Optimering af model for spredning af luftforurening
DEFF Research Database (Denmark)
Pedersen, Jens Christian
2008-01-01
De nuværende luftforureningsmodeller har problemer med at bevare massen af diverse kemiske stoffer og med at der ind i mellem optræder negative værdier. Derfor arbejder specialestuderende Ayoe Buus Hansen på om at forbedre den model DMU bruger til at beskrive transport og spredning af luftforuren...... luftforurening på alle skalaer på den nordlige halvkugle ved at sammenligne tre alternative beregningsmodeller. ...
Zafar, Ammar
2013-12-01
This paper investigates the energy-efficiency enhancement of a variable-gain dual-hop amplify-and-forward (AF) relay network utilizing selective relaying. The objective is to minimize the total consumed power while keeping the end-to-end signal-to-noise-ratio (SNR) above a certain peak value and satisfying the peak power constraints at the source and relay nodes. To achieve this objective, an optimal relay selection and power allocation strategy is derived by solving the power minimization problem. Numerical results show that the derived optimal strategy enhances the energy-efficiency as compared to a benchmark scheme in which both the source and the selected relay transmit at peak power. © 2013 IEEE.
Optimering af en psykisk lidelse
DEFF Research Database (Denmark)
Rønberg, Mette; Blæsbjerg, Christina
2014-01-01
of ADHD. The article will demonstrate how adults with ADHD attempt to improve themselves by initiating optimizing practices such as brain training (neurofeedback) and medication. The positive interpretation of ADHD is influenced by an increasing demand for productivity and a moral imperative on self...
Zafar, Ammar; Radaydeh, Redha Mahmoud Mesleh; Chen, Yunfei; Alouini, Mohamed-Slim
2013-01-01
This paper investigates the energy-efficiency enhancement of a variable-gain dual-hop amplify-and-forward (AF) relay network utilizing selective relaying. The objective is to minimize the total consumed power while keeping the end-to-end signal
Energy Efficient Design for Two-Way AF Relay Networks
Directory of Open Access Journals (Sweden)
Yong Li
2014-01-01
Full Text Available Conventional designs on two-way relay networks mainly focus on the spectral efficiency (SE rather than energy efficiency (EE. In this paper, we consider a system where two source nodes communicate with each other via an amplify-and-forward (AF relay node and study the power allocation schemes to maximize EE while ensuring a certain data rate. We propose an optimal energy-efficient power allocation algorithm based on iterative search technique. In addition, a closed-form suboptimal solution is derived with reduced complexity and negligible performance degradation. Numerical results show that the proposed schemes can achieve considerable EE improvement compared with conventional designs.
Optimering af byggeprocessen via bedre/forøget brug af digitale modeller
DEFF Research Database (Denmark)
Carlsen, Mads; Grøn, Dorte Marie Frilund; Alon, Nevo
2013-01-01
Projektet klarlægger nødvendigheden for, og muligheder i, en struktureret og konsekvent planlægning ved anvendelsen af BIM i relation til projektering, udførelse og drift af byggeri. Der er udarbejdet et planlægningsværktøj, der muliggør en sådan planlægning. Samtidig kortlægges de nødvendige data......, der kan udtrækkes af en BIM model ved gennemførelsen af en LCA simulering. Projektet afsluttes med en præsentation af en udviklet demonstratorapplikation til gennemførelse af LCA simuleringer koblet med BIM modellen....
Subregional innovation – indikatorer til optimering af den erhvervsrettede innovationspolitik
DEFF Research Database (Denmark)
Mortensen, Peter Stendahl; Graversen, Ebbe Krogh; Haase, Sanne Schioldann
områder tilgodeses bedst muligt. Desuden kan en differentieret, subregional innovations-politik give erhvervslivet bedre udbytte end en samlet regional eller national innovationspolitik. Selvom Danmark er et lille land, er der store geografiske forskelle internt i landets erhvervsstruktur og i...... virksomhedernes innovationsaktiviteter. Som resultat af en udvidelse af den danske del af CIS 2006-undersøgelsen2 med ekstra virksomheder kan der gives en betydeligt mere nuanceret karak-teristik af virksomheder helt ned på subregionalt niveau. Analysen underbygger, at de innovations-politiske tiltag, der sættes......, lokal brug af resultaterne er nødvendig. Først gennemgås de valgte målepunkter. Det primære er en opdeling i praksis- og forsknings-orientering af virksomheders innovationstilgang, hvorved der identificeres fire grupper af innovationsaktive virksomheder. Det andet er korrektion af de anvendte...
Optimering af økologiske produkters kvalitet (QACCP)
DEFF Research Database (Denmark)
Lauridsen, Charlotte; Kristensen, Hanne Lakkenborg; Jørgensen, Henry
2011-01-01
Forbrugerne efterspørger i stigende grad sundere og mere sikre fødevarer af høj kvalitet, og mange forbrugere har en forventning om, at økologiske fødevarer har højere kvalitet end ikke-økologiske. Det har man hidtil ikke kunnet bevise, bl.a. pga. manglen på videnskabelige undersøgelser af økolog...
Fairness-Aware Energy-Efficient Resource Allocation for AF Co-Operative OFDMA Networks
Bedeer, Ebrahim; Alorainy, Abdulaziz; Hossain, Md. Jahangir; Amin, Osama; Alouini, Mohamed-Slim
2015-01-01
In this paper, we adopt an energy-efficiency (EE) metric, named worst-EE, that is suitable for EE fairness optimization in the uplink transmission of amplify-and-forward (AF) cooperative orthogonal frequency division multiple access (OFDMA) networks. More specifically, we assign subcarriers and allocate powers for mobile and relay stations in order to maximize the worst-EE, i.e., to maximize the EE of the mobile station (MS) with the lowest EE value, subject to MSs transmit power, relay station (RS) transmit power, and MSs quality-of-service (QoS) constraints. The formulated primal max-min optimization problem is nonconvex fractional mixed integer nonlinear program, i.e., NP-hard to solve. We provide a novel optimization framework that studies the structure of the primal problem and prove that the dual min-max optimization problem attains the same optimal solution of the primal problem. Additionally, we propose a modified Dinkelbach algorithm, named dual Dinkelbach, to achieve the optimal solution of the dual problem in a polynomial time complexity. We further exploit the structure of the obtained optimal solution and develop a low complexity suboptimal heuristic. Numerical results show the effectiveness of the proposed algorithm to improve the network performance in terms of fairness between MSs, worst-EE, and average network transmission rate when compared to traditional schemes that maximize the EE of the whole network. Presented results also show that the suboptimal heuristic balances the achieved performance and the computational complexity.
Fairness-Aware Energy-Efficient Resource Allocation for AF Co-Operative OFDMA Networks
Bedeer, Ebrahim
2015-09-23
In this paper, we adopt an energy-efficiency (EE) metric, named worst-EE, that is suitable for EE fairness optimization in the uplink transmission of amplify-and-forward (AF) cooperative orthogonal frequency division multiple access (OFDMA) networks. More specifically, we assign subcarriers and allocate powers for mobile and relay stations in order to maximize the worst-EE, i.e., to maximize the EE of the mobile station (MS) with the lowest EE value, subject to MSs transmit power, relay station (RS) transmit power, and MSs quality-of-service (QoS) constraints. The formulated primal max-min optimization problem is nonconvex fractional mixed integer nonlinear program, i.e., NP-hard to solve. We provide a novel optimization framework that studies the structure of the primal problem and prove that the dual min-max optimization problem attains the same optimal solution of the primal problem. Additionally, we propose a modified Dinkelbach algorithm, named dual Dinkelbach, to achieve the optimal solution of the dual problem in a polynomial time complexity. We further exploit the structure of the obtained optimal solution and develop a low complexity suboptimal heuristic. Numerical results show the effectiveness of the proposed algorithm to improve the network performance in terms of fairness between MSs, worst-EE, and average network transmission rate when compared to traditional schemes that maximize the EE of the whole network. Presented results also show that the suboptimal heuristic balances the achieved performance and the computational complexity.
Efficient AUC optimization for classification
Calders, T.; Jaroszewicz, S.; Kok, J.N.; Koronacki, J.; Lopez de Mantaras, R.; Matwin, S.; Mladenic, D.; Skowron, A.
2007-01-01
In this paper we show an efficient method for inducing classifiers that directly optimize the area under the ROC curve. Recently, AUC gained importance in the classification community as a mean to compare the performance of classifiers. Because most classification methods do not optimize this
Optimum behavioral influence upon the industry; Optimal adfaerspaevirkning af industrien
Energy Technology Data Exchange (ETDEWEB)
Andersen, Hans; Prip, J.; Bossen, H.
2006-07-01
The overall purpose is to provide electricity supply companies' energy consultants with the best possible access to future tools and messages which can maintain and develop energy efficient behaviour within the companies. (BA)
Optimum behavioral influence upon the industry; Optimal adfaerspaevirkning af industrien
Energy Technology Data Exchange (ETDEWEB)
Andersen, Hans; Prip, J; Bossen, H
2006-07-01
The overall purpose is to provide electricity supply companies' energy consultants with the best possible access to future tools and messages which can maintain and develop energy efficient behaviour within the companies. (BA)
Pilot power optimization for AF relaying using maximum likelihood channel estimation
Wang, Kezhi
2014-09-01
Bit error rates (BERs) for amplify-and-forward (AF) relaying systems with two different pilot-symbol-aided channel estimation methods, disintegrated channel estimation (DCE) and cascaded channel estimation (CCE), are derived in Rayleigh fading channels. Based on these BERs, the pilot powers at the source and at the relay are optimized when their total transmitting powers are fixed. Numerical results show that the optimized system has a better performance than other conventional nonoptimized allocation systems. They also show that the optimal pilot power in variable gain is nearly the same as that in fixed gain for similar system settings. andcopy; 2014 IEEE.
Miljøoptimering af afvaskning ved tryk med vandfortyndbar flexotrykfarve
DEFF Research Database (Denmark)
Larsen, Henrik Fred; Helweg, Christian; Pedersen, Anne Rathmann
Rapporten beskriver praksis ved afvaskning af vandfortyndbare flexotrykfarver i emballageindustrien og anviser muligheder for indførelse af renere teknologi til reduktion af spildevandsbelastningen. Anbefalingerne omfatter a) udformning af farveværker med henblik på effektiv tømning af farve og e...
Enhancement of the CIGS solar cell's efficiency by anti-reflection coating with teflon AF
Energy Technology Data Exchange (ETDEWEB)
Bae, Hong-Sub; Kim, Chan; Rhee, Il-Su [Kyungpook National University, Daegu (Korea, Republic of); Jo, Hyun-Jun; Kim, Dae-Hwan [Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of); Hong, Sung-Wook [Daegu University, Gyeongsan (Korea, Republic of)
2014-11-15
An anti-reflection (AR) layer of Teflon AF was deposited on the front surface of a Cu(In,Ga)Se{sub 2} (CIGS) solar cell with a structure of grid/TCO/ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo/glass by using the spin coating method. This AR layer reduced the front-surface reflection, which resulted in high efficiency for the CIGS solar cell. The thickness of the Teflon AF layer was varied to determine the thickness that gave the highest transmittance of incident light into the active absorber of the CIGS solar cell. The optimum thickness of the Teflon AF layer was found to be 105 nm. CIGS solar cells with a Teflon AF layer of 105 nm were constructed, and their efficiencies were compared with those of solar cells without a Teflon AF layer. The average increase in the relative efficiency of the solar cells was 2.63% due to the inclusion of an anti-reflection layer of Teflon AF.
Optimization analysis of propulsion motor control efficiency
Directory of Open Access Journals (Sweden)
CAI Qingnan
2017-12-01
Full Text Available [Objectives] This paper aims to strengthen the control effect of propulsion motors and decrease the energy used during actual control procedures.[Methods] Based on the traditional propulsion motor equivalence circuit, we increase the iron loss current component, introduce the definition of power matching ratio, calculate the highest efficiency of a motor at a given speed and discuss the flux corresponding to the power matching ratio with the highest efficiency. In the original motor vector efficiency optimization control module, an efficiency optimization control module is added so as to achieve motor efficiency optimization and energy conservation.[Results] MATLAB/Simulink simulation data shows that the efficiency optimization control method is suitable for most conditions. The operation efficiency of the improved motor model is significantly higher than that of the original motor model, and its dynamic performance is good.[Conclusions] Our motor efficiency optimization control method can be applied in engineering to achieve energy conservation.
Energy efficient design for MIMO two-way AF multiple relay networks
Alsharoa, Ahmad M.
2014-04-01
This paper studies the energy efficient transmission and the power allocation problem for multiple two-way relay networks equipped with multi-input multi-output antennas where each relay employs an amplify-and-forward strategy. The goal is to minimize the total power consumption without degrading the quality of service of the terminals. In our analysis, we start by deriving closed-form expressions of the optimal powers allocated to terminals. We then employ a strong optimization tool based on the particle swarm optimization technique to find the optimal power allocated at each relay antenna. Our numerical results illustrate the performance of the proposed scheme and show that it achieves a sub-optimal solution very close to the optimal one.
Efficient Reanalysis Procedures in Structural Topology Optimization
DEFF Research Database (Denmark)
Amir, Oded
This thesis examines efficient solution procedures for the structural analysis problem within topology optimization. The research is motivated by the observation that when the nested approach to structural optimization is applied, most of the computational effort is invested in repeated solutions...... on approximate reanalysis. For cases where memory limitations require the utilization of iterative equation solvers, we suggest efficient procedures based on alternative termination criteria for such solvers. These approaches are tested on two- and three-dimensional topology optimization problems including...
Wang, Wei; Wang, Huasheng; Hu, Hongbo; Peng, Huasong; Zhang, Xuehong
2015-05-01
As a global regulatory gene in Streptomyces, afsR can activate the biosynthesis of many secondary metabolites. The effect of afsR on the biosynthesis of a phenazine metabolite, lomofungin, was studied in Streptomyces lomondensis S015. There was a 2.5-fold increase of lomofungin production in the afsR-overexpressing strain of S. lomondensis S015 N1 compared with the wild-type strain. Meanwhile, the transcription levels of afsR and two important genes involved in the biosynthesis of lomofungin (i.e., phzC and phzE) were significantly upregulated in S. lomondensis S015 N1. The optimization of metal chlorides was investigated to further increase the production of lomofungin in the afsR-overexpressing strain. The addition of different metal chlorides to S. lomondensis S015 N1 cultivations showed that CaCl2, FeCl2, and MnCl2 led to an increase in lomofungin biosynthesis. The optimum concentrations of these metal chlorides were obtained using response surface methodology. CaCl2 (0.04 mM), FeCl2 (0.33 mM), and MnCl2 (0.38 mM) gave a maximum lomofungin production titer of 318.0 ± 10.7 mg/l, which was a 4.1-fold increase compared with that of S. lomondensis S015 N1 without the addition of a metal chloride. This work demonstrates that the biosynthesis of phenazine metabolites can be induced by afsR. The results also indicate that metal chlorides addition might be a simple and useful strategy for improving the production of other phenazine metabolites in Streptomyces.
On the efficiency of chaos optimization algorithms for global optimization
International Nuclear Information System (INIS)
Yang Dixiong; Li Gang; Cheng Gengdong
2007-01-01
Chaos optimization algorithms as a novel method of global optimization have attracted much attention, which were all based on Logistic map. However, we have noticed that the probability density function of the chaotic sequences derived from Logistic map is a Chebyshev-type one, which may affect the global searching capacity and computational efficiency of chaos optimization algorithms considerably. Considering the statistical property of the chaotic sequences of Logistic map and Kent map, the improved hybrid chaos-BFGS optimization algorithm and the Kent map based hybrid chaos-BFGS algorithm are proposed. Five typical nonlinear functions with multimodal characteristic are tested to compare the performance of five hybrid optimization algorithms, which are the conventional Logistic map based chaos-BFGS algorithm, improved Logistic map based chaos-BFGS algorithm, Kent map based chaos-BFGS algorithm, Monte Carlo-BFGS algorithm, mesh-BFGS algorithm. The computational performance of the five algorithms is compared, and the numerical results make us question the high efficiency of the chaos optimization algorithms claimed in some references. It is concluded that the efficiency of the hybrid optimization algorithms is influenced by the statistical property of chaotic/stochastic sequences generated from chaotic/stochastic algorithms, and the location of the global optimum of nonlinear functions. In addition, it is inappropriate to advocate the high efficiency of the global optimization algorithms only depending on several numerical examples of low-dimensional functions
DEFF Research Database (Denmark)
Birkholm, Klavs
2010-01-01
En undersøgelse af anvendelsen af medicin til optimering af koncentration, hukommelse og følelsestonus. Efterfulgt af etiske overvejelser og anbefalinger til det politiske system......En undersøgelse af anvendelsen af medicin til optimering af koncentration, hukommelse og følelsestonus. Efterfulgt af etiske overvejelser og anbefalinger til det politiske system...
Park, Kihong; Alouini, Mohamed-Slim
2013-01-01
In this paper, we study a two-hop relaying network consisting of one source, one destination, and three amplify-and-forward (AF) relays with multiple antennas. To compensate for the capacity prelog factor loss of 1/2$ due to the half-duplex relaying
An Efficient Algorithm for Unconstrained Optimization
Directory of Open Access Journals (Sweden)
Sergio Gerardo de-los-Cobos-Silva
2015-01-01
Full Text Available This paper presents an original and efficient PSO algorithm, which is divided into three phases: (1 stabilization, (2 breadth-first search, and (3 depth-first search. The proposed algorithm, called PSO-3P, was tested with 47 benchmark continuous unconstrained optimization problems, on a total of 82 instances. The numerical results show that the proposed algorithm is able to reach the global optimum. This work mainly focuses on unconstrained optimization problems from 2 to 1,000 variables.
Energy Technology Data Exchange (ETDEWEB)
NONE
2005-03-15
The present report presents results from two closely related projects, carried out in parallel, under the PSO-F and U 2002. The one project is 'Survey of controllability in de-centralized combined heat and power plants' project number PSO 4724 and is fully reported here. The other project: 'Optimal operation of priority production units, project number PSO 4712, only the part project 'Technological foundations is reported here. In project 4724 the technical conditions that matter regarding controllability of electricity production in de-centralized heat and power stations are surveyed. In this context the term controllability means how fast and to which extent the load factors of the plants can be changed. Also, is has been investigated which options are available for improving the controllability, their potentials and estimates on required investments associated. The investigation covers CHP plants having a production capacity of up to 30 MW of electricity. The main part of the de-centralized CHP plants are based on spark ignited internal combustion engines (Otto engines). Most of these engines are fuelled by natural gas and a smaller part by biogas. A minor number are gas turbines fuelled by natural gas and steam turbines in industrial applications, waste incineration plants or in combined cycle power plants. The mapping has among others consisted of a number of visits on selected different types of plants including interview with people responsible for the daily operation. From these interviews data on the actual operating strategy and technical data have been provided. In addition suppliers of engines and other equipment involved have been contacted for technical information or recommendations regarding possible changes in operation strategy. Searching the Internet has been widely used for identification of technical investigations concerning e.g. operation and maintenance of relevant equipment. Finally, substantial statistical data from
Energy Technology Data Exchange (ETDEWEB)
Didriksen, H.; Sandvig Nielsen, J.; Weel Hansen, M.
2001-06-01
The aim of the project is to present a procedure to optimize existing drying processes. The optimization deals with energy consumption, capacity utilization and product quality. Other factors can also be included in the optimization, e.g. minimization of volume of discharged air. The optimization of existing drying processes will use calculation tool based on a mathematical simulation model for the process to calculate the most optimum operation situation on the basis of given conditions. In the project mathematical models have been developed precisely with this aim. The calculation tools have been developed with a user interface so that the tools can be used by technical staff in industrial companies and by consultants. The project also illustrates control of drying processes. Based on the developed models, the effect of using different types of control strategies by means of model simulations is illustrated. Three types of drying processes are treated: drum dryers, disc dryers and drying chambers. The work with the development of the simulation models has been very central in the project, as these have to be the basis for the optimization of the processes. The work is based on a large amount of information from academical literature and knowledge and experience about modelling thermal processes at dk-TEKNIK. The models constitute the core in the simulation programmes. The models describe the most important physical effects in connection with mass and energy transfer and transport under the drying for the three treated drying technologies. (EHS)
Efficient reanalysis techniques for robust topology optimization
DEFF Research Database (Denmark)
Amir, Oded; Sigmund, Ole; Lazarov, Boyan Stefanov
2012-01-01
efficient robust topology optimization procedures based on reanalysis techniques. The approach is demonstrated on two compliant mechanism design problems where robust design is achieved by employing either a worst case formulation or a stochastic formulation. It is shown that the time spent on finite...
Minimax robust power split in AF relays based on uncertain long-term CSI
Nisar, Muhammad Danish; Alouini, Mohamed-Slim
2011-01-01
An optimal power control among source and relay nodes in presence of channel state information (CSI) is vital for an efficient amplify and forward (AF) based cooperative communication system. In this work, we study the optimal power split (power
Improving the efficiency of aerodynamic shape optimization
Burgreen, Greg W.; Baysal, Oktay; Eleshaky, Mohamed E.
1994-01-01
The computational efficiency of an aerodynamic shape optimization procedure that is based on discrete sensitivity analysis is increased through the implementation of two improvements. The first improvement involves replacing a grid-point-based approach for surface representation with a Bezier-Bernstein polynomial parameterization of the surface. Explicit analytical expressions for the grid sensitivity terms are developed for both approaches. The second improvement proposes the use of Newton's method in lieu of an alternating direction implicit methodology to calculate the highly converged flow solutions that are required to compute the sensitivity coefficients. The modified design procedure is demonstrated by optimizing the shape of an internal-external nozzle configuration. Practically identical optimization results are obtained that are independent of the method used to represent the surface. A substantial factor of 8 decrease in computational time for the optimization process is achieved by implementing both of the design procedure improvements.
Efficient optimization of electrostatic interactions between biomolecules.
Energy Technology Data Exchange (ETDEWEB)
Bardhan, J. P.; Altman, M. D.; White, J. K.; Tidor, B.; Mathematics and Computer Science; MIT
2007-01-01
We present a PDE-constrained approach to optimizing the electrostatic interactions between two biomolecules. These interactions play important roles in the determination of binding affinity and specificity, and are therefore of significant interest when designing a ligand molecule to bind tightly to a receptor. Using a popular continuum model and physically reasonable assumptions, the electrostatic component of the binding free energy is a convex, quadratic function of the ligand charge distribution. Traditional optimization methods require exhaustive pre-computation, and the expense has precluded a full exploration of the promise of electrostatic optimization in biomolecule analysis and design. In this paper we describe an approach in which the electrostatic simulations and optimization problem are solved simultaneously; unlike many PDE- constrained optimization frameworks, the proposed method does not incorporate the PDE as a set of equality constraints. This co-optimization approach can be used by itself to solve unconstrained problems or those with linear equality constraints, or in conjunction with primal-dual interior point methods to solve problems with inequality constraints. Model problems demonstrate that the co-optimization method is computationally efficient and can be used to solve realistic problems.
