Energy Technology Data Exchange (ETDEWEB)
Egli, S.
2005-07-01
In municipal waste treatment plants energy is produced by burning the waste in a boiler. The hot flue gases from the boiler are cooled when they transfer their heat energy to steam passing through nearby pipes. This heated steam, in turn, not only transfers its energy to a turbogenerator to produce electricity, but is also used for district heating (hot water and/or steam). The electricity from the turbogenerator is used for the plant's own needs and surplus power is sold to the public grid. The overall energy efficiency of individual plants vary from under 20% for pure generation of electricity to over 70% for combined heat and power generation and year-round utilisation of heat. A rough evaluation of the existing statistical data of Swiss waste treatment plants shows that both the generation of electricity and implementation of district heating have a considerable potential for optimisation. The generation of electricity has a considerable optimisation potential realisable by not only lowering the plant's own electricity consumption, but also by increasing the efficiency of the electricity generation itself. This report offers a summary of solutions for overall optimisation and provides a catalogue of measures including checklists for the individual plant areas, allowing improvement measures to be systematically determined. The checklists are thus an aid allowing fast estimation of the optimisation potential. (author)
Coşkun, Filiz; Sayalı, Zeynep Ceyda; Gürbüz, Emine; Balcı, Fuat
2015-01-01
Optimal Time Discrimination Journal: Quarterly Journal of Experimental Psychology Manuscript ID: QJE-STD 14-039.R1 Manuscript Type: Standard Article Date Submitted by the Author: n/a Complete List of Authors: Çoskun, Filiz; Koç University, Psychology Sayalı Ungerer, Zeynep; Koç University, Psychology Gürbüz, Emine; Koç University, Psychology Balcı, Fuat; Koç University, Psychology Keywords: Decision making, Interval Timing, Optimality, Response Times, Temporal ...
Real time production optimization
Energy Technology Data Exchange (ETDEWEB)
Saputelli, Luigi; Otavio, Joao; Araujo, Turiassu; Escorcia, Alvaro [Halliburton, Houston, TX (United States). Landmark Division
2004-07-01
Production optimization encompasses various activities of measuring, analyzing, modeling, prioritizing and implementing actions to enhance productivity of a field. We present a state-of-the-art framework for optimizing production on a continuous basis as new sensor data is acquired in real time. Permanently acquired data is modeled and analyzed in order to create predictive models. A model based control strategy is used to regulate well and field instrumentation. The optimum field operating point, which changes with time, satisfies the maximum economic return. This work is a starting point for further development in automatic, intelligent reservoir technologies which get the most out of the abilities of permanent, instrumented wells and remotely activated downhole completions. The strategy, tested with history-matched data from a compartmentalised giant field, proved to reduce operating costs while increasing oil recovery by 27% in this field. (author)
... Prevention Week National Prescription Drug Take-Back Day Emergency Checklist If someone may have been poisoned, call ... may save you from a visit to the emergency room. Below is a checklist to help you ...
Time-Space Topology Optimization
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard
2008-01-01
A method for space-time topology optimization is outlined. The space-time optimization strategy produces structures with optimized material distributions that vary in space and in time. The method is demonstrated for one-dimensional wave propagation in an elastic bar that has a time-dependent Young...
Time-Space Topology Optimization
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard
2008-01-01
A method for space-time topology optimization is outlined. The space-time optimization strategy produces structures with optimized material distributions that vary in space and in time. The method is demonstrated for one-dimensional wave propagation in an elastic bar that has a time-dependent Young......’s modulus and is subjected to a transient load. In the example an optimized dynamic structure is demonstrated that compresses a propagating Gauss pulse....
Checklists for external validity
DEFF Research Database (Denmark)
Dyrvig, Anne-Kirstine; Kidholm, Kristian; Gerke, Oke; Vondeling, Hindrik
2014-01-01
RATIONALE, AIMS AND OBJECTIVES: The quality of the current literature on external validity varies considerably. An improved checklist with validated items on external validity would aid decision-makers in judging similarities among circumstances when transferring evidence from a study setting to an....... The retrieved checklist items were assessed for (i) the methodology used in primary literature, justifying inclusion of each item; and (ii) the number of times each item appeared in checklists. RESULTS: Fifteen papers were identified, presenting a total of 21 checklists for external validity, yielding...... a total of 38 checklist items. Empirical support was considered the most valid methodology for item inclusion. Assessment of methodological justification showed that none of the items were supported empirically. Other kinds of literature justified the inclusion of 22 of the items, and 17 items were...
Is it time to use checklists in mental health care auditing?
Directory of Open Access Journals (Sweden)
Jacob Polackiewicz
2011-02-01
Full Text Available A key strategy for improving the quality of mental health care is the design and implementation of a mechanism for on-site inspection and clinical auditing. We discuss the use of checklists in auditing providing an objective, comprehensive system for recording and analyzing multi-disciplinary, clinical auditing in mental health services. We believe such an approach can identify potential risks and allow for better decision making.
Is it time to use checklists in mental health care auditing?
Abramowitz, Moshe Z.; Polackiewicz, Jacob; Grinshpoon, Alexander
2011-01-01
A key strategy for improving the quality of mental health care is the design and implementation of a mechanism for on-site inspection and clinical auditing. We discuss the use of checklists in auditing providing an objective, comprehensive system for recording and analyzing multi-disciplinary, clinical auditing in mental health services. We believe such an approach can identify potential risks and allow for better decision making. PMID:25478101
Directory of Open Access Journals (Sweden)
Gerald Sendlhofer
Full Text Available A surgical safety checklist (SSC was implemented and routinely evaluated within our hospital. The purpose of this study was to analyze compliance, knowledge of and satisfaction with the SSC to determine further improvements.The implementation of the SSC was observed in a pilot unit. After roll-out into each operating theater, compliance with the SSC was routinely measured. To assess subjective and objective knowledge, as well as satisfaction with the SSC implementation, an online survey (N = 891 was performed.During two test runs in a piloting unit, 305 operations were observed, 175 in test run 1 and 130 in test run 2. The SSC was used in 77.1% of all operations in test run 1 and in 99.2% in test run 2. Within used SSCs, completion rates were 36.3% in test run 1 and 1.6% in test run 2. After roll-out, three unannounced audits took place and showed that the SSC was used in 95.3%, 91.9% and 89.9%. Within used SSCs, completion rates decreased from 81.7% to 60.6% and 53.2%. In 2014, 164 (18.4% operating team members responded to the online survey, 160 of which were included in the analysis. 146 (91.3% consultants and nursing staff reported to use the SSC regularly in daily routine.These data show that the implementation of new tools such as the adapted WHO SSC needs constant supervision and instruction until it becomes self-evident and accepted. Further efforts, consisting mainly of hands-on leadership and training are necessary.
TimeNET Optimization Environment
Directory of Open Access Journals (Sweden)
Christoph Bodenstein
2015-12-01
Full Text Available In this paper a novel tool for simulation-based optimization and design-space exploration of Stochastic Colored Petri nets (SCPN is introduced. The working title of this tool is TimeNET Optimization Environment (TOE. Targeted users of this tool are people modeling complex systems with SCPNs in TimeNET who want to find parameter sets that are optimal for a certain performance measure (fitness function. It allows users to create and simulate sets of SCPNs and to run different optimization algorithms based on parameter variation. The development of this tool was motivated by the need to automate and speed up tests of heuristic optimization algorithms to be applied for SCPN optimization. A result caching mechanism is used to avoid recalculations.
A Quasi Time Optimal Receding Horizon Control
Bania, Piotr
2007-01-01
This paper presents a quasi time optimal receding horizon control algorithm. The proposed algorithm generates near time optimal control when the state of the system is far from the target. When the state attains a certain neighbourhood of the aim, it begins the adaptation of the cost function. The purpose of this adaptation is to move from the time optimal control to the stabilizing control. Sufficient conditions for the stability of the closed loop system and the manner of the adaptation of ...
Time optimal paths for high speed maneuvering
Energy Technology Data Exchange (ETDEWEB)
Reister, D.B.; Lenhart, S.M.
1993-01-01
Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.
Nursing home checklist Name of nursing home: ____________________________________________________ Address: ________________________________________________________________ Phone number: __________________________________________________________ Date of visit: _____________________________________________________________ Basic information Yes No Notes Is the nursing home Medicare certified? Is the nursing ...
A Checklist to Improve Patient Safety in Interventional Radiology
International Nuclear Information System (INIS)
To develop a specific RADiological Patient Safety System (RADPASS) checklist for interventional radiology and to assess the effect of this checklist on health care processes of radiological interventions. On the basis of available literature and expert opinion, a prototype checklist was developed. The checklist was adapted on the basis of observation of daily practice in a tertiary referral centre and evaluation by users. To assess the effect of RADPASS, in a series of radiological interventions, all deviations from optimal care were registered before and after implementation of the checklist. In addition, the checklist and its use were evaluated by interviewing all users. The RADPASS checklist has two parts: A (Planning and Preparation) and B (Procedure). The latter part comprises checks just before starting a procedure (B1) and checks concerning the postprocedural care immediately after completion of the procedure (B2). Two cohorts of, respectively, 94 and 101 radiological interventions were observed; the mean percentage of deviations of the optimal process per intervention decreased from 24 % before implementation to 5 % after implementation (p < 0.001). Postponements and cancellations of interventions decreased from 10 % before implementation to 0 % after implementation. Most users agreed that the checklist was user-friendly and increased patient safety awareness and efficiency. The first validated patient safety checklist for interventional radiology was developed. The use of the RADPASS checklist reduced deviations from the optimal process by three quarters and was associated with less procedure postponements.
Optimizing departure times in vehicle routes
Kok, A.L.; Hans, E.W.; Schutten, J.M.J.
2008-01-01
Most solution methods for the vehicle routing problem with time windows (VRPTW) develop routes from the earliest feasible departure time. However, in practice, temporal traffic congestions make that such solutions are not optimal with respect to minimizing the total duty time. Furthermore, VRPTW sol
Time Optimal Reachability Analysis Using Swarm Verification
DEFF Research Database (Denmark)
Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand
2016-01-01
and planning problems, response time optimization etc. We propose swarm verification to accelerate time optimal reachability using the real-time model-checker Uppaal. In swarm verification, a large number of model checker instances execute in parallel on a computer cluster using different, typically randomized...... search strategies. We develop four swarm algorithms and evaluate them with four models in terms scalability, and time- and memory consumption. Three of these cooperate by exchanging costs of intermediate solutions to prune the search using a branch-and-bound approach. Our results show that swarm...
Optimization of time characteristics in activation analysis
International Nuclear Information System (INIS)
Full text: The activation analysis temporal characteristics optimization methods developed at present are aimed at determination of optimal values of the three important parameters - irradiation time, cooling time and measurement time. In the performed works, especially in [1-5] the activation analysis processes are described, the optimal values of optimization parameters are obtained from equations solved, and the computational results are given for these parameters for a number of elements. However, the equations presented in [2] were inaccurate, did not allow one to have optimization parameters results for one element content calculations, and it did not take into account background dependence of time. Therefore, we proposed modified equations to determine the optimal temporal parameters and iteration processes for the solution of these equations. It is well-known that the activity of studied sample during measurements does not change significantly, i.e. measurement time is much shorter than the half-life, thus the processes taking place can be described by the Poisson probability distribution, and in general case one can apply binomial distribution. The equation and iteration processes use in this research describe both probability distributions. Expectedly, the cooling time iteration expressions obtained for one element analysis case are similar for the both distribution types, as the optimised time values occurred to be of the same order as half-life values, whereas the cooling time, as we observed, depends on the ratio of the studied sample's peak value to the background peak, and can be significantly larger than the half-life value. This pattern is general, and can be derived from the optimized time expressions, which is supported by the experimental data on short-living isotopes [3,4]. For the isotopes with large half-lives, up to years, like cobalt-60, the cooling time values given in the above mentioned works are equal to months which, apparently
Optimal Investment Strategy to Minimize Occupation Time
Bayraktar, Erhan
2008-01-01
We find the optimal investment strategy to minimize the expected time that an individual's wealth stays below zero, the so-called {\\it occupation time}. The individual consumes at a constant rate and invests in a Black-Scholes financial market consisting of one riskless and one risky asset, with the risky asset's price process following a geometric Brownian motion. We also consider an extension of this problem by penalizing the occupation time for the degree to which wealth is negative.
... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... Weather Information on Specific Types of Emergencies Winter Weather Checklists Language: English Español (Spanish) Recommend on Facebook ...
Optimal lead time for dengue forecast.
Directory of Open Access Journals (Sweden)
Yien Ling Hii
Full Text Available BACKGROUND: A dengue early warning system aims to prevent a dengue outbreak by providing an accurate prediction of a rise in dengue cases and sufficient time to allow timely decisions and preventive measures to be taken by local authorities. This study seeks to identify the optimal lead time for warning of dengue cases in Singapore given the duration required by a local authority to curb an outbreak. METHODOLOGY AND FINDINGS: We developed a Poisson regression model to analyze relative risks of dengue cases as functions of weekly mean temperature and cumulative rainfall with lag times of 1-5 months using spline functions. We examined the duration of vector control and cluster management in dengue clusters > = 10 cases from 2000 to 2010 and used the information as an indicative window of the time required to mitigate an outbreak. Finally, we assessed the gap between forecast and successful control to determine the optimal timing for issuing an early warning in the study area. Our findings show that increasing weekly mean temperature and cumulative rainfall precede risks of increasing dengue cases by 4-20 and 8-20 weeks, respectively. These lag times provided a forecast window of 1-5 months based on the observed weather data. Based on previous vector control operations, the time needed to curb dengue outbreaks ranged from 1-3 months with a median duration of 2 months. Thus, a dengue early warning forecast given 3 months ahead of the onset of a probable epidemic would give local authorities sufficient time to mitigate an outbreak. CONCLUSIONS: Optimal timing of a dengue forecast increases the functional value of an early warning system and enhances cost-effectiveness of vector control operations in response to forecasted risks. We emphasize the importance of considering the forecast-mitigation gaps in respective study areas when developing a dengue forecasting model.
Argos: An Optimized Time-Series Photometer
Indian Academy of Sciences (India)
Anjum S. Mukadam; R. E. Nather
2005-06-01
We designed a prime focus CCD photometer, Argos, optimized for high speed time-series measurements of blue variables (Nather & Mukadam 2004) for the 2.1 m telescope at McDonald Observatory. Lack of any intervening optics between the primary mirror and the CCD makes the instrument highly efficient.We measure an improvement in sensitivity by a factor of nine over the 3-channel PMT photometers used on the same telescope and for the same exposure time. The CCD frame transfer operation triggered by GPS synchronized pulses serves as an electronic shutter for the photometer. This minimizes the dead time between exposures, but more importantly, allows a precise control of the start and duration of the exposure. We expect the uncertainty in our timing to be less than 100 s.
Distributed System Design Checklist
Hall, Brendan; Driscoll, Kevin
2014-01-01
This report describes a design checklist targeted to fault-tolerant distributed electronic systems. Many of the questions and discussions in this checklist may be generally applicable to the development of any safety-critical system. However, the primary focus of this report covers the issues relating to distributed electronic system design. The questions that comprise this design checklist were created with the intent to stimulate system designers' thought processes in a way that hopefully helps them to establish a broader perspective from which they can assess the system's dependability and fault-tolerance mechanisms. While best effort was expended to make this checklist as comprehensive as possible, it is not (and cannot be) complete. Instead, we expect that this list of questions and the associated rationale for the questions will continue to evolve as lessons are learned and further knowledge is established. In this regard, it is our intent to post the questions of this checklist on a suitable public web-forum, such as the NASA DASHLink AFCS repository. From there, we hope that it can be updated, extended, and maintained after our initial research has been completed.
Optimal timing of carbon sequestration policies
Lafforgue, Gilles; MOREAUX Michel
2015-01-01
Carbon capture and storage (CCS) is one of the most promising abatement options to curb CO2 emissions of the energy sector. Usually, in models where the atmospheric carbon stock is constrained to not exceed a given ceiling and under constant average costs, it is never optimal to deploy CCS before the time at which this ceiling is reached. In this paper, we show that, when the CCS technology is submitted to decreasing returns to scale, abatement activities must begin earlier, i.e. before the c...
Checklist for clinical readiness published
Scientists from NCI, together with collaborators from outside academic centers, have developed a checklist of criteria to evaluate the readiness of complex molecular tests that will guide decisions made during clinical trials. The checklist focuses on tes
A Perspective on Behaviour Checklists.
Colmar, Susan
1988-01-01
Discusses the growing use by educational psychologists and teachers of developmental and academic behavior checklists. Identifies the minimum criteria necessary for checklists and criticizes their use as many fail to meet these standards. Describes the limitations, misuse, and narrow focus of behavior checklists. (GEA)
DETERMINATION METHOD OF OPTIMAL SUPPORTING TIME IN HEADING FACE
Institute of Scientific and Technical Information of China (English)
杜长龙; 曹红波; 王燕宁; 张艳
1997-01-01
This paper has put forward a concept of optimal supporting time through analysing the influence of the supporting time in the heading face on the supporting result of surrounding rock. The method of the optimal supporting time determined by graphical method is discussed, and the calculating formula for determining the optimal supporting time through the analysis method is derived.
Surgical checklists: the human factor.
LENUS (Irish Health Repository)
O Connor, Paul
2013-05-14
BACKGROUND: Surgical checklists has been shown to improve patient safety and teamwork in the operating theatre. However, despite the known benefits of the use of checklists in surgery, in some cases the practical implementation has been found to be less than universal. A questionnaire methodology was used to quantitatively evaluate the attitudes of theatre staff towards a modified version of the World Health Organisation (WHO) surgical checklist with relation to: beliefs about levels of compliance and support, impact on patient safety and teamwork, and barriers to the use of the checklist. METHODS: Using the theory of planned behaviour as a framework, 14 semi-structured interviews were conducted with theatre personnel regarding their attitudes towards, and levels of compliance with, a checklist. Based upon the interviews, a 27-item questionnaire was developed and distribute to all theatre personnel in an Irish hospital. RESULTS: Responses were obtained from 107 theatre staff (42.6% response rate). Particularly for nurses, the overall attitudes towards the effect of the checklist on safety and teamworking were positive. However, there was a lack of rigour with which the checklist was being applied. Nurses were significantly more sensitive to the barriers to the use of the checklist than anaesthetists or surgeons. Moreover, anaesthetists were not as positively disposed to the surgical checklist as surgeons and nurse. This finding was attributed to the tendency for the checklist to be completed during a period of high workload for the anaesthetists, resulting in a lack of engagement with the process. CONCLUSION: In order to improve the rigour with which the surgical checklist is applied, there is a need for: the involvement of all members of the theatre team in the checklist process, demonstrated support for the checklist from senior personnel, on-going education and training, and barriers to the implementation of the checklist to be addressed.
Time optimal control problems for some non-smooth systems
Lou, Hongwei; Wen, Junjie; Xu, Yashan
2013-01-01
Time optimal control problems for some non-smooth systems in general form are considered. The non-smoothness is caused by singularity. It is proved that Pontryagin's maximum principle holds for at least one optimal relaxed control. Thus, Pontryagin's maximum principle holds when the optimal classical control is a unique optimal relaxed control. By constructing an auxiliary controlled system which admits the original optimal classical control as its unique optimal relaxed control, one get a ch...
Time optimal paths for a constant speed unicycle
Energy Technology Data Exchange (ETDEWEB)
Reister, D.B.
1991-01-01
This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed unicycle. The time optimal paths consist of sequences of arcs of circles and straight lines. The maximum principle introduced concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. 10 refs., 6 figs.
Optimizing near real time accountability for reprocessing
International Nuclear Information System (INIS)
Near Real Time Accountability (NRTA) of actinides at high precision in reprocessing plants has been a long sought-after goal in the safeguards community. Achieving this goal is hampered by the difficulty of making precision measurements in the reprocessing environment, equipment cost, and impact to plant operations. Thus the design of future reprocessing plants requires an optimization of different approaches. The Separations and Safeguards Performance Model, developed at Sandia National Laboratories, was used to evaluate a number of NRTA strategies in a UREX+ reprocessing plant. Strategies examined include the incorporation of additional actinide measurements of internal plant vessels, more use of process monitoring data, and the option of periodic draining of inventory to key tanks. Preliminary results show that the addition of measurement technologies can increase the overall measurement uncertainty due to additional error propagation, so care must be taken when designing an advanced system. Initial results also show that relying on a combination of different NRTA techniques will likely be the best option. The model provides a platform for integrating all the data. The modeling results for the different NRTA options under various material loss conditions will be presented.
Human Factors Checklist: Think Human Factors - Focus on the People
Miller, Darcy; Stelges, Katrine; Barth, Timothy; Stambolian, Damon; Henderson, Gena; Dischinger, Charles; Kanki, Barbara; Kramer, Ian
2016-01-01
A quick-look Human Factors (HF) Checklist condenses industry and NASA Agency standards consisting of thousands of requirements into 14 main categories. With support from contractor HF and Safety Practitioners, NASA developed a means to share key HF messages with Design, Engineering, Safety, Project Management, and others. It is often difficult to complete timely assessments due to the large volume of HF information. The HF Checklist evolved over time into a simple way to consider the most important concepts. A wide audience can apply the checklist early in design or through planning phases, even before hardware or processes are finalized or implemented. The checklist is a good place to start to supplement formal HF evaluation. The HF Checklist was based on many Space Shuttle processing experiences and lessons learned. It is now being applied to ground processing of new space vehicles and adjusted for new facilities and systems.
The effect of optimism bias on time preference
Tal Shavit
2013-01-01
This paper examines the effect of optimism bias on monetary time preference and risk tolerance. The results of a survey show that preference towards the present increases with optimism bias. I argue that the factor which affects time preference is the individualâ€™s concern regarding future events, as measured by optimism bias.
Surgical Safety Checklists : an Update
BERGS, J.; Hellings, Johan; CLEEMPUT, Irina; SIMONS, Pascale; ZUREL, Ozhan; Vertriest, Sonja; Vandijck, Dominique
2014-01-01
Surgical safety checklists aim to improve patient safety by prompting the attention of the surgical team towards critical steps during the operation. The checklist's items are aimed to improve compliance with proven interventions, and to facilitate multidisciplinary communication and teamwork. Based on the current literature, corroborated by systematic reviews and meta-analysis, surgical safety checklists have a positive impact on communication and reduce postoperative complications including...
