate astronomic conditions (e.g., lunar phase) for each science project. Scheduled telescope configurations can be used to perform safety checks of actual configuration during telescope operations. Programmatic information is automatically input into nightly telescope operator (TO) logs by the system. The TO's provide additional information into the system on telescope usage, observing conditions (e.g., weather conditions), and observatory closure (e.g., from instrument malfunction or inclement weather). All of this information is synthesized to assess telescope and observatory performance. Web interfaces to the system can be used by observers to submit information, such as travel plans, instrumentation requirements, and observing catalogs. A service request (SR) (i.e., trouble report) system has also been developed for tracking operational issues. The specific needs of the MMTO have been met through in-house software development of this integrated scheduling and program management system.

  8. The LSST Scheduler from design to construction

    Science.gov (United States)

    Delgado, Francisco; Reuter, Michael A.

    2016-07-01

    The Large Synoptic Survey Telescope (LSST) will be a highly robotic facility, demanding a very high efficiency during its operation. To achieve this, the LSST Scheduler has been envisioned as an autonomous software component of the Observatory Control System (OCS), that selects the sequence of targets in real time. The Scheduler will drive the survey using optimization of a dynamic cost function of more than 200 parameters. Multiple science programs produce thousands of candidate targets for each observation, and multiple telemetry measurements are received to evaluate the external and the internal conditions of the observatory. The design of the LSST Scheduler started early in the project supported by Model Based Systems Engineering, detailed prototyping and scientific validation of the survey capabilities required. In order to build such a critical component, an agile development path in incremental releases is presented, integrated to the development plan of the Operations Simulator (OpSim) to allow constant testing, integration and validation in a simulated OCS environment. The final product is a Scheduler that is also capable of running 2000 times faster than real time in simulation mode for survey studies and scientific validation during commissioning and operations.

  9. SCHEDULING PROBLEMS-AN OVERVIEW

    Institute of Scientific and Technical Information of China (English)

    Asmuliardi MULUK; Hasan AKPOLAT; Jichao XU

    2003-01-01

    There seems to be a significant gap between the theoretical and the practical aspects of scheduling problems in the job shop environment. Theoretically, scheduling systems are designed on the basis of an optimum approach to the scheduling model. However in the practice, the optimum that is built into the scheduling applications seems to face some challenges when dealing with the dynamic character of a scheduling system, for instance machine breakdown or change of orders. Scheduling systems have become quite complex in the past few years. Competitive business environments and shorter product life cycles are the imminent challenges being faced by many companies these days.These challenges push companies to anticipate a demand driven supply chain in their business environment. A demand-driven supply chain incorporates the customer view into the supply chain processes. As a consequence of this, scheduling as a core process of the demand-driven supply chain must also reflect the customer view. In addition, other approaches to solving scheduling problems, for instance approaches based on human factors, prefer the scheduling system to be more flexible in both design and implementation. After discussion of these factors, the authors propose the integration of a different set of criteria for the development of scheduling systems which not only appears to have a better flexibility but also increased customer-focus.

  10. Optical vortex array in spatially varying lattice

    CERN Document Server

    Kapoor, Amit; Senthilkumaran, P; Joseph, Joby

    2015-01-01

    We present an experimental method based on a modified multiple beam interference approach to generate an optical vortex array arranged in a spatially varying lattice. This method involves two steps which are: numerical synthesis of a consistent phase mask by using two-dimensional integrated phase gradient calculations and experimental implementation of produced phase mask by utilizing a phase only spatial light modulator in an optical 4f Fourier filtering setup. This method enables an independent variation of the orientation and period of the vortex lattice. As working examples, we provide the experimental demonstration of various spatially variant optical vortex lattices. We further confirm the existence of optical vortices by formation of fork fringes. Such lattices may find applications in size dependent trapping, sorting, manipulation and photonic crystals.

  11. Scattering by a draining bathtub vortex

    Science.gov (United States)

    Dolan, Sam R.; Oliveira, Ednilton S.

    2013-06-01

    We present an analysis of scattering by a fluid-mechanical “black hole analogue,” known as the draining bathtub vortex: a two-dimensional flow that possesses both a sonic horizon and an ergoregion. We consider the scattering of a plane wave of fixed frequency impinging upon the vortex. At low frequency, we encounter a modified Aharonov-Bohm effect. At high frequencies, we observe regular “orbiting” oscillations in the scattering length, due to interference between contra-orbiting rays. We present approximate formulas for both effects and a selection of numerical results obtained by summing partial-wave series. Finally, we examine interference patterns in the vicinity of the vortex and highlight the prospects for experimental investigation.

  12. Scattering by a draining bathtub vortex

    CERN Document Server

    Dolan, Sam R

    2013-01-01

    We present an analysis of scattering by a fluid-mechanical `black hole analogue', known as the draining bathtub (DBT) vortex: a two-dimensional flow which possesses both a sonic horizon and an ergoregion. We consider the scattering of a plane wave of fixed frequency impinging upon the vortex. At low frequency, we encounter a modified Aharonov-Bohm effect. At high frequencies, we observe regular `orbiting' oscillations in the scattering length, due to interference between contra-orbiting rays. We present approximate formulae for both effects, and a selection of numerical results obtained by summing partial-wave series. Finally, we examine interference patterns in the vicinity of the vortex, and highlight the prospects for experimental investigation.