Park, Kihong
2013-02-01
In this paper, we study a two-hop relaying network consisting of one source, one destination, and three amplify-and-forward (AF) relays with multiple antennas. To compensate for the capacity prelog factor loss of 1/2$ due to the half-duplex relaying, alternate transmission is performed among three relays, and the inter-relay interference due to the alternate relaying is aligned to make additional degrees of freedom. In addition, suboptimal linear filter designs at the nodes are proposed to maximize the achievable sum rate for different fading scenarios when the destination utilizes a minimum mean-square error filter. © 1967-2012 IEEE.
Efficient Iris Localization via Optimization Model
Directory of Open Access Journals (Sweden)
Qi Wang
2017-01-01
Full Text Available Iris localization is one of the most important processes in iris recognition. Because of different kinds of noises in iris image, the localization result may be wrong. Besides this, localization process is time-consuming. To solve these problems, this paper develops an efficient iris localization algorithm via optimization model. Firstly, the localization problem is modeled by an optimization model. Then SIFT feature is selected to represent the characteristic information of iris outer boundary and eyelid for localization. And SDM (Supervised Descent Method algorithm is employed to solve the final points of outer boundary and eyelids. Finally, IRLS (Iterative Reweighted Least-Square is used to obtain the parameters of outer boundary and upper and lower eyelids. Experimental result indicates that the proposed algorithm is efficient and effective.
Efficient search by optimized intermittent random walks
International Nuclear Information System (INIS)
Oshanin, Gleb; Lindenberg, Katja; Wio, Horacio S; Burlatsky, Sergei
2009-01-01
We study the kinetics for the search of an immobile target by randomly moving searchers that detect it only upon encounter. The searchers perform intermittent random walks on a one-dimensional lattice. Each searcher can step on a nearest neighbor site with probability α or go off lattice with probability 1 - α to move in a random direction until it lands back on the lattice at a fixed distance L away from the departure point. Considering α and L as optimization parameters, we seek to enhance the chances of successful detection by minimizing the probability P N that the target remains undetected up to the maximal search time N. We show that even in this simple model, a number of very efficient search strategies can lead to a decrease of P N by orders of magnitude upon appropriate choices of α and L. We demonstrate that, in general, such optimal intermittent strategies are much more efficient than Brownian searches and are as efficient as search algorithms based on random walks with heavy-tailed Cauchy jump-length distributions. In addition, such intermittent strategies appear to be more advantageous than Levy-based ones in that they lead to more thorough exploration of visited regions in space and thus lend themselves to parallelization of the search processes.
Optimizing Temporal Queries: Efficient Handling of Duplicates
DEFF Research Database (Denmark)
Toman, David; Bowman, Ivan Thomas
2001-01-01
, these query languages are implemented by translating temporal queries into standard relational queries. However, the compiled queries are often quite cumbersome and expensive to execute even using state-of-the- art relational products. This paper presents an optimization technique that produces more efficient...... translated SQL queries by taking into account the properties of the encoding used for temporal attributes. For concreteness, this translation technique is presented in the context of SQL/TP; however, these techniques are also applicable to other temporal query languages....
Energy efficiency improvement by gear shifting optimization
Directory of Open Access Journals (Sweden)
Blagojevic Ivan A.
2013-01-01
Full Text Available Many studies have proved that elements of driver’s behavior related to gear selection have considerable influence on the fuel consumption. Optimal gear shifting is a complex task, especially for inexperienced drivers. This paper presents an implemented idea for gear shifting optimization with the aim of fuel consumption minimization with more efficient engine working regimes. Optimized gear shifting enables the best possible relation between vehicle motion regimes and engine working regimes. New theoretical-experimental approach has been developed using On-Board Diagnostic technology which so far has not been used for this purpose. The matrix of driving modes according to which tests were performed is obtained and special data acquisition system and analysis process have been developed. Functional relations between experimental test modes and adequate engine working parameters have been obtained and all necessary operations have been conducted to enable their use as inputs for the designed algorithm. The created Model has been tested in real exploitation conditions on passenger car with Otto fuel injection engine and On-Board Diagnostic connection without any changes on it. The conducted tests have shown that the presented Model has significantly positive effects on fuel consumption which is an important ecological aspect. Further development and testing of the Model allows implementation in wide range of motor vehicles with various types of internal combustion engines.
Energy efficient design for MIMO two-way AF multiple relay networks
Alsharoa, Ahmad M.; Ghazzai, Hakim; Alouini, Mohamed-Slim
2014-01-01
This paper studies the energy efficient transmission and the power allocation problem for multiple two-way relay networks equipped with multi-input multi-output antennas where each relay employs an amplify-and-forward strategy. The goal
Optimized systems for energy efficient optical tweezing
Kampmann, R.; Kleindienst, R.; Grewe, A.; Bürger, Elisabeth; Oeder, A.; Sinzinger, S.
2013-03-01
Compared to conventional optics like singlet lenses or even microscope objectives advanced optical designs help to develop properties specifically useful for efficient optical tweezers. We present an optical setup providing a customized intensity distribution optimized with respect to large trapping forces. The optical design concept combines a refractive double axicon with a reflective parabolic focusing mirror. The axicon arrangement creates an annular field distribution and thus clears space for additional integrated observation optics in the center of the system. Finally the beam is focused to the desired intensity distribution by a parabolic ring mirror. The compact realization of the system potentially opens new fields of applications for optical tweezers such as in production industries and micro-nano assembly.
Enhancing the efficiency of constrained dual-hop variable-gain AF relaying under nakagami-m fading
Zafar, Ammar
2014-07-01
This paper studies power allocation for performance constrained dual-hop variable-gain amplify-and-forward (AF) relay networks in Nakagami- $m$ fading. In this context, the performance constraint is formulated as a constraint on the end-to-end signal-to-noise-ratio (SNR) and the overall power consumed is minimized while maintaining this constraint. This problem is considered under two different assumptions of the available channel state information (CSI) at the relays, namely full CSI at the relays and partial CSI at the relays. In addition to the power minimization problem, we also consider the end-to-end SNR maximization problem under a total power constraint for the partial CSI case. We provide closed-form solutions for all the problems which are easy to implement except in two cases, namely selective relaying with partial CSI for power minimization and SNR maximization, where we give the solution in the form of a one-variable equation which can be solved efficiently. Numerical results are then provided to characterize the performance of the proposed power allocation algorithms considering the effects of channel parameters and CSI availability. © 2014 IEEE.
Alsharoa, Ahmad M.
2014-06-01
In this paper, the problem of power allocation for a multiple-input multiple-output two-way system is investigated in underlay Cognitive Radio (CR) set-up. In the CR underlay mode, secondary users are allowed to exploit the spectrum allocated to primary users in an opportunistic manner by respecting a tolerated temperature limit. The secondary networks employ an amplify-and-forward two-way relaying technique in order to maximize the sum rate under power budget and interference constraints. In this context, we formulate an optimization problem that is solved in two steps. First, we derive a closed-form expression of the optimal power allocated to terminals. Then, we employ a strong optimization tool based on particle swarm optimization algorithm to find the power allocated to secondary relays. Simulation results demonstrate the efficiency of the proposed solution and analyze the impact of some system parameters on the achieved performance. © 2014 IEEE.
Efficient dynamic optimization of logic programs
Laird, Phil
1992-01-01
A summary is given of the dynamic optimization approach to speed up learning for logic programs. The problem is to restructure a recursive program into an equivalent program whose expected performance is optimal for an unknown but fixed population of problem instances. We define the term 'optimal' relative to the source of input instances and sketch an algorithm that can come within a logarithmic factor of optimal with high probability. Finally, we show that finding high-utility unfolding operations (such as EBG) can be reduced to clause reordering.
Energy Technology Data Exchange (ETDEWEB)
Soerensen, J.N.; Shen, W.Z.; Zhu, W.J.; Borbye, J.; Okulov, V.L.; Mikkelsen, R. (DTU Mekanik, Kgs. Lyngby (Denmark)); Gaunaa, M.; Rethore, P.-E.; Soerensen, N.N. (Danmarks Tekniske Univ. Risoe DTU, Afd. for Vindenergi, Roskilde (Denmark))
2011-03-15
The aim of the project was to suggest and analyse new shapes of wing tips for wind turbines to optimize their performance. Several simple wing tips and their flow topology were analysed, and the impact of different design variables was determined in order to establish which design has the best effect for the performance. For the numerical flow calculations, primarily the Navier-Stokes code EllipSys was used. As a supplement to the viscous Navier-Stokes calculations, in-viscous calculations were made using a lifting-line theory. This is a simple technique to determine the load distribution along the wing tip in those cases where viscous effects can be neglected. A large part of the project has focused on improving accuracy of the lifting-line method. Besides forming the basis for improved tip configurations, the calculations were also used to improve the so-called tip correction. Based on the numerical results from CFD calculations an improved tip correction was developed. (ln)
Exergetic efficiency optimization for an irreversible heat pump ...
Indian Academy of Sciences (India)
This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is ...
Kantian Optimization, Social Ethos, and Pareto Efficiency
John E. Roemer
2012-01-01
Although evidence accrues in biology, anthropology and experimental economics that homo sapiens is a cooperative species, the reigning assumption in economic theory is that individuals optimize in an autarkic manner (as in Nash and Walrasian equilibrium). I here postulate an interdependent kind of optimizing behavior, called Kantian. It is shown that in simple economic models, when there are negative externalities (such as congestion effects from use of a commonly owned resource) or positive ...
Finite-size effect on optimal efficiency of heat engines.
Tajima, Hiroyasu; Hayashi, Masahito
2017-07-01
The optimal efficiency of quantum (or classical) heat engines whose heat baths are n-particle systems is given by the strong large deviation. We give the optimal work extraction process as a concrete energy-preserving unitary time evolution among the heat baths and the work storage. We show that our optimal work extraction turns the disordered energy of the heat baths to the ordered energy of the work storage, by evaluating the ratio of the entropy difference to the energy difference in the heat baths and the work storage, respectively. By comparing the statistical mechanical optimal efficiency with the macroscopic thermodynamic bound, we evaluate the accuracy of the macroscopic thermodynamics with finite-size heat baths from the statistical mechanical viewpoint. We also evaluate the quantum coherence effect on the optimal efficiency of the cycle processes without restricting their cycle time by comparing the classical and quantum optimal efficiencies.
Energy Technology Data Exchange (ETDEWEB)
Birck Laustsen, J.; Johnsen, K.
2008-07-01
The report describes methods for characterizing sun shades and determining their energy related and optical properties. In connection with the project two calculation tools have been developed for evaluation of sun shades' impact on indoor climate, daylight conditions and energy consumption in buildings. One calculation tool works during the early draft phase, while the other is used during the detailed design of buildings. Combined they form a solid planning basis which will further energy efficient use of sun shades. (BA)
Lean and Efficient Software: Whole-Program Optimization of Executables
2015-09-30
Lean and Efficient Software: Whole-Program Optimization of Executables” Project Summary Report #5 (Report Period: 7/1/2015 to 9/30/2015...TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Lean and Efficient Software: Whole-Program Optimization of Executables 5a...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Lean and Efficient Software: Whole-Program
DEFF Research Database (Denmark)
Hansen, Ernst Jan de Place
2008-01-01
Beskrivelse af hvordan man ved udbygning af eksisterende kloaknet og ved nytænkning af planlægning af nye bydele kan sikre sig langsigtet mod konsekvenserne af klimaændinger og kraftigere nedbør...
Efficient evolutionary algorithms for optimal control
López Cruz, I.L.
2002-01-01
If optimal control problems are solved by means of gradient based local search methods, convergence to local solutions is likely. Recently, there has been an increasing interest in the use
Optimal Energy Taxation for Environment and Efficiency
Energy Technology Data Exchange (ETDEWEB)
Pak, Y.D. [Korea Energy Economics Institute, Euiwang (Korea)
2001-11-01
Main purpose of this research is to investigate about how to use energy tax system to reconcile environmental protection and economic growth, and promote sustainable development with the emphasis of double dividend hypothesis. As preliminary work to attain this target, in this limited study I will investigate the specific conditions under which double dividend hypothesis can be valid, and set up the model for optimal energy taxation. The model will be used in the simulation process in the next project. As the beginning part in this research, I provide a brief review about energy taxation policies in Sweden, Netherlands, and the United States. From this review it can be asserted that European countries are more aggressive in the application of environmental taxes like energy taxes for a cleaner environment than the United States. In next part I examined the rationale for optimal environmental taxation in the first-best and the second-best setting. Then I investigated energy taxation how it can provoke various distortions in markets and be connected to the marginal environmental damages and environmental taxation. In the next chapter, I examined the environmentally motivated taxation in the point of optimal commodity taxation view. Also I identified the impacts of environmental taxation in various circumstances intensively to find out when the environment tax can yield double dividend after taking into account of even tax-interaction effects. Then it can be found that even though in general the environmental tax exacerbates the distortion in the market rather than alleviates, it can also improve the welfare and the employment under several specific circumstances which are classified as various inefficiencies in the existing tax system. (author). 30 refs.
Optimization of a high efficiency FEL amplifier
International Nuclear Information System (INIS)
Schneidmiller, E.A.; Yurkov, M.V.
2014-10-01
The problem of an efficiency increase of an FEL amplifier is now of great practical importance. Technique of undulator tapering in the post-saturation regime is used at the existing X-ray FELs LCLS and SACLA, and is planned for use at the European XFEL, Swiss FEL, and PAL XFEL. There are also discussions on the future of high peak and average power FELs for scientific and industrial applications. In this paper we perform detailed analysis of the tapering strategies for high power seeded FEL amplifiers. Application of similarity techniques allows us to derive universal law of the undulator tapering.
Optimal database locks for efficient integrity checking
DEFF Research Database (Denmark)
Martinenghi, Davide
2004-01-01
In concurrent database systems, correctness of update transactions refers to the equivalent effects of the execution schedule and some serial schedule over the same set of transactions. Integrity constraints add further semantic requirements to the correctness of the database states reached upon...... the execution of update transactions. Several methods for efficient integrity checking and enforcing exist. We show in this paper how to apply one such method to automatically extend update transactions with locks and simplified consistency tests on the locked entities. All schedules produced in this way...
A Method for Determining Optimal Residential Energy Efficiency Packages
Energy Technology Data Exchange (ETDEWEB)
Polly, B. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gestwick, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bianchi, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Anderson, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Christensen, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Judkoff, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States)
2011-04-01
This report describes an analysis method for determining optimal residential energy efficiency retrofit packages and, as an illustrative example, applies the analysis method to a 1960s-era home in eight U.S. cities covering a range of International Energy Conservation Code (IECC) climate regions. The method uses an optimization scheme that considers average energy use (determined from building energy simulations) and equivalent annual cost to recommend optimal retrofit packages specific to the building, occupants, and location.
DEFF Research Database (Denmark)
Le, T.H.A.; Pham, D. T.; Canh, Nam Nguyen
2010-01-01
Both the efficient and weakly efficient sets of an affine fractional vector optimization problem, in general, are neither convex nor given explicitly. Optimization problems over one of these sets are thus nonconvex. We propose two methods for optimizing a real-valued function over the efficient...... and weakly efficient sets of an affine fractional vector optimization problem. The first method is a local one. By using a regularization function, we reformulate the problem into a standard smooth mathematical programming problem that allows applying available methods for smooth programming. In case...... the objective function is linear, we have investigated a global algorithm based upon a branch-and-bound procedure. The algorithm uses Lagrangian bound coupling with a simplicial bisection in the criteria space. Preliminary computational results show that the global algorithm is promising....
A Concept for Optimizing Behavioural Effectiveness & Efficiency
Barca, Jan Carlo; Rumantir, Grace; Li, Raymond
Both humans and machines exhibit strengths and weaknesses that can be enhanced by merging the two entities. This research aims to provide a broader understanding of how closer interactions between these two entities can facilitate more optimal goal-directed performance through the use of artificial extensions of the human body. Such extensions may assist us in adapting to and manipulating our environments in a more effective way than any system known today. To demonstrate this concept, we have developed a simulation where a semi interactive virtual spider can be navigated through an environment consisting of several obstacles and a virtual predator capable of killing the spider. The virtual spider can be navigated through the use of three different control systems that can be used to assist in optimising overall goal directed performance. The first two control systems use, an onscreen button interface and a touch sensor, respectively to facilitate human navigation of the spider. The third control system is an autonomous navigation system through the use of machine intelligence embedded in the spider. This system enables the spider to navigate and react to changes in its local environment. The results of this study indicate that machines should be allowed to override human control in order to maximise the benefits of collaboration between man and machine. This research further indicates that the development of strong machine intelligence, sensor systems that engage all human senses, extra sensory input systems, physical remote manipulators, multiple intelligent extensions of the human body, as well as a tighter symbiosis between man and machine, can support an upgrade of the human form.
Optimal control of operation efficiency of belt conveyor systems
International Nuclear Information System (INIS)
Zhang, Shirong; Xia, Xiaohua
2010-01-01
The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment or operation levels. Switching control and variable speed control are proposed in literature to improve energy efficiency of belt conveyors. The current implementations mostly focus on lower level control loops or an individual belt conveyor without operational considerations at the system level. In this paper, an optimal switching control and a variable speed drive (VSD) based optimal control are proposed to improve the energy efficiency of belt conveyor systems at the operational level, where time-of-use (TOU) tariff, ramp rate of belt speed and other system constraints are considered. A coal conveying system in a coal-fired power plant is taken as a case study, where great saving of energy cost is achieved by the two optimal control strategies. Moreover, considerable energy saving resulting from VSD based optimal control is also proved by the case study.
Optimal control of operation efficiency of belt conveyor systems
Energy Technology Data Exchange (ETDEWEB)
Zhang, Shirong [Department of Automation, Wuhan University, Wuhan 430072 (China); Xia, Xiaohua [Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria 0002 (South Africa)
2010-06-15
The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment or operation levels. Switching control and variable speed control are proposed in literature to improve energy efficiency of belt conveyors. The current implementations mostly focus on lower level control loops or an individual belt conveyor without operational considerations at the system level. In this paper, an optimal switching control and a variable speed drive (VSD) based optimal control are proposed to improve the energy efficiency of belt conveyor systems at the operational level, where time-of-use (TOU) tariff, ramp rate of belt speed and other system constraints are considered. A coal conveying system in a coal-fired power plant is taken as a case study, where great saving of energy cost is achieved by the two optimal control strategies. Moreover, considerable energy saving resulting from VSD based optimal control is also proved by the case study. (author)
Efficiency Optimization in Class-D Audio Amplifiers
DEFF Research Database (Denmark)
Yamauchi, Akira; Knott, Arnold; Jørgensen, Ivan Harald Holger
2015-01-01
This paper presents a new power efficiency optimization routine for designing Class-D audio amplifiers. The proposed optimization procedure finds design parameters for the power stage and the output filter, and the optimum switching frequency such that the weighted power losses are minimized under...... the given constraints. The optimization routine is applied to minimize the power losses in a 130 W class-D audio amplifier based on consumer behavior investigations, where the amplifier operates at idle and low power levels most of the time. Experimental results demonstrate that the optimization method can...... lead to around 30 % of efficiency improvement at 1.3 W output power without significant effects on both audio performance and the efficiency at high power levels....
AF Bands Air Force Band Recordings Air National Guard Band of the Midwest Air National Guard Band of U.S. Air Force Bands U.S. Air Force Heartland of America Band U.S. Air Force Heritage of America Band U.S. Air Forces in Europe Band US Air Forces Central Command Band Medical 42d Medical Group 59th
Modeling and energy efficiency optimization of belt conveyors
International Nuclear Information System (INIS)
Zhang, Shirong; Xia, Xiaohua
2011-01-01
Highlights: → We take optimization approach to improve operation efficiency of belt conveyors. → An analytical energy model, originating from ISO 5048, is proposed. → Then an off-line and an on-line parameter estimation schemes are investigated. → In a case study, six optimization problems are formulated with solutions in simulation. - Abstract: The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment and operation levels. Specifically, variable speed control, an equipment level intervention, is recommended to improve operation efficiency of belt conveyors. However, the current implementations mostly focus on lower level control loops without operational considerations at the system level. This paper intends to take a model based optimization approach to improve the efficiency of belt conveyors at the operational level. An analytical energy model, originating from ISO 5048, is firstly proposed, which lumps all the parameters into four coefficients. Subsequently, both an off-line and an on-line parameter estimation schemes are applied to identify the new energy model, respectively. Simulation results are presented for the estimates of the four coefficients. Finally, optimization is done to achieve the best operation efficiency of belt conveyors under various constraints. Six optimization problems of a typical belt conveyor system are formulated, respectively, with solutions in simulation for a case study.
Energirenovering af parcelhuse
DEFF Research Database (Denmark)
Aggerholm, Søren
af de tre huse består i efterisolering af lofter op til 300 mm, udskiftning af almindelige termoruder til energiruder, og installation af solvarmeanlæg til produktion af varmt brugsvand. I de tre huse er der ved energirenoveringen opnået en reduktion af energiforbruget på 16-22 procent. Rapporten...
Anvendelse af alternative isoleringsmaterialer
DEFF Research Database (Denmark)
Hansen, Ernst Jan de Place
2003-01-01
Resume af By og Byg Anvisning 207 om anvendelse af alternative isoleringsmaterialer, udarbejdet af Statens Byggeforskningsinstitut under udviklingsprogrammet "Miljø- og arbejdsmiljøvenlig isolering"......Resume af By og Byg Anvisning 207 om anvendelse af alternative isoleringsmaterialer, udarbejdet af Statens Byggeforskningsinstitut under udviklingsprogrammet "Miljø- og arbejdsmiljøvenlig isolering"...
Method for Determining Optimal Residential Energy Efficiency Retrofit Packages
Energy Technology Data Exchange (ETDEWEB)
Polly, B.; Gestwick, M.; Bianchi, M.; Anderson, R.; Horowitz, S.; Christensen, C.; Judkoff, R.
2011-04-01
Businesses, government agencies, consumers, policy makers, and utilities currently have limited access to occupant-, building-, and location-specific recommendations for optimal energy retrofit packages, as defined by estimated costs and energy savings. This report describes an analysis method for determining optimal residential energy efficiency retrofit packages and, as an illustrative example, applies the analysis method to a 1960s-era home in eight U.S. cities covering a range of International Energy Conservation Code (IECC) climate regions. The method uses an optimization scheme that considers average energy use (determined from building energy simulations) and equivalent annual cost to recommend optimal retrofit packages specific to the building, occupants, and location. Energy savings and incremental costs are calculated relative to a minimum upgrade reference scenario, which accounts for efficiency upgrades that would occur in the absence of a retrofit because of equipment wear-out and replacement with current minimum standards.
Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances
Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana
2016-04-01
Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.
An efficient multilevel optimization method for engineering design
Vanderplaats, G. N.; Yang, Y. J.; Kim, D. S.
1988-01-01
An efficient multilevel deisgn optimization technique is presented. The proposed method is based on the concept of providing linearized information between the system level and subsystem level optimization tasks. The advantages of the method are that it does not require optimum sensitivities, nonlinear equality constraints are not needed, and the method is relatively easy to use. The disadvantage is that the coupling between subsystems is not dealt with in a precise mathematical manner.
Efficient solution method for optimal control of nuclear systems
International Nuclear Information System (INIS)
Naser, J.A.; Chambre, P.L.