Surgical checklists: the human factor
O’Connor, Paul; Reddin, Catriona; O’Sullivan, Michael; O’Duffy, Fergal; Keogh, Ivan
2013-01-01
Background Surgical checklists has been shown to improve patient safety and teamwork in the operating theatre. However, despite the known benefits of the use of checklists in surgery, in some cases the practical implementation has been found to be less than universal. A questionnaire methodology was used to quantitatively evaluate the attitudes of theatre staff towards a modified version of the World Health Organisation (WHO) surgical checklist with relation to: beliefs about levels of compli...
System optimal traffic assignment with departure time choice
Chow, A. H. F.
2007-01-01
This thesis investigates analytical dynamic system optimal assignment with departure time choice in a rigorous and original way. Dynamic system optimal assignment is formulated here as a state-dependent optimal control problem. A fixed volume of traffic is assigned to departure times and routes such that the total system travel cost is minimized. Although the system optimal assignment is not a realistic representation of traffic, it provides a bound on performance and shows how...
Human factors of flight-deck checklists: The normal checklist
Degani, Asaf; Wiener, Earl L.
1991-01-01
Although the aircraft checklist has long been regarded as the foundation of pilot standardization and cockpit safety, it has escaped the scrutiny of the human factors profession. The improper use, or the non-use, of the normal checklist by flight crews is often cited as the probable cause or at least a contributing factor to aircraft accidents. An attempt is made to analyze the normal checklist, its functions, format, design, length, usage, and the limitations of the humans who must interact with it. The development of the checklist from the certification of a new model to its delivery and use by the customer are discussed. The influence of the government, particularly the FAA Principle Operations Inspector, the manufacturer's philosophy, the airline's culture, and the end user, the pilot, influence the ultimate design and usage of this device. The effects of airline mergers and acquisitions on checklist usage and design are noted. In addition, the interaction between production pressures and checklist usage and checklist management are addressed. Finally, a list of design guidelines for normal checklists is provided.
Computational methods to obtain time optimal jet engine control
Basso, R. J.; Leake, R. J.
1976-01-01
Dynamic Programming and the Fletcher-Reeves Conjugate Gradient Method are two existing methods which can be applied to solve a general class of unconstrained fixed time, free right end optimal control problems. New techniques are developed to adapt these methods to solve a time optimal control problem with state variable and control constraints. Specifically, they are applied to compute a time optimal control for a jet engine control problem.
Local Times, Optimal Stopping and Semimartingales
Jacka, S. D.
1993-01-01
Let $X$ be a semimartingale, and $S$ its Snell envelope. Under the assumption that $X$ and $S$ are continuous semimartingales in $H^1$, this article obtains a new, maximal, characterisation of $S$, and gives an application to the optimal stopping of functions of diffusions. We present a counterexample to the standard assertion that $S$ is just "a martingale on the go-region and $X$ on the stop-region."
Optimal time-consistent government debt maturity
Debortoli, Davide; Nunes, Ricardo; Yared, Pierre
2016-01-01
This paper develops a model of optimal government debt maturity in which the government cannot issue state-contingent bonds and cannot commit to fiscal policy. If the government can perfectly commit, it fully insulates the economy against government spending shocks by purchasing short-term assets and issuing long-term debt. These positions are quantitatively very large relative to GDP and do not need to be actively managed by the government. Our main result is that these conclu...
Optimal Control with Time Delays via the Penalty Method
Directory of Open Access Journals (Sweden)
Mohammed Benharrat
2014-01-01
Full Text Available We prove necessary optimality conditions of Euler-Lagrange type for a problem of the calculus of variations with time delays, where the delay in the unknown function is different from the delay in its derivative. Then, a more general optimal control problem with time delays is considered. Main result gives a convergence theorem, allowing us to obtain a solution to the delayed optimal control problem by considering a sequence of delayed problems of the calculus of variations.
Time-limited optimal dynamics beyond the Quantum Speed Limit
DEFF Research Database (Denmark)
Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan;
2015-01-01
time-varying control. The problem is addressed in the framework of Hilbert space geometry offering an intuitive interpretation of optimal control algorithms. This approach leads to a necessary criterion for control optimality applicable as a measure of algorithm convergence. The time fidelity trade...
Checklists in Neurosurgery to Decrease Preventable Medical Errors: A Review.
Enchev, Yavor
2015-10-01
Neurosurgery represents a zero tolerance environment for medical errors, especially preventable ones like all types of wrong site surgery, complications due to the incorrect positioning of patients for neurosurgical interventions and complications due to failure of the devices required for the specific procedure. Following the excellent and encouraging results of the safety checklists in intensive care medicine and in other surgical areas, the checklist was naturally introduced in neurosurgery. To date, the reported world experience with neurosurgical checklists is limited to 15 series with fewer than 20,000 cases in various neurosurgical areas. The purpose of this review was to study the reported neurosurgical checklists according to the following parameters: year of publication; country of origin; area of neurosurgery; type of neurosurgical procedure-elective or emergency; person in charge of the checklist completion; participants involved in completion; whether they prevented incorrect site surgery; whether they prevented complications due to incorrect positioning of the patients for neurosurgical interventions; whether they prevented complications due to failure of the devices required for the specific procedure; their specific aims; educational preparation and training; the time needed for checklist completion; study duration and phases; number of cases included; barriers to implementation; efforts to implementation; team appreciation; and safety outcomes. Based on this analysis, it could be concluded that neurosurgical checklists represent an efficient, reliable, cost-effective and time-saving tool for increasing patient safety and elevating the neurosurgeons' self-confidence. Every neurosurgical department must develop its own neurosurgical checklist or adopt and modify an existing one according to its specific features and needs in an attempt to establish or develop its safety culture. The world, continental, regional and national neurosurgical societies
CAI, Dapeng
2008-01-01
We aim to construct the optimal solutions to the undiscounted continuous-time infinite horizon optimization problems, the objective functionals of which may be unbounded. We identify the condition under which the limit of the solutions to the finite horizon problems is optimal for the infinite horizon problems under the overtaking criterion.
Vehicle Optimal Velocity Curves for Minimum-Time Maneuver
Li-xia Zhang; Fu-quan Pan; Xiao-yuan Chen; Feng-yuan Wang; Jun Lu; Qi-ming Tong
2014-01-01
A problem in vehicle minimum-time maneuver is the assumption that a vehicle passes through a given path in a minimal amount of time without deviating from the boundary of the given path. Vehicle handling inverse dynamics provides a new perspective to solve such problem. Based on inverse dynamics, this paper transformed the problem of optimal vehicle velocity for minimum-time maneuver into that of optimal control with the objective function of minimum time. The path for minimum vehicle travel ...
Benchmarking of World Health Organization surgical safety checklist
International Nuclear Information System (INIS)
To compare the quality of our services with the World Health Organization (WHO) surgical safety recommendations as a reference, to improve our services if they fall short of that of the WHO, and to publish our additional standards, so that they may be included in future revision of WHO checklist. We conducted this study on 15th July 2008 at the Armed Forces Hospital, Wadi Al-Dawasir, Kingdom of Saudi Arabia. We compared each WHO safety standard item with its corresponding standard in our checklist. There were 4 possibilities for the comparison: that our performance meet, was less than or exceeded the quality-of-care measures in the WHO checklist, or that there are additional safety measures in either checklist that need to be considered by each party. Since its introduction in 1997, our checklist was applied to 11828 patients and resulted in error-free outcomes. Benchmarking proved that our surgical safety performance does not only match the standards of the WHO surgical safety checklist, but also exceeds it in other safety areas (for example measures to prevent perioperative hypothermia and venous thromboembolism). Benchmarking is a continuous quality improvement process aimed at providing the best available at the time in healthcare, and we recommend its adoption by healthcare providers. The WHO surgical safety checklist is a bold step in the right direction towards safer surgical outcomes. Feedback from other medical establishments should be encouraged. (author)
Optimal Infinite Runs in One-Clock Priced Timed Automata
DEFF Research Database (Denmark)
David, Alexandre; Ejsing-Duun, Daniel; Fontani, Lisa; Larsen, Kim Guldstrand; Popescu, Vasile; Haubach Smedegård, Jacob
We address the problem of finding an infinite run with the optimal cost-time ratio in a one-clock priced timed automaton and pro- vide an algorithmic solution. Through refinements of the quotient graph obtained by strong time-abstracting bisimulation partitioning, we con- struct a graph with time...... of the one-clock priced timed automaton....
Engineering applications of discrete-time optimal control
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui; Ravn, Hans V.
1990-01-01
Many problems of design and operation of engineering systems can be formulated as optimal control problems where time has been discretisized. This is also true even if 'time' is not involved in the formulation of the problem, but rather another one-dimensional parameter. This paper gives a review...... of some well-known and new results in discrete time optimal control methods applicable to practical problem solving within engineering. Emphasis is placed on dynamic programming, the classical maximum principle and generalized versions of the maximum principle for optimal control of discrete time...
Engineering applications of discrete-time optimal control
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui; Ravn, Hans V.
1990-01-01
of some well-known and new results in discrete time optimal control methods applicable to practical problem solving within engineering. Emphasis is placed on dynamic programming, the classical maximum principle and generalized versions of the maximum principle for optimal control of discrete time......Many problems of design and operation of engineering systems can be formulated as optimal control problems where time has been discretisized. This is also true even if 'time' is not involved in the formulation of the problem, but rather another one-dimensional parameter. This paper gives a review...
Time optimal route planning algorithm of LBS online navigation
Li, Yong; Bao, Shitai; Su, Kui; Fang, Qiushui; Yang, Jingfeng
2011-02-01
This paper proposes a time optimal route planning optimization algorithm in the mode of LBS online navigation based on the improved Dijkstra algorithms. Combined with the returning real-time location information by on-line users' handheld terminals, the algorithm can satisfy requirement of the optimal time in the mode of LBS online navigation. A navigation system is developed and applied in actual navigation operations. Operating results show that the algorithm could form a reasonable coordination on the basis of shortest route and fastest velocity in the requirement of optimal time. The algorithm could also store the calculated real-time route information in the cache to improve the efficiency of route planning and to reduce the planning time-consuming.
Model Parameterization Tailored to Real-Time Optimization
Chachuat, B.; Srinivasan, B.; Bonvin, D.
2008-01-01
Challenges in real-time process optimization mainly arise from the inability to build and adapt accurate models for complex physico-chemical processes. This paper surveys different ways of using measurements to compensate for model uncertainty in the context of process optimization. Three approaches can be distinguished according to the quantities that are adapted: model- parameter adaptation updates the parameters of the process model and repeats the optimization, modi...
Multicriteria Optimization of Antennas in Time-Domain
Directory of Open Access Journals (Sweden)
J. Lacik
2010-04-01
Full Text Available An original approach to the time-domain multicriteria optimization of antennas is presented. For a given excitation pulse, the time-domain objective function takes the “time-domain impedance matching”, distortion of responses at the feeding point and in a desired radiating direction (with respect to the excitation pulse, and the radiated energy in the desired direction into account. The objective function is tested on the optimization of a bow-tie antenna using the particle swarm optimization. The proposed approach is suitable for the design of broadband antennas.
Travel time impacts analysis of system-wide signal timing optimization methodology
Ainchil Cayuela, Luis María
2014-01-01
This study analyzes the economic impact that users would experience with the travel time variation due to system-wide signal timing optimization. To do this, a comprehensive analysis of travel time user benefits is conducted using traffic volume, speed and other attributes of road network, before and after signal timing optimization.
Directory of Open Access Journals (Sweden)
Sangjun Park
2014-01-01
Full Text Available We consider a two-stage supply chain with one supplier and one retailer. The retailer sells a product to customer and the supplier provides a product in a make-to-order mode. In this case, the supplier’s decisions on service time and service level and the retailer’s decision on retail price have effects on customer demand. We develop optimization models to determine the optimal retail price, the optimal guaranteed service time, the optimal service level, and the optimal capacity to maximize the expected profit of the whole supply chain. The results of numerical experiments show that it is more profitable to determine the optimal price, the optimal guaranteed service time, and the optimal service level simultaneously and the proposed model is more profitable in service level sensitive market.
Time/Computationally Optimal Network Architecture: Wireless Sensor Fusion
Devi, Gadi Gayathri; Kumari, Priya; Jyoshna, Eslavath; Deepika; Murthy, Garimella Rama
2013-01-01
In this research paper, the problems dealing with sensor network architecture, sensor fusion are addressed. Time/Computationally optimal network architectures are investigated. Some novel ideas on sensor fusion are proposed.
Fully efficient time-parallelized quantum optimal control algorithm
Riahi, M. K.; Salomon, J.; Glaser, S. J.; Sugny, D.
2016-04-01
We present a time-parallelization method that enables one to accelerate the computation of quantum optimal control algorithms. We show that this approach is approximately fully efficient when based on a gradient method as optimization solver: the computational time is approximately divided by the number of available processors. The control of spin systems, molecular orientation, and Bose-Einstein condensates are used as illustrative examples to highlight the wide range of applications of this numerical scheme.
Timing optimization utilizing order statistics and multichannel digital silicon photomultipliers
Mandai, S.; Venialgo, E.; Charbon, E.
2014-01-01
We present an optimization technique utilizing order statistics with a multichannel digital silicon photomultiplier (MD-SiPM) for timing measurements. Accurate timing measurements are required by 3D rangefinding and time-of-flight positron emission tomography, to name a few applications. We have dem
Time discretization and quantization methods for optimal multiple switching problem
Paul, Gassiat; Kharroubi, Idris; Pham, Huyen
2011-01-01
In this paper, we study probabilistic numerical methods based on optimal quantization algorithms for computing the solution to optimal multiple switching problems with regime-dependent state process. We first consider a discrete-time approximation of the optimal switching problem, and analyze its rate of convergence. Given a time step $h$, the error is in general of order $(h \\log(1/h))^{1/2}$, and of order $h^{1/2}$ when the switching costs do not depend on the state process. We next propose...
Time-Optimal Frictionless Atom Cooling in Harmonic Traps
Stefanatos, Dionisis; Li, Jr-Shin
2012-01-01
Frictionless atom cooling in harmonic traps is formulated as a time-optimal control problem and a synthesis of optimal controlled trajectories is obtained. This work has already been used to determine the minimum time for transition between two thermal states and to show the emergence of the third law of classical thermodynamics from quantum thermodynamics. It can also find application in the fast adiabatic-like expansion of Bose-Einstein condensates, with possible applications in atom interferometry. This paper is based on our recently published article in SIAM J. Control Optim.
Bunin, Gene; François, Grégory; Bonvin, Dominique
2013-01-01
The idea of iterative process optimization based on collected output measurements, or "real-time optimization" (RTO), has gained much prominence in recent decades, with many RTO algorithms being proposed, researched, and developed. While the essential goal of these schemes is to drive the process to its true optimal conditions without violating any safety-critical, or "hard", constraints, no generalized, unified approach for guaranteeing this behavior exists. In this two-part paper, we propos...
Bunin, Gene; François, Grégory; Bonvin, Dominique
2013-01-01
The idea of iterative process optimization based on collected output measurements, or "real-time optimization" (RTO), has gained much prominence in recent decades, with many RTO algorithms being proposed, researched, and developed. While the essential goal of these schemes is to drive the process to its true optimal conditions without violating any safety-critical, or "hard", constraints, no generalized, unified approach for guaranteeing this behavior exists. In this two-part paper, we propos...
Solar sail time-optimal interplanetary transfer trajectory design
Institute of Scientific and Technical Information of China (English)
Sheng-Ping Gong; Yun-Feng Gao; Jun-Feng Li
2011-01-01
The fuel consumption associated with some interplanetary transfer trajectories using chemical propulsion is not affordable.A solar sail is a method of propulsion that does not consume fuel.Transfer time is one of the most pressing problems of solar sail transfer trajectory design.This paper investigates the time-optimal interplanetary transfer trajectories to a circular orbit of given inclination and radius.The optimal control law is derived from the principle of maximization.An indirect method is used to solve the optimal control problem by selecting values for the initial adjoint variables,which are normalized within a unit sphere.The conditions for the existence of the time-optimal transfer are dependent on the lightness number of the sail and the inclination and radius of the target orbit.A numerical method is used to obtain the boundary values for the time-optimal transfer trajectories.For the cases where no time-optimal transfer trajectories exist,first-order necessary conditions of the optimal control are proposed to obtain feasible solutions.The results show that the transfer time decreases as the minimum distance from the Sun decreases during the transfer duration.For a solar sail with a small lightness number,the transfer time may be evaluated analytically for a three-phase transfer trajectory.The analytical results are compared with previous results and the associated numerical results.The transfer time of the numerical result here is smaller than the transfer time from previous results and is larger than the analytical result.
Optimal Control Modification for Time-Scale Separated Systems
Nguyen, Nhan T.
2012-01-01
Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. A model matching conditions in the transformed time coordinate results in an increase in the actuator command that effectively compensate for the slow actuator dynamics. Simulations demonstrate effectiveness of the method.
Time-optimal feedback control for linear systems
International Nuclear Information System (INIS)
The paper deals with the results of qualitative investigations of the time-optimal feedback control for linear systems with constant coefficients. In the first section, after some definitions and notations, two examples are given and it is shown that even the time-optimal control problem for linear systems with constant coefficients which looked like ''completely solved'' requires a further qualitative investigation of the stability to ''permanent perturbations'' of optimal feedback control. In the second section some basic results of the linear time-optimal control problem are reviewed. The third section deals with the definition of Boltyanskii's ''regular synthesis'' and its connection to Filippov's theory of right-hand side discontinuous differential equations. In the fourth section a theorem is proved concerning the stability to perturbations of time-optimal feedback control for linear systems with scalar control. In the last two sections it is proved that, if the matrix which defines the system has only real eigenvalues or is three-dimensional, the time-optimal feedback control defines a regular synthesis and therefore is stable to perturbations. (author)
Shen, Meie; Chen, Wei-Neng; Zhang, Jun; Chung, Henry Shu-Hung; Kaynak, Okyay
2013-04-01
The optimal selection of parameters for time-delay embedding is crucial to the analysis and the forecasting of chaotic time series. Although various parameter selection techniques have been developed for conventional uniform embedding methods, the study of parameter selection for nonuniform embedding is progressed at a slow pace. In nonuniform embedding, which enables different dimensions to have different time delays, the selection of time delays for different dimensions presents a difficult optimization problem with combinatorial explosion. To solve this problem efficiently, this paper proposes an ant colony optimization (ACO) approach. Taking advantage of the characteristic of incremental solution construction of the ACO, the proposed ACO for nonuniform embedding (ACO-NE) divides the solution construction procedure into two phases, i.e., selection of embedding dimension and selection of time delays. In this way, both the embedding dimension and the time delays can be optimized, along with the search process of the algorithm. To accelerate search speed, we extract useful information from the original time series to define heuristics to guide the search direction of ants. Three geometry- or model-based criteria are used to test the performance of the algorithm. The optimal embeddings found by the algorithm are also applied in time-series forecasting. Experimental results show that the ACO-NE is able to yield good embedding solutions from both the viewpoints of optimization performance and prediction accuracy. PMID:23144038
Discrete-time inverse optimal control for nonlinear systems
Sanchez, Edgar N
2013-01-01
Discrete-Time Inverse Optimal Control for Nonlinear Systems proposes a novel inverse optimal control scheme for stabilization and trajectory tracking of discrete-time nonlinear systems. This avoids the need to solve the associated Hamilton-Jacobi-Bellman equation and minimizes a cost functional, resulting in a more efficient controller. Design More Efficient Controllers for Stabilization and Trajectory Tracking of Discrete-Time Nonlinear Systems The book presents two approaches for controller synthesis: the first based on passivity theory and the second on a control Lyapunov function (CLF). Th
Optimal control for parabolic-hyperbolic system with time delay
International Nuclear Information System (INIS)
In this paper we consider an optimal control problem for a system described by a linear partial differential equation of the parabolic-hyperbolic type with time delay in the state. The right-hand side of this equation and the initial conditions are not continuous functions usually, but they are measurable functions belonging to L2 or Lsup(infinity) spaces. Therefore, the solution of this equation is given by a certain Sobolev space. The time delay in the state is constant, but it can be also a function of time. The control time T is fixed in our problem. Making use of the Milutin-Dubovicki theorem, necessary and sufficient conditions of optimality with the quadratic performance functional and constrained control are derived for the Dirichlet problem. The flow chart of the algorithm which can be used in the numerical solving of certain optimization problems for distributed systems is also presented. (author)
Time dependent optimal switching controls in online selling models
Energy Technology Data Exchange (ETDEWEB)
Bradonjic, Milan [Los Alamos National Laboratory; Cohen, Albert [MICHIGAN STATE UNIV
2010-01-01
We present a method to incorporate dishonesty in online selling via a stochastic optimal control problem. In our framework, the seller wishes to maximize her average wealth level W at a fixed time T of her choosing. The corresponding Hamilton-Jacobi-Bellmann (HJB) equation is analyzed for a basic case. For more general models, the admissible control set is restricted to a jump process that switches between extreme values. We propose a new approach, where the optimal control problem is reduced to a multivariable optimization problem.
Asset Allocation, Time Diversification and Portfolio Optimization for Retirement
Kamphol Panyagometh
2011-01-01
Using the data of stock, commodity and bond indexes from 2002 to November 2010, this research was carried out by employing Bootstrapping Simulation technique to find an optimal portfolio (portfolio optimization) for retirement, and the effect of diversification based on increased length of investment period (time diversification) with respect to the lengths of retirement investment period and the amounts required for spending after retirement in various occasions. The study analyzed for an op...
Time Optimized Algorithm for Web Document Presentation Adaptation
DEFF Research Database (Denmark)
Pan, Rong; Dolog, Peter
2010-01-01
Currently information on the web is accessed through different devices. Each device has its own properties such as resolution, size, and capabilities to display information in different format and so on. This calls for adaptation of information presentation for such platforms. This paper proposes...... content-optimized and time-optimized algorithms for information presentation adaptation for different devices based on its hierarchical model. The model is formalized in order to experiment with different algorithms....
The Ryder Cognitive Aid Checklist for Trauma Anesthesia.