  13. Alternate powers in Serrin's swirling vortex solutions

    CERN Document Server

    Bělík, Pavel; Scholz, Kurt; Shvartsman, Mikhail M

    2012-01-01

    We consider a modification of the fluid flow model for a swirling vortex developed by J. Serrin, where velocity decreases as the reciprocal of the distance from the vortex axis. Recent studies, based on radar data of selected severe weather events, indicate that the angular momentum in a tornado may not be constant with the radius, and thus suggest a different scaling of the velocity/radial distance dependence. Motivated by this suggestion, we consider Serrin's approach with the assumption that the velocity decreases as the reciprocal of the distance from the vortex axis to the power b with a general b>0. This leads to a boundary-value problem for a system of nonlinear differential equations. We analyze this problem for particular cases, both with nonzero and zero viscosity, discuss the question of existence of solutions, and use numerical techniques to describe those solutions that we cannot obtain analytically.

  14. Holographic Vortex Pair Annihilation in Superfluid Turbulence

    CERN Document Server

    Du, Yiqiang; Tian, Yu; Zhang, Hongbao

    2014-01-01

    We make a first principles investigation of the dynamical evolution of vortex number in a two-dimensional (2D) turbulent superfluid by holography through numerically solving its highly non-trivial gravity dual. With the randomly placed vortices and antivortices prepared as initial states, we find that the temporal evolution of the vortex number can be well fit statistically by two-body decay due to the vortex pair annihilation featured relaxation process remarkably from a very early time on. In particular, subtracted by the universal offset, the power law fit indicates that our holographic turbulent superfluid exhibits an apparently different decay pattern from the superfluid recently experimented in highly oblate Bose-Einstein condensates.

  15. Vortex knots in tangled quantum eigenfunctions

    CERN Document Server

    Taylor, Alexander J

    2016-01-01

    Tangles of string typically become knotted, from macroscopic twine down to long-chain macromolecules such as DNA. Here we demonstrate that knotting also occurs in quantum wavefunctions, where the tangled filaments are vortices (nodal lines/phase singularities). The probability that a vortex loop is knotted is found to increase with its length, and a wide gamut of knots from standard tabulations occur. The results follow from computer simulations of random superpositions of degenerate eigenstates of three simple quantum systems: a cube with periodic boundaries, the isotropic 3-dimensional harmonic oscillator and the 3-sphere. In the latter two cases, vortex knots occur frequently, even in random eigenfunctions at relatively low energy, and are constrained by the spatial symmetries of the modes. The results suggest that knotted vortex structures are generic in complex 3-dimensional wave systems, establishing a topological commonality between wave chaos, polymers and turbulent Bose-Einstein condensates.

  16. Vortex noise from nonrotating cylinders and airfoils

    Science.gov (United States)

    Schlinker, R. H.; Amiet, R. K.; Fink, M. R.

    1976-01-01

    An experimental study of vortex-shedding noise was conducted in an acoustic research tunnel over a Reynolds-number range applicable to full-scale helicopter tail-rotor blades. Two-dimensional tapered-chord nonrotating models were tested to simulate the effect of spanwise frequency variation on the vortex-shedding mechanism. Both a tapered circular cylinder and tapered airfoils were investigated. The results were compared with data for constant-diameter cylinder and constant-chord airfoil models also tested during this study. Far-field noise, surface pressure fluctuations, and spanwise correlation lengths were measured for each configuration. Vortex-shedding noise for tapered cylinders and airfoils was found to contain many narrowband-random peaks which occurred within a range of frequencies corresponding to a predictable Strouhal number referenced to the maximum and minimum chord. The noise was observed to depend on surface roughness and Reynolds number.

  17. Convectively driven vortex flows in the Sun

    CERN Document Server

    Bonet, J A; Almeida, J Sanchez; Cabello, I; Domingo, V

    2008-01-01

    We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.

  18. Downstream Thermal Evolution of Vortex Cores

    Science.gov (United States)

    Gómez-Barea, A.; Herrada, M. A.; Pérez-Saborid, M.; Barrero, A.

    1999-11-01

    The downstream evolution of the total temperature field in a quasi-incompressible axisymmetric vortex core has been computed. Starting at an initial station (z=0) with velocity profiles of the Burgers type and given temperature distributions, the numerical results of the evolution show that, according to experimental results, the total temperature in the near-axis region decreases substantially due to the work done by pressure and viscous forces together with the effect of both convection and conduction of heat. Depending on the values of the parameters characterizing the initial profiles and on the value of the Prandtl number, the vortex either breaks down or eventually reaches a self-similar regime. The results obtained shed light on the basic physics involved in the thermal separation phenomenon which appears inside Ranque-Hilsch vortex tubes.

  19. Chiral specific electron vortex beam spectroscopy

    CERN Document Server

    Yuan, J; Babiker, M

    2013-01-01

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  20. Introduction to vortex filaments in equilibrium

    CERN Document Server

    Andersen, Timothy D

    2014-01-01

    This book presents fundamental concepts and seminal results to the study of vortex filaments in equilibrium. It also presents new discoveries in quasi-2D vortex structures with applications to geophysical fluid dynamics and magnetohydrodynamics in plasmas.  It fills a gap in the vortex statistics literature by simplifying the mathematical introduction to this complex topic, covering numerical methods, and exploring a wide range of applications with numerous examples. The authors have produced an introduction that is clear and easy to read, leading the reader step-by-step into this topical area. Alongside the theoretical concepts and mathematical formulations, interesting applications are discussed. This combination makes the text useful for students and researchers in mathematics and physics.