1981-01-01
To improve the utilization of existing fuel sources, the use of optimization techniques is becoming more important. A technique for solving systems of coupled ordinary differential equations with initial, boundary, and/or intermediate conditions is given. This method has a number of inherent advantages over existing techniques as well as being efficient in terms of computer time and space requirements. An example of computing the optimal control for a spatially dependent reactor model with and without temperature feedback is given. 10 refs
Lean and Efficient Software: Whole Program Optimization of Executables
2016-12-31
19b. TELEPHONE NUMBER (Include area code) 12/31/2016 Final Technical Report (Phase I - Base Period) 30-06-2014 - 31-12-2016 Lean and Efficient...Software: Whole-Program Optimization of Executables Final Report Evan Driscoll Tom Johnson GrammaTech, Inc. 531 Esty Street Ithaca, NY 14850 Office of...hardening U U U UU 30 Tom Johnson (607) 273-7340 x.134 Page 1 of 30 “ Lean and Efficient Software: Whole-Program Optimization of Executables
Optimal shaping and positioning of energy-efficient buildings
Directory of Open Access Journals (Sweden)
Barović Dušan D.
2017-01-01
Full Text Available Due to the number of variables and the complexity of objective functions, optimal design of an energy-efficient building is hard combinatorial problem of multi-objective optimisation. Therefore, it is necessary to describe structure and its position in surroundings precisely but by as few variables as possible. This paper presents methodology for finding adequate methodology for defining geometry and orientation of a given building, as well as its elements of importance for energy-efficiency analysis.
A fractional optimal control problem for maximizing advertising efficiency
Igor Bykadorov; Andrea Ellero; Stefania Funari; Elena Moretti
2007-01-01
We propose an optimal control problem to model the dynamics of the communication activity of a firm with the aim of maximizing its efficiency. We assume that the advertising effort undertaken by the firm contributes to increase the firm's goodwill and that the goodwill affects the firm's sales. The aim is to find the advertising policies in order to maximize the firm's efficiency index which is computed as the ratio between "outputs" and "inputs" properly weighted; the outputs are represented...
Modeling Vertical Flow Treatment Wetland Hydraulics to Optimize Treatment Efficiency
2011-03-24
be forced to flow in a 90 serpentine manner back and forth as it moves upward through the wetland (think waiting in line at Disneyland ). This...Flow Treatment Wetland Hydraulics to Optimize Treatment Efficiency 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR
Efficiency optimized control of medium-size induction motor drives
DEFF Research Database (Denmark)
Abrahamsen, F.; Blaabjerg, Frede; Pedersen, John Kim
2000-01-01
The efficiency of a variable speed induction motor drive can be optimized by adaption of the motor flux level to the load torque. In small drives (<10 kW) this can be done without considering the relatively small converter losses, but for medium-size drives (10-1000 kW) the losses can not be disr......The efficiency of a variable speed induction motor drive can be optimized by adaption of the motor flux level to the load torque. In small drives (... not be disregarded without further analysis. The importance of the converter losses on efficiency optimization in medium-size drives is analyzed in this paper. Based on the experiments with a 90 kW drive it is found that it is not critical if the converter losses are neglected in the control, except...... that the robustness towards load disturbances may unnecessarily be reduced. Both displacement power factor and model-based efficiency optimizing control methods perform well in medium-size drives. The last strategy is also tested on a 22 kW drive with good results....
Optimization of aerodynamic efficiency for twist morphing MAV wing
Directory of Open Access Journals (Sweden)
N.I. Ismail
2014-06-01
Full Text Available Twist morphing (TM is a practical control technique in micro air vehicle (MAV flight. However, TM wing has a lower aerodynamic efficiency (CL/CD compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.
Comparing effectiveness and efficiency in technical specifications and maintenance optimization
International Nuclear Information System (INIS)
Martorell, Sebastian; Sanchez, Ana; Carlos, Sofia; Serradell, Vicente
2002-01-01
Optimization of technical specification requirements and maintenance (TS and M) has been found interesting from the very beginning at Nuclear Power Plants (NPPs). However, the resolution of such a kind of optimization problem has been limited often to focus only on individual TS and M-related parameters (STI, AOT, PM frequency, etc.) and/or adopting an individual optimization criterion (availability, costs, plant risks, etc.). Nevertheless, a number of reasons exist (e.g. interaction, similar scope, etc.) that justify the interest to focus on the coordinated optimization of all of the relevant TS and M-related parameters based on multiple criteria. The purpose of this paper is on signifying benefits and improvement areas in performing the coordinated optimization of TS and M through reviewing the effectiveness and efficiency of common strategies for optimizing TS and M at system level. A case of application is provided for a stand-by safety-related system to demonstrate the basic procedure and to extract a number of conclusions and recommendations from the results achieved. Thus, it is concluded that the optimized values depend on the particular TS and M-related parameters being involved and the solutions with the largest benefit (minimum risk or minimum cost) are achieved when considering the simultaneous optimization of all of them, although increased computational resources are also required. Consequently, it is necessary to analyze not only the value reached but also the performance of the optimization procedure through effectiveness and efficiency measures which lead to recommendations on potential improvement areas
ProxImaL: efficient image optimization using proximal algorithms
Heide, Felix
2016-07-11
Computational photography systems are becoming increasingly diverse, while computational resources-for example on mobile platforms-are rapidly increasing. As diverse as these camera systems may be, slightly different variants of the underlying image processing tasks, such as demosaicking, deconvolution, denoising, inpainting, image fusion, and alignment, are shared between all of these systems. Formal optimization methods have recently been demonstrated to achieve state-of-the-art quality for many of these applications. Unfortunately, different combinations of natural image priors and optimization algorithms may be optimal for different problems, and implementing and testing each combination is currently a time-consuming and error-prone process. ProxImaL is a domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety of linear and nonlinear image formation models and cost functions, advanced image priors, and noise models. The compiler intelligently chooses the best way to translate a problem formulation and choice of optimization algorithm into an efficient solver implementation. In applications to the image processing pipeline, deconvolution in the presence of Poisson-distributed shot noise, and burst denoising, we show that a few lines of ProxImaL code can generate highly efficient solvers that achieve state-of-the-art results. We also show applications to the nonlinear and nonconvex problem of phase retrieval.
An Efficient PageRank Approach for Urban Traffic Optimization
Directory of Open Access Journals (Sweden)
Florin Pop
2012-01-01
to determine optimal decisions for each traffic light, based on the solution given by Larry Page for page ranking in Web environment (Page et al. (1999. Our approach is similar with work presented by Sheng-Chung et al. (2009 and Yousef et al. (2010. We consider that the traffic lights are controlled by servers and a score for each road is computed based on efficient PageRank approach and is used in cost function to determine optimal decisions. We demonstrate that the cumulative contribution of each car in the traffic respects the main constrain of PageRank approach, preserving all the properties of matrix consider in our model.
Energy efficient LED layout optimization for near-uniform illumination
Ali, Ramy E.; Elgala, Hany
2016-09-01
In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.
Efficient topology optimization in MATLAB using 88 lines of code
DEFF Research Database (Denmark)
Andreassen, Erik; Clausen, Anders; Schevenels, Mattias
2011-01-01
The paper presents an efficient 88 line MATLAB code for topology optimization. It has been developed using the 99 line code presented by Sigmund (Struct Multidisc Optim 21(2):120–127, 2001) as a starting point. The original code has been extended by a density filter, and a considerable improvemen...... of the basic code to include recent PDE-based and black-and-white projection filtering methods. The complete 88 line code is included as an appendix and can be downloaded from the web site www.topopt.dtu.dk....
Mathematical efficiency calibration with uncertain source geometries using smart optimization
International Nuclear Information System (INIS)
Menaa, N.; Bosko, A.; Bronson, F.; Venkataraman, R.; Russ, W. R.; Mueller, W.; Nizhnik, V.; Mirolo, L.
2011-01-01
The In Situ Object Counting Software (ISOCS), a mathematical method developed by CANBERRA, is a well established technique for computing High Purity Germanium (HPGe) detector efficiencies for a wide variety of source shapes and sizes. In the ISOCS method, the user needs to input the geometry related parameters such as: the source dimensions, matrix composition and density, along with the source-to-detector distance. In many applications, the source dimensions, the matrix material and density may not be well known. Under such circumstances, the efficiencies may not be very accurate since the modeled source geometry may not be very representative of the measured geometry. CANBERRA developed an efficiency optimization software known as 'Advanced ISOCS' that varies the not well known parameters within user specified intervals and determines the optimal efficiency shape and magnitude based on available benchmarks in the measured spectra. The benchmarks could be results from isotopic codes such as MGAU, MGA, IGA, or FRAM, activities from multi-line nuclides, and multiple counts of the same item taken in different geometries (from the side, bottom, top etc). The efficiency optimization is carried out using either a random search based on standard probability distributions, or using numerical techniques that carry out a more directed (referred to as 'smart' in this paper) search. Measurements were carried out using representative source geometries and radionuclide distributions. The radionuclide activities were determined using the optimum efficiency and compared against the true activities. The 'Advanced ISOCS' method has many applications among which are: Safeguards, Decommissioning and Decontamination, Non-Destructive Assay systems and Nuclear reactor outages maintenance. (authors)
Air conditioning with methane: Efficiency and economics optimization parameters
International Nuclear Information System (INIS)
Mastrullo, R.; Sasso, M.; Sibilio, S.; Vanoli, R.
1992-01-01
This paper presents an efficiency and economics evaluation method for methane fired cooling systems. Focus is on direct flame two staged absorption systems and alternative engine driven compressor sets. Comparisons are made with conventional vapour compression plants powered by electricity supplied by the national grid. A first and second law based thermodynamics analysis is made in which fuel use coefficients and exergy yields are determined. The economics analysis establishes annual energy savings, unit cooling energy production costs, payback periods and economics/efficiency optimization curves useful for preliminary feasibility studies
On-line efficiency optimization of a synchronous reluctance motor
Energy Technology Data Exchange (ETDEWEB)
Lubin, Thierry; Razik, Hubert; Rezzoug, Abderrezak [Groupe de Recherche en Electrotechnique et Electronique de Nancy, GREEN, CNRS-UMR 7037, Universite Henri Poincare, BP 239, 54506 Vandoeuvre-les-Nancy Cedex (France)
2007-04-15
This paper deals with an on-line optimum-efficiency control of a synchronous reluctance motor drive. The input power minimization control is implemented with a search controller using Fibonacci search algorithm. It searches the optimal reference value of the d-axis stator current for which the input power is minimum. The input power is calculated from the measured dc-bus current and dc-bus voltage of the inverter. A rotor-oriented vector control of the synchronous reluctance machine with the optimization efficiency controller is achieved with a DSP board (TMS302C31). Experimental results are presented to validate the proposed control methods. It is shown that stability problems can appear during the search process. (author)
Optimal power and efficiency of quantum Stirling heat engines
Yin, Yong; Chen, Lingen; Wu, Feng
2017-01-01
A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.
Improving the efficiency of aerodynamic shape optimization procedures
Burgreen, Greg W.; Baysal, Oktay; Eleshaky, Mohamed E.
1992-01-01
The computational efficiency of an aerodynamic shape optimization procedure which is based on discrete sensitivity analysis is increased through the implementation of two improvements. The first improvement involves replacing a grid point-based approach for surface representation with a Bezier-Bernstein polynomial parameterization of the surface. Explicit analytical expressions for the grid sensitivity terms are developed for both approaches. The second improvement proposes the use of Newton's method in lieu of an alternating direction implicit (ADI) methodology to calculate the highly converged flow solutions which are required to compute the sensitivity coefficients. The modified design procedure is demonstrated by optimizing the shape of an internal-external nozzle configuration. A substantial factor of 8 decrease in computational time for the optimization process was achieved by implementing both of the design improvements.
DEFF Research Database (Denmark)
Jessen, K.; Boysen Larsen, B.; Bundgaard, P.
Denne rapport indeholder resultaterne af den natur- og miljøovervågning, der blev iværksat som en del af naturgenopretningen af Skjern Å 1999-2002. Ved projektet ophørte den kunstige afvanding af den vestlige del af Skjern Å dalen. Størstedelen af de dyrkede arealer ændredes til ekstensive græsni...
Efficient relaxations for joint chance constrained AC optimal power flow
Energy Technology Data Exchange (ETDEWEB)
Baker, Kyri; Toomey, Bridget
2017-07-01
Evolving power systems with increasing levels of stochasticity call for a need to solve optimal power flow problems with large quantities of random variables. Weather forecasts, electricity prices, and shifting load patterns introduce higher levels of uncertainty and can yield optimization problems that are difficult to solve in an efficient manner. Solution methods for single chance constraints in optimal power flow problems have been considered in the literature, ensuring single constraints are satisfied with a prescribed probability; however, joint chance constraints, ensuring multiple constraints are simultaneously satisfied, have predominantly been solved via scenario-based approaches or by utilizing Boole's inequality as an upper bound. In this paper, joint chance constraints are used to solve an AC optimal power flow problem while preventing overvoltages in distribution grids under high penetrations of photovoltaic systems. A tighter version of Boole's inequality is derived and used to provide a new upper bound on the joint chance constraint, and simulation results are shown demonstrating the benefit of the proposed upper bound. The new framework allows for a less conservative and more computationally efficient solution to considering joint chance constraints, specifically regarding preventing overvoltages.
Shape optimization for aerodynamic efficiency and low observability
Vinh, Hoang; Van Dam, C. P.; Dwyer, Harry A.
1993-01-01
Field methods based on the finite-difference approximations of the time-domain Maxwell's equations and the potential-flow equation have been developed to solve the multidisciplinary problem of airfoil shaping for aerodynamic efficiency and low radar cross section (RCS). A parametric study and an optimization study employing the two analysis methods are presented to illustrate their combined capabilities. The parametric study shows that for frontal radar illumination, the RCS of an airfoil is independent of the chordwise location of maximum thickness but depends strongly on the maximum thickness, leading-edge radius, and leadingedge shape. In addition, this study shows that the RCS of an airfoil can be reduced without significant effects on its transonic aerodynamic efficiency by reducing the leading-edge radius and/or modifying the shape of the leading edge. The optimization study involves the minimization of wave drag for a non-lifting, symmetrical airfoil with constraints on the airfoil maximum thickness and monostatic RCS. This optimization study shows that the two analysis methods can be used effectively to design aerodynamically efficient airfoils with certain desired RCS characteristics.
High-efficiency design optimization of a centrifugal pump
Energy Technology Data Exchange (ETDEWEB)
Heo, Man Woong; Ma, Sang Bum; Shim, Hyeon Seok; Kim, Kwang Yong [Dept. of Mechanical Engineering, Inha University, Incheon (Korea, Republic of)
2016-09-15
Design optimization of a backward-curved blades centrifugal pump with specific speed of 150 has been performed to improve hydraulic performance of the pump using surrogate modeling and three-dimensional steady Reynolds-averaged Navier-Stokes analysis. The shear stress transport model was used for the analysis of turbulence. Four geometric variables defining the blade hub inlet angle, hub contours, blade outlet angle, and blade angle profile of impeller were selected as design variables, and total efficiency of the pump at design flow rate was set as the objective function for the optimization. Thirty-six design points were chosen using the Latin hypercube sampling, and three different surrogate models were constructed using the objective function values calculated at these design points. The optimal point was searched from the constructed surrogate model by using sequential quadratic programming. The optimum designs of the centrifugal pump predicted by the surrogate models show considerable increases in efficiency compared to a reference design. Performance of the best optimum design was validated compared to experimental data for total efficiency and head.
The computational optimization of heat exchange efficiency in stack chimneys
Energy Technology Data Exchange (ETDEWEB)
Van Goch, T.A.J.
2012-02-15
For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a
Energy Technology Data Exchange (ETDEWEB)
NONE
2005-07-01
Even without high and volatile oil prices, which have led to a downgrading of the prospects of economic growth in Europe, there would be very good reasons for the European Union to make a strong push towards a re-invigorated programme promoting energy efficiency at all levels of European society. This green paper seeks to act as a catalyst, leading to a renewed energy efficiency initiative at all levels of European society - EU, national, regional and local. Furthermore, this Green Paper seeks to make a significant contribution, by way of example and leadership, to kick-start an international effort to contribute to addressing climatic change through energy efficiency. China presently uses more than five times as much energy as the EU to produce one unit of GDP, USA uses approximately 50% more than EU. With exploding energy demand, in particular in China and India, energy efficiency must be one of the key policies to try to reconcile, on the one hand, the increased energy needs of the developing world to power growth and improve living conditions and, on the other hand, combat global warming. This Green Paper, and the momentum created in following it up, should put the EU at the forefront of efforts to make energy efficiency a global priority. (BA)
Efficiency optimization potential in supercritical Organic Rankine Cycles
Energy Technology Data Exchange (ETDEWEB)
Schuster, A.; Aumann, R. [Technische Universitaet Muenchen Institute of Energy Systems Boltzmannstr. 15, 85748 Garching (Germany); Karellas, S. [National Technical University of Athens Laboratory of Steam Boilers and Thermal Plants Heroon Polytechniou 9, 15780 Athens (Greece)
2010-02-15
Nowadays, the use of Organic Rankine Cycle (ORC) in decentralised applications is linked with the fact that this process allows the use of low temperature heat sources and offers an advantageous efficiency in small-scale concepts. Many state-of-the-art and innovative applications can successfully use the ORC process. In this process, according to the heat source level, special attention must be drawn to the choice of the appropriate working fluid, which is a factor that affects the thermal and exergetic efficiency of the cycle. The investigation of supercritical parameters of various working fluids in ORC applications seems to bring promising results concerning the efficiency of the application. This paper presents the results from a simulation of the ORC and the optimization potential of the process when using supercritical parameters. In order to optimize the process, various working fluids are considered and compared concerning their thermal efficiency and the usable percentage of heat. The reduction of exergy losses is discussed based on the need of surplus heat exchanger surface. (author)
Optimal and efficient decoding of concatenated quantum block codes
International Nuclear Information System (INIS)
Poulin, David
2006-01-01
We consider the problem of optimally decoding a quantum error correction code--that is, to find the optimal recovery procedure given the outcomes of partial ''check'' measurements on the system. In general, this problem is NP hard. However, we demonstrate that for concatenated block codes, the optimal decoding can be efficiently computed using a message-passing algorithm. We compare the performance of the message-passing algorithm to that of the widespread blockwise hard decoding technique. Our Monte Carlo results using the five-qubit and Steane's code on a depolarizing channel demonstrate significant advantages of the message-passing algorithms in two respects: (i) Optimal decoding increases by as much as 94% the error threshold below which the error correction procedure can be used to reliably send information over a noisy channel; and (ii) for noise levels below these thresholds, the probability of error after optimal decoding is suppressed at a significantly higher rate, leading to a substantial reduction of the error correction overhead
Energy Technology Data Exchange (ETDEWEB)
Skovsgaard Nielsen, L.; Mognesen, Martin Frank; Pade, L.L.
2007-06-15
Since 1977 green taxes have been used in the Danish power and heat sector. Green taxes principally assure an efficient, market-based reduction of pollution by reducing the energy consumption or increasing the share of renewable energy in power and heat production. This report takes its point of departure in four potential barriers which prevent a marketbased, cost-effective increase of the proportion of renewable energy in power and heat production. We primarily concentrate on three policy measures. 5. green and lessgreen taxes; 6. mandatory combined heat and power production; 7. fuel restrictions. Furthermore, we analyse a fourth characteristic in the law: 8. high transactions costs connected to the enlargement of renewable energy. The purpose of the report is to describe how the four potential barriers contradict the theoretically efficient application of green taxes in the power and heat sector. We do this: 1) by clarifying how legislation in the power and heat sector affects the extension of renewable energy; and 2) by evaluating the theoretically efficient application of green taxes in the power and heat sector in relation to legislation. (au)
Efficiency optimization of green phosphorescent organic light-emitting device
Energy Technology Data Exchange (ETDEWEB)
Park, Jung Soo; Jeon, Woo Sik; Yu, Jae Hyung [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Pode, Ramchandra, E-mail: rbpode@khu.ac.k [Department of Physics, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of); Kwon, Jang Hyuk, E-mail: jhkwon@khu.ac.k [Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701 (Korea, Republic of)
2011-03-01
Using a narrow band gap host of bis[2-(2-hydroxyphenyl)-pyridine]beryllium (Bepp{sub 2}) and green phosphorescent Ir(ppy){sub 3} [fac-tris(2-phenylpyridine) iridium III] guest concentration as low as 2%, high efficiency phosphorescent organic light-emitting diode (PHOLED) is realized. Current and power efficiencies of 62.5 cd/A (max.), 51.0 lm/W (max.), and external quantum efficiency (max.) of 19.8% are reported in this green PHOLED. A low current efficiency roll-off value of 10% over the brightness of 10,000 cd/m{sup 2} is noticed in this Bepp{sub 2} single host device. Such a high efficiency is obtained by the optimization of the doping concentration with the knowledge of the hole trapping and the emission zone situations in this host-guest system. It is suggested that the reported device performance is suitable for applications in high brightness displays and lighting.
Utilization of Flexible Airspace Structure in Flight Efficiency Optimization
Directory of Open Access Journals (Sweden)
Tomislav Mihetec
2013-04-01
Full Text Available With increasing air traffic demand in the Pan-European airspace there is a need for optimizing the use of the airspace structure (civilian and military in a manner that would satisfy the requirements of civil and military users. In the area of Europe with the highest levels of air traffic (Core area 32% of the volume of airspace above FL 195 is shared by both civil and military users. Until the introduction of the concept of flexible use of airspace, flexible airspace structures were 24 hours per day unavailable for commercial air transport. Flexible use of airspace concept provides a substantial level of dynamic airspace management by the usage of conditional routes. This paper analyses underutilization of resources, flexible airspace structures in the Pan-European airspace, especially in the south-eastern part of the traffic flows (East South Axis, reducing the efficiency of flight operations, as result of delegating the flexible structures to military users. Based on previous analysis, utilization model for flexible use of airspace is developed (scenarios with defined airspace structure. The model is based on the temporal, vertical, and modular airspace sectorisation parameters in order to optimize flight efficiency. The presented model brings significant improvement in flight efficiency (in terms of reduced flight distance for air carriers that planned to fly through the selected flexible airspace structure (LI_RST-49.
Efficiency Improvements of Antenna Optimization Using Orthogonal Fractional Experiments
Directory of Open Access Journals (Sweden)
Yen-Sheng Chen
2015-01-01
Full Text Available This paper presents an extremely efficient method for antenna design and optimization. Traditionally, antenna optimization relies on nature-inspired heuristic algorithms, which are time-consuming due to their blind-search nature. In contrast, design of experiments (DOE uses a completely different framework from heuristic algorithms, reducing the design cycle by formulating the surrogates of a design problem. However, the number of required simulations grows exponentially if a full factorial design is used. In this paper, a much more efficient technique is presented to achieve substantial time savings. By using orthogonal fractional experiments, only a small subset of the full factorial design is required, yet the resultant response surface models are still effective. The capability of orthogonal fractional experiments is demonstrated through three examples, including two tag antennas for radio-frequency identification (RFID applications and one internal antenna for long-term-evolution (LTE handheld devices. In these examples, orthogonal fractional experiments greatly improve the efficiency of DOE, thereby facilitating the antenna design with less simulation runs.