Behrens, Vicente; Dudaryk, Roman; Nedeff, Nicholas; Tobin, Joshua M; Varon, Albert J
2016-05-01
Despite mixed results regarding the clinical utility of checklists, the anesthesia community is increasingly interested in advancing research around this important topic. Although several checklists have been developed to address routine perioperative care, few checklists in the anesthesia literature specifically target the management of trauma patients. We adapted a recently published "trauma and emergency checklist" for the initial phase of resuscitation and anesthesia of critically ill trauma patients into an applicable perioperative cognitive aid in the form of a pictogram that can be downloaded by the medical community. The Ryder Cognitive Aid Checklist for Trauma Anesthesia is a letter-sized, full-color document consisting of 2 pages and 5 sections. This cognitive aid describes the essential steps to be performed: before patient arrival to the hospital, on patient arrival to the hospital, during the initial assessment and management, during the resuscitation phase, and for postoperative care. A brief online survey is also presented to obtain feedback for improvement of this tool. The variability in utility of cognitive aids may be because of the specific clinical task being performed, the skill level of the individuals using the cognitive aid, overall quality of the cognitive aid, or organizational challenges. Once optimized, future research should be focused at ensuring successful implementation and customization of this tool. PMID:27101496
Analysis and Optimization of Distributed Real-Time Embedded Systems
DEFF Research Database (Denmark)
Pop, Paul; Eles, Petru; Peng, Zebo;
2006-01-01
characteristic to this class of systems: mapping of functionality, the optimization of the access to the communication channel, and the assignment of scheduling policies to processes. Optimization heuristics aiming at producing a schedulable system, with a given amount of resources, are presented.......An increasing number of real-time applications are today implemented using distributed heterogeneous architectures composed of interconnected networks of processors. The systems are heterogeneous not only in terms of hardware and software components, but also in terms of communication protocols and...... such heterogeneous distributed real-time embedded systems. More specifically, we discuss the schedulability analysis of hard real-time systems, highlighting particular aspects related to the heterogeneous and distributed nature of the applications. We also introduce several design optimization problems...
Optimal Time-Trial Bicycle Racing with Headwinds and Tailwinds
Anton, A Brad
2013-01-01
Many time-trial and triathlon bicycle races take place on relatively flat, closed-circuit courses. In the absence of hills, riding-speed is limited almost solely by aerodynamic drag; consequently, winds can have a big effect on elapsed times. I analyze the special case of a straight out-and-back race in a steady wind, assuming the rider has a given total amount of energy to expend and can choose only two speeds - the aided speed with tailwind and the hindered speed into headwind. In this ideal circumstance the problem of choosing optimal riding speeds reduces to a constrained nonlinear optimization that can be solved with elementary calculus. My analysis reveals a practical rule of thumb that can be used more generally to choose optimal riding speeds for time-trial racing on closed-circuit courses in the presence of headwinds and tailwinds.
An Optimizing Framework for Real-time Scheduling
Sundharam, Sakthivel Manikandan; Altmeyer, Sebastian; Navet, Nicolas
2016-01-01
Scheduling is crucial in real-time applications. For any real-time system, the desired scheduling policy can be selected based on the scheduling problem itself and the underlying system constraints. This paper discusses a novel optimization framework which automates the selection and configuration of the scheduling policy. The objective is to let designer state the permissible timing behavior of the system in a declarative manner. The system synthesis step involving both ...
Optimal Conditional Reachability for Multi-Priced Timed Automata
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Rasmussen, Jacob Illum
2005-01-01
In this paper, we prove decidability of the optimal conditional reachability problem for multi-priced timed automata, an extension of timed automata with multiple cost variables evolving according to given rates for each location. More precisely, we consider the problem of determining the minimal...... cost of reaching a given target state, with respect to some primary cost variable, while respecting upper bound constraints on the remaining (secondary) cost variables. Decidability is proven by constructing a zone-based algorithm that always terminates while synthesizing the optimal cost with a single...
Optimal estimation of recurrence structures from time series
beim Graben, Peter; Sellers, Kristin K.; Fröhlich, Flavio; Hutt, Axel
2016-05-01
Recurrent temporal dynamics is a phenomenon observed frequently in high-dimensional complex systems and its detection is a challenging task. Recurrence quantification analysis utilizing recurrence plots may extract such dynamics, however it still encounters an unsolved pertinent problem: the optimal selection of distance thresholds for estimating the recurrence structure of dynamical systems. The present work proposes a stochastic Markov model for the recurrent dynamics that allows for the analytical derivation of a criterion for the optimal distance threshold. The goodness of fit is assessed by a utility function which assumes a local maximum for that threshold reflecting the optimal estimate of the system's recurrence structure. We validate our approach by means of the nonlinear Lorenz system and its linearized stochastic surrogates. The final application to neurophysiological time series obtained from anesthetized animals illustrates the method and reveals novel dynamic features of the underlying system. We propose the number of optimal recurrence domains as a statistic for classifying an animals' state of consciousness.
Ruiz-Cruz, Riemann; Sanchez, Edgar N; Ornelas-Tellez, Fernando; Loukianov, Alexander G; Harley, Ronald G
2013-12-01
In this paper, the authors propose a particle swarm optimization (PSO) for a discrete-time inverse optimal control scheme of a doubly fed induction generator (DFIG). For the inverse optimal scheme, a control Lyapunov function (CLF) is proposed to obtain an inverse optimal control law in order to achieve trajectory tracking. A posteriori, it is established that this control law minimizes a meaningful cost function. The CLFs depend on matrix selection in order to achieve the control objectives; this matrix is determined by two mechanisms: initially, fixed parameters are proposed for this matrix by a trial-and-error method and then by using the PSO algorithm. The inverse optimal control scheme is illustrated via simulations for the DFIG, including the comparison between both mechanisms. PMID:24273145
Quickest Time Herding and Detection for Optimal Social Learning
Krishnamurthy, Vikram
2010-01-01
This paper considers social learning amongst rational agents (for example, sensors in a network). We consider three models of social learning in increasing order of sophistication. In the first model, based on its private observation of a noisy underlying state process, each agent selfishly optimizes its local utility and broadcasts its action. This protocol leads to a herding behavior where the agents eventually choose the same action irrespective of their observations. We then formulate a second more general model where each agent is benevolent and chooses its sensor-mode to optimize a social welfare function to facilitate social learning. Using lattice programming and stochastic orders, it is shown that the optimal decision each agent makes is characterized by a switching curve on the space of Bayesian distributions. We then present a third more general model where social learning takes place to achieve quickest time change detection. Both geometric and phase-type change time distributions are considered. ...
S. F. El-Zoghdy; M. A. Shohla; El-Sawy, A. A.; M. Nofal
2012-01-01
The starting time in the machine time scheduling problem will be assumed stochastic follows certain distribution. A hybrid algorithm combines the mutation operation with particle swarm optimization algorithm with constriction factor has been developed to find best starting time for each machine in each cycle when starting time follows normal distribution.
Optimization of ''reverse time of flight'' neutron scattering devices
International Nuclear Information System (INIS)
The ''reverse time of flight'' (RTOF) elastic neutron scattering technique for powdered samples is briefly described. The advantages and some problems of this high resolution technique are discussed. The main task is to illustrate opportunities and solutions for an optimization of a RTOF instrument, especially for the neutron chopper device and the detector system. (orig.)
An optimal real-time controller for vertical plasma stabilization
Cruz, N; Coda, S; Duval, B P; Le, H B; Rodrigues, A P; Varandas, C A F; Correia, C M B A; Goncalves, B S
2014-01-01
Modern Tokamaks have evolved from the initial axisymmetric circular plasma shape to an elongated axisymmetric plasma shape that improves the energy confinement time and the triple product, which is a generally used figure of merit for the conditions needed for fusion reactor performance. However, the elongated plasma cross section introduces a vertical instability that demands a real-time feedback control loop to stabilize the plasma vertical position and velocity. At the Tokamak \\`a Configuration Variable (TCV) in-vessel poloidal field coils driven by fast switching power supplies are used to stabilize highly elongated plasmas. TCV plasma experiments have used a PID algorithm based controller to correct the plasma vertical position. In late 2013 experiments a new optimal real-time controller was tested improving the stability of the plasma. This contribution describes the new optimal real-time controller developed. The choice of the model that describes the plasma response to the actuators is discussed. The ...
Finite time exergoeconomic performance optimization of a thermoacoustic heat engine
Directory of Open Access Journals (Sweden)
Xuxian Kan, Lingen Chen, Fengrui Sun, Feng Wu
2011-01-01
Full Text Available Finite time exergoeconomic performance optimization of a generalized irreversible thermoacoustic heat engine with heat resistance, heat leakage, thermal relaxation, and internal dissipation is investigated in this paper. Both the real part and the imaginary part of the complex heat transfer exponent change the optimal profit rate versus efficiency relationship quantitatively. The operation of the generalized irreversible thermoacoustic engine is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the generalized irreversible thermoacoustic engine is performed by taking profit rate as the objective. The analytical formulas about the profit rate and thermal efficiency of the thermoacoustic engine are derived. Furthermore, the comparative analysis of the influences of various factors on the relationship between optimal profit rate and the thermal efficiency of the generalized irreversible thermoacoustic engine is carried out by detailed numerical examples. The optimal zone on the performance of the thermoacoustic heat engine is obtained by numerical analysis. The results obtained herein may be useful for the selection of the operation parameters for real thermoacoustic heat engines.
Optimizing the search for transiting planets in long time series
Ofir, Aviv
2014-01-01
Context. Transit surveys, both ground- and space-based, have already accumulated a large number of light curves that span several years. Aims: The search for transiting planets in these long time series is computationally intensive. We wish to optimize the search for both detection and computational efficiencies. Methods: We assume that the searched systems can be described well by Keplerian orbits. We then propagate the effects of different system parameters to the detection parameters. Results: We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS, one is either fairly insensitive to long-period planets or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3 yr long dataset). We also show how the physical system parameters, such as the host star's size and mass, directly affect transit detection. This understanding can then be used to optimize the search for every star individually. Conclusions: By considering Keplerian dynamics explicitly rather than implicitly one can optimally search the BLS parameter space. The presented Optimal BLS enhances the detectability of both very short and very long period planets, while allowing such searches to be done with much reduced resources and time. The Matlab/Octave source code for Optimal BLS is made available. The MATLAB code is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A138
Resource-Optimal Scheduling Using Priced Timed Automata
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Rasmussen, Jacob Illum; Subramani, K.
2004-01-01
In this paper, we show how the simple structure of the linear programs encountered during symbolic minimum-cost reachability analysis of priced timed automata can be exploited in order to substantially improve the performance of the current algorithm. The idea is rooted in duality of linear progr......-80 percent performance gain. As a main application area, we show how to solve energy-optimal task graph scheduling problems using the framework of priced timed automata....
Optimal Control Theory for Time-Dependent Quantum Transport
Zhang, Yu
2015-01-01
Optical techniques have been employed to coherently control the quantum transport through nanojunctions. Conventional works on optical control of quantum transport usually applied a tailored electrical pulses to perform specific tasks. In this work, an opposite way is employed and a time-dependent driving field is searched to force the system behave in desired pattern. In order to achieve the goal, an optimal control theory for time-dependent quantum transport is developed. The theory provide...
Part-Time Unemployment and Optimal Unemployment Insurance
Ek, Susanne; Holmlund, Bertil
2011-01-01
A significant fraction of the labor force consists of employed workers who are part-time unemployed (underemployed) in the sense that they are unable to work as much as they prefer. This paper develops a search and matching model to study the design of optimal unemployment insurance in an economy with unemployment as well as part-time unemployment. Part-time unemployment provides income insurance and serves as a stepping stone to full-time jobs. Unemployment benefits for part-timers increase ...
Comparison of time optimal control for two level quantum systems
Institute of Scientific and Technical Information of China (English)
Shuang Cong; Jie Wen; Xubo Zou
2014-01-01
The time optimal problem for a two level quantum sys-tem is studied. We compare two different control strategies of bang-bang control and the geometric control, respectively, es-pecial y in the case of minimizing the time of steering the state from North Pole to South Pole on the Bloch sphere with bounded control. The time performances are compared for different param-eters by the individual numerical simulation experiments, and the experimental results are analyzed. The results show that the ge-ometric control spends less time than the bang-bang control does.
Optimal moving grids for time-dependent partial differential equations
Wathen, A. J.
1992-01-01
Various adaptive moving grid techniques for the numerical solution of time-dependent partial differential equations were proposed. The precise criterion for grid motion varies, but most techniques will attempt to give grids on which the solution of the partial differential equation can be well represented. Moving grids are investigated on which the solutions of the linear heat conduction and viscous Burgers' equation in one space dimension are optimally approximated. Precisely, the results of numerical calculations of optimal moving grids for piecewise linear finite element approximation of PDE solutions in the least-squares norm are reported.
Optimal Time to Invest Energy Storage System under Uncertainty Conditions
Directory of Open Access Journals (Sweden)
Yongma Moon
2014-04-01
Full Text Available This paper proposes a model to determine the optimal investment time for energy storage systems (ESSs in a price arbitrage trade application under conditions of uncertainty over future profits. The adoption of ESSs can generate profits from price arbitrage trade, which are uncertain because the future marginal prices of electricity will change depending on supply and demand. In addition, since the investment is optional, an investor can delay adopting an ESS until it becomes profitable, and can decide the optimal time. Thus, when we evaluate this investment, we need to incorporate the investor’s option which is not captured by traditional evaluation methods. In order to incorporate these aspects, we applied real option theory to our proposed model, which provides an optimal investment threshold. Our results concerning the optimal time to invest show that if future profits that are expected to be obtained from arbitrage trade become more uncertain, an investor needs to wait longer to invest. Also, improvement in efficiency of ESSs can reduce the uncertainty of arbitrage profit and, consequently, the reduced uncertainty enables earlier ESS investment, even for the same power capacity. Besides, when a higher rate of profits is expected and ESS costs are higher, an investor needs to wait longer. Also, by comparing a widely used net present value model to our real option model, we show that the net present value method underestimates the value for ESS investment and misleads the investor to make an investment earlier.
Time-Optimal Real-Time Test Case Generation using UPPAAL
DEFF Research Database (Denmark)
Hessel, Anders; Larsen, Kim Guldstrand; Nielsen, Brian;
2004-01-01
Testing is the primary software validation technique used by industry today, but remains ad hoc, error prone, and very expensive. A promising improvement is to automatically generate test cases from formal models of the system under test. We demonstrate how to automatically generate real......-time conformance test cases from timed automata specifications. Specifically we demonstrate how to fficiently generate real-time test cases with optimal execution time i.e test cases that are the fastest possible to execute. Our technique allows time optimal test cases to be generated using manually formulated...... test purposes or generated automatically from various coverage criteria of the model....
Optimal redundant systems for works with random processing time
International Nuclear Information System (INIS)
This paper studies the optimal redundant policies for a manufacturing system processing jobs with random working times. The redundant units of the parallel systems and standby systems are subject to stochastic failures during the continuous production process. First, a job consisting of only one work is considered for both redundant systems and the expected cost functions are obtained. Next, each redundant system with a random number of units is assumed for a single work. The expected cost functions and the optimal expected numbers of units are derived for redundant systems. Subsequently, the production processes of N tandem works are introduced for parallel and standby systems, and the expected cost functions are also summarized. Finally, the number of works is estimated by a Poisson distribution for the parallel and standby systems. Numerical examples are given to demonstrate the optimization problems of redundant systems
Optimal Real-time Dispatch for Integrated Energy Systems
Energy Technology Data Exchange (ETDEWEB)
Firestone, Ryan Michael
2007-05-31
This report describes the development and application of a dispatch optimization algorithm for integrated energy systems (IES) comprised of on-site cogeneration of heat and electricity, energy storage devices, and demand response opportunities. This work is intended to aid commercial and industrial sites in making use of modern computing power and optimization algorithms to make informed, near-optimal decisions under significant uncertainty and complex objective functions. The optimization algorithm uses a finite set of randomly generated future scenarios to approximate the true, stochastic future; constraints are included that prevent solutions to this approximate problem from deviating from solutions to the actual problem. The algorithm is then expressed as a mixed integer linear program, to which a powerful commercial solver is applied. A case study of United States Postal Service Processing and Distribution Centers (P&DC) in four cities and under three different electricity tariff structures is conducted to (1) determine the added value of optimal control to a cogeneration system over current, heuristic control strategies; (2) determine the value of limited electric load curtailment opportunities, with and without cogeneration; and (3) determine the trade-off between least-cost and least-carbon operations of a cogeneration system. Key results for the P&DC sites studied include (1) in locations where the average electricity and natural gas prices suggest a marginally profitable cogeneration system, optimal control can add up to 67% to the value of the cogeneration system; optimal control adds less value in locations where cogeneration is more clearly profitable; (2) optimal control under real-time pricing is (a) more complicated than under typical time-of-use tariffs and (b) at times necessary to make cogeneration economic at all; (3) limited electric load curtailment opportunities can be more valuable as a compliment to the cogeneration system than alone; and
Free Final-Time Optimal Control for HIV Viral Dynamics
Pachpute, Gaurav
2011-01-01
In this paper, we examine a well-established model for HIV wild-type infection. The algorithm for steepest descent method for fixed final-time is stated and a modified method for free final-time is presented. The first type of cost functional considered, seeks to minimize the total time of therapy. An easy implementation for this problem suggests that it can be effective in the early stages of treatment as well as for individual-based studies, due to the "hit first and hit hard" nature of optimal control. An LQR based cost functional is also presented and the solution is found using steepest descent method. It suggests that the optimal therapy must remain high until the patient shows signs of recovery after which, the therapy gradually decreases. This is in line with the biomedical philosophy. Solution to a modified problem which includes a weight for total time is approximated using the modified algorithm. It shows a considerable drop in the total period. We conclude that, a decreased and optimized therapy p...
A checklist for endonasal transsphenoidal anterior skull base surgery.
Laws, Edward R; Wong, Judith M; Smith, Timothy R; de Los Reyes, Kenneth; Aglio, Linda S; Thorne, Alison J; Cote, David J; Esposito, Felice; Cappabianca, Paolo; Gawande, Atul
2016-06-01
OBJECT Approximately 250 million surgical procedures are performed annually worldwide, and data suggest that major complications occur in 3%-17% of them. Many of these complications can be classified as avoidable, and previous studies have demonstrated that preoperative checklists improve operating room teamwork and decrease complication rates. Although the authors' institution has instituted a general preoperative "time-out" designed to streamline communication, flatten vertical authority gradients, and decrease procedural errors, there is no specific checklist for transnasal transsphenoidal anterior skull base surgery, with or without endoscopy. Such minimally invasive cranial surgery uses a completely different conceptual approach, set-up, instrumentation, and operative procedure. Therefore, it can be associated with different types of complications as compared with open cranial surgery. The authors hypothesized that a detailed, procedure-specific, preoperative checklist would be useful to reduce errors, improve outcomes, decrease delays, and maximize both teambuilding and operational efficiency. Thus, the object of this study was to develop such a checklist for endonasal transsphenoidal anterior skull base surgery. METHODS An expert panel was convened that consisted of all members of the typical surgical team for transsphenoidal endoscopic cases: neurosurgeons, anesthesiologists, circulating nurses, scrub technicians, surgical operations managers, and technical assistants. Beginning with a general checklist, procedure-specific items were added and categorized into 4 pauses: Anesthesia Pause, Surgical Pause, Equipment Pause, and Closure Pause. RESULTS The final endonasal transsphenoidal anterior skull base surgery checklist is composed of the following 4 pauses. The Anesthesia Pause consists of patient identification, diagnosis, pertinent laboratory studies, medications, surgical preparation, patient positioning, intravenous/arterial access, fluid management
Hard and Soft Sub-Time-Optimal Robust Controllers
DEFF Research Database (Denmark)
Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr;
2010-01-01
In many applicational tasks of motion control – fundamental for research in robotics – problems associated with uncertain and/or varying load (a mass or moment of inertia) can present a substantial difficulty during the synthesis of practical controlling systems. The random concept, where the load...... has been treated as a stochastic process, is presented in this paper. As a result, through a generalization of the classic switching curve occurring in the time-optimal approach, two control structures have been investigated: the hard, defined on the basis of the rules of the statistical decision...... theory, and also the soft, which additionally allows the elimination of rapid changes in control values. The methodology proposed here may be easily adopted for other elements commonly found in mechanical systems, e.g. parameters of drive or motion resistance, giving the sub-time-optimal controlling...
An exercise on discrete-time intertemporal optimization
Fidelina B. Natividad-Carlos
2013-01-01
This paper, using the different alternative methods of dynamic optimization - the Lagrange/Kuhn-Tucker (LKT) method, the substitution method, the Hamiltonian method, and the dynamic programming approach - derives the conditions that must be satisfied by the solution to the so-called Ramsey problem, hopefully in a way that can be understood by advanced undergraduate economics students. This is done by assuming that time is discrete and that, for simplicity but without loss of generality, there...
Scheduling with Optimized Communication for Time-Triggered Embedded Systems
DEFF Research Database (Denmark)
Pop, Paul; Eles, Petru; Peng, Zebo
1999-01-01
We present an approach to process scheduling for synthesis of safety-critical distributed embedded systems.Our system model captures both the flow of data and that of control. The communication model is based on a time-triggered protocol. We take into consideration overheads due to communication...... and the execution environment.Communications have been optimized thr ough packaging of messages into slots with a pr operly selected order andlengths. Several experiments demonstrate the efficiency of the approach....
Parareal in time intermediate targets methods for optimal control problem
Maday, Yvon; Salomon, Julien
2012-01-01
In this paper, we present a method that enables solving in parallel the Euler-Lagrange system associated with the optimal control of a parabolic equation. Our approach is based on an iterative update of a sequence of intermediate targets that gives rise to independent sub-problems that can be solved in parallel. This method can be coupled with the parareal in time algorithm. Numerical experiments show the efficiency of our method.
FAME Storage Time in an Optimized Natural Antioxidant Mixture
Rodolfo Lopes Coppo; Dionísio Borsato; Jaqueline Laís Pereira; Hágata Cremasco da Silva
2013-01-01
The study of B100 biodiesel oxidation stability, and its conservation, is extremely important to control its quality, especially regarding storage. Many spices have shown antioxidant effect and are the targets of study. Knowing the oxidation process in greater detail allows a reliable storage period to be stipulated for the biodiesel without its degradation until the time of use. Results have shown that according to the accelerated stove method, the optimal mixture, composed of 100% of oregan...