Beskrivelse og modellering af produktionssystemer, Tulip
DEFF Research Database (Denmark)
Jacobsen, Peter
1997-01-01
produktionssystemer til brug ved optimering af drift og planlægning/udvikling af nye produktionssystemer. For at opnå et nødvendigt informationsgrundlag udføres projektet i samarbejde med udvalgte virksomheder.Rapporten er udført i samarbejde med Tulip International A/S i Vejle, hvor den del, der omfatter...
DEFF Research Database (Denmark)
Toft, Helle Mary; Jessing, Carla Tønder; Nymann, Anette
Artiklerne belyser vejledning af unge og vejledning af voksne. I relation til unge drejer det sig om: 1. vejledning af unge med vanskeligheder i forhold til uddannelse - her unge med særlige vejledningsbehov, og mentorordninger for unge, og 2. vejledning af unge i ungdomsuddannelser og i erhvervs...
Undervisning af tosprogede elever
DEFF Research Database (Denmark)
Horst, Christian
2003-01-01
Artiklen fremdrager hovedresultaterne fra Virginia P. Collier's og Wayne P. Thomas's længdeundersøgelser af tosprogede elever i USA, som formentlig er de mest omfattende undersøgelser af undervisningen af tosprogede elever overhovedet. Resultaterne diskuteres i relation til udviklingen af en...
DEFF Research Database (Denmark)
Toft, Herdis
Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform.......Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform....
DEFF Research Database (Denmark)
Jensen, Søren Østergaard; Rose, Jørgen; Mørck, Ove
Nærværende rapport udgør en del af afrapporteringen af PSO ELFORSK projektet Vejledning for energirenovering af boligblokke til lavenergiklasse 2015 og 2020. Arbejdet har været finansieret af PSO midler via ELFORSK, projekt: 347-023. Formålet med projektet er at udvikle en vejledning for dybtgående...
Energirenovering af Traneparken
DEFF Research Database (Denmark)
Rose, Jørgen; Thomsen, Kirsten Engelund; Mørck, Ove
Nærværende rapport udgør en del af afrapporteringen af PSO ELFORSK projektet Vejledning for energirenovering af boligblokke til lavenergiklasse 2015 og 2020. Arbejdet har været finansieret af PSO midler via ELFORSK, projekt: 347-023. Formålet med projektet er at udvikle en vejledning for dybtgående...
DEFF Research Database (Denmark)
Petersen, Jens; Petersen, Bjørn Molt; Blicher-Mathiesen, Gitte
2006-01-01
I forbindelse med kommunalreformen ønskes en ensartet forvaltning af reglerne for vurdering af virkninger på miljøet (VVM) ved ansøgninger om udvidelse af husdyrbrug, herunder beregning af nitratudvaskningen. Rapporten foreslår et beregningskoncept, der bygger på den ansøgende bedrifts samlede kv...
More efficient optimization of long-term water supply portfolios
Kirsch, Brian R.; Characklis, Gregory W.; Dillard, Karen E. M.; Kelley, C. T.
2009-03-01
The use of temporary transfers, such as options and leases, has grown as utilities attempt to meet increases in demand while reducing dependence on the expansion of costly infrastructure capacity (e.g., reservoirs). Earlier work has been done to construct optimal portfolios comprising firm capacity and transfers, using decision rules that determine the timing and volume of transfers. However, such work has only focused on the short-term (e.g., 1-year scenarios), which limits the utility of these planning efforts. Developing multiyear portfolios can lead to the exploration of a wider range of alternatives but also increases the computational burden. This work utilizes a coupled hydrologic-economic model to simulate the long-term performance of a city's water supply portfolio. This stochastic model is linked with an optimization search algorithm that is designed to handle the high-frequency, low-amplitude noise inherent in many simulations, particularly those involving expected values. This noise is detrimental to the accuracy and precision of the optimized solution and has traditionally been controlled by investing greater computational effort in the simulation. However, the increased computational effort can be substantial. This work describes the integration of a variance reduction technique (control variate method) within the simulation/optimization as a means of more efficiently identifying minimum cost portfolios. Random variation in model output (i.e., noise) is moderated using knowledge of random variations in stochastic input variables (e.g., reservoir inflows, demand), thereby reducing the computing time by 50% or more. Using these efficiency gains, water supply portfolios are evaluated over a 10-year period in order to assess their ability to reduce costs and adapt to demand growth, while still meeting reliability goals. As a part of the evaluation, several multiyear option contract structures are explored and compared.
Decomposition based parallel processing technique for efficient collaborative optimization
International Nuclear Information System (INIS)
Park, Hyung Wook; Kim, Sung Chan; Kim, Min Soo; Choi, Dong Hoon
2000-01-01
In practical design studies, most of designers solve multidisciplinary problems with complex design structure. These multidisciplinary problems have hundreds of analysis and thousands of variables. The sequence of process to solve these problems affects the speed of total design cycle. Thus it is very important for designer to reorder original design processes to minimize total cost and time. This is accomplished by decomposing large multidisciplinary problem into several MultiDisciplinary Analysis SubSystem (MDASS) and processing it in parallel. This paper proposes new strategy for parallel decomposition of multidisciplinary problem to raise design efficiency by using genetic algorithm and shows the relationship between decomposition and Multidisciplinary Design Optimization(MDO) methodology
Optimal Learning for Efficient Experimentation in Nanotechnology and Biochemistry
2015-12-22
AFRL-AFOSR-VA-TR-2016-0018 Optimal Learning for Efficient Experimentation in Nanotechnology, Biochemistry Warren Powell TRUSTEES OF PRINCETON... Biochemistry 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1-0200 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Warren Powell 5d. PROJECT NUMBER 5e...scientists. 15. SUBJECT TERMS Biochemistry 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF 19a. NAME OF RESPONSIBLE PERSON Warren
A new efficient mixture screening design for optimization of media.
Rispoli, Fred; Shah, Vishal
2009-01-01
Screening ingredients for the optimization of media is an important first step to reduce the many potential ingredients down to the vital few components. In this study, we propose a new method of screening for mixture experiments called the centroid screening design. Comparison of the proposed design with Plackett-Burman, fractional factorial, simplex lattice design, and modified mixture design shows that the centroid screening design is the most efficient of all the designs in terms of the small number of experimental runs needed and for detecting high-order interaction among ingredients. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.
Optimization design of power efficiency of exponential impedance transformer
International Nuclear Information System (INIS)
Wang Meng; Zou Wenkang; Chen Lin; Guan Yongchao; Fu Jiabin; Xie Weiping
2011-01-01
The paper investigates the optimization design of power efficiency of exponential impedance transformer with analytic method and numerical method. In numerical calculation, a sine wave Jantage with hypothesis of rising edge equivalence is regarded as the forward-going Jantage at input of transformer, and its dominant angular frequency is determined by typical rise-time of actual Jantage waveforms. At the same time, dissipative loss in water dielectric is neglected. The numerical results of three typical modes of impedance transformation, viz. linear mode, saturation mode and steep mode,are compared. Pivotal factors which affect the power efficiency of exponential impedance transformer are discussed, and a certain extent quantitative range of intermediate variables and accordance coefficients are obtained. Finally, the paper discusses some important issues in actual design, such as insulation safety factor in structure design, effects of coupling capacitance on impedance calculation, and dissipative loss in water dielectric. (authors)
Opportunities of Optimization in Administrative Structures for Efficient Management
Directory of Open Access Journals (Sweden)
Venelin Terziev
2017-12-01
Full Text Available Current paper presents studies on the administrative structures in order to optimize the activities and the overall management through the example of the Bulgarian Commission for Protection against Discrimination. It aims at establishing duplicate functions in the organization under study. The main tasks in the analysis are related to the display of the basic findings and conclusions for the strongest sides and the fields for improvement regarding the relevance, the effectiveness and the efficiency of the administration of the Commission for Protection against Discrimination in Bulgaria. The following areas are thoroughly and critically analyzed: relevance of the functions and efficiency of the activity. As a result of the study a Strategy for Organizational Development and a Training Plan have been drafted.
Alsharoa, Ahmad M.
2014-02-01
In this letter, we consider a multiple-input multiple-output two-way cognitive radio system under a spectrum sharing scenario, where primary and secondary users operate on the same frequency band. The secondary terminals aims to exchange different messages with each other using multiple relays where each relay employs an amplify-and-forward strategy. The main objective of our work is to maximize the secondary sum rate allowed to share the spectrum with the primary users by respecting a primary user tolerated interference threshold. In this context, we derive an analytical expression of the optimal power allocated to each antenna of the terminals. We then discuss the impact of some system parameters on the performance in the numerical result section. © 2012 IEEE.
An Efficient Optimization Method for Solving Unsupervised Data Classification Problems
Directory of Open Access Journals (Sweden)
Parvaneh Shabanzadeh
2015-01-01
Full Text Available Unsupervised data classification (or clustering analysis is one of the most useful tools and a descriptive task in data mining that seeks to classify homogeneous groups of objects based on similarity and is used in many medical disciplines and various applications. In general, there is no single algorithm that is suitable for all types of data, conditions, and applications. Each algorithm has its own advantages, limitations, and deficiencies. Hence, research for novel and effective approaches for unsupervised data classification is still active. In this paper a heuristic algorithm, Biogeography-Based Optimization (BBO algorithm, was adapted for data clustering problems by modifying the main operators of BBO algorithm, which is inspired from the natural biogeography distribution of different species. Similar to other population-based algorithms, BBO algorithm starts with an initial population of candidate solutions to an optimization problem and an objective function that is calculated for them. To evaluate the performance of the proposed algorithm assessment was carried on six medical and real life datasets and was compared with eight well known and recent unsupervised data classification algorithms. Numerical results demonstrate that the proposed evolutionary optimization algorithm is efficient for unsupervised data classification.
New drilling optimization technologies make drilling more efficient
Energy Technology Data Exchange (ETDEWEB)
Chen, D.C.-K. [Halliburton Energy Services, Calgary, AB (Canada). Sperry Division
2004-07-01
Several new technologies have been adopted by the upstream petroleum industry in the past two decades in order to optimize drilling operations and improve drilling efficiency. Since financial returns from an oil and gas investment strongly depend on drilling costs, it is important to reduce non-productive time due to stuck pipes, lost circulation, hole cleaning and well bore stability problems. The most notable new technologies are the use of computer-based instrumentation and data acquisition systems, integrated rig site systems and networks, and Measurement-While-Drilling and Logging-While-Drilling (MWD/LWD) systems. Drilling optimization should include solutions for drillstring integrity, hydraulics management and wellbore integrity. New drilling optimization methods emphasize information management and real-time decision making. A recent study for drilling in shallow water in the Gulf of Mexico demonstrates that trouble time accounts for 25 per cent of rig time. This translates to about $1.5 MM U.S. per well. A reduction in trouble time could result in significant cost savings for the industry. This paper presents a case study on vibration prevention to demonstrate how the drilling industry has benefited from new technologies. 13 refs., 10 figs.
Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach
Amin, Osama
2015-04-23
In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.
Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach
Amin, Osama; Bedeer, Ebrahim; Ahmed, Mohamed; Dobre, Octavia
2015-01-01
In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.
Energy-Efficient Optimization for HARQ Schemes over Time-Correlated Fading Channels
Shi, Zheng; Ma, Shaodan; Yang, Guanghua; Alouini, Mohamed-Slim
2018-01-01
in the optimization, which further differentiates this work from prior ones. Using a unified expression of asymptotic outage probabilities, optimal transmission powers and optimal rate are derived in closed-forms to maximize the energy efficiency while satisfying
Lyden af musik - er lyden af idealisme
DEFF Research Database (Denmark)
Eigtved, Michael
2015-01-01
Programartiklen til Det Ny Teaters opsætning af Rodgers & Hammersteins The Sound of Music, undersøger musicalgenrens - og især de konkrete ophavsmænds- affinitet til fremstillingen af såvel idealistiske som ideologiske universer.......Programartiklen til Det Ny Teaters opsætning af Rodgers & Hammersteins The Sound of Music, undersøger musicalgenrens - og især de konkrete ophavsmænds- affinitet til fremstillingen af såvel idealistiske som ideologiske universer....
Styring af kommunal digitalisering
DEFF Research Database (Denmark)
Jæger, Birgit
2017-01-01
Digitalisering af både interne arbejdsprocesser og kommunikation med borgere og virksomheder har længe været en vigtig faktor i moderniseringen af den offentlige sektor. Derfor er der stort fokus på styring af digitaliseringen. Denne artikel undersøger, dels hvordan digitaliseringen i den kommunale...... sektor styres, og dels hvilke styringsparadigmer der kan identificeres. Med udgangspunkt i en konkret kommune analyseres styringen af digitalisering gennem et hierarki af offentlige digitaliseringsstrategier. Gennem udvikling af en helt ny form for organisering, en såkaldt Digitaliseringsforening...
Parallel processing based decomposition technique for efficient collaborative optimization
International Nuclear Information System (INIS)
Park, Hyung Wook; Kim, Sung Chan; Kim, Min Soo; Choi, Dong Hoon
2001-01-01
In practical design studies, most of designers solve multidisciplinary problems with large sized and complex design system. These multidisciplinary problems have hundreds of analysis and thousands of variables. The sequence of process to solve these problems affects the speed of total design cycle. Thus it is very important for designer to reorder the original design processes to minimize total computational cost. This is accomplished by decomposing large multidisciplinary problem into several MultiDisciplinary Analysis SubSystem (MDASS) and processing it in parallel. This paper proposes new strategy for parallel decomposition of multidisciplinary problem to raise design efficiency by using genetic algorithm and shows the relationship between decomposition and Multidisciplinary Design Optimization(MDO) methodology
Assisted closed-loop optimization of SSVEP-BCI efficiency
Directory of Open Access Journals (Sweden)
Jacobo eFernandez-Vargas
2013-02-01
Full Text Available We designed a novel assisted closed-loop optimization protocol to improve the efficiency of brain computer interfaces (BCI based on steady state visually evoked potentials (SSVEP. In traditional paradigms, the control over the BCI-performance completely depends on the subjects’ ability to learn from the given feedback cues. By contrast, in the proposed protocol both the subject and the machine share information and control over the BCI goal. Generally, the innovative assistance consists in the delivery of online information together with the online adaptation of BCI stimuli properties. In our case, this adaptive optimization process is realized by (i a closed-loop search for the best set of SSVEP flicker frequencies and (ii feedback of actual SSVEP magnitudes to both the subject and the machine. These closed-loop interactions between subject and machine are evaluated in real-time by continuous measurement of their efficiencies, which are used as online criteria to adapt the BCI control parameters. The proposed protocol aims to compensate for variability in possibly unknown subjects’ state and trait dimensions. In a study with N = 18 subjects, we found significant evidence that our protocol outperformed classic SSVEP-BCI control paradigms. Evidence is presented that it takes indeed into account interindividual variabilities: e.g. under the new protocol, baseline resting state EEG measures predict subjects’ BCI performances. This paper illustrates the promising potential of assisted closed-loop protocols in BCI systems. Probably their applicability might be expanded to innovative uses, e.g. as possible new diagnostic/therapeutic tools for clinical contexts and as new paradigms for basic research.
DEFF Research Database (Denmark)
Bjerg, Helle
2011-01-01
På baggrund af interview med tre elevgenerationer fremanalyseres skolens virkningsfuldhed i skoling af lyst i et historisk perspektiv. I afhandlingen udvikles to teoretisk-analytiske optikker: Skolen som ideologisk rum - med inspiration fra Slavoj Zizeks ideologikritik, samt Skolen som affektivt...
DEFF Research Database (Denmark)
Frello, Birgitta
2007-01-01
Med udgangspunkt i John Fords Western, Forfølgeren fra 1956, præsenteres en analyse af repræsentationer af race og overskridelse af raceskel, særligt i relation til konstitueringen af subjektpositioner, hvorfra spørgsmål om hvidhed og ikke-hvidhed kan afgøres.......Med udgangspunkt i John Fords Western, Forfølgeren fra 1956, præsenteres en analyse af repræsentationer af race og overskridelse af raceskel, særligt i relation til konstitueringen af subjektpositioner, hvorfra spørgsmål om hvidhed og ikke-hvidhed kan afgøres....
Udforskning af journalistiske moralnormer
DEFF Research Database (Denmark)
Mogensen, Kirsten
2010-01-01
Kirsten Mogensen beskriver professionelle journalistiske normer. Med udgangspunkt i amerikansk tv's dækning af begivenhederne 11. september kombinerer Kirsten Mogensen kvalitative interviews og tekstanalyse for på den måde at beskrive professionelle journalistiske normer. Metoden er en kombinatio...... af halvstrukturerede, udforskende interviews med både kvantitative og kvalitative analyser af den faktiske dækning, og er primært udledt af Alf Ross' essay om normer og direktiver....
DEFF Research Database (Denmark)
Tække, Jesper
2009-01-01
Bogen: 'En verden af medier – Medialiseringen af politik, sprog, religion og leg' anmeldes. Anmeldelsen kan læses på: http://ojs.statsbiblioteket.dk/index.php/mediekultur/article/view/1370/1499 Udgivelsesdato: 2009......Bogen: 'En verden af medier – Medialiseringen af politik, sprog, religion og leg' anmeldes. Anmeldelsen kan læses på: http://ojs.statsbiblioteket.dk/index.php/mediekultur/article/view/1370/1499 Udgivelsesdato: 2009...
Ensretning af historieundervisningen
DEFF Research Database (Denmark)
Rønhede, Søren
2008-01-01
"Det er ikke kun i Putins Rusland, at statsmagten vil dirigere historieundervisningen." (Politiken havde fokuseret på "ensretning af historieundervisningen" i Rusland) "Kanonen fra 2006 er undfanget af Udvalget til Styrkelse af Historie i Folkeskolen. Dette udvalg havde regeringen nedsat; men bid...... bidrager kanonen til faglig styrkelse?" spørges der. Det vises, at flere kanonpunkter ikke er fagligt funderede, men af mytologisk art....
Abdelhady, Amr, M.; Amin, Osama; Alouini, Mohamed-Slim
2016-01-01
Multi-teir hetrogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-teir architecture known as Phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that computes the SE and EE resource allocation for Phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and the ration of Phantom cellresource blocks to the total number or resource blocks. We aim to investigate the effect of some system parameters to acheive improved SE or EE performance at a non-significant loss in EE or SE performance, respectively. It was found that the system parameters can be tuned so that the EE solution does not yield a significant loss in the SE performance.
Abdelhady, Amr, M.
2016-01-06
Multi-teir hetrogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-teir architecture known as Phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that computes the SE and EE resource allocation for Phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and the ration of Phantom cellresource blocks to the total number or resource blocks. We aim to investigate the effect of some system parameters to acheive improved SE or EE performance at a non-significant loss in EE or SE performance, respectively. It was found that the system parameters can be tuned so that the EE solution does not yield a significant loss in the SE performance.
DEFF Research Database (Denmark)
Thomsen, Iben Margrete; Kristoffersen, Palle
2004-01-01
Ingen midler er p.t. godkendt og dermed lovlige til bekæmpelse af elmesyge i Danmark. Lovprisning af nye behandlinger ses f.eks. på internettet, men dokumentation mangler. Økonomien og nytten ved en kemisk bekæmpelse frem for sanering af syge træer skal afvejes nøje....
DEFF Research Database (Denmark)
Jensen, Henning Høgh
2005-01-01
Det globale marked for uddannelse er i voldsom vækst og er ved at blive et af Danmarks vigtigste vareområder. Hvorledes kan KVL agere i globaliseringen af uddannelse for at sikre en høj kvalitet af egne kandidater med gode jobmuligheder?...
Livscyklusvurdering af basiskemikalier
DEFF Research Database (Denmark)
Olsen, Stig Irving
1998-01-01
Dette resumé af metoder og væsentlige erfaringer fra erhvervsforskerprojektet Livscyklusvurdering af basiskemikalier er skrevet i erkendelse af, at hovedrapporten er for omfattende til en hurtig introduktion i problemstillingerne. Formålet med denne rapport er derfor at give et kort overblik over...
Digital formidling af kulturarv
DEFF Research Database (Denmark)
En af tidens store kulturelle dagsordner drejer sig om digital tilgængeliggørelse af kulturarv. Fortidens spor dukker op i nye former på nettet - næsten alle kulturinstitutioner arbejder med, og befolkningen har fået helt nye muligheder for at se med og deltage. Digital formidling af kulturarv...
DEFF Research Database (Denmark)
Vaaben, Nana Katrine
2001-01-01
som både Claude Levi-Strauss lægger op til i sine klassiske studier af "den vilde tanke", og som Jean Baudrillard siden har lagt op til i sine analyser af samlere som en slags ekstreme forbrugere, der er i færd med at komplettere deres identitet gennem besiddelser af genstande. Imidlertid tillægger...
Generalized field-splitting algorithms for optimal IMRT delivery efficiency
Energy Technology Data Exchange (ETDEWEB)
Kamath, Srijit [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Sahni, Sartaj [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Li, Jonathan [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Ranka, Sanjay [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States)
2007-09-21
Intensity-modulated radiation therapy (IMRT) uses radiation beams of varying intensities to deliver varying doses of radiation to different areas of the tissue. The use of IMRT has allowed the delivery of higher doses of radiation to the tumor and lower doses to the surrounding healthy tissue. It is not uncommon for head and neck tumors, for example, to have large treatment widths that are not deliverable using a single field. In such cases, the intensity matrix generated by the optimizer needs to be split into two or three matrices, each of which may be delivered using a single field. Existing field-splitting algorithms used the pre-specified arbitrary split line or region where the intensity matrix is split along a column, i.e., all rows of the matrix are split along the same column (with or without the overlapping of split fields, i.e., feathering). If three fields result, then the two splits are along the same two columns for all rows. In this paper we study the problem of splitting a large field into two or three subfields with the field width as the only constraint, allowing for an arbitrary overlap of the split fields, so that the total MU efficiency of delivering the split fields is maximized. Proof of optimality is provided for the proposed algorithm. An average decrease of 18.8% is found in the total MUs when compared to the split generated by a commercial treatment planning system and that of 10% is found in the total MUs when compared to the split generated by our previously published algorithm. For more information on this article, see medicalphysicsweb.org.
Aktiv regulering: Optimering af effektregulering
DEFF Research Database (Denmark)
Bindner, H.
1999-01-01
The current report is part of the reporting of the work executed as part of the project 'Active Control and Wind Turbine Dynamics'. The project has been supported by the Danish Energy Agency under contract EFP91, ENS j.nr. 1364/91-0003. Projectparticipants were Vestas Wind Systems A/S, DTU...... with the LQG-controllers have shown that it is very important to include robustness considerations in the design of these moreadvanced controllers. The model developed in the project can be applied in the design of controllers for variable speed wind turbines if a model of the frequency converted is included....
Drechsler, Martin
2017-02-01
Auctions have been proposed as alternatives to payments for environmental services when spatial interactions and costs are better known to landowners than to the conservation agency (asymmetric information). Recently, an auction scheme was proposed that delivers optimal conservation in the sense that social welfare is maximized. I examined the social welfare and the budget efficiency delivered by this scheme, where social welfare represents the difference between the monetized ecological benefit and the conservation cost incurred to the landowners and budget efficiency is defined as maximizing the ecological benefit for a given conservation budget. For the analysis, I considered a stylized landscape with land patches that can be used for agriculture or conservation. The ecological benefit was measured by an objective function that increases with increasing number and spatial aggregation of conserved land patches. I compared the social welfare and the budget efficiency of the auction scheme with an agglomeration payment, a policy scheme that considers spatial interactions and that was proposed recently. The auction delivered a higher level of social welfare than the agglomeration payment. However, the agglomeration payment was more efficient budgetarily than the auction, so the comparative performances of the 2 schemes depended on the chosen policy criterion-social welfare or budget efficiency. Both policy criteria are relevant for conservation. Which one should be chosen depends on the problem at hand, for example, whether social preferences should be taken into account in the decision of how much money to invest in conservation or whether the available conservation budget is strictly limited. © 2016 Society for Conservation Biology.
Energy Technology Data Exchange (ETDEWEB)
Danig, P.O. [Danmarks Tekniske Universitet (Denmark); Pedersen, J.K.; Ritchie, E. [Aalborg Universitet (Denmark); Kierkegaard, P. [CETEC E/F (Denmark)
1997-12-31
The aim of the project was to determine an energy optimum solution for household refrigerators comprising the whole system from electric power supply to the cooled food. The basic idea was to replace the normal ON/OFF control with continuous operation, but so that the engine`s speed of rotation and thereby the performance of the compressor should be controlled according to the cooling demand. A 325 l Gram refrigerator model KS350 was used in the experiments and as a reference. In conventional operation - with a 3,13 cm{sup 3} compressor using ON/OFF control - this refrigerator on average used 33 W at the ISO point (ISO 7371 standard). The most important technical results are that continuous operation of refrigerators uses substantial less energy than ON/OFF control, and that this mode of operation improves the quality of the stored food. A compressor which is small enough to even a refrigerator of the size of 325 l does not exist on the market. A new compressor type must therefore be developed which must by combined and optimized with a pinion. A new compressor type with pinion will, when developed, demand substantial production changes at costs of probably a three-figure million amount. There is no doubt that the continuous operation of refrigerators will become dominating in the future, and globally it will result in a decrease of the energy consumption of 2-3%. (LN)
ARCgame - gamification af undervisning
DEFF Research Database (Denmark)
Jensen, Camilla Gyldendahl
2014-01-01
Gamification er et begreb, der anvendes til at beskrive brugen af spilelementer i andre miljøer for at forbedre brugernes oplevelse. Følgende tekst har til formål at behandle emnet i forhold til af opnå en forståelse for de elementer der indvirker på en ”gamification af et undervisningsforløb”, her...
DEFF Research Database (Denmark)
Lorenzen, Tobias Hiort
2012-01-01
latterliggørelse indenfor en sådan teori. Sociologiens begreb om ”un-laughter” angives som en mulig udvej af dette problem. I forlængelse af dette kritiseres den moderne humor-psykologis lære om populationers humor-patologi og til slut argumenteres der for at en moderne dannelse af humor må have en moralsk...
DEFF Research Database (Denmark)
større arbejdsgrupper, og det kan være selvorganiserede store udviklingsprogrammer. Et projekt kører sjældent alene, og derfor er der ikke kun tale om projektledelse, men i lige så høj grad om ledelse af projekter. Ledelse af virksomhedens mylder af projekter er ikke let, og forfatterne gennemgår derfor...
Strategisk ledelse af evalueringskulturen
Directory of Open Access Journals (Sweden)
Gitte Orlowitz
2016-02-01
Full Text Available Hvis evaluering skal anvendes til at udvikle uddannelser, er en af ledelsen vigtigste opgaver at udvikle en strategi for udvikling af evalueringskulturen – herunder strategier for udvikling af kommunikation og evalueringskapacitet. Den strategiske ledelse kan i den sammenhæng anvendes til at håndtere de ofte modsatte krav, som eksterne og interne interessenter stiller til evaluering.
Improving efficiency (optimization) of CIGS thin film solar cell using ...
African Journals Online (AJOL)
Jsc ,Voc , FF and Quantum efficiency (QE) decrease due to absorption of electrons of electrons to the surface of back connection and their participation in recomposition. Efficiency increases from 20.3399% to 21.3721% by increasing impurity density of absorbent layer and efficiency increases to 28.9266% and the quantum ...
Domestic energy management methodology for optimizing efficiency in Smart Grids
Molderink, Albert; Bakker, Vincent; Bosman, M.G.C.; Hurink, Johann L.; Smit, Gerardus Johannes Maria
2009-01-01
Increasing energy prices and the greenhouse effect lead to more awareness of energy efficiency of electricity supply. During the last years, a lot of domestic technologies have been developed to improve this efficiency. These technologies on their own already improve the efficiency, but more can be
Ledelse af Organisationens Kreativitet
DEFF Research Database (Denmark)
Hedemann, Lars
2008-01-01
forskel, så er man som leder nødt til at arbejde mere målrettet med de medarbejdere som forventes at præstere et kreativt udbytte. Inspireret af analyseværktøjet "KEYS, Assessing the Work Environment for Creativity" udviklet af den amerikanske psykolog og ledelsesforsker ved Harvard University, Teresa...... Amabile, blev en undersøgelse derfor gennemført i udviklingsafdelingerne, Idéland og Idélab hos Bang og Olufsen, for at få et indblik i anvendeligheden af KEYS som inspirationskilde for succesfuld ledelse af organisationens kreativitet....
Auditory-like filterbank: An optimal speech processor for efficient ...
Indian Academy of Sciences (India)
The transmitter and the receiver in a communication system have to be designed optimally with respect to one another to ensure reliable and efﬁcient communication. Following this principle, we derive an optimal ﬁlterbank for processing speech signal in the listener's auditory system (receiver), so that maximum information ...
Efficient use of iterative solvers in nested topology optimization
DEFF Research Database (Denmark)
Amir, Oded; Stolpe, Mathias; Sigmund, Ole
2009-01-01
In the nested approach to structural optimization, most of the computational effort is invested in the solution of the finite element analysis equations. In this study, it is suggested to reduce this computational cost by using an approximation to the solution of the nested problem, generated...... measures. The approximation is shown to be sufficiently accurate for the practical purpose of optimization even though the nested equation system is not solved accurately. The approach is tested on several medium-scale topology optimization problems, including three dimensional minimum compliance problems...
Efficient use of iterative solvers in nested topology optimization
DEFF Research Database (Denmark)
Amir, Oded; Stolpe, Mathias; Sigmund, Ole
2010-01-01
In the nested approach to structural optimization, most of the computational effort is invested in the solution of the analysis equations. In this study, it is suggested to reduce this computational cost by using an approximation to the solution of the analysis problem, generated by a Krylov....... The approximation is computationally shown to be sufficiently accurate for the purpose of optimization though the nested equation system is not necessarily solved accurately. The approach is tested on several large-scale topology optimization problems, including minimum compliance problems and compliant mechanism...
ProxImaL: efficient image optimization using proximal algorithms
Heide, Felix; Diamond, Steven; Nieß ner, Matthias; Ragan-Kelley, Jonathan; Heidrich, Wolfgang; Wetzstein, Gordon
2016-01-01
domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety
Efficient Sensor Placement Optimization Using Gradient Descent and Probabilistic Coverage
Directory of Open Access Journals (Sweden)
Vahab Akbarzadeh
2014-08-01
Full Text Available We are proposing an adaptation of the gradient descent method to optimize the position and orientation of sensors for the sensor placement problem. The novelty of the proposed method lies in the combination of gradient descent optimization with a realistic model, which considers both the topography of the environment and a set of sensors with directional probabilistic sensing. The performance of this approach is compared with two other black box optimization methods over area coverage and processing time. Results show that our proposed method produces competitive results on smaller maps and superior results on larger maps, while requiring much less computation than the other optimization methods to which it has been compared.
Three Essays on Robust Optimization of Efficient Portfolios
Liu, Hao
2013-01-01
The mean-variance approach was first proposed by Markowitz (1952), and laid the foundation of the modern portfolio theory. Despite its theoretical appeal, the practical implementation of optimized portfolios is strongly restricted by the fact that the two inputs, the means and the covariance matrix of asset returns, are unknown and have to be estimated by available historical information. Due to the estimation risk inherited from inputs, desired properties of estimated optimal portfolios are ...
Nonlinear Multidimensional Assignment Problems Efficient Conic Optimization Methods and Applications
2015-06-24
WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Arizona State University School of Mathematical & Statistical Sciences 901 S...SUPPLEMENTARY NOTES 14. ABSTRACT The major goals of this project were completed: the exact solution of previously unsolved challenging combinatorial optimization... combinatorial optimization problem, the Directional Sensor Problem, was solved in two ways. First, heuristically in an engineering fashion and second, exactly
Global optimization of silicon nanowires for efficient parametric processes
DEFF Research Database (Denmark)
Vukovic, Dragana; Xu, Jing; Mørk, Jesper
2013-01-01
We present a global optimization of silicon nanowires for parametric single-pump mixing. For the first time, the effect of surface roughness-induced loss is included in the analysis, significantly influencing the optimum waveguide dimensions.......We present a global optimization of silicon nanowires for parametric single-pump mixing. For the first time, the effect of surface roughness-induced loss is included in the analysis, significantly influencing the optimum waveguide dimensions....
DEFF Research Database (Denmark)
Hansen, Rasmus Thorning
2008-01-01
En generel beskrivelse af de problemer specialestuderende sidder med og hvorledes coaching kan hjælpe med at (gen)skabe motivation og fokus......En generel beskrivelse af de problemer specialestuderende sidder med og hvorledes coaching kan hjælpe med at (gen)skabe motivation og fokus...
Dialektisk billede af Benjamin
DEFF Research Database (Denmark)
Bøggild, Jacob
2004-01-01
Anmeldelse af Lars Brückner: "Løse blade. Læseren, kritikeren og fortælleren Walter Benjamin"......Anmeldelse af Lars Brückner: "Løse blade. Læseren, kritikeren og fortælleren Walter Benjamin"...
Administration af informationsmodeller
DEFF Research Database (Denmark)
Hundebøl, Jesper
2013-01-01
En informationsmodel er i denne sammenhæng en digital repræsentation af et givent byggeri. Både offentlige og private bygherrer anvender informationsmodeller, når der 'bygges digitalt'. I denne artikel undersøges det, hvilke konkrete udfordringer der følger af digitaliseringen, hvor gennemgribend...
DEFF Research Database (Denmark)
Reeler, Nini Elisabeth Abildgaard; Nielsen, Ole Faurskov; Sauer, Stephan P. A.
2013-01-01
Et samspil mellem kunst og kemi. I et samarbejde mellem Statens Museum for Kunst og Kemisk Institut på KU er Ramanspek-troskopi brugt til at definere sammensætningen af blandinger af blyhvidt og calcit i maleriers hvide pigmenter....
Midtvejsevaluering af EGA handlingsplanen
DEFF Research Database (Denmark)
Møller, Niels; Hasle, Peter; Christiansen, Jørgen Møller
Center for Alternativ Samfundsanalyse (CASA) og Institut for Teknologi og Samfund ved Danmarks Tekniske Universitet har gennemført denne midtvejsevaluering af arbejdsmarkedets parters handlingsplan mod reduktion af ensidigt gentaget arbejde. Undersøgelsen viser, at der er sket en betydelig...
Anvendelse af genmodificerede planter
DEFF Research Database (Denmark)
Møller, F.
I rapporten vurderes mulighederne for at gennemføre velfærdsøkonomiske analyser af anvendelsen af genmodificerede planter. Der gøres rede for kravene til konse-kvensbeskrivelsen og for mulighederne for at prissætte såvel de markedsrelaterede som de ikke-markedsrelaterede konsekvenser. Mulighederne...
Kvalitetsvurdering af sundhedsoplysende materiale
DEFF Research Database (Denmark)
Osler, Merete; Bech, Lars; Sybille, Bojlén
1990-01-01
Lægeforeningens Hygiejnekomités arbejdsgruppe vedrørende sundhedsoplysning har udarbejdet en "huskeliste" til brug for en kvalitetsvurdering af skriftligt sundhedsoplysende materiale......Lægeforeningens Hygiejnekomités arbejdsgruppe vedrørende sundhedsoplysning har udarbejdet en "huskeliste" til brug for en kvalitetsvurdering af skriftligt sundhedsoplysende materiale...
Implementering af evidensbaseret praksis
DEFF Research Database (Denmark)
Scheel, Linda Schumann; Tewes, Marianne; Petersen, Preben Ulrich
2015-01-01
Projektet omhandler implementering af den kliniske retningslinje om identifikation, forebyggelse og behandling af delirium – i denne sammenhæng relateret til hjertepatienter. Projektet foregår på to hospitaler i Hjertecentret på Rigshospitalet, et intensivt afsnit og et sengeafsnit, i tæt...
Implementering af evidensbaseret praksis
DEFF Research Database (Denmark)
Scheel, Linda Schumann; Hansen, Ida Rode
2014-01-01
Projektet omhandler implementering af den kliniske retningslinje om identifikation, forebyggelse og behandling af delirium – i denne sammenhæng relateret til hjertepatienter. Projektet foregår på to hospitaler i Hjertecentret på Rigshospitalet, et intensivt afsnit og et sengeafsnit, i tæt...
DEFF Research Database (Denmark)
Larsen, J.; Ballisager, C.C.
Denne SBI-anvisning indeholder en gennemgang af de jordbunds- og grundvandsforhold, som er bestemmende for funderingen af en bygning. Specielt gennemgås de betingelser, der skal være opfyldt, for at man på forsvarlig måde kan fundere en mindre bygning i traditionel udformning. Publikationen...
DEFF Research Database (Denmark)
Kjær Minke, Linda; Birkmose, Sofie Meldal
2016-01-01
Som led i Kriminalforsorgens flerårsaftale 2013-2016 blev det åbne statsfængsel Søbysøgård i januar 2015 udvidet med 42 lukkede pladser i den nybyggede afdeling H. Nærværende evaluering kortlægger de erfaringer personalet og indsatte har gjort sig i løbet af det første år. Etableringen af den...... lukkede fængselsafdeling H giver en unik mulighed for at følge henholdsvis hvilke faktorer, der bidrager til udvikling af fængselskultur, og hvordan de respektive faktorer influerer på udvikling af fængselskulturen. Evalueringens metoder består af kvalitative og kvantitative metoder såsom dokumentanalyse...
Use Conditions and Efficiency Measurements of DC Power Optimizers for Photovoltaic Systems: Preprint
Energy Technology Data Exchange (ETDEWEB)
Deline, C.; MacAlpine, S.
2013-10-01
No consensus standard exists for estimating annual conversion efficiency of DC-DC converters or power optimizers in photovoltaic (PV) applications. The performance benefits of PV power electronics including per-panel DC-DC converters depend in large part on the operating conditions of the PV system, along with the performance characteristics of the power optimizer itself. This work presents acase study of three system configurations that take advantage of the capabilities of DC power optimizers. Measured conversion efficiencies of DC-DC converters are applied to these scenarios to determine the annual weighted operating efficiency. A simplified general method of reporting weighted efficiency is given, based on the California Energy Commission's CEC efficiency rating and severalinput / output voltage ratios. Efficiency measurements of commercial power optimizer products are presented using the new performance metric, along with a description of the limitations of the approach.
Efficient transportation for Vermont : optimal statewide transit networks.
2011-01-01
"Public transit systems are receiving increased attention as viable solutions to problems with : transportation system robustness, energy-efficiency and equity. The over-reliance on a single : mode, the automobile, is a threat to system robustness. I...
Novel Area Optimization in FPGA Implementation Using Efficient VHDL Code
Zulfikar, Z
2012-01-01
A new novel method for area efficiency in FPGA implementation is presented. The method is realized through flexibility and wide capability of VHDL coding. This method exposes the arithmetic operations such as addition, subtraction and others. The design technique aim to reduce occupies area for multi stages circuits by selecting suitable range of all value involved in every step of calculations. Conventional and efficient VHDL coding methods are presented and the synthesis result is compared....
Sundhedseffekter af luftforurening-beregningspriser
DEFF Research Database (Denmark)
Andersen, M. S.; Frohn, L. M.; Jensen, S. S.
Denne rapport afrapporterer det fortsatte arbejde med udvikling af miljøøkonomiske beregningspriser. På grundlag af EcoSense 4.0 fra ExternE-projektet, er der foretaget nye beregninger af eksternaliteter ved luftforurening med sundhedseffekter. Samtidig giver rapporten en vurdering af luftspredni......Denne rapport afrapporterer det fortsatte arbejde med udvikling af miljøøkonomiske beregningspriser. På grundlag af EcoSense 4.0 fra ExternE-projektet, er der foretaget nye beregninger af eksternaliteter ved luftforurening med sundhedseffekter. Samtidig giver rapporten en vurdering af...
Efficient Approximation of Optimal Control for Markov Games
DEFF Research Database (Denmark)
Fearnley, John; Rabe, Markus; Schewe, Sven
2011-01-01
We study the time-bounded reachability problem for continuous-time Markov decision processes (CTMDPs) and games (CTMGs). Existing techniques for this problem use discretisation techniques to break time into discrete intervals, and optimal control is approximated for each interval separately...
On multigrid-CG for efficient topology optimization
DEFF Research Database (Denmark)
Amir, Oded; Aage, Niels; Lazarov, Boyan Stefanov
2014-01-01
reduction is obtained by exploiting specific characteristics of a multigrid preconditioned conjugate gradients (MGCG) solver. In particular, the number of MGCG iterations is reduced by relating it to the geometric parameters of the problem. At the same time, accurate outcome of the optimization process...
Efficient amplification of photonic qubits by optimal quantum cloning
Czech Academy of Sciences Publication Activity Database
Bartkiewicz, K.; Černoch, A.; Lemr, K.; Soubusta, Jan; Stobińska, M.
2014-01-01
Roč. 89, č. 6 (2014), "062322-1"-"062322-10" ISSN 1050-2947 Institutional support: RVO:68378271 Keywords : optimal quantum cloning * cryptography * qubit * phase-independent quantum amplifier Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.808, year: 2014
Optimal Energy Efficiency Fairness of Nodes in Wireless Powered Communication Networks.
Zhang, Jing; Zhou, Qingjie; Ng, Derrick Wing Kwan; Jo, Minho
2017-09-15
In wireless powered communication networks (WPCNs), it is essential to research energy efficiency fairness in order to evaluate the balance of nodes for receiving information and harvesting energy. In this paper, we propose an efficient iterative algorithm for optimal energy efficiency proportional fairness in WPCN. The main idea is to use stochastic geometry to derive the mean proportionally fairness utility function with respect to user association probability and receive threshold. Subsequently, we prove that the relaxed proportionally fairness utility function is a concave function for user association probability and receive threshold, respectively. At the same time, a sub-optimal algorithm by exploiting alternating optimization approach is proposed. Through numerical simulations, we demonstrate that our sub-optimal algorithm can obtain a result close to optimal energy efficiency proportional fairness with significant reduction of computational complexity.
A dynamic optimization on economic energy efficiency in development: A numerical case of China
International Nuclear Information System (INIS)
Wang, Dong
2014-01-01
This paper is based on dynamic optimization methodology to investigate the economic energy efficiency issues in developing countries. The paper introduces some definitions about energy efficiency both in economics and physics, and establishes a quantitative way for measuring the economic energy efficiency. The linkage between economic energy efficiency, energy consumption and other macroeconomic variables is demonstrated primarily. Using the methodology of dynamic optimization, a maximum problem of economic energy efficiency over time, which is subjected to the extended Solow growth model and instantaneous investment rate, is modelled. In this model, the energy consumption is set as a control variable and the capital is regarded as a state variable. The analytic solutions can be derived and the diagrammatic analysis provides saddle-point equilibrium. A numerical simulation based on China is also presented; meanwhile, the optimal paths of investment and energy consumption can be drawn. The dynamic optimization encourages governments in developing countries to pursue higher economic energy efficiency by controlling the energy consumption and regulating the investment state as it can conserve energy without influencing the achievement of steady state in terms of Solow model. If that, a sustainable development will be achieved. - Highlights: • A new definition on economic energy efficiency is proposed mathematically. • A dynamic optimization modelling links economic energy efficiency with other macroeconomic variables in long run. • Economic energy efficiency is determined by capital stock level and energy consumption. • Energy saving is a key solution for improving economic energy efficiency
Performance indices and evaluation of algorithms in building energy efficient design optimization
International Nuclear Information System (INIS)
Si, Binghui; Tian, Zhichao; Jin, Xing; Zhou, Xin; Tang, Peng; Shi, Xing
2016-01-01
Building energy efficient design optimization is an emerging technique that is increasingly being used to design buildings with better overall performance and a particular emphasis on energy efficiency. To achieve building energy efficient design optimization, algorithms are vital to generate new designs and thus drive the design optimization process. Therefore, the performance of algorithms is crucial to achieving effective energy efficient design techniques. This study evaluates algorithms used for building energy efficient design optimization. A set of performance indices, namely, stability, robustness, validity, speed, coverage, and locality, is proposed to evaluate the overall performance of algorithms. A benchmark building and a design optimization problem are also developed. Hooke–Jeeves algorithm, Multi-Objective Genetic Algorithm II, and Multi-Objective Particle Swarm Optimization algorithm are evaluated by using the proposed performance indices and benchmark design problem. Results indicate that no algorithm performs best in all six areas. Therefore, when facing an energy efficient design problem, the algorithm must be carefully selected based on the nature of the problem and the performance indices that matter the most. - Highlights: • Six indices of algorithm performance in building energy optimization are developed. • For each index, its concept is defined and the calculation formulas are proposed. • A benchmark building and benchmark energy efficient design problem are proposed. • The performance of three selected algorithms are evaluated.
Boosting the IGCLC process efficiency by optimizing the desulfurization step
International Nuclear Information System (INIS)
Hamers, H.P.; Romano, M.C.; Spallina, V.; Chiesa, P.; Gallucci, F.; Sint Annaland, M. van
2015-01-01
Highlights: • Pre-CLC hot gas desulfurization and post-CLC desulfurization are assessed. • Process efficiency increases by 0.5–1% points with alternative desulfurization methods. • Alternative desulfurization methods are more beneficial for CFB configurations. - Abstract: In this paper the influence of the desulfurization method on the process efficiency of an integrated gasification chemical-looping combustion (IGCLC) systems is investigated for both packed beds and circulating fluidized bed CLC systems. Both reactor types have been integrated in an IGCLC power plant, in which three desulfurization methods have been compared: conventional cold gas desulfurization with Selexol (CGD), hot gas desulfurization with ZnO (HGD) and flue gas desulfurization after the CLC reactors (post-CLC). For CLC with packed bed reactors, the efficiency gain of the alternative desulfurization methods is about 0.5–0.7% points. This is relatively small, because of the relatively large amount of steam that has to be mixed with the fuel to avoid carbon deposition on the oxygen carrier. The HGD and post-CLC configurations do not contain a saturator and therefore more steam has to be mixed with a negative influence on the process efficiency. Carbon deposition is not an issue for circulating fluidized bed systems and therefore a somewhat higher efficiency gain of 0.8–1.0% point can be reached for this reactor system, assuming that complete fuel conversion can be reached and no sulfur species are formed on the solid, which is however thermodynamically possible for iron and manganese based oxygen carriers. From this study, it can be concluded that the adaptation of the desulfurization method results in higher process efficiencies, especially for the circulating fluidized bed system, while the number of operating units is reduced.