Information Theoretic Optimality of Observation Driven Time Series Models
Blasques, Francisco; Koopman, Siem Jan; Lucas, André
2014-01-01
We investigate the information theoretic optimality properties of the score function of the predictive likelihood as a device to update parameters in observation driven time-varying parameter models. The results provide a new theoretical justification for the class of generalized autoregressive score models, which covers the GARCH model as a special case. Our main contribution is to show that only parameter updates based on the score always reduce the local Kullback-Leibler divergence between...
Nearly time-optimal paths for a ground vehicle
Institute of Scientific and Technical Information of China (English)
David A. ANISI; Johan HAMBERG; Xiaoming HU
2003-01-01
It is well known that the sufficient family of time-optimal paths for both Dubins' as well as Reeds-Shepp' s car models consist of the concatenation of circular arcs with maxmum curvature and straight line segments, all tangentially connected.These time-optimal solutions suffer from some drawbacks. Their discontinuous curvature profde, together with the wear and impairment on the control equipment that the bang-bang solutions induce, calls for "smoother" and more supple reference paths to follow. Avoiding the bang-bang solutions also raises the robustness with respect to any possible uncertainties. In this paper, our main tool for generating these "nearly time-optimal", but nevertheless continuous-curvature paths, is to use the Pontryagin Maximum Principle (PMP) and make an appropriate and cunning choice of the Lagrangian function. Despite some rewarding simuhtion results, this concept tums out to be numerically divergent at some instances. Upon a more careful investigation, it can be concluded that the problem at hand is nearly singular. This is seen by applying the PMP to Dubins' car and studying the corresponding two point boundary value problem, which turn out to be singuhr. Realizing this, one is able to contradict the widespread belief that all the information about the motion of a mobile platform lies in the initial values of the auxiliary variables associated with the PMP.
Optimal Stochastic Restart Renders Fluctuations in First Passage Times Universal
Reuveni, Shlomi
2016-04-01
Stochastic restart may drastically reduce the expected run time of a computer algorithm, expedite the completion of a complex search process, or increase the turnover rate of an enzymatic reaction. These diverse first-passage-time (FPT) processes seem to have very little in common but it is actually quite the other way around. Here we show that the relative standard deviation associated with the FPT of an optimally restarted process, i.e., one that is restarted at a constant (nonzero) rate which brings the mean FPT to a minimum, is always unity. We interpret, further generalize, and discuss this finding and the implications arising from it.
Chaos Time Series Prediction Based on Membrane Optimization Algorithms
Directory of Open Access Journals (Sweden)
Meng Li
2015-01-01
Full Text Available This paper puts forward a prediction model based on membrane computing optimization algorithm for chaos time series; the model optimizes simultaneously the parameters of phase space reconstruction (τ,m and least squares support vector machine (LS-SVM (γ,σ by using membrane computing optimization algorithm. It is an important basis for spectrum management to predict accurately the change trend of parameters in the electromagnetic environment, which can help decision makers to adopt an optimal action. Then, the model presented in this paper is used to forecast band occupancy rate of frequency modulation (FM broadcasting band and interphone band. To show the applicability and superiority of the proposed model, this paper will compare the forecast model presented in it with conventional similar models. The experimental results show that whether single-step prediction or multistep prediction, the proposed model performs best based on three error measures, namely, normalized mean square error (NMSE, root mean square error (RMSE, and mean absolute percentage error (MAPE.
Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.
Griffin, T W; Zapata, S D
2016-08-01
The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the
The Optimal Timing of Adoption of a Green Technology
International Nuclear Information System (INIS)
We study the optimal timing of adoption of a cleaner technology and its effects on the rate of growth of an economy in the context of an AK endogenous growth model. We show that the results depend upon the behavior of the marginal utility of environmental quality with respect to consumption. When it is increasing, we derive the capital level at the optimal timing of adoption. We show that this capital threshold is independent of the initial conditions on the stock of capital, implying that capital-poor countries tend to take longer to adopt. Also, country-specific characteristics, as the existence of high barriers to adoption, may lead to different capital thresholds for different countries. If the marginal utility of environmental quality decreases with consumption, a country should never delay adoption; the optimal policy is either to adopt immediately or, if adoption costs are too high, to never adopt. The policy implications of these results are discussed in the context of the international debate surrounding the environmental political agenda
ROAMing terrain (Real-time Optimally Adapting Meshes)
Energy Technology Data Exchange (ETDEWEB)
Duchaineau, M.; Wolinsky, M.; Sigeti, D.E.; Miller, M.C.; Aldrich, C.; Mineev, M.
1997-07-01
Terrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor stimulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly, and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame. Our method, dubbed Real-time Optimally Adapting Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from pre-processed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and priority-computation deferral lists. ROAM execution time is proportionate to the number of triangle changes per frame, which is typically a few percent of the output mesh size, hence ROAM performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.
Optimal time-critical scheduling via resource augmentation
Energy Technology Data Exchange (ETDEWEB)
Phillips, C.A. [Sandia National Labs., Albuquerque, NM (United States); Stein, C. [Dartmouth College, Hanover, NH (United States). Dept. of Computer Science; Torng, E. [Michigan State Univ., East Lansing, MI (United States). Dept. of Computer Science; Wein, J. [Polytechnic Univ., Brooklyn, NY (United States). Dept. of Computer Science
1997-04-01
We consider two fundamental problems in dynamic scheduling: scheduling to meet deadlines in a preemptive multiprocessor setting, and scheduling to provide good response time in a number of scheduling environments. When viewed from the perspective of traditional worst-case analysis, no good on-line algorithms exist for these problems, and for some variants no good off-line algorithms exist unless {Rho} = {Nu}{Rho}. We study these problems using a relaxed notion of competitive analysis, introduced by Kalyanasundaram and Pruhs, in which the on-line algorithm is allowed more resources than the optimal off-line algorithm to which it is compared. Using this approach, we establish that several well-known on-line algorithms, that have poor performance from an absolute worst-case perspective, are optimal for the problems in question when allowed moderately more resources. For the optimization of average flow time, these are the first results of any sort, for any {Nu}{Rho}-hard version of the problem, that indicate that it might be possible to design good approximation algorithms.
Optimizing timing performance of silicon photomultiplier-based scintillation detectors
International Nuclear Information System (INIS)
Precise timing resolution is crucial for applications requiring photon time-of-flight (ToF) information such as ToF positron emission tomography (PET). Silicon photomultipliers (SiPM) for PET, with their high output capacitance, are known to require custom preamplifiers to optimize timing performance. In this paper, we describe simple alternative front-end electronics based on a commercial low-noise RF preamplifier and methods that have been implemented to achieve excellent timing resolution. Two radiation detectors with L(Y)SO scintillators coupled to Hamamatsu SiPMs (MPPC S10362–33-050C) and front-end electronics based on an RF amplifier (MAR-3SM+), typically used for wireless applications that require minimal additional circuitry, have been fabricated. These detectors were used to detect annihilation photons from a Ge-68 source and the output signals were subsequently digitized by a high speed oscilloscope for offline processing. A coincident resolving time (CRT) of 147 ± 3 ps FWHM and 186 ± 3 ps FWHM with 3 × 3 × 5 mm3 and with 3 × 3 × 20 mm3 LYSO crystal elements were measured, respectively. With smaller 2 × 2 × 3 mm3 LSO crystals, a CRT of 125 ± 2 ps FWHM was achieved with slight improvement to 121 ± 3 ps at a lower temperature (15° C). Finally, with the 20 mm length crystals, a degradation of timing resolution was observed for annihilation photon interactions that occur close to the photosensor compared to shallow depth-of-interaction (DOI). We conclude that commercial RF amplifiers optimized for noise, besides their ease of use, can produce excellent timing resolution comparable to best reported values acquired with custom readout electronics. On the other hand, as timing performance degrades with increasing photon DOI, a head-on detector configuration will produce better CRT than a side-irradiated setup for longer crystals. (paper)
A Novel Real-time Optimization Methodology for Chemical Plants
Institute of Scientific and Technical Information of China (English)
黄静雯; 李宏光
2012-01-01
In this paper, a novel approach termed process goose queue (PGQ) is suggested to deal with real-time optimization (RTO) of chemical plants. Taking advantage of the ad-hoc structure of PGQ which imitates biologic nature of flying wild geese, a chemical plant optimization problem can be re-formulated as a combination of a multi-layer PGQ and a PGQ-Objective according to the relationship among process variables involved in the objective and constraints. Subsequently, chemical plant RTO solutions are converted into coordination issues among PGQs which could be dealt with in a novel way. Accordingly, theoretical definitions, adjustment rule and implementing procedures associated with the approach are explicitly introduced together with corresponding enabling algorithms. Finally, an exemplary chemical plant is employed to demonstrate the feasibility and validity of the contribution.
Discrete Time Optimal Adaptive Control for Linear Stochastic Systems
Institute of Scientific and Technical Information of China (English)
JIANG Rui; LUO Guiming
2007-01-01
The least-squares(LS)algorithm has been used for system modeling for a long time. Without any excitation conditions, only the convergence rate of the common LS algorithm can be obtained. This paper analyzed the weighted least-squares(WLS)algorithm and described the good properties of the WLS algorithm. The WLS algorithm was then used for daptive control of linear stochastic systems to show that the linear closed-loop system was globally stable and that the system identification was consistent. Compared to the past optimal adaptive controller,this controller does not impose restricted conditions on the coefficients of the system, such as knowing the first coefficient before the controller. Without any persistent excitation conditions, the analysis shows that, with the regulation of the adaptive control, the closed-loop system was globally stable and the adaptive controller converged to the one-step-ahead optimal controller in some sense.
Optimal trading strategies—a time series approach
Bebbington, Peter A.; Kühn, Reimer
2016-05-01
Motivated by recent advances in the spectral theory of auto-covariance matrices, we are led to revisit a reformulation of Markowitz’ mean-variance portfolio optimization approach in the time domain. In its simplest incarnation it applies to a single traded asset and allows an optimal trading strategy to be found which—for a given return—is minimally exposed to market price fluctuations. The model is initially investigated for a range of synthetic price processes, taken to be either second order stationary, or to exhibit second order stationary increments. Attention is paid to consequences of estimating auto-covariance matrices from small finite samples, and auto-covariance matrix cleaning strategies to mitigate against these are investigated. Finally we apply our framework to real world data.
Coleman, Matthew C; Block, David E
2006-10-20
We have previously shown the usefulness of historical data for fermentation process optimization. The methodology developed includes identification of important process inputs, training of an artificial neural network (ANN) process model, and ultimately use of the ANN model with a genetic algorithm to find the optimal values of each critical process input. However, this approach ignores the time-dependent nature of the system, and therefore, does not fully utilize the available information within a database. In this work, we propose a method for incorporating time-dependent optimization into our previously developed three-step optimization routine. This is achieved by an additional step that uses a fermentation model (consisting of coupled ordinary differential equations (ODE)) to interpret important time-course features of the collected data through adjustments in model parameters. Important process variables not explicitly included in the model were then identified for each model parameter using automatic relevance determination (ARD) with Gaussian process (GP) models. The developed GP models were then combined with the fermentation model to form a hybrid neural network model that predicted the time-course activity of the cell and protein concentrations of novel fermentation conditions. A hybrid-genetic algorithm was then used in conjunction with the hybrid model to suggest optimal time-dependent control strategies. The presented method was implemented upon an E. coli fermentation database generated in our laboratory. Optimization of two different criteria (final protein yield and a simplified economic criteria) was attempted. While the overall protein yield was not increased using this methodology, we were successful in increasing a simplified economic criterion by 15% compared to what had been previously observed. These process conditions included using 35% less arabinose (the inducer) and 33% less typtone in the media and reducing the time required to reach
A Random Time-Varying Particle Swarm Optimization for the Real Time Location Systems
Zhu, Hui; Tanabe, Yuji; Baba, Takaaki
The particle swarm optimizer (PSO) is a stochastic, population-based optimization technique that can be applied to a wide range of applications. This paper presents a random time variable PSO algorithm, called the PSO-RTVIWAC, introducing random time-varying inertia weight and acceleration coefficients to significantly improve the performance of the original algorithms. The PSO-RTVIWAC method originates from the random inertia weight (PSO-RANDIW) and time-varying acceleration coefficients (PSO-TVAC) methods. Through the efficient control of search and convergence to the global optimum solution, the PSO-RTVIWAC method is capable of tracking and optimizing the position evaluate in the highly nonlinear real-time location systems (RTLS). Experimental results are compared with three previous PSO approaches from the literatures, showing that the new optimizer significantly outperforms previous approaches. Simply employing a few particles and iterations, a reasonable good positioning accuracy is obtained with the PSO-RTVIWAC method. This property makes the PSO-RTVIWAC method become more attractive since the computation efficiency is improved considerably, i.e. the computation can be completed in an extremely short time, which is crucial for the RTLS. By implementing a hardware design of PSO-RTVIWAC, the computations can simultaneously be performed using hardware to reduce the processing time. Due to a small number of particles and iterations, the hardware resource is saved and the area cost is reduced in the FPGA implementation. An improvement of positioning accuracy is observed with PSO-RTVIWAC method, compared with Taylor Series Expansion (TSE) and Genetic Algorithm (GA). Our experiments on the PSO-RTVIWAC to track and optimize the position evaluate have demonstrated that it is especially effective in dealing with optimization functions in the nonlinear dynamic environments.
Real-time optimizations for integrated smart network camera
Desurmont, Xavier; Lienard, Bruno; Meessen, Jerome; Delaigle, Jean-Francois
2005-02-01
We present an integrated real-time smart network camera. This system is composed of an image sensor, an embedded PC based electronic card for image processing and some network capabilities. The application detects events of interest in visual scenes, highlights alarms and computes statistics. The system also produces meta-data information that could be shared between other cameras in a network. We describe the requirements of such a system and then show how the design of the system is optimized to process and compress video in real-time. Indeed, typical video-surveillance algorithms as background differencing, tracking and event detection should be highly optimized and simplified to be used in this hardware. To have a good adequation between hardware and software in this light embedded system, the software management is written on top of the java based middle-ware specification established by the OSGi alliance. We can integrate easily software and hardware in complex environments thanks to the Java Real-Time specification for the virtual machine and some network and service oriented java specifications (like RMI and Jini). Finally, we will report some outcomes and typical case studies of such a camera like counter-flow detection.
The optimal time for conception after fallopian tube recanalization therapy
International Nuclear Information System (INIS)
Objective: To discuss the optimal time for conception after fallopian tube recanalization therapy. Methods: Fallopian tube recanalization procedure was carried out on 950 obstructed fallopian tubes in 635 infertile women. All the patients were followed up. The time of getting conception after the procedure was observed and recorded in all patients, and the results were analyzed. Results: The pregnancy rate in the first four months was significantly different from the pregnancy rate after the first four months, while no significant difference in the pregnancy rate existed between the second four months and the third four months after the treatment. The pregnancy rate of the first six months after recanalization treatment was significantly higher than that of the second six months. The ectopic pregnancy rate was relatively high after the first four months and it gradually declined to a quite lower level after six months. Conclusion: The optimal time for conception after fallopian tube recanalization therapy is within the first four months after the interventional treatment. During the first six months after the treatment, the opportunities of getting pregnant should be actively created, and special measures for getting fertilization should be energetically adopted during the first four months after a successful recanalization procedure. (authors)
Opposing selection and environmental variation modify optimal timing of breeding.
Tarwater, Corey E; Beissinger, Steven R
2013-09-17
Studies of evolution in wild populations often find that the heritable phenotypic traits of individuals producing the most offspring do not increase proportionally in the population. This paradox may arise when phenotypic traits influence both fecundity and viability and when there is a tradeoff between these fitness components, leading to opposing selection. Such tradeoffs are the foundation of life history theory, but they are rarely investigated in selection studies. Timing of breeding is a classic example of a heritable trait under directional selection that does not result in an evolutionary response. Using a 22-y study of a tropical parrot, we show that opposing viability and fecundity selection on the timing of breeding is common and affects optimal breeding date, defined by maximization of fitness. After accounting for sampling error, the directions of viability (positive) and fecundity (negative) selection were consistent, but the magnitude of selection fluctuated among years. Environmental conditions (rainfall and breeding density) primarily and breeding experience secondarily modified selection, shifting optimal timing among individuals and years. In contrast to other studies, viability selection was as strong as fecundity selection, late-born juveniles had greater survival than early-born juveniles, and breeding later in the year increased fitness under opposing selection. Our findings provide support for life history tradeoffs influencing selection on phenotypic traits, highlight the need to unify selection and life history theory, and illustrate the importance of monitoring survival as well as reproduction for understanding phenological responses to climate change. PMID:24003118
Exposure Time Optimization for Highly Dynamic Star Trackers
Directory of Open Access Journals (Sweden)
Xinguo Wei
2014-03-01
Full Text Available Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers.
Exposure time optimization for highly dynamic star trackers.
Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun
2014-01-01
Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776
Optimizing the search for transiting planets in long time series
Ofir, Aviv
2013-01-01
Context: Transit surveys, both ground- and space- based, have already accumulated a large number of light curves that span several years. Aims: The search for transiting planets in these long time series is computationally intensive. We wish to optimize the search for both detection and computational efficiencies. Methods: We assume that the searched systems can be well described by Keplerian orbits. We then propagate the effects of different system parameters to the detection parameters. Results: We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS one is either rather insensitive to long-period planets, or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3yr long dataset...
Time Optimal Synchronization Procedure and Associated Feedback Loops
Angoletta, Maria Elena; CERN. Geneva. ATS Department
2016-01-01
A procedure to increase the speed of currently used synchronization loops in a synchrotron by an order of magnitude is presented. Beams dynamics constraint imposes an upper limit on excursions in stable phase angle, and the procedure presented exploits this limit to arrive in the synchronized state from an arbitrary initial state in the fastest possible way. Detailed corrector design for beam phase loop, differential frequency loop and final synchronization loop is also presented. Finally, an overview of the synchronization methods currently deployed in some other CERN’s machines is provided, together with a brief comparison with the newly proposed time-optimal algorithm.
Optimization of recurrent neural networks for time series modeling
DEFF Research Database (Denmark)
Pedersen, Morten With
1997-01-01
solution obtained as well as computation time required. 3. A theoretical definition of the generalization error for recurrent networks is provided. This definition justifies a commonly adopted approach for estimating generalization ability. 4. The viability of pruning recurrent networks by the Optimal...... observed series. Two recurrent models rooted in statistical physics are considered in this respect, namely the ``Boltzmann chain'' and the ``Boltzmann zipper'' and a comprehensive tutorial on these models is provided. Boltzmann chains and zippers are found to benefit as well from second-order training and...
NEW DESIGN OF ROBUST OPTIMAL ARBITRARY TIME-DELAY FILTER
Institute of Scientific and Technical Information of China (English)
WANG Xiaojun; SHAO Huihe
2007-01-01
Zero placement method in the frequency domain is utilized to design robust multi-hump EI optimal arbitrary time-delay filter (OATF) by placing two or more filter zeros near the system poles. A total insensitive OATF can be also achieved if the problem of insensitivity to damping errors is considered. This design strategy is easier to derive and implement. Applications in the anti-swing control of overhead cranes verify the fine performance of this strategy. A better suppression of the load vibrations is obtained using the proposed new OATF, which is more robust to the variation of the cable length.
Time and volume based optimal pricing strategies for telecommunication networks
Kasap, Nihat
2008-01-01
In the recent past, there have been several initiatives by major network providers such as Turk Telekom lead the industry towards network capacity distribution in Turkey. In this study, we use a monopoly pricing model to examine the optimal pricing strategies for “pay-per-volume” and “pay-per-time” based leasing of data networks. Traditionally, network capacity distribution includes short/long term bandwidth and/or usage time leasing. Each consumer has a choice to select volume based pricing ...
Directory of Open Access Journals (Sweden)
V. Karyadinata
2012-09-01
Full Text Available Introduction. Patient safety and the avoidance of inhospital adverse events is a key focus of clinical practice and medical audit. A large of proportion of medical errors affect surgical patients in the peri-operative setting. Safety checklists have been adopted by the medical profession from the aviation industry as a cheap and reliable method of avoiding errors which arise from complex or stressful situations. Current evidence suggests that the use of periooperative checklists has led to a decrease in surgical morbidity and hospital costs. Aim. To assess the quality of implementation of a modified patient safety checklist in a UK district general hospital. Methods. An observational tool was designed to assess in real time the peri-operative performance of the surgical safety checklist in patients undergoing general surgical, urological or orthopaedic procedures. Initiation of the checklist, duration of performance and staff participation were audited in real time. Results. 338 cases were monitored. Nurses were most active in initiating the safety checklist. The checklist was performed successfully in less than a minute in most cases. 11-24% of staff (according to professional group present in the operating room did not participate in the checklist. Critical safety checks (patient identity and procedure name were performed in all cases across all specialties. Variations were noted in checking other categories, such as deep vein thrombosis (DVT prophylaxis or patient warming. Conclusions. There is still a potential for improving the practice and culture of surgical patient safety activities. Staff training and designation of patient safety leadership roles is needed in increasing compliance and implementation of patient safety mechanism, such as peri-operative checklists. There is significant data to advocate the need to implement patient safety surgical checklists internationally
Time Optimal Run-time Evaluation of Distributed Timing Constraints in Process Control Software
DEFF Research Database (Denmark)
Drejer, N.; Kristensen, C.H.
1993-01-01
This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes.........This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes......
An Optimized Multikeying Chaotic Encryption for Real Time Applications
Directory of Open Access Journals (Sweden)
R. Tamijetchelvy
2013-12-01
Full Text Available In recent years, the availability of wireless technologies has become prominent solution for next generation wireless networks (NGWN. Hence the demand for secure communication is an important research issue. Cryptography is recognized as the best method of data protection against active and passive attacks. Therefore a novel chaotic cryptographic scheme is proposed for real time communication. Chaos signals are random behaviour, continuous and sensitive dependence on initial conditions. However, it has been shown that most of these chaotic methods have a low level of security because of single keying concept. In this paper an optimized fast encryption scheme based on chaotic signal with multi key is justified for video frame. Simulation results show that the proposed chaotic encryption scheme outperforms the existing scheme in terms of considerable reduction in encryption and decryption time. The security of the proposed scheme is also analysed by various cryptanalysis attacks.
On asymptotic optimality of Merton's myopic portfolio strategies for discrete time market
Alexandra Rodkina; Nikolai Dokuchaev
2014-01-01
This paper studies the properties of discrete time stochastic optimal control problems associated with portfolio selection. We investigate if optimal continuous time strategies can be used effectively for a discrete time market after a straightforward discretization. We found that Merton's strategy approximates the performance of the optimal strategy in a discrete time model with the sufficiently small time steps
Time Scale Optimization and the Hunt for Astronomical Cycles in Deep Time Strata
Meyers, Stephen R.