Efficient Guiding Towards Cost-Optimality in UPPAAL
DEFF Research Database (Denmark)
Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas S.
2001-01-01
with prices on both locations and transitions. The presented algorithm is based on a symbolic semantics of UTPA, and an efficient representation and operations based on difference bound matrices. In analogy with Dijkstra’s shortest path algorithm, we show that the search order of the algorithm can be chosen......In this paper we present an algorithm for efficiently computing the minimum cost of reaching a goal state in the model of Uniformly Priced Timed Automata (UPTA). This model can be seen as a submodel of the recently suggested model of linearly priced timed automata, which extends timed automata...
Novel Area Optimization in FPGA Implementation Using Efficient VHDL Code
Directory of Open Access Journals (Sweden)
. Zulfikar
2012-10-01
Full Text Available A new novel method for area efficiency in FPGA implementation is presented. The method is realized through flexibility and wide capability of VHDL coding. This method exposes the arithmetic operations such as addition, subtraction and others. The design technique aim to reduce occupies area for multi stages circuits by selecting suitable range of all value involved in every step of calculations. Conventional and efficient VHDL coding methods are presented and the synthesis result is compared. The VHDL code which limits range of integer values is occupies less area than the one which is not. This VHDL coding method is suitable for multi stage circuits.
Novel Area Optimization in FPGA Implementation Using Efficient VHDL Code
Directory of Open Access Journals (Sweden)
Zulfikar .
2015-05-01
Full Text Available A new novel method for area efficiency in FPGA implementation is presented. The method is realized through flexibility and wide capability of VHDL coding. This method exposes the arithmetic operations such as addition, subtraction and others. The design technique aim to reduce occupies area for multi stages circuits by selecting suitable range of all value involved in every step of calculations. Conventional and efficient VHDL coding methods are presented and the synthesis result is compared. The VHDL code which limits range of integer values is occupies less area than the one which is not. This VHDL coding method is suitable for multi stage circuits.
Optimization of high-efficiency components; Optimieren auf hohem Niveau
Energy Technology Data Exchange (ETDEWEB)
Neumann, Eva
2009-07-01
High efficiency is a common feature of modern current inverters and is not a unique selling proposition. Other factors that influence the buyer's decision are cost reduction, reliability and service, optimum grid integration, and the challenges of the competitive thin film technology. (orig.)
Optimizing the efficiency of femtosecond-laser-written holograms
DEFF Research Database (Denmark)
Wædegaard, Kristian Juncher; Hansen, Henrik Dueholm; Balling, Peter
2013-01-01
Computer-generated binary holograms are written on a polished copper surface using single 800-nm, 120-fs pulses from a 1-kHz-repetition-rate laser system. The hologram efficiency (i.e. the power in the holographic reconstructed image relative to the incoming laser power) is investigated...
Efficient Guiding Towards Cost-Optimality in Uppaal
DEFF Research Database (Denmark)
Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas S.
2001-01-01
with prices on both locations and transitions. The presented algorithm is based on a symbolic semantics of UTPA, and an efficient representation and operations based on difference bound matrices. In analogy with Dijkstra’s shortest path algorithm, we show that the search order of the algorithm can be chosen...
Online optimization of a multi-conversion-level DC home microgrid for system efficiency enhancement
DEFF Research Database (Denmark)
Boscaino, V.; Guerrero, J. M.; Ciornei, I.
2017-01-01
stages, three paralleled DC/DC converters are implemented. A Genetic Algorithm performs the on-line optimization of the DC network’s global efficiency, generating the optimal current sharing ratios of the concurrent power converters. The overall DC/DC conversion system including the optimization section......In this paper, an on-line management system for the optimal efficiency operation of a multi-bus DC home distribution system is proposed. The operation of the system is discussed with reference to a distribution system with two conversion stages and three voltage levels. In each of the conversion...
Energy Technology Data Exchange (ETDEWEB)
Fjellerup, J.
1989-08-15
Gasification of fuels derived from biomass is of interest in connection with combined cycle systems. During gasification tar compounds can be produced, and these can block further stages of the process. As gas turbines are very sensitive to tar compounds it is necessary to remove the tar completely from the gas. The most effective method appears to be catalytic cracking and it is suggested that dolomite is an effective and cheap catalysator. Based on a survey of relevant literature, the aim was to discover optimal conditions for the process of dolomite cracking. It is concluded that it is important to decarbonate the dolomite before use, that dolomite is not suitable for use in fluidized beds as it can become eroded and is subsequently very quickly blown out, and that it is important to hold the temperature at a level of ca. 800 deg. C. Conditions for fixed bed cracking both with and without steam are also desderibed. (AB) 15 refs.
DEFF Research Database (Denmark)
Strandgaard, Lone Bak
organisationen blandt ledere og medarbejdere samt eksternt, uden for organisationen, hos dens kunder. Ph.d.-afhandlingen På sporet af innovation har som formål at bidrage til forståelse af, hvordan organisationers arbejde med digital selvbetjening kan fremmes, set i et innovationsteoretisk perspektiv. Foruden en...... indføring i innovationsteorien og dens udvikling belyser afhandlingens resultater hvordan at innovationspotentialet kan styrkes gennem organisatorisk åbenhed og samarbejde i alle dele af den innovative proces. Dette gælder ved både idéudvikling, realisering og spredning af nye digitale løsninger.......Flere og flere private og offentlige servicer digitaliseres, så kunder, borgere og virksomheder, i øget grad betjener sig selv. Digital selvbetjening kan potentielt effektivisere driften og skabe bedre kundeservice. Men processen har udfordringer, da den kan kræve omfattende omstilling internt i...
DEFF Research Database (Denmark)
Dette dokument udgør slutrapporten for netværkssamarbejdet ”Testnet”, som er udført i perioden 1.4.2006 til 31.12.2008. Netværket beskæftiger sig navnlig med emner inden for test af indlejret og teknisk software, men et antal eksempler på problemstillinger og løsninger forbundet med test af...... administrativ software indgår også. Rapporten er opdelt i følgende 3 dele: Overblik. Her giver vi et resumé af netværkets formål, aktiviteter og resultater. State of the art af software test ridses op. Vi omtaler, at CISS og netværket tager nye tiltag. Netværket. Formål, deltagere og behandlede emner på ti...
DEFF Research Database (Denmark)
SUPERVISION AF PSYKOTERAPI indtager en central position i uddannelsen og udviklingen af psykoterapeuter. Trods flere lighedspunkter med psykoterapi, undervisning og konsultation er psykoterapisupervision et selvstændigt virksomhedsområde. Supervisor må foruden at være en trænet psykoterapeut kende...... supervisionens rammer og indplacering i forhold til organisation og samfund. En række kapitler drejer sig om supervisors opgaver, roller og kontrolfunktion, supervision set fra supervisandens perspektiv samt betragtninger over relationer og processer i supervision. Der drøftes fordele og ulemper ved de...... forskellige måder, hvorpå en sag kan fremlægges. Bogens første del afsluttes med refleksioner over de etiske aspekter ved psykoterapisupervision. Bogens anden del handler om de særlige forhold, der gør sig gældende ved supervision af en række specialiserede behandlingsformer eller af psykoterapi med bestemte...
FEM Optimal Design of Energy Efficient Induction Machines
Directory of Open Access Journals (Sweden)
TUDORACHE, T.
2009-06-01
Full Text Available This paper deals with a comparative numerical analysis of performances of several design solutions of induction machines with improved energy efficiency. Starting from a typical cast aluminum cage induction machine this study highlights the benefit of replacing the classical cast aluminum cage with a cast copper cage in the manufacture of future generation of high efficiency induction machines used as motors or generators. Then the advantage of replacement of standard electrical steel with higher grade steel with smaller losses is pointed out. The numerical analysis carried out in the paper is based on 2D plane-parallel finite element approach of the induction machine, the numerical results being discussed and compared with experimental measurements.
Sammenligning af kvaliteten af kommunernes sagsbehandling
DEFF Research Database (Denmark)
Rasmussen, Martin
flere forskellige spørgsmål fra praksis¬undersøgelser i samme sammenligning. Vi foreslår også, at metoder til såkaldte ’multi¬ple sammenligninger’ bruges til dele af undersøgelserne. Det er en ældre og ikke særlig kendt metode, men den er særdeles relevant både i den konkrete anvendelse og i andre...
International Nuclear Information System (INIS)
Han, In-Su; Park, Sang-Kyun; Chung, Chang-Bock
2016-01-01
Highlights: • A proton exchange membrane fuel cell system is operationally optimized. • A constrained optimization problem is formulated to maximize fuel cell efficiency. • Empirical and semi-empirical models for most system components are developed. • Sensitivity analysis is performed to elucidate the effects of major operating variables. • The optimization results are verified by comparison with actual operation data. - Abstract: This paper presents an operation optimization method and demonstrates its application to a proton exchange membrane fuel cell system. A constrained optimization problem was formulated to maximize the efficiency of a fuel cell system by incorporating practical models derived from actual operations of the system. Empirical and semi-empirical models for most of the system components were developed based on artificial neural networks and semi-empirical equations. Prior to system optimizations, the developed models were validated by comparing simulation results with the measured ones. Moreover, sensitivity analyses were performed to elucidate the effects of major operating variables on the system efficiency under practical operating constraints. Then, the optimal operating conditions were sought at various system power loads. The optimization results revealed that the efficiency gaps between the worst and best operation conditions of the system could reach 1.2–5.5% depending on the power output range. To verify the optimization results, the optimal operating conditions were applied to the fuel cell system, and the measured results were compared with the expected optimal values. The discrepancies between the measured and expected values were found to be trivial, indicating that the proposed operation optimization method was quite successful for a substantial increase in the efficiency of the fuel cell system.
Effekten af absolut kumulation
DEFF Research Database (Denmark)
Kyvsgaard, Britta; Klement, Christian
2012-01-01
Som led i finansloven for 2011 blev regeringen og forligspartierne enige om at undersøge reglerne om strafudmåling ved samtidig pådømmelse af flere kriminelle forhold og i forbindelse hermed vurdere konsekvenserne af at ændre de gældende regler i forhold til kapacitetsbehovet i Kriminalforsorgens...... samlet bødesum ved en absolut kumulation i forhold til en modereret kumulation, som nu er gældende....
DEFF Research Database (Denmark)
Östman, Lars
2011-01-01
Europa og den vestlige verden er ramt af en økonomisk krise. Det er en krise, der er anderledes, end den vi har været vant til fx fra 1980'erne.......Europa og den vestlige verden er ramt af en økonomisk krise. Det er en krise, der er anderledes, end den vi har været vant til fx fra 1980'erne....
Evaluering af kollegial supervision
DEFF Research Database (Denmark)
Petersen, Anne Line Bjerre Folsgaard; Bager, Lene Tortzen; Jørgensen, Mette Eg
2015-01-01
Videoen er en evaluering af arbejdet med en metodisk tilgang til kollegial supervision på VIA Ergoterapeutuddannelsen gennem et par år. Evalueringen sætter fokus på selve metoden, der er anvendt til kollegial supervision. Derudover er der fokus på erfaringer og udbytte af at arbejde systematisk med...... kollegial supervision blandt undervisere på VIA Ergoterapeutuddannelsen....
Biological optimization systems for enhancing photosynthetic efficiency and methods of use
Hunt, Ryan W.; Chinnasamy, Senthil; Das, Keshav C.; de Mattos, Erico Rolim
2012-11-06
Biological optimization systems for enhancing photosynthetic efficiency and methods of use. Specifically, methods for enhancing photosynthetic efficiency including applying pulsed light to a photosynthetic organism, using a chlorophyll fluorescence feedback control system to determine one or more photosynthetic efficiency parameters, and adjusting one or more of the photosynthetic efficiency parameters to drive the photosynthesis by the delivery of an amount of light to optimize light absorption of the photosynthetic organism while providing enough dark time between light pulses to prevent oversaturation of the chlorophyll reaction centers are disclosed.
Efficiency Optimization Methods in Low-Power High-Frequency Digitally Controlled SMPS
Directory of Open Access Journals (Sweden)
Aleksandar Prodić
2010-06-01
Full Text Available This paper gives a review of several power efficiency optimization techniques that are utilizing advantages of emerging digital control in high frequency switch-mode power supplies (SMPS, processing power from a fraction of watt to several hundreds of watts. Loss mechanisms in semiconductor components are briefly reviewed and the related principles of online efficiency optimization through power stage segmentation and gate voltage variation presented. Practical implementations of such methods utilizing load prediction or data extraction from a digital control loop are shown. The benefits of the presented efficiency methods are verified through experimental results, showing efficiency improvements, ranging from 2% to 30%,depending on the load conditions.
Optimal Energy-Efficient Sensing and Power Allocation in Cognitive Radio Networks
Directory of Open Access Journals (Sweden)
Xia Wu
2014-01-01
Full Text Available We consider a joint optimization of sensing parameter and power allocation for an energy-efficient cognitive radio network (CRN in which the primary user (PU is protected. The optimization problem to maximize the energy efficiency of CRN is formulated as a function of two variables, which are sensing time and transmit power, subject to the average interference power to the PU and the target detection probability. During the optimizing process, the quality of service parameter (the minimum rate acceptable to secondary users (SUs has also been taken into consideration. The optimal solutions are analyzed and an algorithm combined with fractional programming that maximizes the energy efficiency for CRN is presented. Numerical results show that the performance improvement is achieved by the joint optimization of sensing time and power allocation.
Optimizing Sampling Efficiency for Biomass Estimation Across NEON Domains
Abercrombie, H. H.; Meier, C. L.; Spencer, J. J.
2013-12-01
Over the course of 30 years, the National Ecological Observatory Network (NEON) will measure plant biomass and productivity across the U.S. to enable an understanding of terrestrial carbon cycle responses to ecosystem change drivers. Over the next several years, prior to operational sampling at a site, NEON will complete construction and characterization phases during which a limited amount of sampling will be done at each site to inform sampling designs, and guide standardization of data collection across all sites. Sampling biomass in 60+ sites distributed among 20 different eco-climatic domains poses major logistical and budgetary challenges. Traditional biomass sampling methods such as clip harvesting and direct measurements of Leaf Area Index (LAI) involve collecting and processing plant samples, and are time and labor intensive. Possible alternatives include using indirect sampling methods for estimating LAI such as digital hemispherical photography (DHP) or using a LI-COR 2200 Plant Canopy Analyzer. These LAI estimations can then be used as a proxy for biomass. The biomass estimates calculated can then inform the clip harvest sampling design during NEON operations, optimizing both sample size and number so that standardized uncertainty limits can be achieved with a minimum amount of sampling effort. In 2011, LAI and clip harvest data were collected from co-located sampling points at the Central Plains Experimental Range located in northern Colorado, a short grass steppe ecosystem that is the NEON Domain 10 core site. LAI was measured with a LI-COR 2200 Plant Canopy Analyzer. The layout of the sampling design included four, 300 meter transects, with clip harvests plots spaced every 50m, and LAI sub-transects spaced every 10m. LAI was measured at four points along 6m sub-transects running perpendicular to the 300m transect. Clip harvest plots were co-located 4m from corresponding LAI transects, and had dimensions of 0.1m by 2m. We conducted regression analyses
Efficient computation of optimal oligo-RNA binding.
Hodas, Nathan O; Aalberts, Daniel P
2004-01-01
We present an algorithm that calculates the optimal binding conformation and free energy of two RNA molecules, one or both oligomeric. This algorithm has applications to modeling DNA microarrays, RNA splice-site recognitions and other antisense problems. Although other recent algorithms perform the same calculation in time proportional to the sum of the lengths cubed, O((N1 + N2)3), our oligomer binding algorithm, called bindigo, scales as the product of the sequence lengths, O(N1*N2). The algorithm performs well in practice with the aid of a heuristic for large asymmetric loops. To demonstrate its speed and utility, we use bindigo to investigate the binding proclivities of U1 snRNA to mRNA donor splice sites.
Energy Technology Data Exchange (ETDEWEB)
Andriushchenko, A.I.
1981-01-01
The problems of increasing the efficiency and optimizing the operational conditions of a thermoelectric power plant and providing efficient operational conditions of the primary and auxillary equipment at a thermoelectric power plant are examined. Methodologies and designs for optimizing the primary parameters of the power-generating equipment based on economic factors are given. A number of recommendations for designing equipment based on the research results are given.
Directory of Open Access Journals (Sweden)
Peng Wang
2013-01-01
Full Text Available This paper presents a novel biologically inspired metaheuristic algorithm called seven-spot ladybird optimization (SLO. The SLO is inspired by recent discoveries on the foraging behavior of a seven-spot ladybird. In this paper, the performance of the SLO is compared with that of the genetic algorithm, particle swarm optimization, and artificial bee colony algorithms by using five numerical benchmark functions with multimodality. The results show that SLO has the ability to find the best solution with a comparatively small population size and is suitable for solving optimization problems with lower dimensions.
Active load sharing technique for on-line efficiency optimization in DC microgrids
DEFF Research Database (Denmark)
Sanseverino, E. Riva; Zizzo, G.; Boscaino, V.
2017-01-01
Recently, DC power distribution is gaining more and more importance over its AC counterpart achieving increased efficiency, greater flexibility, reduced volumes and capital cost. In this paper, a 24-120-325V two-level DC distribution system for home appliances, each including three parallel DC......-DC converters, is modeled. An active load sharing technique is proposed for the on-line optimization of the global efficiency of the DC distribution network. The algorithm aims at the instantaneous efficiency optimization of the whole DC network, based on the on-line load current sampling. A Look Up Table......, is created to store the real efficiencies of the converters taking into account components tolerances. A MATLAB/Simulink model of the DC distribution network has been set up and a Genetic Algorithm has been employed for the global efficiency optimization. Simulation results are shown to validate the proposed...
Fast Generation of Near-Optimal Plans for Eco-Efficient Stowage of Large Container Vessels
DEFF Research Database (Denmark)
Pacino, Dario; Delgado, Alberto; Jensen, Rune Møller
2011-01-01
Eco-efficient stowage plans that are both competitive and sustainable have become a priority for the shipping industry. Stowage planning is NP-hard and is a challenging optimization problem in practice. We propose a new 2-phase approach that generates near-optimal stowage plans and fulfills indus...
An efficient cost function for the optimization of an n-layered isotropic cloaked cylinder
International Nuclear Information System (INIS)
Paul, Jason V; Collins, Peter J; Coutu, Ronald A Jr
2013-01-01
In this paper, we present an efficient cost function for optimizing n-layered isotropic cloaked cylinders. Cost function efficiency is achieved by extracting the expression for the angle independent scatterer contribution of an associated Green's function. Therefore, since this cost function is not a function of angle, accounting for every bistatic angle is not necessary and thus more efficient than other cost functions. With this general and efficient cost function, isotropic cloaked cylinders can be optimized for many layers and material parameters. To demonstrate this, optimized cloaked cylinders made of 10, 20 and 30 equal thickness layers are presented for TE and TM incidence. Furthermore, we study the effect layer thickness has on optimized cloaks by optimizing a 10 layer cloaked cylinder over the material parameters and individual layer thicknesses. The optimized material parameters in this effort do not exhibit the dual nature that is evident in the ideal transformation optics design. This indicates that the inevitable field penetration and subsequent PEC boundary condition at the cylinder must be taken into account for an optimal cloaked cylinder design. Furthermore, a more effective cloaked cylinder can be designed by optimizing both layer thickness and material parameters than by additional layers alone. (paper)
Miao, Zhidong; Liu, Dake; Gong, Chen
2017-10-01
Inductive wireless power transfer (IWPT) is a promising power technology for implantable biomedical devices, where the power consumption is low and the efficiency is the most important consideration. In this paper, we propose an optimization method of impedance matching networks (IMN) to maximize the IWPT efficiency. The IMN at the load side is designed to achieve the optimal load, and the IMN at the source side is designed to deliver the required amount of power (no-more-no-less) from the power source to the load. The theoretical analyses and design procedure are given. An IWPT system for an implantable glaucoma therapeutic prototype is designed as an example. Compared with the efficiency of the resonant IWPT system, the efficiency of our optimized system increases with a factor of 1.73. Besides, the efficiency of our optimized IWPT system is 1.97 times higher than that of the IWPT system optimized by the traditional maximum power transfer method. All the discussions indicate that the optimization method proposed in this paper could achieve a high efficiency and long working time when the system is powered by a battery.
Salcedo-Sanz, S.; Del Ser, J.; Landa-Torres, I.; Gil-López, S.; Portilla-Figueras, J. A.
2014-01-01
This paper presents a novel bioinspired algorithm to tackle complex optimization problems: the coral reefs optimization (CRO) algorithm. The CRO algorithm artificially simulates a coral reef, where different corals (namely, solutions to the optimization problem considered) grow and reproduce in coral colonies, fighting by choking out other corals for space in the reef. This fight for space, along with the specific characteristics of the corals' reproduction, produces a robust metaheuristic algorithm shown to be powerful for solving hard optimization problems. In this research the CRO algorithm is tested in several continuous and discrete benchmark problems, as well as in practical application scenarios (i.e., optimum mobile network deployment and off-shore wind farm design). The obtained results confirm the excellent performance of the proposed algorithm and open line of research for further application of the algorithm to real-world problems. PMID:25147860
Optimization of photovoltaic energy production through an efficient switching matrix
Directory of Open Access Journals (Sweden)
Pietro Romano
2013-09-01
Full Text Available This work presents a preliminary study on the implementation of a new system for power output maximization of photovoltaic generators under non-homogeneous conditions. The study evaluates the performance of an efficient switching matrix and the relevant automatic reconfiguration control algorithms. The switching matrix is installed between the PV generator and the inverter, allowing a large number of possible module configurations. PV generator, switching matrix and the intelligent controller have been simulated in Simulink. The proposed reconfiguration system improved the energy extracted by the PV generator under non-uniform solar irradiation conditions. Short calculation times of the proposed control algorithms allow its use in real time applications even where a higher number of PV modules is required.
Optimizing link efficiency for gated DPCCH transmission on HSUPA
DEFF Research Database (Denmark)
Zarco, Carlos Ruben Delgado; Wigard, Jeroen; Kolding, T. E.
2007-01-01
consider the E-DCH performance degradation caused by gating on other radio procedures relying on the DPCCH, such as inner and outer loop power control. Our studies show that gating is beneficial for both for 2 and 10 ms transmission time intervals. The gains in terms of LE with a Vehicular A 30 kmph......To minimize the terminal's transmission power in bursty uplink traffic conditions, the evolved High-Speed Uplink Packet Access (HSUPA) concept in 3GPP WCDMA includes a feature known as Dedicated Physical Control Channel (DPCCH) gating. We present here a detailed link level study of gating from...... a link efficiency (LE) perspective; LE being expressed in bits per second per Watt. While the overall gain mechanisms of gating are well known, we show how special challenges related to discontinuous Enhanced Dedicated Channel (E-DCH) transmission can be addressed for high link and system performance. We...
Efficient distribution of toy products using ant colony optimization algorithm
Hidayat, S.; Nurpraja, C. A.
2017-12-01
CV Atham Toys (CVAT) produces wooden toys and furniture, comprises 13 small and medium industries. CVAT always attempt to deliver customer orders on time but delivery costs are high. This is because of inadequate infrastructure such that delivery routes are long, car maintenance costs are high, while fuel subsidy by the government is still temporary. This study seeks to minimize the cost of product distribution based on the shortest route using one of five Ant Colony Optimization (ACO) algorithms to solve the Vehicle Routing Problem (VRP). This study concludes that the best of the five is the Ant Colony System (ACS) algorithm. The best route in 1st week gave a total distance of 124.11 km at a cost of Rp 66,703.75. The 2nd week route gave a total distance of 132.27 km at a cost of Rp 71,095.13. The 3rd week best route gave a total distance of 122.70 km with a cost of Rp 65,951.25. While the 4th week gave a total distance of 132.27 km at a cost of Rp 74,083.63. Prior to this study there was no effort to calculate these figures.
Optimizing Eco-Efficiency Across the Procurement Portfolio.
Pelton, Rylie E O; Li, Mo; Smith, Timothy M; Lyon, Thomas P
2016-06-07
Manufacturing organizations' environmental impacts are often attributable to processes in the firm's upstream supply chain. Environmentally preferable procurement (EPP) and the establishment of environmental purchasing criteria can potentially reduce these indirect impacts. Life-cycle assessment (LCA) can help identify the purchasing criteria that are most effective in reducing environmental impacts. However, the high costs of LCA and the problems associated with the comparability of results have limited efforts to integrate procurement performance with quantitative organizational environmental performance targets. Moreover, environmental purchasing criteria, when implemented, are often established on a product-by-product basis without consideration of other products in the procurement portfolio. We develop an approach that utilizes streamlined LCA methods, together with linear programming, to determine optimal portfolios of product impact-reduction opportunities under budget constraints. The approach is illustrated through a simulated breakfast cereal manufacturing firm procuring grain, containerboard boxes, plastic packaging, electricity, and industrial cleaning solutions. Results suggest that extending EPP decisions and resources to the portfolio level, recently made feasible through the methods illustrated herein, can provide substantially greater CO2e and water-depletion reductions per dollar spend than a product-by-product approach, creating opportunities for procurement organizations to participate in firm-wide environmental impact reduction targets.
GMG: A Guaranteed, Efficient Global Optimization Algorithm for Remote Sensing.
Energy Technology Data Exchange (ETDEWEB)
D' Helon, CD
2004-08-18
The monocular passive ranging (MPR) problem in remote sensing consists of identifying the precise range of an airborne target (missile, plane, etc.) from its observed radiance. This inverse problem may be set as a global optimization problem (GOP) whereby the difference between the observed and model predicted radiances is minimized over the possible ranges and atmospheric conditions. Using additional information about the error function between the predicted and observed radiances of the target, we developed GMG, a new algorithm to find the Global Minimum with a Guarantee. The new algorithm transforms the original continuous GOP into a discrete search problem, thereby guaranteeing to find the position of the global minimum in a reasonably short time. The algorithm is first applied to the golf course problem, which serves as a litmus test for its performance in the presence of both complete and degraded additional information. GMG is further assessed on a set of standard benchmark functions and then applied to various realizations of the MPR problem.
Efficient optimal joint channel estimation and data detection for massive MIMO systems
Alshamary, Haider Ali Jasim
2016-08-15
In this paper, we propose an efficient optimal joint channel estimation and data detection algorithm for massive MIMO wireless systems. Our algorithm is optimal in terms of the generalized likelihood ratio test (GLRT). For massive MIMO systems, we show that the expected complexity of our algorithm grows polynomially in the channel coherence time. Simulation results demonstrate significant performance gains of our algorithm compared with suboptimal non-coherent detection algorithms. To the best of our knowledge, this is the first algorithm which efficiently achieves GLRT-optimal non-coherent detections for massive MIMO systems with general constellations.
DEFF Research Database (Denmark)
Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe
2015-01-01
.The energy efficiency is optimized using a proposed new automatic winding layout (AWL) technique and a comprehensive loss model.The AWL technique generates a large number of transformer winding layouts.The transformer parasitics such as dc resistance, leakage inductance and self-capacitance are calculated...... for each winding layout.An optimization technique is formulated to minimize the sum of energy losses during charge and discharge operations.The efficiency and energy loss distribution results from the optimization routine provide a deep insight into the high voltage transformer designand its impact...
Model-Based Energy Efficiency Optimization of a Low-Temperature Adsorption Dryer
Atuonwu, J.C.; Straten, G. van; Deventer, H.C. van; Boxtel, A.J.B. van
2011-01-01
Low-temperature drying is important for heat-sensitive products, but at these temperatures conventional convective dryers have low energy efficiencies. To overcome this challenge, an energy efficiency optimization procedure is applied to a zeolite adsorption dryer subject to product quality. The
Haseli, Y.
2013-01-01
The idea is to find out whether 2nd law efficiency optimization may be a suitable trade-off between maximum work output and maximum 1st law efficiency designs for a regenerative gas turbine engine operating on the basis of an open Brayton cycle. The primary emphasis is placed on analyzing the ideal
FUZZY-LOGIC-BASED CONTROLLERS FOR EFFICIENCY OPTIMIZATION OF INVERTER-FED INDUCTION MOTOR DRIVES
This paper describes a fuzzy-logic-based energy optimizing controller to improve the efficiency of induction motor/drives operating at various load (torque) and speed conditions. Improvement of induction motor efficiency is important not only from the considerations of energy sav...
Directory of Open Access Journals (Sweden)
Sie Long Kek
2015-01-01
Full Text Available A computational approach is proposed for solving the discrete time nonlinear stochastic optimal control problem. Our aim is to obtain the optimal output solution of the original optimal control problem through solving the simplified model-based optimal control problem iteratively. In our approach, the adjusted parameters are introduced into the model used such that the differences between the real system and the model used can be computed. Particularly, system optimization and parameter estimation are integrated interactively. On the other hand, the output is measured from the real plant and is fed back into the parameter estimation problem to establish a matching scheme. During the calculation procedure, the iterative solution is updated in order to approximate the true optimal solution of the original optimal control problem despite model-reality differences. For illustration, a wastewater treatment problem is studied and the results show the efficiency of the approach proposed.
A genetic algorithm applied to a PWR turbine extraction optimization to increase cycle efficiency
International Nuclear Information System (INIS)
Sacco, Wagner F.; Schirru, Roberto
2002-01-01
In nuclear power plants feedwater heaters are used to heat feedwater from its temperature leaving the condenser to final feedwater temperature using steam extracted from various stages of the turbines. The purpose of this process is to increase cycle efficiency. The determination of the optimal fraction of mass flow rate to be extracted from each stage of the turbines is a complex optimization problem. This kind of problem has been efficiently solved by means of evolutionary computation techniques, such as Genetic Algorithms (GAs). GAs, which are systems based upon principles from biological genetics, have been successfully applied to several combinatorial optimization problems in nuclear engineering, as the nuclear fuel reload optimization problem. We introduce the use of GAs in cycle efficiency optimization by finding an optimal combination of turbine extractions. In order to demonstrate the effectiveness of our approach, we have chosen a typical PWR as case study. The secondary side of the PWR was simulated using PEPSE, which is a modeling tool used to perform integrated heat balances for power plants. The results indicate that the GA is a quite promising tool for cycle efficiency optimization. (author)
DEFF Research Database (Denmark)
Li, Qingnan; Andersen, Michael A. E.; Thomsen, Ole Cornelius
2011-01-01
Nowadays, efficiency and power density are the most important issues for Power Factor Correction (PFC) converters development. However, it is a challenge to reach both high efficiency and power density in a system at the same time. In this paper, taking a Bridgeless PFC (BPFC) as an example......, a useful compromise between efficiency and power density of the Boost inductors on 3.2kW is achieved using an optimized design procedure. The experimental verifications based on the optimized inductor are carried out from 300W to 3.2kW at 220Vac input....
International Nuclear Information System (INIS)
Navardi, Mohammad Javad; Babaghorbani, Behnaz; Ketabi, Abbas
2014-01-01
Highlights: • This paper proposes a new method to optimize a Switched Reluctance Motor (SRM). • A combination of SOA and GA with Finite Element Method (FEM) analysis is employed to solve the SRM design optimization. • The results show that optimized SRM obtains higher average torque and higher efficiency. - Abstract: In this paper, performance optimization of Switched Reluctance Motor (SRM) was determined using Seeker Optimization Algorithm (SOA). The most efficient aim of the algorithm was found for maximum torque value at a minimum mass of the entire construction, following changing the geometric parameters. The optimization process was carried out using a combination of Seeker Optimization Algorithm and Finite Element Method (FEM). Fitness value was calculated by FEM analysis using COMSOL3.4, and the SOA was realized by MATLAB. The proposed method has been applied for a case study and it has been also compared with Genetic Algorithm (GA). The results show that the optimized motor using SOA had higher torque value and efficiency with lower mass and torque ripple, exhibiting the validity of this methodology for SRM design
Increase of Gas-Turbine Plant Efficiency by Optimizing Operation of Compressors
Matveev, V.; Goriachkin, E.; Volkov, A.
2018-01-01
The article presents optimization method for improving of the working process of axial compressors of gas turbine engines. Developed method allows to perform search for the best geometry of compressor blades automatically by using optimization software IOSO and CFD software NUMECA Fine/Turbo. The calculation of the compressor parameters was performed for work and stall point of its performance map on each optimization step. Study was carried out for seven-stage high-pressure compressor and three-stage low-pressure compressors. As a result of optimization, improvement of efficiency was achieved for all investigated compressors.
Game-Theoretic Rate-Distortion-Complexity Optimization of High Efficiency Video Coding
DEFF Research Database (Denmark)
Ukhanova, Ann; Milani, Simone; Forchhammer, Søren
2013-01-01
profiles in order to tailor the computational load to the different hardware and power-supply resources of devices. In this work, we focus on optimizing the quantization parameter and partition depth in HEVC via a game-theoretic approach. The proposed rate control strategy alone provides 0.2 dB improvement......This paper presents an algorithm for rate-distortioncomplexity optimization for the emerging High Efficiency Video Coding (HEVC) standard, whose high computational requirements urge the need for low-complexity optimization algorithms. Optimization approaches need to specify different complexity...
DEFF Research Database (Denmark)
Winstrup, Mie; Levin, Gregor
2011-01-01
Fragmentering af naturen er en trussel mod biodiversiteten, og etablering af økologiske forbindelser/korridorer mellem naturområderne er én måde hvorved nedgangen i biodiversitet kan stoppes. Med Næstved Kommune som case-område har jeg undersøgt, hvordan analyser i GIS kan bruges til at udvælge...... omdannet til reelle korridorer, hvor bredden afhænger af arealdækket som forbindelserne krydser. I implementerings øjemed er det anvendeligt at vide om nogle forbindelser er særlig vigtige for at skabe mere sammenhængende natur. GIS er anvendeligt hertil, idet GIS kan bruges til at bestemme den enkelte...
Videoanalyse af social interaktion
DEFF Research Database (Denmark)
Igennem de sidste 40 år er videooptagelser af praksis blevet anvendt som et redskab i forskning af social interaktion inden for f.eks. læring, design, mediering, kommunikationstræning og i sundhedsvæsenet. Videoanalyse af social interaktion giver et stærkt metodisk, teoretisk og praktisk blik ind i...... videoanalyse og viser, hvordan man som forsker og studerende kan bruge videoanalyse til at undersøge social interaktion. Bogens temaer og spørgsmål udgør således en grundsten i arbejdet med videoanalyse på professions-, universitets- og forskeruddannelser såvel som i forskning mere generelt og omfatter: - de...
DEFF Research Database (Denmark)
Bertelsen, Niels Haldor; Hansen, Ernst Jan de Place
Repræsentanter for byggesektoren har på 11 dialogmøder drøftet Erhvervs- og Byggestyrelsens "Vision 2020 - Byggeri med mening". Drøftelserne førte til formulering af en lang række initiativforslag til realisering af visionen. Den mest centrale udfordring bliver at reducere fejl og mangler i...... byggeriet. Branchen lægger også vægt på, at styringen af Vision 2020s reaisering sker i byggesektoren. Initiativforslagene er i rapporten samlet under 3 hovedområder. Det første hovedområde lægger vægt på bygningerne, brugerbehov og det globale samfund. Det andet omhandler processen og leverancesystemet...
Energy-Efficient Optimization for HARQ Schemes over Time-Correlated Fading Channels
Shi, Zheng
2018-03-19
Energy efficiency of three common hybrid automatic repeat request (HARQ) schemes including Type I HARQ, HARQ with chase combining (HARQ-CC) and HARQ with incremental redundancy (HARQ-IR), is analyzed and joint power allocation and rate selection to maximize the energy efficiency is investigated in this paper. Unlike prior literature, time-correlated fading channels is considered and two widely concerned quality of service (QoS) constraints, i.e., outage and goodput constraints, are also considered in the optimization, which further differentiates this work from prior ones. Using a unified expression of asymptotic outage probabilities, optimal transmission powers and optimal rate are derived in closed-forms to maximize the energy efficiency while satisfying the QoS constraints. These closed-form solutions then enable a thorough analysis of the maximal energy efficiencies of various HARQ schemes. It is revealed that with low outage constraint, the maximal energy efficiency achieved by Type I HARQ is
Centralisering af FM organisationer
DEFF Research Database (Denmark)
Nielsen, Susanne Balslev
2016-01-01
Centralisering af FM organisationer kan let føre til mange frustrerende arbejds- dage for medarbejdere og deres ledere. Denne artikel giver et bud på hvad kom- muner og andre kan gøre for at komme bedre igennem en omorganisering.......Centralisering af FM organisationer kan let føre til mange frustrerende arbejds- dage for medarbejdere og deres ledere. Denne artikel giver et bud på hvad kom- muner og andre kan gøre for at komme bedre igennem en omorganisering....
DEFF Research Database (Denmark)
Kuratering af Samtidskunst er den første bogudgivelse i Danmark, der fokuserer på kuratering som fag og praksis. Kuratering spiller en stadig større rolle i samtidskunsten. Bogen er en introduktion til skiftende forståelser af udstillings- og kuratorpraksisser og deres udfordringer, indkredset ge...... Kofod Olsen, Teresa Gleadowe, Helle Ryberg, Kirse Junge-Stevnsborg, Malene Natascha Ratcliffe, Pelin Uran, Jacob Fabricius, Lotte Juul Petersen, Jacob Lillemose, Solvej Helweg Ovesen, Frederikke Hansen & Tone Olaf Nielsen (kuratorisk aktion) og Temporary Services....
Two-way cooperative AF relaying in spectrum-sharing systems: Enhancing cell-edge performance
Xia, Minghua
2012-09-01
In this contribution, two-way cooperative amplify-and-forward (AF) relaying technique is integrated into spectrumsharing wireless systems to improve spectral efficiency of secondary users (SUs). In order to share the available spectrum resources originally dedicated to primary users (PUs), the transmit power of a SU is optimized with respect to the average tolerable interference power at primary receivers. By analyzing outage probability and achievable data rate at the base station and at a cell-edge SU, our results reveal that the uplink performance is dominated by the average tolerable interference power at primary receivers, while the downlink always behaves like conventional one-way AF relaying and its performance is dominated by the average signal-to-noise ratio (SNR). These important findings provide fresh perspectives for system designers to improve spectral efficiency of secondary users in next-generation broadband spectrum-sharing wireless systems. © 2012 IEEE.
Efficiency enhancement of a gas turbine cycle using an optimized tubular recuperative heat exchanger
International Nuclear Information System (INIS)
Sayyaadi, Hoseyn; Mehrabipour, Reza
2012-01-01
A simple gas turbine cycle namely as the Kraftwerk Union AG unit including a Siemens gas turbine model V93.1 with 60 MW nominal power and 26.0% thermal efficiency utilized in the Fars power plant located is considered for the efficiency enhancement. A typical tubular vertical recuperative heat exchanger is designed in order to integrate into the cycle as an air pre-heater for thermal efficiency improvement. Thermal and geometric specifications of the recuperative heat exchanger are obtained in a multi-objective optimization process. The exergetic efficiency of the gas cycle is maximized while the payback time for the capital investment of the recuperator is minimized. Combination of these objectives and decision variables with suitable engineering and physical constraints makes a set of the MINLP optimization problem. Optimization programming is performed using the NSGA-II algorithm and Pareto optimal frontiers are obtained in three cases including the minimum, average and maximum ambient air temperatures. In each case, the final optimal solution has been selected using three decision-making approaches including the fuzzy Bellman-Zadeh, LINMAP and TOPSIS methods. It has been shown that the TOPSIS and LINMAP decision-makers when applied on the Pareto frontier which is obtained at average ambient air temperature yields best results in comparison to other cases. -- Highlights: ► A simple Brayton gas cycle is considered for the efficiency improvement by integrating of a recuperator. ► Objective functions based on thermodynamic and economic analysis are obtained. ► The payback time for the capital investment is minimized and the exergetic efficiency of the system is maximized. ► Pareto optimal frontiers at various site conditions are obtained. ► A final optimal configuration is found using various decision-making approaches.
International Nuclear Information System (INIS)
Kempf, Nicholas; Zhang, Yanliang
2016-01-01
Highlights: • A three-dimensional automotive thermoelectric generator (TEG) model is developed. • Heat exchanger design and TEG configuration are optimized for maximum fuel efficiency increase. • Heat exchanger conductivity has a strong influence on maximum fuel efficiency increase. • TEG aspect ratio and fin height increase with heat exchanger thermal conductivity. • A 2.5% fuel efficiency increase is attainable with nanostructured half-Heusler modules. - Abstract: Automotive fuel efficiency can be increased by thermoelectric power generation using exhaust waste heat. A high-temperature thermoelectric generator (TEG) that converts engine exhaust waste heat into electricity is simulated based on a light-duty passenger vehicle with a 4-cylinder gasoline engine. Strategies to optimize TEG configuration and heat exchanger design for maximum fuel efficiency improvement are provided. Through comparison of stainless steel and silicon carbide heat exchangers, it is found that both the optimal TEG design and the maximum fuel efficiency increase are highly dependent on the thermal conductivity of the heat exchanger material. Significantly higher fuel efficiency increase can be obtained using silicon carbide heat exchangers at taller fins and a longer TEG along the exhaust flow direction when compared to stainless steel heat exchangers. Accounting for major parasitic losses, a maximum fuel efficiency increase of 2.5% is achievable using newly developed nanostructured bulk half-Heusler thermoelectric modules.
International Nuclear Information System (INIS)
Qianqian, Li; Xiaofeng, Jiang; Shaohong, Zhang
2010-01-01
Simulated Annealing Algorithm (SAA) for solving combinatorial optimization problems is a popular method for loading pattern optimization. The main purpose of this paper is to understand the underlying search mechanism of SAA and to study its efficiency. In this study, a general SAA that employs random pair exchange of fuel assemblies to search for the optimum fuel Loading Pattern (LP) is applied to an exhaustively searched LP optimization benchmark problem. All the possible LPs of the benchmark problem have been enumerated and evaluated via the use of the very fast and accurate Hybrid Harmonics and Linear Perturbation (HHLP) method, such that the mechanism of SA for LP optimization can be explicitly analyzed and its search efficiency evaluated. The generic core geometry itself dictates that only a small number LPs can be generated by performing random single pair exchanges and that the LPs are necessarily mostly similar to the initial LP. This phase space effect turns out to be the basic mechanism in SAA that can explain its efficiency and good local search ability. A measure of search efficiency is introduced which shows that the stochastic nature of SAA greatly influences the variability of its search efficiency. It is also found that using fuel assembly k-infinity distribution as a technique to filter the LPs can significantly enhance the SAA search efficiency. (authors)
Kaya, Mine; Hajimirza, Shima
2018-05-25
This paper uses surrogate modeling for very fast design of thin film solar cells with improved solar-to-electricity conversion efficiency. We demonstrate that the wavelength-specific optical absorptivity of a thin film multi-layered amorphous-silicon-based solar cell can be modeled accurately with Neural Networks and can be efficiently approximated as a function of cell geometry and wavelength. Consequently, the external quantum efficiency can be computed by averaging surrogate absorption and carrier recombination contributions over the entire irradiance spectrum in an efficient way. Using this framework, we optimize a multi-layer structure consisting of ITO front coating, metallic back-reflector and oxide layers for achieving maximum efficiency. Our required computation time for an entire model fitting and optimization is 5 to 20 times less than the best previous optimization results based on direct Finite Difference Time Domain (FDTD) simulations, therefore proving the value of surrogate modeling. The resulting optimization solution suggests at least 50% improvement in the external quantum efficiency compared to bare silicon, and 25% improvement compared to a random design.
Evaluering af naturfaglige kompetencer
DEFF Research Database (Denmark)
Dolin, Jens; Nielsen, Jan Alexis; Tidemand, Sofie
2017-01-01
Artiklen skitserer kort de sidste 40-50 års udvikling i naturfagene op til det nuværende fokus på undersøgelsesbaseret undervisning og udvikling af kompetencer. Den påpeger hvorledes mange traditionelle evalueringsformer, især brugt ved eksamen, ikke er i stand til at indfange de ønskede kompeten...
DEFF Research Database (Denmark)
Thomsen, Torsten Bøgh
2016-01-01
Kritisk omtale og kontekstualisering af Andrea Wulfs, "The Invention of Nature: Alexander von Humboldt’s New World". Der er en direkte forbindelse imellem oplysningstidens naturforståelse og den nuværende klimakrisevirkelighed. Alexander von Humboldt opfandt ikke bare naturen, han påpegede også det...
Digitalisering af undervisning
DEFF Research Database (Denmark)
Christiansen, René B.; Hansen, Søren; Rossen, Svend
2010-01-01
Rapporten er et bestillingsarbejde fra FU (Forskning og Udvikling) og viser en række eksempler på hvorledes undervisningsforløb kan konstrueres online. Herunder ved brug af både LMS-systemer og web 2.0-værktøjer...
DEFF Research Database (Denmark)
Søgaard, Villy
2008-01-01
Forskellige lande arbejder med meget forskellige definitioner af begrebet landdistrikt. Arbejdspapiret diskuterer først en række generelle krav til definitioner og anbefaler på den baggrund konkrete justeringer i forhold til den hidtidige danske praksis på området. Arbejdspapiret er blevet til i...
DEFF Research Database (Denmark)
Hjarvard, Stig
selvstændig institution, der forvalter samfundets fælles kommunikation, sætter de spillereglerne for andre aktører, og de er samtidig en selvfølgelig del af hverdagslivets kommunikation mellem familie, venner og kolleger. I samspillet mellem de gamle massemedier og nye interaktive medier opstår forandringer...