2016-04-01
A valuable attribute of astrochronology is the direct link between chronometer and climate change, providing a remarkable opportunity to constrain the evolution of the surficial Earth System. Consequently, the hunt for astronomical cycles in strata has spurred the development of a rich conceptual framework for climatic/oceanographic change, and has allowed exploration of the geologic record with unprecedented temporal resolution. Accompanying these successes, however, has been a persistent skepticism about appropriate astrochronologic testing and circular reasoning: how does one reliably test for astronomical cycles in stratigraphic data, especially when time is poorly constrained? From this perspective, it would seem that the merits and promise of astrochronology (e.g., a geologic time scale measured in ≤400 kyr increments) also serves as its Achilles heel, if the confirmation of such short rhythms defies rigorous statistical testing. To address these statistical challenges in astrochronologic testing, a new approach has been developed that (1) explicitly evaluates time scale uncertainty, (2) is resilient to common problems associated with spectrum confidence level assessment and 'multiple testing', and (3) achieves high statistical power under a wide range of conditions (it can identify astronomical cycles when present in data). Designated TimeOpt (for "time scale optimization"; Meyers 2015), the method employs a probabilistic linear regression model framework to investigate amplitude modulation and frequency ratios (bundling) in stratigraphic data, while simultaneously determining the optimal time scale. This presentation will review the TimeOpt method, and demonstrate how the flexible statistical framework can be further extended to evaluate (and optimize upon) complex sedimentation rate models, enhancing the statistical power of the approach, and addressing the challenge of unsteady sedimentation. Meyers, S. R. (2015), The evaluation of eccentricity
Middle School Physical Education: Good Sport Checklist.
Tenoschok, Mike
2001-01-01
Presents a checklist for monitoring middle school students' behavior during athletics. The checklist highlights: sportsmanship (e.g., playing by the rules, being a good loser, and playing fair); respect (refraining from fighting, avoiding alcohol and other drugs, and shaking hands with opponents); and teamwork (practicing hard, not embarrassing…
Statistically defining optimal conditions of coagulation time of skim milk
International Nuclear Information System (INIS)
Milk consist huge amount of largely water and different proteins. Kappa-kazein of these milk proteins can be coagulated by Mucor miehei rennet enzyme, is an aspartic protease which cleavege 105 (phenly alanine)-106 (methionine) peptide bond. It is commonly used clotting milk proteins for cheese production in dairy industry. The aim of this study to measure milk clotting times of skim milk by using Mucor Miehei rennet and determination of optimal conditions of milk clotting time by mathematical modelling. In this research, milk clotting times of skim milk were measured at different pHs (3.0, 4.0, 5.0, 6.0, 7.0, 8.0) and temperatures (20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 degree C). It was used statistical approach for defining best pH and temperature for milk clotting time of skim milk. Milk clotting activity was increase at acidic pHs and high temperatures. (author)
Optimal Selling Time in Stock Market over a Finite Time Horizon
Institute of Scientific and Technical Information of China (English)
S.C.P. YAM; S.P. YUNG; W. ZHOU
2012-01-01
In this paper,we examine the best time to sell a stock at a price being as close as possible to its highest price over a finite time horizon [0,T],where the stock price is modelled by a geometric Brownian motion and the 'closeness' is measured by the relative error of the stock price to its highest price over [0,T]. More precisely,we want to optimize the expression:V*=sup0≤τ≤T IE[Vτ/MT],where (Vt)t≥0 is a geometric Brownish motion with constant drift α and constant volatility σ ＞ 0,Mt =max0≤s≤t Vs is the running maximum of the stock price,and the supremum is taken over all possible stopping times 0 ＜ τ ＜ Tadapted to the natural filtration (Ft)t≥0 of the stock price.The above problem has been considered by Shiryaev,Xu and Zhou (2008) and Du Toit and Peskir (2009).In this paper we provide an independent proof that when α =1/2σ2,a selling strategy is optimal if and only if it sells the stock either at the terminal time T or at the moment when the stock price hits its maximum price so far.Besides,when α ＞ 1/2σ2,selling the stock at the terminal time T is the unique optimal selling strategy.Our approach to the problem is purely probabilistic and has been inspired by relating the notion of dominant stopping pτ of a stopping time τ to the optimal stopping strategy arisen in the classical "Secretary Problem".
FAME Storage Time in an Optimized Natural Antioxidant Mixture
Directory of Open Access Journals (Sweden)
Rodolfo Lopes Coppo
2013-01-01
Full Text Available The study of B100 biodiesel oxidation stability, and its conservation, is extremely important to control its quality, especially regarding storage. Many spices have shown antioxidant effect and are the targets of study. Knowing the oxidation process in greater detail allows a reliable storage period to be stipulated for the biodiesel without its degradation until the time of use. Results have shown that according to the accelerated stove method, the optimal mixture, composed of 100% of oregano extract, can confer a 535-day shelf life to biodiesel without evident oxidation. According to the results obtained by the Rancimat method, the ideal mixture consists of 100% rosemary, resulting in 483 days of storage. The application of the process variable showed that the accelerated stove method was more suitable to determine oxidative stability of biodiesel.
Kia, Solmaz S.; Cortes, Jorge; Martinez, Sonia
2014-01-01
This paper proposes a novel class of distributed continuous-time coordination algorithms to solve network optimization problems whose cost function is a sum of local cost functions associated to the individual agents. We establish the exponential convergence of the proposed algorithm under (i) strongly connected and weight-balanced digraph topologies when the local costs are strongly convex with globally Lipschitz gradients, and (ii) connected graph topologies when the local costs are strongl...
Design time optimization for hardware watermarking protection of HDL designs.
Castillo, E; Morales, D P; García, A; Parrilla, L; Todorovich, E; Meyer-Baese, U
2015-01-01
HDL-level design offers important advantages for the application of watermarking to IP cores, but its complexity also requires tools automating these watermarking algorithms. A new tool for signature distribution through combinational logic is proposed in this work. IPP@HDL, a previously proposed high-level watermarking technique, has been employed for evaluating the tool. IPP@HDL relies on spreading the bits of a digital signature at the HDL design level using combinational logic included within the original system. The development of this new tool for the signature distribution has not only extended and eased the applicability of this IPP technique, but it has also improved the signature hosting process itself. Three algorithms were studied in order to develop this automated tool. The selection of a cost function determines the best hosting solutions in terms of area and performance penalties on the IP core to protect. An 1D-DWT core and MD5 and SHA1 digital signatures were used in order to illustrate the benefits of the new tool and its optimization related to the extraction logic resources. Among the proposed algorithms, the alternative based on simulated annealing reduces the additional resources while maintaining an acceptable computation time and also saving designer effort and time. PMID:25861681
On selection of the optimal data time interval for real-time hydrological forecasting
Directory of Open Access Journals (Sweden)
J. Liu
2013-09-01
Full Text Available With the advancement in modern telemetry and communication technologies, hydrological data can be collected with an increasingly higher sampling rate. An important issue deserving attention from the hydrological community is which suitable time interval of the model input data should be chosen in hydrological forecasting. Such a problem has long been recognised in the control engineering community but is a largely ignored topic in operational applications of hydrological forecasting. In this study, the intrinsic properties of rainfall–runoff data with different time intervals are first investigated from the perspectives of the sampling theorem and the information loss using the discrete wavelet transform tool. It is found that rainfall signals with very high sampling rates may not always improve the accuracy of rainfall–runoff modelling due to the catchment low-pass-filtering effect. To further investigate the impact of a data time interval in real-time forecasting, a real-time forecasting system is constructed by incorporating the probability distributed model (PDM with a real-time updating scheme, the autoregressive moving-average (ARMA model. Case studies are then carried out on four UK catchments with different concentration times for real-time flow forecasting using data with different time intervals of 15, 30, 45, 60, 90 and 120 min. A positive relation is found between the forecast lead time and the optimal choice of the data time interval, which is also highly dependent on the catchment concentration time. Finally, based on the conclusions from the case studies, a hypothetical pattern is proposed in three-dimensional coordinates to describe the general impact of the data time interval and to provide implications of the selection of the optimal time interval in real-time hydrological forecasting. Although nowadays most operational hydrological systems still have low data sampling rates (daily or hourly, the future is that higher
On selection of the optimal data time interval for real-time hydrological forecasting
Directory of Open Access Journals (Sweden)
J. Liu
2012-09-01
Full Text Available With the advancement in modern telemetry and communication technologies, hydrological data can be collected with an increasingly higher sampling rate. An important issue deserving attention from the hydrological community is what suitable time interval of the model input data should be chosen in hydrological forecasting. Such a problem has long been recognised in the control engineering community but is a largely ignored topic in operational applications of hydrological forecasting. In this study, the intrinsic properties of rainfall-runoff data with different time intervals are first investigated from the perspectives of the sampling theorem and the information loss using the discrete wavelet decomposition tool. It is found that rainfall signals with very high sampling rates may not always improve the accuracy of rainfall-runoff modelling due to the catchment low-pass filtering effect. To further investigate the impact of data time interval in real-time forecasting, a real-time forecasting system is constructed by incorporating the Probability Distributed Model (PDM with a real-time updating scheme, the autoregressive-moving average (ARMA model. Case studies are then carried out on four UK catchments with different concentration times for real-time flow forecasting using data with different time intervals of 15 min, 30 min, 45 min, 60 min, 90 min and 120 min. A positive relation is found between the forecast lead time and the optimal choice of the data time interval, which is also highly dependent on the catchment concentration time. Finally, based on the conclusions from the case studies, a hypothetical pattern is proposed in three-dimensional coordinates to describe the general impact of the data time interval and to provide implications on the selection of the optimal time interval in real-time hydrological forecasting. Although nowadays most operational hydrological systems still have low data sampling rates (daily or hourly, the trend in
Schlier, Björn; Moritz, Steffen; Lincoln, Tania M
2016-07-30
Research increasingly assesses momentary changes in paranoia in order to elucidate causal mechanisms. Observed or manipulated changes in postulated causal factors should result in fluctuations in state paranoid ideation. Previous studies often employed a state-adapted Paranoia Checklist (Freeman et al., 2005) to measure state paranoia. This study examined whether the Paranoia Checklist or subsets of its items are appropriate for this purpose. Thirteen studies (N=860) were subjected to meta-analyses of each Paranoia Checklist item. We selected items based on (1) whether they showed pre-to-post change in the expected direction and (2) whether this effect was larger in experimental vs. control conditions. All resulting item selections were cross-validated on a hold-out sample (n=1893). Finally, we explored how much variation in paranoia was captured by the state-adapted version in a brief ambulatory assessment study (N=32). A thirteen item State Paranoia Checklist as well as a five item and a three item Brief State Paranoia Checklist were extracted. Cross validation revealed better model fit and increased sensitivity to change. Multilevel analysis indicated 25-30% of the variance in the Brief State Paranoia Checklists to be due to intra-individual daily fluctuations in paranoia. Our analyses produced reliable and valid revised scales. Increases in change sensitivity indicate that future assessment of state paranoia in experimental and ambulatory assessment studies can be optimized by using the revised scales. PMID:27227702
Time domain topology optimization of 3D nanophotonic devices
DEFF Research Database (Denmark)
Elesin, Yuriy; Lazarov, Boyan Stefanov; Jensen, Jakob Søndergaard; Sigmund, Ole
2014-01-01
We present an efficient parallel topology optimization framework for design of large scale 3D nanophotonic devices. The code shows excellent scalability and is demonstrated for optimization of broadband frequency splitter, waveguide intersection, photonic crystal-based waveguide and nanowire-base......-based waveguide. The obtained results are compared to simplified 2D studies and we demonstrate that 3D topology optimization may lead to significant performance improvements. © 2013 Elsevier B.V. All rights reserved....
Optimized iPhone Real-TimeRendering
Hellstrand, Peter
2011-01-01
Rendering is the process of generating an image from a model. This process requires heavy computations. The iPhone has very limited hardware. The purpose of this project is to optimize the rendering process in the iPhone game "Top Gear, Stunt School" developed by Resolution Interactive AB. This thesis describes the evaluation and implementation of different optimizations used for the game.
Ruby Lake National Wildlife Refuge wildlife checklist
US Fish and Wildlife Service, Department of the Interior — Checklist with habitat, season, and abundance codes for wildlife species at Ruby Lake NWR. Includes bird, mammal, amphibian, reptile, and fish species.
How to decide the optimal scheme and the optimal time for construction
International Nuclear Information System (INIS)
Since the development in Norway began some 105 years ago the mean annual generation has reached approximately 110 TWh. This means that there is a large potential for uprating and refurbishing (U/R). A project undertaken by the Norwegian Water Resources and Energy Administration (NVE) has identified energy resources by means of U/R to about 10 TWh annual generation. One problem in harnessing the potential owned by small and medium sized electricity boards is the lack of simple tools to help us carry out the right decisions. The paper describes a simple model to find the best solution of scheme and the optimal time to start. The principle of present value is used. The main input is: production, price, annual costs of maintenance, the remaining lifetime and the social rate of return. The model calculates the present value of U/R/N for different points of time to start U/R/N. In addition the present value of the existing plant is calculated. Several alternatives can be considered. The best one will be the one which gives the highest present value according to the value of the existing plant. The internal rate of return is also calculated. To be aware of the sensitivity a star diagram is shown. The model gives the opportunity to include environmental charges and the value of effect (peak power). (Author)
Time optimal controls of the linear Fitzhugh–Nagumo equation with pointwise control constraints
Kunisch, Karl; Wang, Lijuan
2012-01-01
Time optimal control governed by the internally controlled linear Fitzhugh–Nagumo equation with pointwise control constraint is considered. Making use of Ekeland’s variational principle, we obtain Pontryagin’s maximum principle for a time optimal control problem. Using the maximum principle, the bang–bang property of the optimal controls is established under appropriate assumptions.
Analysis and Optimization of Heterogeneous Real-Time Embedded Systems
DEFF Research Database (Denmark)
Pop, Paul; Eles, Petru; Peng, Zebo
2005-01-01
of several networks interconnected via gateways. We present a schedulability analysis for safety-critical applications distributed on multi-cluster systems and briefly highlight characteristic design optimization problems: the partitioning and mapping of functionality, and the packing of application...
On Nonlinear Continuous-time Optimal Control of Penicillin Cultivation
Czech Academy of Sciences Publication Activity Database
Pčolka, M.; Čelikovský, Sergej
Curich: IEEE, 2013, s. 4442-4447. ISBN 978-3-9524173-4-8. [The European Control Conference 2013 (ECC). Curich (CH), 17.06.2013-19.06.2013] R&D Projects: GA MŠk(CZ) LG12016; GA ČR GA13-20433S Institutional support: RVO:67985556 Keywords : Optimal control * feedback control * optimization Subject RIV: BC - Control Systems Theory
Designing optimal stimuli to control neuronal spike timing
Yashar Ahmadian
2010-01-01
We develop fast computational methods for optimally designing a natural or artificial stimulus to make a neuron emit a desired spike train. We consider three specific examples of artificial stimulation methods: extracellular electrical stimulation (Salzman et al. 1990), two-photon uncaging of caged neurotransmitters (Nikolenko et al., 2008), and optical activation of genetically implanted light-sensitive ion channels (Han et al. 2007). We also consider the case of optimizing a sensory stimulu...
Convertible Subordinated Debt Financing and Optimal Investment Timing
Kyoko Yagi; Ryuta Takashima
2010-01-01
In this paper, we examine the optimal investment policy of the firm which is financed by issuing equity, straight debt and convertible debt with the senior-sub structure. The senior-sub structure gives preference to straight debt over convertible debt and to convertible debt over equity when the default occurs. We investigate how the senior-sub structure affects the optimal policies for default, conversion and investment the values of equity, straight debt, convertible debt and investment. In...
Fullmer, Rees; Liang, Jinsong; Chen, YangQuan
2004-01-01
Spacecraft attitude control using only magnetic coils suffers from a slowly varying uncontrollable axis. This lack of controllability results in marginal stability, slow slew maneuvering and convergence to equilibrium positions. In this paper the open-loop time-optimal control and continuous optimization solutions for magnetic attitude control of a nadir-pointing satellite are presented. Nonlinear time-varying models with constrained inputs are considered instead of the linearized model gener...
Density resolutionary optimization of real time radiotherapy portal imagings
International Nuclear Information System (INIS)
Objective: Electronic portal imaging devices (EPIDs) are widely used as a replacement of portal films for patient position verification, but the image quality is not always optimal. Because of very low density resolution, the portal imaging is difficult to be used clinically. In this study, several transforming models and the optimization exposure or acquisition conditions were studied for optimization portal imaging, which based on DicomRT platform built by ourselves. Methods: 6 MV X-ray from Varian 21EX linac was used to generate portal images by Portal Vision aSi500 amorphous silicon detector image acquisition system. The density resolution study was based on the number of the lines which could be seen in the image of a special Las Vegas image quality test board. The optimization calculating models were focused on equalization after stretch transforming discrete wavelet transform (DWT) and Butter worth high pass filters. The calculation was performed in Matlab language. Results: The optimal numbers of MU, average frames and reset number were 4 - 5, 3 - 4 and 2 - 3, respectively. The density resolution of optimized imaging via equalization after stretch transforming, DWT and Butter worth high pass filter transforming was markedly improved. The bone structure could be definitely distinguished. The number of lines distinguished in Las Vegas image via equalization after stretch transforming, DWT and Better worth high pass filter transforming was 3, 4 and 5, respectively. Conclusions: The proposed transforming systems, including DWT edge detection and Butter worth high pass filter transform, are suitable for improving density resolving power of MV X-ray portal image. (authors)
Optimal experiment design for time-lapse traveltime tomography
Energy Technology Data Exchange (ETDEWEB)
Ajo-Franklin, J.B.
2009-10-01
Geophysical monitoring techniques offer the only noninvasive approach capable of assessing both the spatial and temporal dynamics of subsurface fluid processes. Increasingly, permanent sensor arrays in boreholes and on the ocean floor are being deployed to improve the repeatability and increase the temporal sampling of monitoring surveys. Because permanent arrays require a large up-front capital investment and are difficult (or impossible) to re-configure once installed, a premium is placed on selecting a geometry capable of imaging the desired target at minimum cost. We present a simple approach to optimizing downhole sensor configurations for monitoring experiments making use of differential seismic traveltimes. In our case, we use a design quality metric based on the accuracy of tomographic reconstructions for a suite of imaging targets. By not requiring an explicit singular value decomposition of the forward operator, evaluation of this objective function scales to problems with a large number of unknowns. We also restrict the design problem by recasting the array geometry into a low dimensional form more suitable for optimization at a reasonable computational cost. We test two search algorithms on the design problem: the Nelder-Mead downhill simplex method and the Multilevel Coordinate Search algorithm. The algorithm is tested for four crosswell acquisition scenarios relevant to continuous seismic monitoring, a two parameter array optimization, several scenarios involving four parameter length/offset optimizations, and a comparison of optimal multi-source designs. In the last case, we also examine trade-offs between source sparsity and the quality of tomographic reconstructions. One general observation is that asymmetric array lengths improve localized image quality in crosswell experiments with a small number of sources and a large number of receivers. Preliminary results also suggest that high-quality differential images can be generated using only a small
Yamaleev, N. K.; Diskin, B.; Nielsen, E. J.
2009-01-01
.We study local-in-time adjoint-based methods for minimization of ow matching functionals subject to the 2-D unsteady compressible Euler equations. The key idea of the local-in-time method is to construct a very accurate approximation of the global-in-time adjoint equations and the corresponding sensitivity derivative by using only local information available on each time subinterval. In contrast to conventional time-dependent adjoint-based optimization methods which require backward-in-time integration of the adjoint equations over the entire time interval, the local-in-time method solves local adjoint equations sequentially over each time subinterval. Since each subinterval contains relatively few time steps, the storage cost of the local-in-time method is much lower than that of the global adjoint formulation, thus making the time-dependent optimization feasible for practical applications. The paper presents a detailed comparison of the local- and global-in-time adjoint-based methods for minimization of a tracking functional governed by the Euler equations describing the ow around a circular bump. Our numerical results show that the local-in-time method converges to the same optimal solution obtained with the global counterpart, while drastically reducing the memory cost as compared to the global-in-time adjoint formulation.
An intermediate targets method for time parallelization in optimal control
Maday, Yvon; Riahi, Kamel
2011-01-01
In this paper, we present a method that enables to solve in parallel the Euler-Lagrange system associated with the optimal control of a parabolic equation. Our approach is based on an iterative update of a sequence of intermediate targets and gives rise independent sub-problems that can be solved in parallel. Numerical experiments show the efficiency of our method.
Real-Time Optimization for Economic Model Predictive Control
DEFF Research Database (Denmark)
Sokoler, Leo Emil; Edlund, Kristian; Frison, Gianluca;
2012-01-01
In this paper, we develop an efficient homogeneous and self-dual interior-point method for the linear programs arising in economic model predictive control. To exploit structure in the optimization problems, the algorithm employs a highly specialized Riccati iteration procedure. Simulations show...
World checklist of hornworts and liverworts.
Söderström, Lars; Hagborg, Anders; von Konrat, Matt; Bartholomew-Began, Sharon; Bell, David; Briscoe, Laura; Brown, Elizabeth; Cargill, D Christine; Costa, Denise P; Crandall-Stotler, Barbara J; Cooper, Endymion D; Dauphin, Gregorio; Engel, John J; Feldberg, Kathrin; Glenny, David; Gradstein, S Robbert; He, Xiaolan; Heinrichs, Jochen; Hentschel, Jörn; Ilkiu-Borges, Anna Luiza; Katagiri, Tomoyuki; Konstantinova, Nadezhda A; Larraín, Juan; Long, David G; Nebel, Martin; Pócs, Tamás; Puche, Felisa; Reiner-Drehwald, Elena; Renner, Matt A M; Sass-Gyarmati, Andrea; Schäfer-Verwimp, Alfons; Moragues, José Gabriel Segarra; Stotler, Raymond E; Sukkharak, Phiangphak; Thiers, Barbara M; Uribe, Jaime; Váňa, Jiří; Villarreal, Juan Carlos; Wigginton, Martin; Zhang, Li; Zhu, Rui-Liang
2016-01-01
A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution. PMID:26929706
World checklist of hornworts and liverworts
Söderström, Lars; Hagborg, Anders; von Konrat, Matt; Bartholomew-Began, Sharon; Bell, David; Briscoe, Laura; Brown, Elizabeth; Cargill, D. Christine; Costa, Denise P.; Crandall-Stotler, Barbara J.; Cooper, Endymion D.; Dauphin, Gregorio; Engel, John J.; Feldberg, Kathrin; Glenny, David; Gradstein, S. Robbert; He, Xiaolan; Heinrichs, Jochen; Hentschel, Jörn; Ilkiu-Borges, Anna Luiza; Katagiri, Tomoyuki; Konstantinova, Nadezhda A.; Larraín, Juan; Long, David G.; Nebel, Martin; Pócs, Tamás; Puche, Felisa; Reiner-Drehwald, Elena; Renner, Matt A.M.; Sass-Gyarmati, Andrea; Schäfer-Verwimp, Alfons; Moragues, José Gabriel Segarra; Stotler, Raymond E.; Sukkharak, Phiangphak; Thiers, Barbara M.; Uribe, Jaime; Váňa, Jiří; Villarreal, Juan Carlos; Wigginton, Martin; Zhang, Li; Zhu, Rui-Liang
2016-01-01
Abstract A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution. PMID:26929706
A Glowworm Optimization Method for the Design of Web Services
Directory of Open Access Journals (Sweden)
Koffka Khan
2012-09-01
Full Text Available A method for adaptive usability evaluation of B2C eCommerce web services is proposed. For measuring eCommerce usability a checklist integrating eCommerce quality and usability is developed. By a Glowworm swarm optimization (GSO neural networks-based model the usability dimensions and their checklist items are adaptively selected. A case study for usability evaluation of an eCommerce anthurium retail website is carried out. The experimental results show that GSO with neural networks supports the allocation of usability problems and the defining of relevant improvement measures. The main advantage of the approach is the adaptive selection of most significant checklist dimensions and items and thus significant reduction of the time for usability evaluation and design.
Robust fuel- and time-optimal control of uncertain flexible space structures
Wie, Bong; Sinha, Ravi; Sunkel, John; Cox, Ken
1993-01-01
The problem of computing open-loop, fuel- and time-optimal control inputs for flexible space structures in the face of modeling uncertainty is investigated. Robustified, fuel- and time-optimal pulse sequences are obtained by solving a constrained optimization problem subject to robustness constraints. It is shown that 'bang-off-bang' pulse sequences with a finite number of switchings provide a practical tradeoff among the maneuvering time, fuel consumption, and performance robustness of uncertain flexible space structures.
稻垣, 陽介; イナガキ, ヨウスケ; Yousuke, Inagaki
2007-01-01
The efficiency of Monte Carlo simulated annealing algorithm based on the generalized statistics of Tsallis (GSA) is compared with conventional simulated annealing (CSA) based on Boltzmann-Gibbs statistics. Application to the discrete-time optimal growth problem demonstrates that the replacement of CSA by GSA has the potential to speed up optimizations with no loss of accuracy in finding optimal policy function.
Turnpike theory of continuous-time linear optimal control problems
Zaslavski, Alexander J
2015-01-01
Individual turnpike results are of great interest due to their numerous applications in engineering and in economic theory; in this book the study is focused on new results of turnpike phenomenon in linear optimal control problems. The book is intended for engineers as well as for mathematicians interested in the calculus of variations, optimal control, and in applied functional analysis. Two large classes of problems are studied in more depth. The first class studied in Chapter 2 consists of linear control problems with periodic nonsmooth convex integrands. Chapters 3-5 consist of linear control problems with autonomous nonconvex and nonsmooth integrands. Chapter 6 discusses a turnpike property for dynamic zero-sum games with linear constraints. Chapter 7 examines genericity results. In Chapter 8, the description of structure of variational problems with extended-valued integrands is obtained. Chapter 9 ends the exposition with a study of turnpike phenomenon for dynamic games with extended value integran...
Bayesian Optimization Algorithm, Population Sizing, and Time to Convergence
Energy Technology Data Exchange (ETDEWEB)
Pelikan, M.; Goldberg, D.E.; Cantu-Paz, E.
2000-01-19
This paper analyzes convergence properties of the Bayesian optimization algorithm (BOA). It settles the BOA into the framework of problem decomposition used frequently in order to model and understand the behavior of simple genetic algorithms. The growth of the population size and the number of generations until convergence with respect to the size of a problem is theoretically analyzed. The theoretical results are supported by a number of experiments.
Optimal time switching from tayloristic to holistic workplace organization
Vallée, Thomas; Moreno-Galbis, Eva
2010-01-01
The introduction of information and communication technologies over the past decades has fostered a process of internal workplace reorganization of firms who have tried to maximize their performance. Using a two stage optimal control technique, this paper provides analytical solutions to the conditions under which an economy decides to adopt a new organizational regime characterized by multitasking and an horizontal hierarchical structure (holistic organization). We consider two flexibility o...
Checklist interruption and resumption: A linguistic study
Linde, Charlotte; Goguen, Joseph
1987-01-01
This study forms part of a project investigating the relationships among the formal structure of aviation procedures, the ways in which the crew members are taught to execute them, and the ways in which thet are actually performed in flight. Specifically, this report examines the interactions between the performance of checklists and interruptions, considering both interruptions by radio communications and by other crew members. The data consists of 14 crews' performance of a full mission simulation of a higher ratio of checklist speech acts to all speech acts within the span of the performance of the checklist. Further, it is not number of interruptions but length of interruptions which is associated with crew performance quality. Use of explicit holds is also associated with crew performance.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The optimal control problem was studied for linear time-varying systems, which was affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions. To damp the effect of disturbances in an optimal fashion, we obtained a new feedforward and feedback optimal control law and gave the control algorithm by solving a Riccati differential equation and a matrix differential equation. Simulation results showed that the achieved optimal control law was realizable, efficient and robust to reject the external disturbances.
Numerical Simulation of Real-Time Trajectory Optimization for Helicopter Noise Abatement
Ikaida, Hiroshi; Tsuchiya, Takeshi; Ishii, Hirokazu; Gomi, Hiromi; Okuno, Yoshinori
This study was an attempt to obtain optimal landing approaches for helicopters to reduce ground noise impact. Simulations and real flight tests in our previous study confirmed that flights along pre-calculated optimal trajectories resulted in lower noise levels than flights along conventional approach paths. However, some experiments did not show the expected optimization effects because of unforeseen disturbances. This paper therefore improves the algorithms in order to realize practical real-time optimization, which can involve external disturbances. To validate the effect of the new method, various computer simulations were conducted under real flight experimental scenarios. The obtained optimal solutions were characterized by steep flight path angles, which can avoid the generation of loud noise, the avoidance of noise sensitive points, and short flight times. These are different from conventional landing approaches. The optimal trajectories resulted in noise reduction on the ground, which shows the effectiveness and potential of the proposed real-time trajectory optimization method.
Exposure Time Optimization for Highly Dynamic Star Trackers
Xinguo Wei; Wei Tan; Jian Li; Guangjun Zhang
2014-01-01
Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect...
Short Form of the Developmental Behaviour Checklist
2007-01-01
A 24-item short form of the 96-item Developmental Behaviour Checklist was developed to provide a brief measure of Total Behaviour Problem Score for research purposes. The short form Developmental Behaviour Checklist (DBC-P24) was chosen for low bias and high precision from among 100 randomly selected item sets. The DBC-P24 was developed from epidemiological data in the first three waves of the Australian Child to Adult Development study, and cross validated for groups with autism, fragile X, ...
Energy Technology Data Exchange (ETDEWEB)
Ott, W.; Kaufmann, Y.; Steiner, P. [Econcept AG, Zuerich (Switzerland); Gilgen, K.; Sartoris, A. [IRAP-HSR, Institut fuer Raumentwicklung an der Hochschule fuer Technik Rapperswil, Rapperswil (Switzerland)
2008-07-01
This report published by the Swiss Federal Office of Energy (SFOE) takes a look at a checklist for investors in large-scale wind-power installations. The authors state that the same questions are often posed in the course of the planning and realisation of wind turbine installations. This document presents a checklist that will help achieve the following goals: Tackling the steps involved in the planning and implementation phases, increasing planning security, systematic implementation in order to reduce risks for investors and to shorten time-scales as well as the reduction of costs. Further, participative processes can be optimised by using comprehensively prepared information in order to reduce the risk of objections during project approval. The structure of the check-list is described and discussed.
WEB CACHING AND RESPONSE TIME OPTIMIZATION BASED ON EVICTION METHOD
Directory of Open Access Journals (Sweden)
S.LATHA SHANMUGAVADIVU
2010-09-01
Full Text Available Caching is a technique first used by memory management to reduce bus traffic and latency of data access. Web traffic has increased tremendously since the beginning of the 1990s.With the significant increase of Web traffic, caching techniques are applied to Web caching to reduce network traffic, user-perceived latency, and serverload by caching the documents in local proxies[5]. In this paper, analization of both advantages and disadvantages of some current Web cache replacement algorithms including lowest relative value algorithm, least weighted usage algorithm and least unified-value (LUV algorithm is done. Based on our analysis, we proposed a new algorithm, called least grade replacement (LGR, which takes recency, frequency, perfect-history, and document size into account for Web cache optimization. The optimal recency coefficients were determined by using 2- and 4-way set associative caches. The cache size was varied from 32 k to 256 k in the simulation. The simulation results showed that the new algorithm (LGR is better than LRU and LFU in terms of hit ratio (BR and byte hit ratio (BHR.
Optimal replacement time estimation for machines and equipment based on cost function
J. Šebo; J. Buša; Demeč, P.; J. Svetlík
2013-01-01
The article deals with a multidisciplinary issue of estimating the optimal replacement time for the machines. Considered categories of machines, for which the optimization method is usable, are of the metallurgical and engineering production. Different models of cost function are considered (both with one and two variables). Parameters of the models were calculated through the least squares method. Models testing show that all are good enough, so for estimation of optimal replacement time is ...
Optimal Control of (Min,+) Linear Time-Varying Systems
Lahaye, Sébastien; Boimond, Jean-Louis; Hardouin, Laurent
1999-01-01
International audience The class of discrete event dynamic systems involving only synchronization phenomena can be seen as linear time-invariant systems in a particular algebraic structure called (min,+) algebra. In the same framework, this paper deals with linear time-varying systems, that is, systems whose parameters may change as functions of time. For example, in a manufacturing system the number of working machines, or the number of trains running in a closed network of railway connec...
Zhang, Can
2011-01-01
This paper studies a time optimal control problem with control constraints of the rectangular type for the linear multi-input time-varying ordinary di?erential equations. The aims of this study are to establish certain necessary and sufficient conditions for the optimal time and time optimal control, and to build up an al- gorithm for the optimal time and time optimal control.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The problem of real-time trajectory optimization for small solid launch vehicle of operational responsive space (ORS) was studied by using pseudospectral method. According to the characteristic of the trajectory design, the dynamics model was set up in the inertia right-angled reference frame, and the equation and parameter at the orbit injection point were simplified and converted. The infinite dimension dynamic optimal control problem was converted to a finite dimension static state optimization problem and the algorithm reduced the complexity so as to become a general algorithm in trajectories optimization. With the trajectories optimization of a three-stage solid vehicle with a liquor upper stage as example, the model of the trajectory optimization was set up and simulations were carried out. The results demonstrated the advantage and validity of the pseudospectral method. The rejection time of fairing was also analyzed by the simulation results, and the optimal flight procedure and trajectory were obtained.
Determination of Optimal Control Strength of Delayed Feedback Control Using Time Series
Institute of Scientific and Technical Information of China (English)
YIN Hua-Wei; LU Wei-Ping; WANG Peng-Ye
2004-01-01
@@ We study controlling chaos using time-delayed feedback control based on chaotic time series without prior knowl edge of dynamical systems, and determine the optimal control parameters for stabilizing unstable periodic orbits with maximal stability.
Optimal paths planning in dynamic transportation networks with random link travel times
Institute of Scientific and Technical Information of China (English)
孙世超; 段征宇; 杨东援
2014-01-01
A theoretical study was conducted on finding optimal paths in transportation networks where link travel times were stochastic and time-dependent (STD). The methodology of relative robust optimization was applied as measures for comparing time-varying, random path travel times for a priori optimization. In accordance with the situation in real world, a stochastic consistent condition was provided for the STD networks and under this condition, a mathematical proof was given that the STD robust optimal path problem can be simplified into a minimum problem in specific time-dependent networks. A label setting algorithm was designed and tested to find travelers’ robust optimal path in a sampled STD network with computation complexity of O(n2+n·m). The validity of the robust approach and the designed algorithm were confirmed in the computational tests. Compared with conventional probability approach, the proposed approach is simple and efficient, and also has a good application prospect in navigation system.
Portfolio Optimization for Hedge Funds through Time-Varying Coefficients
Dewaele, Benoît
2013-01-01
In this paper, we show the interest of the time-varying coefficient model in hedge fund performance assessment and selection. We argue that the alpha of hedge funds is dynamic and that the time-varying alpha captures this dynamic behavior. Therefore, forming portfolios based on their time-varying alpha should lead to outperforming portfolios. Using a persistence analysis, we check this conjecture and show that contrary to top performers in terms of OLS alpha, the top performers in terms of pa...
Cone penetrometer demonstration standard startup review checklist
International Nuclear Information System (INIS)
Startup readiness for the Cone Penetrometer Demonstration in AX Tank Farm will be verified through the application of a Standard Startup Review Checklist. This is a listing of those items essential to demonstrating readiness to start the Cone Penetrometer Demonstration in AX Tank Farm
Hypogeous fungi of Lithuania: a preliminary checklist
Directory of Open Access Journals (Sweden)
Ernestas Kutorga
2013-12-01
Full Text Available The paper reports on hypogeous fungi known from Lithuania, and data on their habitats, phenology, and distribution. References on the collections kept in the herbaria are also pointed out. The information is based on literature data and re-examination of all available voucher specimens. 22 species (12 genera, 3 phyla recorded from 124 localities are presented in a preliminary checklist.
Hypogeous fungi of Lithuania: a preliminary checklist
Ernestas Kutorga; Marija Kataržytė
2013-01-01
The paper reports on hypogeous fungi known from Lithuania, and data on their habitats, phenology, and distribution. References on the collections kept in the herbaria are also pointed out. The information is based on literature data and re-examination of all available voucher specimens. 22 species (12 genera, 3 phyla) recorded from 124 localities are presented in a preliminary checklist.
Preparing for an Agritourism Event: A Checklist
Denise Y. Mainville; Mundy, Karen
2005-01-01
This factsheet provides a checklist for agritourism firms to use to ensure that key aspects of preparation for the event are addressed. The publication is intended to help an existing operation host a special event - it is not intended as a resource for starting an agritourism business.
Pocket Checklists of Indonesian timber trees
Prawira, Soewanda A.; Tantra, I.G.M.; Whitmore, T.C.
1984-01-01
Indonesia as yet does not have a comprehensive account of the forest trees which reach timber size (35 cm dbh = 14 inch or 105 cm gbh = 42 inch). A project has been started in August 1983 by the Botany Section of the Forest Research Institute in Bogor, Indonesia, to prepare pocket checklists of the
Energy Technology Data Exchange (ETDEWEB)
Van Paridon, W.J.A.; Dol, J.J.
2002-11-15
This checklist shows the energy saving options for investments in buildings and installations for flower bulb businesses. Next to an energy efficiency improvement of 22%, the Long-term agreement for energy has also adopted the target of 4% sustainable energy deployment. This checklist therefore indicates for each category whether it is in the sustainable energy category or part of the regular saving options [Dutch] In deze checklist wordt aangegeven waar de mogelijkheden liggen tot besparing van energie bij investeringen in gebouwen en installaties voor bloembollenteeltbedrijven. In de meerjarenafspraak energie heeft de bloembollensector naast de energie efficiency verbetering van 22% ook de doelstelling opgenomen om 4% duurzame energie te gebruiken. In de checklist staat daarom per aspect of deze behoort tot de categorie duurzame energie of tot de normale besparingsopties.
Identification and optimization of traffic bottleneck with signal timing
Shaoxin Yuan; Xiangmo Zhao; Yisheng An
2014-01-01
In urban transportation network, traffic congestion is likely to occur at traffic bottlenecks. The signal timing at intersections together with static properties of left-turn and straight-through lanes of roads are two significant factors causing traffic bottlenecks. A discrete-time model of traffic bottleneck is hence developed to analyze these two factors, and a bottleneck indicator is introduced to estimate the comprehensive bottleneck degree of individual road in regional transportation n...
Response Time Optimization for Replica Selection Service in Data Grids
Directory of Open Access Journals (Sweden)
Husni H.E. AL-Mistarihi
2008-01-01
Full Text Available Problem Statement: Data Grid architecture provides a scalable infrastructure for grid services in order to manage data files and their corresponding replicas that were distributed across the globe. The grid services are designed to support a variety of data grid applications (jobs and projects. Replica selection is a high-level service that chooses a replica location from among many distributed replicas with the minimum response time for the users' jobs. Estimating the response time accurately in the grid environment is not an easy task. The current systems expose high response time in selecting the required replicas because the response time is estimated by considering the data transfer time only. Approach: We proposed a replica selection system that selects the best replica location for the users' running jobs in a minimum response time that can be estimated by considering new factors besides the data transfer time, namely, the storage access latency and the replica requests that waiting in the storage queue. Results: The performance of the proposed system was compared with a similar system that exists in the literature namely, SimpleOptimiser. The simulation results demonstrated that our system performed better than the SimpleOptimiser on an average of 6%. Conclusions: The proposed system can select the best replica location in a lesser response time than the SimpleOptimise. The efficiency of the proposed system is 6% higher than the SimpleOptimise. The efficiency level has a high impact on the quality of service that is perceived by grid users in a data grid environment where the data files are relatively big. For example, the data files produced from the scientific applications are of the size hundreds of Terabytes.
Parameter estimation for time-delay chaotic system by particle swarm optimization
International Nuclear Information System (INIS)
The knowledge about time delays and parameters is very important for control and synchronization of time-delay chaotic system. In this paper, parameter estimation for time-delay chaotic system is given by treating the time delay as an additional parameter. The parameter estimation is converted to an optimization problem, which finds a best parameter combination such that an objective function is minimized. Particle swarm optimization (PSO) is used to optimize the objective function through particles' cooperation and evolution. Two illustrative examples are given to show the validity of the proposed method.
Optimal time decay of the compressible micropolar fluids
Liu, Qingqing; Zhang, Peixin
2016-05-01
This paper primarily studies the large-time behavior of solutions to the Cauchy problem on the compressible micropolar fluid system which is a generalization of the classical Navier-Stokes system. The asymptotic stability of the steady state with the strictly positive constant density, the vanishing velocity, and micro-rotational velocity is established under small perturbation in regular Sobolev space. Moreover, it turns out that both the density and the velocity tend time-asymptotically to the corresponding equilibrium state with rate (1 + t) - 3 / 4 in L2 and the micro-rotational velocity also tends to the equilibrium state with the faster rate (1 + t) - 5 / 4 in L2 norm. The proof is based on the spectrum analysis and time-weighted energy estimate.
Minimising the risk of infection: a peri-operative checklist.
Heller, S; Rezapoor, M; Parvizi, J
2016-01-01
The purpose of this article is to provide the reader with a seven-step checklist that could help in minimising the risk of PJI. The check list includes strategies that can be implemented pre-operatively such as medical optimisation, and reduction of the bioburden by effective skin preparation or actions taking during surgery such as administration of timely and appropriate antibiotics or blood conservation, and finally implementation of post-operative protocols such as efforts to minimise wound drainage and haematoma formation. PMID:26733635
Space-time topology optimization for one-dimensional wave propagation
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard
A space-time extension of the topology optimization method is presented. The formulation, with design variables in both the spatial and temporal domains, is used to create structures with an optimized distribution of material properties that can vary in time. The method is outlined for one......-dimensional transient wave propagation in an elastic rod with time dependent Young's modulus. By two simulation examples it is demonstrated how dynamic structures can display rich dynamic behavior such as wavenumber/frequency shifts and lack of energy conservation. The optimization method's potential for creating...... structures with novel dynamic behavior is illustrated by a simple example; it is shown that an elastic rod in which the optimized stiffness distribution is allowed to vary in time can be much more efficient in prohibiting wave propagation compared to a static bandgap structure. Optimized designs in form of...
Optease Vena Cava Filter Optimal Indwelling Time and Retrievability
International Nuclear Information System (INIS)
The purpose of this study was to assess the indwelling time and retrievability of the Optease IVC filter. Between 2002 and 2009, a total of 811 Optease filters were inserted: 382 for prophylaxis in multitrauma patients and 429 for patients with venous thromboembolic (VTE) disease. In 139 patients [97 men and 42 women; mean age, 36 (range, 17–82) years], filter retrieval was attempted. They were divided into two groups to compare change in retrieval policy during the years: group A, 60 patients with filter retrievals performed before December 31 2006; and group B, 79 patients with filter retrievals from January 2007 to October 2009. A total of 128 filters were successfully removed (57 in group A, and 71 in group B). The mean filter indwelling time in the study group was 25 (range, 3–122) days. In group A the mean indwelling time was 18 (range, 7–55) days and in group B 31 days (range, 8–122). There were 11 retrieval failures: 4 for inability to engage the filter hook and 7 for inability to sheathe the filter due to intimal overgrowth. The mean indwelling time of group A retrieval failures was 16 (range, 15–18) days and in group B 54 (range, 17–122) days. Mean fluoroscopy time for successful retrieval was 3.5 (range, 1–16.6) min and for retrieval failures 25.2 (range, 7.2–62) min. Attempts to retrieve the Optease filter can be performed up to 60 days, but more failures will be encountered with this approach.
Optimal Perceived Timing: Integrating Sensory Information with Dynamically Updated Expectations.
Di Luca, Massimiliano; Rhodes, Darren
2016-01-01
The environment has a temporal structure, and knowing when a stimulus will appear translates into increased perceptual performance. Here we investigated how the human brain exploits temporal regularity in stimulus sequences for perception. We find that the timing of stimuli that occasionally deviate from a regularly paced sequence is perceptually distorted. Stimuli presented earlier than expected are perceptually delayed, whereas stimuli presented on time and later than expected are perceptually accelerated. This result suggests that the brain regularizes slightly deviant stimuli with an asymmetry that leads to the perceptual acceleration of expected stimuli. We present a Bayesian model for the combination of dynamically-updated expectations, in the form of a priori probability of encountering future stimuli, with incoming sensory information. The asymmetries in the results are accounted for by the asymmetries in the distributions involved in the computational process. PMID:27385184
Optimal Time-Reversed Wideband Signals for Distributed Sensing
Kim, Jerry; Mokole, Eric
2015-01-01
This paper considers a distributed wave-based sensing system that probes a scene consisting of multiple interacting idealized targets. Each sensor is a collocated transmit-receive pair that is capable of transmitting arbitrary wideband waveforms. We address the problem of finding the space-time transmit waveform that provides the best target detection performance in the sense of maximizing the energy scattered back into the receivers. Our approach is based on earlier work that constructed the solution by an iterative time-reversal (TR) process. In particular, for the case of idealized point-like scatterers in free space, we examine the frequency dependence of the eigenvalues of the TR operator, and we show that their behavior depends on constructive and destructive interference of the waves traveling along different paths. In addition, we show how these eigenvalues are connected to the poles of the Singularity Expansion Method. Our study of the frequency behavior distinguishes this work from most previous TR ...
Optimal dosing time of acid algaecide for restraining algal growth
Directory of Open Access Journals (Sweden)
Cui-chao PANG
2013-10-01
Full Text Available Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experiments. In the experiments, the pH value of water is significantly affected by Microcystis aeruginosa, and the variation of the pH value is in favor of the growth of the alga. Therefore, using acid algaecide in the period with maximum pH values, i.e., the stable phase, would change the acidity-alkalinity of the water significantly, and would negatively affect algal growth. Acid algaecide does not eliminate the alga effectively if the acid algaecide is dosed in the logarithmic growth phase. Using acid algaecide in the decline phase after algal bloom not only is unfavorable for eliminating the alga, but also prolongs the decline phase, and even brings about next larger algal bloom.
Optimal Perceived Timing: Integrating Sensory Information with Dynamically Updated Expectations
Di Luca, Massimiliano; Rhodes, Darren
2016-01-01
The environment has a temporal structure, and knowing when a stimulus will appear translates into increased perceptual performance. Here we investigated how the human brain exploits temporal regularity in stimulus sequences for perception. We find that the timing of stimuli that occasionally deviate from a regularly paced sequence is perceptually distorted. Stimuli presented earlier than expected are perceptually delayed, whereas stimuli presented on time and later than expected are perceptually accelerated. This result suggests that the brain regularizes slightly deviant stimuli with an asymmetry that leads to the perceptual acceleration of expected stimuli. We present a Bayesian model for the combination of dynamically-updated expectations, in the form of a priori probability of encountering future stimuli, with incoming sensory information. The asymmetries in the results are accounted for by the asymmetries in the distributions involved in the computational process. PMID:27385184
Optimizing FPGA Design For Real Time Video Content Analysis
Ma, Xiaoyin
2016-01-01
The rapid growth of camera and storage capabilities, over the past decade, has resulted in an exponential growth in the size of video repositories, such as YouTube. In 2015, 400 hours of videos are uploaded to YouTube every minute. At the same time, massive amount of images/videos are generated from monitoring cameras for elderly, sick assistance, satellites for earth science research, and telescopes for space exploration. Human annotation and manual manipulation of such videos are infeasible...
Study on application of safety checklist in preventive maintenance activities
International Nuclear Information System (INIS)
The paper describes the principles and the characteristics of safety checklist as a risk evaluation method. Examples of application of safety checklists to preventive maintenance activities such as criteria comparison and checkup items in place in nuclear power plants are illustrated in details with issues appeared in the checklist establishment. Checklist has a good application in the RCM analysis or in the actual preventive maintenance program for Chashma Nuclear Power Plant indicated by concrete instances. In the light of safety checklist which is used to sustain preventive maintenance as a simple and applicable risk analysis approach, we can get deep knowledge of risks of nuclear power plant to perfect preventive maintenance activities. (authors)
Wachsmuth, Gerd
2012-01-01
In this paper we consider an optimal control problem governed by a time-dependent variational inequality arising in quasistatic plasticity with linear kinematic hardening. We address certain continuity properties of the forward operator, which imply the existence of an optimal control. Moreover, a discretization in time is derived and we show that every local minimizer of the continuous problem can be approximated by minimizers of modified, time-discrete problems.
Michael A. Hurni; Kiriakos Kiriakidis
2015-01-01
The authors develop an approach to a “best” time path for Autonomous Underwater Vehicles conducting oceanographic measurements under uncertain current flows. The numerical optimization tool DIDO is used to compute hybrid minimum time and optimal survey paths for a sample of currents between ebb and flow. A simulated meta-experiment is performed where the vehicle traverses the resulting paths under different current strengths per run. The fastest elapsed time emerges from a payoff table. A mul...
Minimum Time Trajectory Optimization of CNC Machining with Tracking Error Constraints
2014-01-01
An off-line optimization approach of high precision minimum time feedrate for CNC machining is proposed. Besides the ordinary considered velocity, acceleration, and jerk constraints, dynamic performance constraint of each servo drive is also considered in this optimization problem to improve the tracking precision along the optimized feedrate trajectory. Tracking error is applied to indicate the servo dynamic performance of each axis. By using variable substitution, the tracking error constra...
Theory for the optimal control of time-averaged quantities in open quantum systems
Grigorenko, Ilia; Garcia, Martin E.; Bennemann, K. H.
2002-01-01
We present variational theory for optimal control over a finite time interval in quantum systems with relaxation. The corresponding Euler-Lagrange equations determining the optimal control field are derived. In our theory the optimal control field fulfills a high order differential equation, which we solve analytically for some limiting cases. We determine quantitatively how relaxation effects limit the control of the system. The theory is applied to open two level quantum systems. An approxi...
Stochastic optimal control and time changed Lévy noises
2014-01-01
List of papers. Paper 1 / Chapter 2: On chaos representation and orthogonal polynomials for the doubly stochastic Poisson process, together with Giulia Di Nunno. Published in Seminar on stochastic analysis, random fields and applications VII, R. Daland, M. Dozzi and F. Russo (eds), vol 67 of Progress in Probability, Springer Basel 2013. doi:10.1007/978-3-0348-0545-2_2 The final publication is available at Springer. Paper 2 / Chapter 3: BSDEs for time-changed Lévy processes and applic...
Approximate Range Emptiness in Constant Time and Optimal Space
DEFF Research Database (Denmark)
Goswami, Mayank; Jørgensen, Allan Grønlund; Larsen, Kasper Green;
2015-01-01
(Llg(L/ε)). Our first contribution is to show that the space/error trade-off cannot be improved asymptotically: Any data structure for answering approximate range emptiness queries on intervals of length up to L with false positive probability ε, must use space Ω(nlg(L/ε))−O(n) bits. On the positive side we show...... that the query time can be improved greatly, to constant time, while matching our space lower bound up to a lower order additive term. This result is achieved through a succinct data structure for (non-approximate 1d) range emptiness/reporting queries, which may be of independent interest.......This paper studies the \\emph{ε-approximate range emptiness} problem, where the task is to represent a set S of n points from {0,…,U−1} and answer emptiness queries of the form "[a;b]∩S≠∅ ?" with a probability of \\emph{false positives} allowed. This generalizes the functionality of \\emph...
Uniform Hashing in Constant Time and Optimal Space
DEFF Research Database (Denmark)
Pagh, Anna Östlin; Pagh, Rasmus
2008-01-01
Many algorithms and data structures employing hashing have been analyzed under the uniform hashing assumption, i.e., the assumption that hash functions behave like truly random functions. Starting with the discovery of universal hash functions, many researchers have studied to what extent this th...... their uniform hashing analysis come true, with high probability, without incurring overhead in time or space. Udgivelsesdato: 2008...... this theoretical ideal can be realized by hash functions that do not take up too much space and can be evaluated quickly. In this paper we present an almost ideal solution to this problem: a hash function $h: U\\rightarrow V$ that, on any set of $n$ inputs, behaves like a truly random function with high probability......, can be evaluated in constant time on a RAM and can be stored in $(1+\\epsilon)n\\log |V| + O(n+\\log\\log |U|)$ bits. Here $\\epsilon$ can be chosen to be any positive constant, so this essentially matches the entropy lower bound. For many hashing schemes this is the first hash function that makes...
Directory of Open Access Journals (Sweden)
Elsbeth C. M. Ten Have
2015-01-01
Full Text Available The implementation of interdisciplinary teams in the intensive care unit (ICU has focused attention on leadership behavior. A daily recurrent situation in ICUs in which both leadership behavior and interdisciplinary teamwork are integrated concerns the interdisciplinary rounds (IDRs. Although IDRs are recommended to provide optimal interdisciplinary and patient-centered care, there are no checklists available for leading physicians. We tested the measurement properties and implementation of a checklist to assess the quality of leadership skills in interdisciplinary rounds. The measurement properties of the checklist, which included 10 essential quality indicators, were tested for interrater reliability and internal consistency and by factor analysis. The interrater reliability among 3 raters was good (κ, 0.85 and the internal consistency was acceptable (α, 0.74. Factor analysis showed all factor loadings on 1 domain (>0.65. The checklist was further implemented during videotaped IDRs which were led by senior physicians and in which 99 patients were discussed. Implementation of the checklist showed a wide range of “no” and “yes” scores among the senior physicians. These results may underline the need for such a checklist to ensure tasks are synchronized within the team.
Marshburn, Thomas; Whitmore, Mihriban; Ortiz, Rosie; Segal, Michele; Smart, Kieran; Hughes, Catherine
2003-01-01
Emergency medical capabilities aboard the ISS include a Crew Medical Officer (CMO) (not necessarily a physician), and back-up, resuscitation equipment, and a medical checklist. It is essential that CMOs have reliable, usable and informative medical protocols that can be carried out independently in flight. The study evaluates the existing ISS Medical Checklist layout against a checklist updated to reflect a human factors approach to structure and organization. Method: The ISS Medical checklist was divided into non-emergency and emergency sections, and re-organized based on alphabetical and a body systems approach. A desk-top evaluation examined the ability of subjects to navigate to specific medical problems identified as representative of likely non-emergency events. A second evaluation aims to focus on the emergency section of the Medical Checklist, based on the preliminary findings of the first. The final evaluation will use Astronaut CMOs as subjects comparing the original checklist against the updated layout in the task of caring for a "downed crewmember" using a Human Patient Simulator [Medical Education Technologies, Inc.]. Results: Initial results have demonstrated a clear improvement of the re-organized sections to determine the solution to the medical problems. There was no distinct advantage for either alternative, although subjects stated having a preference for the body systems approach. In the second evaluation, subjects will be asked to identify emergency medical conditions, with measures including correct diagnosis, time to completion and solution strategy. The third evaluation will compare the original and fully updated checklists in clinical situations. Conclusions: Initial findings indicate that the ISS Medical Checklist will benefit from a reorganization. The present structure of the checklist has evolved over recent years without systematic testing of crewmember ability to diagnose medical problems. The improvements are expected to enable ISS
Real-Time Optimal Control for Rotary Inverted Pendulum
Directory of Open Access Journals (Sweden)
Viroch Sukontanakarn
2009-01-01
Full Text Available Problem statement: The rotary inverted pendulum system was a highly nonlinear model, multivariable and absolutely unstable dynamic system. It was used for testing various design control techniques and in teaching modern control. The objectives of this study were to: (i Develop a real rotary inverted pendulum which derived the mechanical model by using Euler-Lagrange and (ii Design controller algorithm for self-erecting and balancing of a rotary inverted pendulum. Approach: Research shown a convenient way to implement a real-time control in self-erecting a pendulum from downward position and balancing the pendulum in vertical-upright position. An Energy based on PD controller was applied in self-erecting of the pendulum while LQR controller was applied to balance the pendulum. Results: Results of both control techniques from computer simulation and experiment were given to show the effectiveness of these controllers. Conclusion: Both simulations and experiments were confirmed the control efficiency of the method.
Optimal control of nonlinear continuous-time systems in strict-feedback form.
Zargarzadeh, Hassan; Dierks, Travis; Jagannathan, Sarangapani
2015-10-01
This paper proposes a novel optimal tracking control scheme for nonlinear continuous-time systems in strict-feedback form with uncertain dynamics. The optimal tracking problem is transformed into an equivalent optimal regulation problem through a feedforward adaptive control input that is generated by modifying the standard backstepping technique. Subsequently, a neural network-based optimal control scheme is introduced to estimate the cost, or value function, over an infinite horizon for the resulting nonlinear continuous-time systems in affine form when the internal dynamics are unknown. The estimated cost function is then used to obtain the optimal feedback control input; therefore, the overall optimal control input for the nonlinear continuous-time system in strict-feedback form includes the feedforward plus the optimal feedback terms. It is shown that the estimated cost function minimizes the Hamilton-Jacobi-Bellman estimation error in a forward-in-time manner without using any value or policy iterations. Finally, optimal output feedback control is introduced through the design of a suitable observer. Lyapunov theory is utilized to show the overall stability of the proposed schemes without requiring an initial admissible controller. Simulation examples are provided to validate the theoretical results. PMID:26111400
The optimal time path of clean energy R&D policy when patents have finite lifetime
Gerlagh, R.; Kverndokk, S.; Rosendahl, K.E.
2014-01-01
We study the optimal time path for clean energy innovation policy. In a model with emission reduction through clean energy deployment, and with R&D increasing the overall productivity of clean energy, we describe optimal R&D policies jointly with emission pricing policies. We find that while emissio
Free terminal time optimal control problem for the treatment of HIV infection
Directory of Open Access Journals (Sweden)
Amine Hamdache
2016-01-01
to provide the explicit formulations of the optimal controls. The corresponding optimality system with the additional transversality condition for the terminal time is derived and solved numerically using an adapted iterative method with a Runge-Kutta fourth order scheme and a gradient method routine.
Sub-Finsler structures from the time-optimal control viewpoint for some nilpotent distributions
Barilari, Davide; Boscain, Ugo; Donne, Enrico Le; Sigalotti, Mario
2015-01-01
In this paper we study the sub-Finsler geometry as a time-optimal control problem. In particular, we consider non-smooth and non-strictly convex sub-Finsler structures associated with the Heisenberg, Grushin, and Martinet distributions. Motivated by problems in geometric group theory, we characterize extremal curves, discuss their optimality, and calculate the metric spheres, proving their Euclidean rectifiability.
Checklist of the Diptera (Insecta of Finland: an introduction and a summary of results
Directory of Open Access Journals (Sweden)
Jere Kahanpää
2014-09-01
Full Text Available Nearly thirty-five years have passed since Hackman published his “Check list of the Finnish Diptera” (1980. The number of true flies (Diptera known from Finland has increased by more than two thousand species since then. At the same time, hundreds of erroneous records have been recognized and purged from the checklist. ZooKeys issue 441 provides a new checklist of the Diptera species of the Republic of Finland. This introductory paper presents the rationale behind the project, provides technical documentation on the checklist format and sources used, and summarizes the results. The remaining papers in this issue cover one or more Diptera families in detail. Two electronic appendices are provided: supporting data (additional references to first published records and the previous checklist and a complete list of Finnish Diptera taxa in Darwin Core compliant format for easy computer access and processing. The new checklist records 6920 fly species from Finland, 2932 belonging to the nematoceran or lower flies and 3989 to the suborder Brachycera. The changes since 1980 are most prominent in the Lower Diptera. For example, more than 400 non-biting midges (Chironomidae have been added since 1980, and the number of moth flies (Psychodidae known from Finland has more than tripled. Among the larger families, large increases in known Finnish species are also seen in Cecidomyiidae (161% increase, Pipunculidae (98%, and Chironomidae (90%.
Discrete-time neural inverse optimal control for nonlinear systems via passivation.
Ornelas-Tellez, Fernando; Sanchez, Edgar N; Loukianov, Alexander G
2012-08-01
This paper presents a discrete-time inverse optimal neural controller, which is constituted by combination of two techniques: 1) inverse optimal control to avoid solving the Hamilton-Jacobi-Bellman equation associated with nonlinear system optimal control and 2) on-line neural identification, using a recurrent neural network trained with an extended Kalman filter, in order to build a model of the assumed unknown nonlinear system. The inverse optimal controller is based on passivity theory. The applicability of the proposed approach is illustrated via simulations for an unstable nonlinear system and a planar robot. PMID:24807528
Carpentier, Pierre; Cohen, Guy; De Lara, Michel
2015-01-01
The focus of the present volume is stochastic optimization of dynamical systems in discrete time where - by concentrating on the role of information regarding optimization problems - it discusses the related discretization issues. There is a growing need to tackle uncertainty in applications of optimization. For example the massive introduction of renewable energies in power systems challenges traditional ways to manage them. This book lays out basic and advanced tools to handle and numerically solve such problems and thereby is building a bridge between Stochastic Programming and Stochastic Control. It is intended for graduates readers and scholars in optimization or stochastic control, as well as engineers with a background in applied mathematics.
Deterministic Time-inconsistent Optimal Control Problems - an Essentially Cooperative Approach
Institute of Scientific and Technical Information of China (English)
Jiong-min YONG
2012-01-01
A general deterministic time-inconsistent optimal control problem is formulated for ordinary differential equations.To find a time-consistent equilibrium value function and the corresponding time-consistent equilibrium control,a non-cooperative N-person differential game (but essentially cooperative in some sense) is introduced.Under certain conditions,it is proved that the open-loop Nash equilibrium value function of the N-person differential game converges to a time-consistent equilibrium value function of the original problem,which is the value function of a time-consistent optimal control problem.Moreover,it is proved that any optimal control of the time-consistent limit problem is a time-consistent equilibrium control of the original problem.
Directory of Open Access Journals (Sweden)
Mingjian Sun
2015-01-01
Full Text Available Photoacoustic imaging is an innovative imaging technique to image biomedical tissues. The time reversal reconstruction algorithm in which a numerical model of the acoustic forward problem is run backwards in time is widely used. In the paper, a time reversal reconstruction algorithm based on particle swarm optimization (PSO optimized support vector machine (SVM interpolation method is proposed for photoacoustics imaging. Numerical results show that the reconstructed images of the proposed algorithm are more accurate than those of the nearest neighbor interpolation, linear interpolation, and cubic convolution interpolation based time reversal algorithm, which can provide higher imaging quality by using significantly fewer measurement positions or scanning times.
Kasap, Nihat; Tektaş Sivrikaya, Berna; Tektas Sivrikaya, Berna; Delen, Dursun
2013-01-01
In this study, we use a monopoly pricing model to examine the optimal pricing strategies for “pay-per-time”, “pay-per-volume” and “pay-per both time and volume” based leasing of data networks. Traditionally, network capacity distribution includes short/long term bandwidth and/or usage time leasing. Each consumer has a choice to select volume based, connection-time based or both volume and connection-time based pricing. When customers choose connection-time based pricing, their optimal behavio...
International Nuclear Information System (INIS)
This paper presents a new algorithm for solving the optimal contract capacities of a time-of-use (TOU) rates industrial customer. This algorithm is named iteration particle swarm optimization (IPSO). A new index, called iteration best is incorporated into particle swarm optimization (PSO) to improve solution quality and computation efficiency. Expanding line construction cost and contract recovery cost are considered, as well as demand contract capacity cost and penalty bill, in the selection of the optimal contract capacities. The resulting optimal contract capacity effectively reaches the minimum electricity charge of TOU rates users. A significant reduction in electricity costs is observed. The effects of expanding line construction cost and contract recovery cost on the selection of optimal contract capacities can also be estimated. The feasibility of the new algorithm is demonstrated by a numerical example, and the IPSO solution quality and computation efficiency are compared to those of other algorithms. (author)
International Nuclear Information System (INIS)
This paper presents a new algorithm for solving the optimal contract capacities of a time-of-use (TOU) rates industrial customer. This algorithm is named iteration particle swarm optimization (IPSO). A new index, called iteration best is incorporated into particle swarm optimization (PSO) to improve solution quality and computation efficiency. Expanding line construction cost and contract recovery cost are considered, as well as demand contract capacity cost and penalty bill, in the selection of the optimal contract capacities. The resulting optimal contract capacity effectively reaches the minimum electricity charge of TOU rates users. A significant reduction in electricity costs is observed. The effects of expanding line construction cost and contract recovery cost on the selection of optimal contract capacities can also be estimated. The feasibility of the new algorithm is demonstrated by a numerical example, and the IPSO solution quality and computation efficiency are compared to those of other algorithms
A checklist of mammals of Kerala, India
Directory of Open Access Journals (Sweden)
P. O. Nameer
2015-11-01
Full Text Available A checklist of mammals of Kerala State is presented in this paper. Accepted English names, scientific binomen, prevalent vernacular names in Malayalam, IUCN conservation status, endemism, Indian Wildlife (Protection Act schedules, and the appendices in the CITES, pertaining to the mammals of Kerala are also given. The State of Kerala has 118 species of mammals, 15 of which are endemic to Western Ghats, and 29 species fall under the various threatened categories of IUCN.
Pocket Checklists of Indonesian timber trees
Prawira, Soewanda A.; Tantra, I.G.M.; Whitmore, T.C.
1984-01-01
Indonesia as yet does not have a comprehensive account of the forest trees which reach timber size (35 cm dbh = 14 inch or 105 cm gbh = 42 inch). A project has been started in August 1983 by the Botany Section of the Forest Research Institute in Bogor, Indonesia, to prepare pocket checklists of the timber trees of all regions of the country. These lists will include forest-based descriptions, keys and line drawings.
Checklist of the marine macroalgae of Vietnam
Nguyen, T.V.; Le, H.N.; Lin, S. M.; Steen, F. van der; De Clerck, O.
2013-01-01
Despite a rich seaweed flora, information about Vietnamese seaweeds is scattered throughout a large number of often regional publications and, hence, difficult to access. This paper presents an up-to-date checklist of the marine macroalgae of Vietnam, compiled by means of an exhaustive bibliographical search and revision of taxon names. A total of 827 species are reported, of which the Rhodophyta show the highest species number (412 species), followed by the Chlorophyta (180 species), Phaeoph...
Optimal timing of coronary invasive strategy in non-ST-segment elevation acute coronary syndromes
DEFF Research Database (Denmark)
Navarese, Eliano P; Gurbel, Paul A; Andreotti, Felicita; Tantry, Udaya; Jeong, Young-Hoon; Kozinski, Marek; Engstrøm, Thomas; Di Pasquale, Giuseppe; Kochman, Waclaw; Ardissino, Diego; Kedhi, Elvin; Stone, Gregg W; Kubica, Jacek
2013-01-01
The optimal timing of coronary intervention in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACSs) is a matter of debate. Conflicting results among published studies partly relate to different risk profiles of the studied populations.......The optimal timing of coronary intervention in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACSs) is a matter of debate. Conflicting results among published studies partly relate to different risk profiles of the studied populations....
Ferrante, Augusto; Ntogramatzidis, Lorenzo
2013-01-01
The purpose of this paper is to investigate the role that the continuous-time generalised Riccati equation plays within the context of singular linear-quadratic optimal control. This equation has been defined following the analogy with the discrete-time generalised Riccati equation, but, differently from the discrete case, to date the importance of this equation in the context of optimal control is yet to be understood. This note addresses this point. We show in particular that when the conti...
Dynamic real-time substrate feed optimization of anaerobic co-digestion plants
Gaida, Daniel
2014-01-01
In anaerobic co-digestion plants a mix of organic materials is converted to biogas using the anaerobic digestion process. These organic materials, called substrates, can be crops, sludge, manure, organic wastes and many more. They are fed on a daily basis and significantly affect the biogas production process. In this thesis dynamic real-time optimization of the substrate feed for anaerobic co-digestion plants is developed. In dynamic real-time optimization a dynamic simulation model is used ...
Worst-Case Execution Time Based Optimization of Real-Time Java Programs
DEFF Research Database (Denmark)
Hepp, Stefan; Schoeberl, Martin
2012-01-01
optimization is method in lining. It is especially important for languages, like Java, where small setter and getter methods are considered good programming style. In this paper we present and explore WCET driven in lining of Java methods. We use the WCET analysis tool for the Java processor JOP to guide to...
Does the Role Checklist Measure Occupational Participation?
Directory of Open Access Journals (Sweden)
Tore Bonsaksen
2015-07-01
Full Text Available Background: Among the Model of Human Occupation (MOHO assessments, the Role Checklist is one of the most established. In spite of its widespread use, no studies have examined role examples and their association with the three embedded levels of doing, as established in the MOHO theory. Method: A cross-sectional survey of 293 respondents from the US, the UK, Japan, Switzerland, Sweden, and Norway produced 7,182 role examples. The respondents completed Part I of the Role Checklist and provided examples of each internalized role they performed. Responses were classified as occupational skill, occupational performance, or occupational participation. Results: Thirty-three percent of the examples were classified as examples of occupational participation, whereas 65% were classified as examples of occupational performance. Four roles linked mostly with occupational participation, another four roles linked mostly with occupational performance, and the two remaining roles were mixed between occupational participation and occupational performance. Discussion: The Role Checklist assesses a person’s involvement in internalized roles at the level of both occupational participation and occupational performance. There are differences among countries with regard to how roles are perceived and exemplified, and different roles relate differently to the occupational performance and occupational participation levels of doing. There are related implications for occupational therapists.
Optimal Time-Space Trade-Offs for Non-Comparison-Based Sorting
DEFF Research Database (Denmark)
Pagh, Rasmus; Pagter, Jacob Illeborg
2002-01-01
queues and sorting algorithms, this implies that we can deterministically sort time-space optimally in time Θ(T) for T ≥ n(lg lg n)2, and with high probability for T ≥ nlg lg n.Our results imply that recent space lower bounds for deciding element distinctness in o(nlgn) time are nearly tight....
Guthier, C. V.; Aschenbrenner, K. P.; Müller, R.; Polster, L.; Cormack, R. A.; Hesser, J. W.
2016-08-01
This paper demonstrates that optimization strategies derived from the field of compressed sensing (CS) improve computational performance in inverse treatment planning (ITP) for high-dose-rate (HDR) brachytherapy. Following an approach applied to low-dose-rate brachytherapy, we developed a reformulation of the ITP problem with the same mathematical structure as standard CS problems. Two greedy methods, derived from hard thresholding and subspace pursuit are presented and their performance is compared to state-of-the-art ITP solvers. Applied to clinical prostate brachytherapy plans speed-up by a factor of 56–350 compared to state-of-the-art methods. Based on a Wilcoxon signed rank-test the novel method statistically significantly decreases the final objective function value (p optimization times were below one second and thus planing can be considered as real-time capable. The novel CS inspired strategy enables real-time ITP for HDR brachytherapy including catheter optimization. The generated plans are either clinically equivalent or show a better performance with respect to dosimetric measures.
A survey to identify barriers of implementing an antibiotic checklist.
van Daalen, F V; Geerlings, S E; Prins, J M; Hulscher, M E J L
2016-04-01
A checklist is an effective implementation tool, but addressing barriers that might impact on the effectiveness of its use is crucial. In this paper, we explore barriers to the uptake of an antibiotic checklist that aims to improve antibiotic use in daily hospital care. We performed an online questionnaire survey among medical specialists and residents with various professional backgrounds from nine Dutch hospitals. The questionnaire consisted of 23 statements on anticipated barriers hindering the uptake of the checklist. Furthermore, it gave the possibility to add comments. We included 219 completed questionnaires (122 medical specialists and 97 residents) in our descriptive analysis. The top six anticipated barriers included: (1) lack of expectation of improvement of antibiotic use, (2) lack of expected patients' satisfaction by checklist use, (3) lack of feasibility of the checklist, (4) negative previous experiences with other checklists, (5) the complexity of the antibiotic checklist and (6) lack of nurses' expectation of checklist use. Remarkably, 553 comments were made, mostly (436) about the content of the checklist. These insights can be used to improve the specific content of the checklist and to develop an implementation strategy that addresses the identified barriers. PMID:26810059
Optimal Control Modification Adaptive Law for Time-Scale Separated Systems
Nguyen, Nhan T.
2010-01-01
Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. A model matching conditions in the transformed time coordinate results in an increase in the actuator command that effectively compensate for the slow actuator dynamics. Simulations demonstrate effectiveness of the method.
Methodology to Optimize Manufacturing Time for a CNC Using a High Performance Implementation of ACO
Directory of Open Access Journals (Sweden)
Oscar Montiel-Ross
2012-10-01
Full Text Available In this paper, an efficient methodology to generate optimal and/or quasi‐optimal sequences of G commands to minimize the manufacturing time is presented. Our solution starts from original G codes provided by application CAD/CAM software. Here, first we tackled the problem of reducing the time of the travel path for drilling of an industrial robotic manufacturing machine. The methodology can be easily implemented for free distribution or commercial CAD/CAM software without achieving any modification to it. Several experiments that demonstrate how this proposal can help to outperform solutions provided by application software are presented, consistent improvements around 62% were obtained. Moreover, for optimizing the time along the travel path, we present a high performance implementation of Ant Colonies (ACO known as Parallel ACO (P‐ACO that allows achieving the optimization task efficiently by speeding up the original ACO. A Graphical User Interface that integrates the whole process is shown.
Optimal compensator structure for linear time-invariant plant with inaccessible states. M.S. Thesis
Blanvillain, P. J. P.
1974-01-01
The problem is considered of designing an optimal linear time-invariant dynamic compensator for the regulation of an n-th order linear time-invariant plant with m independent outputs. The initial plant state is characterized by its first and second moments, and the cost is usual quadratic infinite-time penalty on the state and control, averaged over the initial plant and compensator states. The compensator is based on a minimal-order Luenberger observer and consequently has fixed dimension n-m. Necessary and sufficient conditions are derived for optimality of the compensator gains. The optimal compensator is shown to be unique if the plant has a particular canonical form, and, in general, for any arbitrary plant, the class of all optimal compensators is precisely determined.
Directory of Open Access Journals (Sweden)
Michael A. Hurni
2015-12-01
Full Text Available The authors develop an approach to a “best” time path for Autonomous Underwater Vehicles conducting oceanographic measurements under uncertain current flows. The numerical optimization tool DIDO is used to compute hybrid minimum time and optimal survey paths for a sample of currents between ebb and flow. A simulated meta-experiment is performed where the vehicle traverses the resulting paths under different current strengths per run. The fastest elapsed time emerges from a payoff table. A multi-objective function is then used to weigh the time to complete a mission versus measurement inaccuracy due to deviation from the desired survey path.
Optimal design of systems that evolve over time using neural networks
Nolan, Michael K.
2007-04-01
Design optimization is challenging when the number of variables becomes large. One method of addressing this problem is to use pattern recognition to decrease the solution space in which the optimizer searches. Human "common sense" is used by designers to narrow the scope of search to a confined area defined by patterns conforming to likely solution candidates. However, computer-based optimization generally does not apply similar heuristics. In this paper, a system is presented that recognizes patterns and adjusts its search for optimal solutions based on these patterns. A design problem was selected that requires the optimization algorithm to assess designs that evolve over time. A small sensor network design is evolved into a larger sensor network design. Optimal design solutions for the small network do not necessarily lead to optimal solutions for the larger network. Systems that are well-positioned to evolve have characteristics that distinguish themselves from systems that are not well-positioned to evolve. In this study, a neural network was able to recognize a pattern whereby flexible sensor networks evolved more successfully than less flexible networks. The optimizing algorithm used this pattern to select candidate systems that showed promise for evolution. A genetic algorithm assisted by a neural network achieved better performance than an unassisted genetic algorithm did. This thesis advocates the merit of neural network use in multi-objective system design optimization and to lay a basis for future study.
Time optimal trajectories for mobile robots with two independently driven wheels
Energy Technology Data Exchange (ETDEWEB)
Reister, D.B.; Pin, F.G.
1992-03-01
This paper addresses the problem of time-optional motions for a mobile platform in a planar environment. The platform has two non-steerable independently driven wheels. The overall mission of the robot is expressed in terms of a sequence of via points at which the platform must be at rest in a given configuration (position and orientation). The objective is to plan time-optimal trajectories between these configurations assuming an unobstructed environment. Using Pontryagin`s maximum principle (PMP), we formally demonstrate that all time optimal motions of the platform for this problem occur for bang-bang controls on the wheels (at each instant, the acceleration on each wheel is either at its upper or lower limit). The PMP, however, only provides necessary conditions for time optimality. To find the time optimal robot trajectories, we first parameterize the bang-bang trajectories using the switch times on the wheels (the times at which the wheel accelerations change sign). With this parameterization, we can fully search the robot trajectory space and find the switch times that will produce particular paths to a desired final configuration of the platform. We show numerically that robot trajectories with three switch times (two on one wheel, one on the other) can reach any position, while trajectories with four switch times can reach any configuration. By numerical comparison with other trajectories involving similar or greater numbers of switch times, we then identify the sets of time-optimal trajectories. These are uniquely defined using ranges of the parameters, and consist of subsets of trajectories with three switch times for the problem when the final orientation of the robot is not specified, and four switch times when a full final configuration is specified. We conclude with a description of the use of the method for trajectory planning for one of our robots.
Time optimal trajectories for mobile robots with two independently driven wheels
Energy Technology Data Exchange (ETDEWEB)
Reister, D.B.; Pin, F.G.
1992-03-01
This paper addresses the problem of time-optional motions for a mobile platform in a planar environment. The platform has two non-steerable independently driven wheels. The overall mission of the robot is expressed in terms of a sequence of via points at which the platform must be at rest in a given configuration (position and orientation). The objective is to plan time-optimal trajectories between these configurations assuming an unobstructed environment. Using Pontryagin's maximum principle (PMP), we formally demonstrate that all time optimal motions of the platform for this problem occur for bang-bang controls on the wheels (at each instant, the acceleration on each wheel is either at its upper or lower limit). The PMP, however, only provides necessary conditions for time optimality. To find the time optimal robot trajectories, we first parameterize the bang-bang trajectories using the switch times on the wheels (the times at which the wheel accelerations change sign). With this parameterization, we can fully search the robot trajectory space and find the switch times that will produce particular paths to a desired final configuration of the platform. We show numerically that robot trajectories with three switch times (two on one wheel, one on the other) can reach any position, while trajectories with four switch times can reach any configuration. By numerical comparison with other trajectories involving similar or greater numbers of switch times, we then identify the sets of time-optimal trajectories. These are uniquely defined using ranges of the parameters, and consist of subsets of trajectories with three switch times for the problem when the final orientation of the robot is not specified, and four switch times when a full final configuration is specified. We conclude with a description of the use of the method for trajectory planning for one of our robots.
Dynamic Planar Convex Hull with Optimal Query Time and O(log n · log log n ) Update Time
DEFF Research Database (Denmark)
Brodal, Gerth Stølting; Jakob, Riko
various queries about the convex hull in optimal O(log n) worst-case time. The data structure requires O(n) space. Applications of the new dynamic convex hull data structure are improved deterministic algorithms for the k-level problem and the red-blue segment intersection problem where all red and all...
Two neural network algorithms for designing optimal terminal controllers with open final time
Plumer, Edward S.
1992-01-01
Multilayer neural networks, trained by the backpropagation through time algorithm (BPTT), have been used successfully as state-feedback controllers for nonlinear terminal control problems. Current BPTT techniques, however, are not able to deal systematically with open final-time situations such as minimum-time problems. Two approaches which extend BPTT to open final-time problems are presented. In the first, a neural network learns a mapping from initial-state to time-to-go. In the second, the optimal number of steps for each trial run is found using a line-search. Both methods are derived using Lagrange multiplier techniques. This theoretical framework is used to demonstrate that the derived algorithms are direct extensions of forward/backward sweep methods used in N-stage optimal control. The two algorithms are tested on a Zermelo problem and the resulting trajectories compare favorably to optimal control results.
Optimal strategies for gravitational wave stochastic background searches in pulsar timing data
Anholm, Melissa; Creighton, Jolien D E; Price, Larry R; Siemens, Xavier
2008-01-01
A low frequency stochastic background of gravitational waves may be detected by pulsar timing experiments in the next five to ten years. Using methods developed to analyze interferometric gravitational wave data, in this paper we lay out the optimal techniques to detect a background of gravitational waves using a pulsar timing array. We show that for pulsar distances and gravitational wave frequencies typical of pulsar timing experiments, neglecting the effect of the metric perturbation at the pulsar does not result in a significant deviation from optimality. We discuss methods for setting upper limits using the optimal statistic, show how to construct skymaps using the pulsar timing array, and consider several issues associated with realistic analysis of pulsar timing data.
Checklist of the Quill mites (Acariformes: Syringophilidae) of the World.
Glowska, Eliza; Chrzanowski, Mateusz; Kaszewska, Katarzyna
2015-01-01
Mites of the family Syringophilidae (Acariformes: Cheyletoidea) are ectoparasites inhabiting the quills of various feather types in many groups of birds. Until now, 334 valid species and 60 genera of quill mites have been described and recorded from 482 bird species (95 families and 24 orders). Currently, the family is divided into 2 subfamilies: Syringophilinae Lavoipierre, 1953 with 260 species grouped in 49 genera, and Picobinae Johnston and Kethley, 1973 with 74 species grouped in 11 genera. Mites of the subfamily Syringophilinae inhabit quills of primaries, secondaries, tertials, rectrices and wing coverts and just occasionally the body feathers; representatives of the subfamily Picobinae live predominantly inside the body feathers. The rapid increase of the knowledge on biodiversity and systematics of quill mites started in end of the 1990s; numerous new descriptions appeared since that time and taxonomic rearrangements make an urgent need to summarize all previous data. We present a complete checklist of the family Syringophilidae of the world including the following data: a species name, author(s), references, a number of first page of description, figure numbers in descriptions, depository of type and non-type materials, host spectrum and geographical distribution. The checklist is additionally provided with the table including bird hosts and associated quill mite species. PMID:26249476
An Optimization Method of Time Window Based on Travel Time and Reliability
Fengjie Fu; Dongfang Ma; Dianhai Wang; Wei Qian
2015-01-01
The dynamic change of urban road travel time was analyzed using video image detector data, and it showed cyclic variation, so the signal cycle length at the upstream intersection was conducted as the basic unit of time window; there was some evidence of bimodality in the actual travel time distributions; therefore, the fitting parameters of the travel time bimodal distribution were estimated using the EM algorithm. Then the weighted average value of the two means was indicated as the travel t...
Ant colony optimization applied to route planning using link travel time predictions
Claes, Rutger; Holvoet, Tom
2011-01-01
Finding the shortest path in a road network is a well known problem. Various proven static algorithms such as Dijkstra and A* are extensively evaluated and implemented. When confronted with dynamic costs, such as link travel time predictions, alternative route planning algorithms have to be applied. This paper applies Ant Colony Optimization combined with link travel time predictions to find routes that reduce the time spend by travels by taking into account link travel time predictions. The ...
Checklists for quality assurance and audit in nuclear medicine
International Nuclear Information System (INIS)
A series of checklists are given which aim to provide some guidance to staff in determining whether their working procedures in nuclear medicine are likely to produce a good service and avoid mistakes. The checklists relate to the special equipment used in nuclear medicine departments, radiopharmaceuticals, nuclear medicine staff, services to medical and other hospital staff and finally the service to patients. The checklists are relevant to an average nuclear medicine department performing less than 2000 imaging studies per year. (U.K.)
Developing and Testing a Vaginal Delivery Safety Checklist.
True, Barbara A; Cochrane, Cindy C; Sleutel, Martha R; Newcomb, Patricia; Tullar, Paul E; Sammons, James H
2016-01-01
Communication failures are the most common root causes of perinatal deaths and injuries. We designed and tested a Vaginal Delivery Safety Checklist to improve communication and assist delivery teams' risk assessments and plans for potential complications of vaginal birth. Delivery teams found the checklist easy, convenient, and helpful. Teams completed the checklist within 2 to 3 minutes and showed improved teamwork, communication, and decision making. PMID:26851050
Dridi, Imen Harbaoui; Ksouri, Mekki; Borne, Pierre
2010-01-01
In This paper we present a genetic algorithm for mulicriteria optimization of a multipickup and delivery problem with time windows (m-PDPTW). The m-PDPTW is an optimization vehicles routing problem which must meet requests for transport between suppliers and customers satisfying precedence, capacity and time constraints. This paper purposes a brief literature review of the PDPTW, present an approach based on genetic algorithms and Pareto dominance method to give a set of satisfying solutions to the m-PDPTW minimizing total travel cost, total tardiness time and the vehicles number.
International Nuclear Information System (INIS)
The formulation and solution of optimization problem for parameters determining the layout of the central part of sodium cooled power reactor taking into account possible changes in fuel charge type during reactor operation time are performed. The losses under change of fuel composition type for two reactor modifications providing for minimum doubling time for oxide and carbide fuels respectively, are estimated
Necessary optimality conditions for the calculus of variations on time scales
Ferreira, Rui A. C.; Torres, Delfim F. M.
2007-01-01
We study more general variational problems on time scales. Previous results are generalized by proving necessary optimality conditions for (i) variational problems involving delta derivatives of more than the first order, and (ii) problems of the calculus of variations with delta-differential side conditions (Lagrange problem of the calculus of variations on time scales).
Optimization of Modulator and Circuits for Low Power Continuous-Time Delta-Sigma ADC
DEFF Research Database (Denmark)
Marker-Villumsen, Niels; Bruun, Erik
2014-01-01
This paper presents a new optimization method for achieving a minimum current consumption in a continuous-time Delta-Sigma analog-to-digital converter (ADC). The method is applied to a continuous-time modulator realised with active-RC integrators and with a folded-cascode operational transconduc...
Travel time forecasting from clustered time series via optimal fusion strategy
Ladino, Andres; Kibangou, Alain; Fourati, Hassen; Canudas De Wit, Carlos
2016-01-01
This paper addresses the problem of travel time forecasting within a highway. Several measurements are captured describing travel times for multiple origin-destination (OD) pairs. A network model is then proposed to infer travel time between origin and destination based on a reduced number of states. The forecast strategy is based on current day and historical data. Historical data is organized into several clusters. For each cluster, a predictor is designed based on the Kalman filtering stra...
Global Carbon Cycle and the Optimal Time Path of a Carbon Tax.
Farzin, Y.H.; Tahvonen, O.
1996-01-01
The existing models of fossil fuel consumption with carbon accumulation imply that the optimal time path of carbon tax is either hump-shaped or monotonically decreasing. These models specify the decay of atmospheric carbon as a constant rate of total concentration. The authors extend this specification to more accurately reflect the global carbon cycle models of climatologists and show that this extension changes the basic economic properties of the optimal carbon tax. Their analysis reveals ...
Optimal Timing of Carbon Capture Policies Under Alternative CCS Cost Functions
Amigues, Jean-Pierre; Lafforgue, Gilles; MOREAUX Michel
2012-01-01
We determine the optimal exploitation time-paths of three types of perfect substitute energy resources: The first one is depletable and carbon-emitting (dirty coal), the second one is also depletable but carbon-free thanks to a carbon capture and storage (CCS) process (clean coal) and the last one is renewable and clean (solar energy). We assume that the atmospheric carbon stock cannot exceed some given ceiling. These optimal paths are considered along with alternative structures of the CCS c...
Patient Safety in Interventional Radiology: A CIRSE IR Checklist.
LENUS (Irish Health Repository)
2012-02-01
Interventional radiology (IR) is an invasive speciality with the potential for complications as with other invasive specialities. The World Health Organization (WHO) produced a surgical safety checklist to decrease the morbidity and mortality associated with surgery. The Cardiovascular and Interventional Society of Europe (CIRSE) set up a task force to produce a checklist for IR. Use of the checklist will, we hope, reduce the incidence of complications after IR procedures. It has been modified from the WHO surgical safety checklist and the RAD PASS from Holland.
The Effects of Task Structure on Time-sharing Efficiency and Resource Allocation Optimality
Tsang, P. S.; Wickens, C. D.
1984-01-01
A distinction was made between two aspects of time sharing performance: time sharing efficiency and attention allocation optimality. A secondary task technique was employed to evaluate the effects of the task structures of the component time shared tasks on both aspects of the time sharing performance. Five pairs of dual tasks differing in their structural configurations were investigated. The primary task was a visual/manual tracking task which requires spatial processing. The secondary task was either another tracking task or a verbal memory task with one of four different input/output configurations. Congruent to a common finding, time-sharing efficiency was observed to decrease with an increasing overlap of resources utilized by the time shared tasks. Research also tends to support the hypothesis that resource allocation is more optimal when the time shared tasks placed heavy demands on common processing resources than when they utilized separate resources.