Anmeldelse af: Gruppepsykologi
DEFF Research Database (Denmark)
Christensen, Bodil
2009-01-01
, kreativitet og nytænkning. Det er her, videnskabens virkelige fremskridt sker.” Sådan lyder et citat af Albert Einstein, som Lars Svedberg bruger for at sætte sin faglige fremstilling om gruppepsykologi i perspektiv. Gruppeorganisationen er nemlig ofte rum for/ eller kan være rum for denne synergieffekt, der...
Benchmarking af kommunernes sagsbehandling
DEFF Research Database (Denmark)
Amilon, Anna
Fra 2007 skal Ankestyrelsen gennemføre benchmarking af kommuernes sagsbehandlingskvalitet. Formålet med benchmarkingen er at udvikle praksisundersøgelsernes design med henblik på en bedre opfølgning og at forbedre kommunernes sagsbehandling. Dette arbejdspapir diskuterer metoder for benchmarking...
DEFF Research Database (Denmark)
Skov, Christian Egander
2015-01-01
Artiklen vil kort skitsere forskellige, samtidige konservative reaktioner på teknikken, hvis destruktive potentiale var blevet åbenbart i og med Første Verdenskrig, og derefter gennem en læsning af Drachmanns politiske og skønlitterære forfatterskab identificere nøgleelementer og begreber i Drach...
Konsekvensanalyse af Kulturby 96
DEFF Research Database (Denmark)
Fridberg, Torben; Koch-Nielsen, Inger
1997-01-01
Rapporten om Kulturby 96 indeholder en beskrivelse af kulturbyårets aktiviteter og responsen herpå fra publikum, turister, presse og samarbejdspartnere i øvrigt. Der redegøres for projektets organisatoriske struktur, herunder Kulturbysekretariatets organisation og rolle. Rapporten indeholder...
DEFF Research Database (Denmark)
Sørensen, Niels Ulrik; Pless, Mette
2015-01-01
). Parallelt hermed fortælles moderne ungdomsliv (i ungdomssociologien) frem gennem ”…theoretical frameworks based on urban experiences which capture neither the lives of rural young people nor the spatial dimensions of the structures and cultures that make up contemporary youth.” (Farrugia 2013......, at yderområder er hårdt ramt af ungdomsarbejdsløshed (Bjørnsted & Andersen 2013), at områderne er præget af høj koncentration af unge med arbejderklassebaggrund (Ottosen et a 2010), mens de uddannelsesorienterede og ressourcestærke unge er tilbøjelige til at flytte væk og ind til byerne (Helve 2003). Og ser man...... stedstilknytning og stedbundne ressourcer. Teoretiske perspektiver, der peger på vigtigheden af en mere ”..spatialised youth sociology that is sensitive to macro-level processes producing different spaces, as well as the local, emplaced ways in which young people are responding to social changest hat shape...
Boligboblen pustes op af bankerne
DEFF Research Database (Denmark)
Ravn, Ib
2017-01-01
Den aktuelle boligboble blæses i vejret af bankerne, der gennem opkøb af realkreditobligationer skaber nye penge og dermed presser boligpriserne i vejret - en kreditfinansieret bolig- eller finansboble....
On Improving Efficiency of Differential Evolution for Aerodynamic Shape Optimization Applications
Madavan, Nateri K.
2004-01-01
Differential Evolution (DE) is a simple and robust evolutionary strategy that has been proven effective in determining the global optimum for several difficult optimization problems. Although DE offers several advantages over traditional optimization approaches, its use in applications such as aerodynamic shape optimization where the objective function evaluations are computationally expensive is limited by the large number of function evaluations often required. In this paper various approaches for improving the efficiency of DE are reviewed and discussed. These approaches are implemented in a DE-based aerodynamic shape optimization method that uses a Navier-Stokes solver for the objective function evaluations. Parallelization techniques on distributed computers are used to reduce turnaround times. Results are presented for the inverse design of a turbine airfoil. The efficiency improvements achieved by the different approaches are evaluated and compared.
Study on Design Optimization of Centrifugal Compressors Considering Efficiency and Weight
International Nuclear Information System (INIS)
Lee, Younghwan; Kang, Shinhyoung; Ha, Kyunggu
2015-01-01
Various centrifugal compressors are currently used extensively in industrial fields, where the design requirements are more complicated. This makes it more difficult to determine the optimal design point of a centrifugal compressor. Traditionally, the efficiency is an important factor for optimization. In this study, the weight of the compressor was also considered. The aim of this study was to present the design tendency considering the stage efficiency and weight. In addition, this study suggested possibility of a selection of compressor design objectives at an early design stage based on the optimization results. Only a vaneless diffuser was considered in this case. The Kriging method was used with sample points from 1D design program data. The optimal points were determined in a substitute design space.
Study on Design Optimization of Centrifugal Compressors Considering Efficiency and Weight
Energy Technology Data Exchange (ETDEWEB)
Lee, Younghwan; Kang, Shinhyoung [Seoul National University, Seoul (Korea, Republic of); Ha, Kyunggu [Hyundai Motor Group, Ulsan (Korea, Republic of)
2015-04-15
Various centrifugal compressors are currently used extensively in industrial fields, where the design requirements are more complicated. This makes it more difficult to determine the optimal design point of a centrifugal compressor. Traditionally, the efficiency is an important factor for optimization. In this study, the weight of the compressor was also considered. The aim of this study was to present the design tendency considering the stage efficiency and weight. In addition, this study suggested possibility of a selection of compressor design objectives at an early design stage based on the optimization results. Only a vaneless diffuser was considered in this case. The Kriging method was used with sample points from 1D design program data. The optimal points were determined in a substitute design space.
Optimization of thermal efficiency of nuclear central power like as PWR
International Nuclear Information System (INIS)
Lapa, Nelbia da Silva
2005-10-01
The main purpose of this work is the definition of operational conditions for the steam and power conservation of Pressurized Water Reactor (PWR) plant in order to increase its system thermal efficiency without changing any component, based on the optimization of operational parameters of the plant. The thermal efficiency is calculated by a thermal balance program, based on conservation equations for homogeneous modeling. The circuit coefficients are estimated by an optimization tool, allowing a more realistic thermal balance for the plans under analysis, as well as others parameters necessary to some component models. With the operational parameter optimization, it is possible to get a level of thermal efficiency that increase capital gain, due to a better relationship between the electricity production and the amount of fuel used, without any need to change components plant. (author)
Vilas, Carlos; Balsa-Canto, Eva; García, Maria-Sonia G; Banga, Julio R; Alonso, Antonio A
2012-07-02
Systems biology allows the analysis of biological systems behavior under different conditions through in silico experimentation. The possibility of perturbing biological systems in different manners calls for the design of perturbations to achieve particular goals. Examples would include, the design of a chemical stimulation to maximize the amplitude of a given cellular signal or to achieve a desired pattern in pattern formation systems, etc. Such design problems can be mathematically formulated as dynamic optimization problems which are particularly challenging when the system is described by partial differential equations.This work addresses the numerical solution of such dynamic optimization problems for spatially distributed biological systems. The usual nonlinear and large scale nature of the mathematical models related to this class of systems and the presence of constraints on the optimization problems, impose a number of difficulties, such as the presence of suboptimal solutions, which call for robust and efficient numerical techniques. Here, the use of a control vector parameterization approach combined with efficient and robust hybrid global optimization methods and a reduced order model methodology is proposed. The capabilities of this strategy are illustrated considering the solution of a two challenging problems: bacterial chemotaxis and the FitzHugh-Nagumo model. In the process of chemotaxis the objective was to efficiently compute the time-varying optimal concentration of chemotractant in one of the spatial boundaries in order to achieve predefined cell distribution profiles. Results are in agreement with those previously published in the literature. The FitzHugh-Nagumo problem is also efficiently solved and it illustrates very well how dynamic optimization may be used to force a system to evolve from an undesired to a desired pattern with a reduced number of actuators. The presented methodology can be used for the efficient dynamic optimization of
International Nuclear Information System (INIS)
Negi, Lalit Mohan; Talegaonkar, Sushama; Jaggi, Manu
2013-01-01
Development of an effective formulation involves careful optimization of a number of excipient and process variables. Sometimes the number of variables is so large that even the most efficient optimization designs require a very large number of trials which put stress on costs as well as time. A creative combination of a number of design methods leads to a smaller number of trials. This study was aimed at the development of nanostructured lipid carriers (NLCs) by using a combination of different optimization methods. A total of 11 variables were first screened using the Plackett–Burman design for their effects on formulation characteristics like size and entrapment efficiency. Four out of 11 variables were found to have insignificant effects on the formulation parameters and hence were screened out. Out of the remaining seven variables, four (concentration of tween-80, lecithin, sodium taurocholate, and total lipid) were found to have significant effects on the size of the particles while the other three (phase ratio, drug to lipid ratio, and sonication time) had a higher influence on the entrapment efficiency. The first four variables were optimized for their effect on size using the Taguchi L9 orthogonal array. The optimized values of the surfactants and lipids were kept constant for the next stage, where the sonication time, phase ratio, and drug:lipid ratio were varied using the Box–Behnken design response surface method to optimize the entrapment efficiency. Finally, by performing only 38 trials, we have optimized 11 variables for the development of NLCs with a size of 143.52 ± 1.2 nm, zeta potential of −32.6 ± 0.54 mV, and 98.22 ± 2.06% entrapment efficiency. (paper)
Effects of upper body parameters on biped walking efficiency studied by dynamic optimization
Directory of Open Access Journals (Sweden)
Kang An
2016-12-01
Full Text Available Walking efficiency is one of the considerations for designing biped robots. This article uses the dynamic optimization method to study the effects of upper body parameters, including upper body length and mass, on walking efficiency. Two minimal actuations, hip joint torque and push-off impulse, are used in the walking model, and minimal constraints are set in a free search using the dynamic optimization. Results show that there is an optimal solution of upper body length for the efficient walking within a range of walking speed and step length. For short step length, walking with a lighter upper body mass is found to be more efficient and vice versa. It is also found that for higher speed locomotion, the increase of the upper body length and mass can make the walking gait optimal rather than other kind of gaits. In addition, the typical strategy of an optimal walking gait is that just actuating the swing leg at the beginning of the step.
An Efficient Approach for Solving Mesh Optimization Problems Using Newton’s Method
Directory of Open Access Journals (Sweden)
Jibum Kim
2014-01-01
Full Text Available We present an efficient approach for solving various mesh optimization problems. Our approach is based on Newton’s method, which uses both first-order (gradient and second-order (Hessian derivatives of the nonlinear objective function. The volume and surface mesh optimization algorithms are developed such that mesh validity and surface constraints are satisfied. We also propose several Hessian modification methods when the Hessian matrix is not positive definite. We demonstrate our approach by comparing our method with nonlinear conjugate gradient and steepest descent methods in terms of both efficiency and mesh quality.
Dannelsen af den ansvarlige elev
DEFF Research Database (Denmark)
Larsen, Jesper
2010-01-01
Denne artikel handler om den del af lærergerningen, der har at gøre med udarbejdelse af elevplaner. Der tages udgangspunkt i en foucaultsk forståelse, hvor beskrivelsen af den enkelte elev udtrykker et særligt normativt ideal om, hvilke former for elevhed der er de ønskværdige i den danske...
Udlejers godkendelse af ny erhvervslejer
DEFF Research Database (Denmark)
Munk-Hansen, Carsten
2009-01-01
I artiklen er taget udgangspunkt i den »klassiske« afståelsessituation, hvor en lejer vil afhænde den i de lejede lokaler drevne virksomhed, og lejeren har afståelsesret til en af udlejer godkendt lejer, uden at kravene til den ny lejer er specificeret. På baggrund af Vestre Landsrets dom af 9/2 ...
Anmeldelse af Evolution, Literature and Film
DEFF Research Database (Denmark)
Grodal, Torben Kragh
2011-01-01
Diskussion af basisproblemer i evolutionær fiktionsteori med udgangspunkt i en anmeldelse af Evolution, Literature and Film......Diskussion af basisproblemer i evolutionær fiktionsteori med udgangspunkt i en anmeldelse af Evolution, Literature and Film...
En genlæsning af John Rawls i lyset af hans diskussion af forholdet til fremtidige generationer
DEFF Research Database (Denmark)
Lübcke, Poul
2009-01-01
På grundlag af en konsekventialistisk rekonstruktion af Rawls' politiske position gøres der rede for Rawls eksplicitte og implicitte vurdering af vores ansvar over for fremtidige generationer......På grundlag af en konsekventialistisk rekonstruktion af Rawls' politiske position gøres der rede for Rawls eksplicitte og implicitte vurdering af vores ansvar over for fremtidige generationer...
Yan, Rongge; Guo, Xiaoting; Cao, Shaoqing; Zhang, Changgeng
2018-05-01
Magnetically coupled resonance (MCR) wireless power transfer (WPT) system is a promising technology in electric energy transmission. But, if its system parameters are designed unreasonably, output power and transmission efficiency will be low. Therefore, optimized parameters design of MCR WPT has important research value. In the MCR WPT system with designated coil structure, the main parameters affecting output power and transmission efficiency are the distance between the coils, the resonance frequency and the resistance of the load. Based on the established mathematical model and the differential evolution algorithm, the change of output power and transmission efficiency with parameters can be simulated. From the simulation results, it can be seen that output power and transmission efficiency of the two-coil MCR WPT system and four-coil one with designated coil structure are improved. The simulation results confirm the validity of the optimization method for MCR WPT system with designated coil structure.
Multiobjective optimal design of runner blade using efficiency and draft tube pulsation criteria
International Nuclear Information System (INIS)
Pilev, I M; Sotnikov, A A; Rigin, V E; Semenova, A V; Cherny, S G; Chirkov, D V; Bannikov, D V; Skorospelov, V A
2012-01-01
In the present work new criteria of optimal design method for turbine runner [1] are proposed. Firstly, based on the efficient method which couples direct simulation of 3D turbulent flow and engineering semi empirical formulas, the combined method is built for hydraulic energy losses estimation in the whole turbine water passage and the efficiency criterion is formulated. Secondly, the criterion of dynamic loads minimization is developed for those caused by vortex rope precession downstream of the runner. This criterion is based on the finding that the monotonic increase of meridional velocity component in the direction to runner hub, downstream of its blades, provides for decreasing the intensity of vortex rope and thereafter, minimization of pressure pulsation amplitude. The developed algorithm was applied to optimal design of 640 MW Francis turbine runner. It can ensure high efficiency at best efficiency operating point as well as diminished pressure pulsations at full load regime.
International Nuclear Information System (INIS)
Huang, Y.-J.; Chen, K.-H.; Yang, C.-H.
2010-01-01
This paper analyzes the cost efficiency and optimal scale of Taiwan's electricity distribution industry. Due to the substantial difference in network density, firms may differ widely in production technology. We employ the stochastic metafrontier approach to estimate the cost efficiency of 24 distribution units during the period 1997-2002. Empirical results find that the average cost efficiency is overestimated using the traditional stochastic frontier model, especially for low density regions. The average cost efficiency of the high density group is significantly higher than that of the low density group as it benefits from network economies. This study also calculates both short-term and long-term optimal scales of electricity distribution firms, lending policy implications for the deregulation of the electricity distribution industry.
Optimization of Thermal Object Nonlinear Control Systems by Energy Efficiency Criterion.
Velichkin, Vladimir A.; Zavyalov, Vladimir A.
2018-03-01
This article presents the results of thermal object functioning control analysis (heat exchanger, dryer, heat treatment chamber, etc.). The results were used to determine a mathematical model of the generalized thermal control object. The appropriate optimality criterion was chosen to make the control more energy-efficient. The mathematical programming task was formulated based on the chosen optimality criterion, control object mathematical model and technological constraints. The “maximum energy efficiency” criterion helped avoid solving a system of nonlinear differential equations and solve the formulated problem of mathematical programming in an analytical way. It should be noted that in the case under review the search for optimal control and optimal trajectory reduces to solving an algebraic system of equations. In addition, it is shown that the optimal trajectory does not depend on the dynamic characteristics of the control object.
An optimized efficient dual junction InGaN/CIGS solar cell: A numerical simulation
Farhadi, Bita; Naseri, Mosayeb
2016-08-01
The photovoltaic performance of an efficient double junction InGaN/CIGS solar cell including a CdS antireflector top cover layer is studied using Silvaco ATLAS software. In this study, to gain a desired structure, the different design parameters, including the CIGS various band gaps, the doping concentration and the thickness of CdS layer are optimized. The simulation indicates that under current matching condition, an optimum efficiency of 40.42% is achieved.
Leila Torkaman; Nasser Ghassembaglou
2015-01-01
Significant quota of Municipal Electrical Energy consumption is related to Decentralized Air Conditioning which is mostly provided by evaporative coolers. So the aim is to optimize design of air conditioners to increase their efficiencies. To achieve this goal, results of practical standardized tests for 40 evaporative coolers in different types collected and simultaneously results for same coolers based on one of EER (Energy Efficiency Ratio) modeling styles are figured ...
International Nuclear Information System (INIS)
Yang Jinghe; Li Jinhai; Li Chunguang
2014-01-01
Disk-loaded waveguide traveling wave structure (TWS), which is widely used in scientific research and industry, is a vital accelerating structure in electron linear accelerator. The power efficiency is an important parameter for designing TWS, which greatly effects the expenses for the fabrication and commercial running. The key parameters related with power efficiency were studied for TWS optimization. The result was proved by experiment result, and it shows some help for accelerator engineering. (authors)
Chen, Xi; Xu, Yixuan; Liu, Anfeng
2017-04-19
High transmission reliability, energy efficiency, and long lifetime are pivotal issues for wireless body area networks (WBANs. However, these performance metrics are not independent of each other, making it hard to obtain overall improvements through optimizing one single aspect. Therefore, a Cross Layer Design Optimal (CLDO) scheme is proposed to simultaneously optimize transmission reliability, energy efficiency, and lifetime of WBANs from several layers. Firstly, due to the fact that the transmission power of nodes directly influences the reliability of links, the optimized transmission power of different nodes is deduced, which is able to maximize energy efficiency in theory under the premise that requirements on delay and jitter are fulfilled. Secondly, a relay decision algorithm is proposed to choose optimized relay nodes. Using this algorithm, nodes will choose relay nodes that ensure a balance of network energy consumption, provided that all nodes transmit with optimized transmission power and the same packet size. Thirdly, the energy consumption of nodes is still unbalanced even with optimized transmission power because of their different locations in the topology of the network. In addition, packet size also has an impact on final performance metrics. Therefore, a synthesized cross layer method for optimization is proposed. With this method, the transmission power of nodes with more residual energy will be enhanced while suitable packet size is determined for different links in the network, leading to further improvements in the WBAN system. Both our comprehensive theoretical analysis and experimental results indicate that the performance of our proposed scheme is better than reported in previous studies. Relative to the relay selection and power control game (RSPCG) scheme, the CLDO scheme can enhance transmission reliability by more than 44.6% and prolong the lifetime by as much as 33.2%.
Efficient Solutions and Cost-Optimal Analysis for Existing School Buildings
Directory of Open Access Journals (Sweden)
Paolo Maria Congedo
2016-10-01
Full Text Available The recast of the energy performance of buildings directive (EPBD describes a comparative methodological framework to promote energy efficiency and establish minimum energy performance requirements in buildings at the lowest costs. The aim of the cost-optimal methodology is to foster the achievement of nearly zero energy buildings (nZEBs, the new target for all new buildings by 2020, characterized by a high performance with a low energy requirement almost covered by renewable sources. The paper presents the results of the application of the cost-optimal methodology in two existing buildings located in the Mediterranean area. These buildings are a kindergarten and a nursery school that differ in construction period, materials and systems. Several combinations of measures have been applied to derive cost-effective efficient solutions for retrofitting. The cost-optimal level has been identified for each building and the best performing solutions have been selected considering both a financial and a macroeconomic analysis. The results illustrate the suitability of the methodology to assess cost-optimality and energy efficiency in school building refurbishment. The research shows the variants providing the most cost-effective balance between costs and energy saving. The cost-optimal solution reduces primary energy consumption by 85% and gas emissions by 82%–83% in each reference building.
International Nuclear Information System (INIS)
Cao, Dingzhou; Murat, Alper; Chinnam, Ratna Babu
2013-01-01
This paper proposes a decomposition-based approach to exactly solve the multi-objective Redundancy Allocation Problem for series-parallel systems. Redundancy allocation problem is a form of reliability optimization and has been the subject of many prior studies. The majority of these earlier studies treat redundancy allocation problem as a single objective problem maximizing the system reliability or minimizing the cost given certain constraints. The few studies that treated redundancy allocation problem as a multi-objective optimization problem relied on meta-heuristic solution approaches. However, meta-heuristic approaches have significant limitations: they do not guarantee that Pareto points are optimal and, more importantly, they may not identify all the Pareto-optimal points. In this paper, we treat redundancy allocation problem as a multi-objective problem, as is typical in practice. We decompose the original problem into several multi-objective sub-problems, efficiently and exactly solve sub-problems, and then systematically combine the solutions. The decomposition-based approach can efficiently generate all the Pareto-optimal solutions for redundancy allocation problems. Experimental results demonstrate the effectiveness and efficiency of the proposed method over meta-heuristic methods on a numerical example taken from the literature.
Energy Technology Data Exchange (ETDEWEB)
Gonzalez-Barrios, P.; Castro, M.; Pérez, O.; Vilaró, D.; Gutiérrez, L.
2017-07-01
Modeling genotype by environment interaction (GEI) is one of the most challenging aspects of plant breeding programs. The use of efficient trial networks is an effective way to evaluate GEI to define selection strategies. Furthermore, the experimental design and the number of locations, replications, and years are crucial aspects of multi-environment trial (MET) network optimization. The objective of this study was to evaluate the efficiency and performance of a MET network of sunflower (Helianthus annuus L.). Specifically, we evaluated GEI in the network by delineating mega-environments, estimating genotypic stability and identifying relevant environmental covariates. Additionally, we optimized the network by comparing experimental design efficiencies. We used the National Evaluation Network of Sunflower Cultivars of Uruguay (NENSU) in a period of 20 years. MET plot yield and flowering time information was used to evaluate GEI. Additionally, meteorological information was studied for each sunflower physiological stage. An optimal network under these conditions should have three replications, two years of evaluation and at least three locations. The use of incomplete randomized block experimental design showed reasonable performance. Three mega-environments were defined, explained mainly by different management of sowing dates. Late sowings dates had the worst performance in grain yield and oil production, associated with higher temperatures before anthesis and fewer days allocated to grain filling. The optimization of MET networks through the analysis of the experimental design efficiency, the presence of GEI, and appropriate management strategies have a positive impact on the expression of yield potential and selection of superior cultivars.
How to share our risks efficiently? Principles for optimal social insurance and pension provision
Teulings, C.N.
2010-01-01
The efficient organisation of social insurance is an important problem for modern societies. The paper discusses evidence that shocks in labour income have largely persistent effects and analyses the implications of this observation for the optimal design of institutions for wage contracting, social
Topology optimization of grating couplers for the efficient excitation of surface plasmons
DEFF Research Database (Denmark)
Andkjær, Jacob Anders; Sigmund, Ole; Nishiwaki, Shinji
2010-01-01
We propose a methodology for a systematic design of grating couplers for efficient excitation of surface plasmons at metal-dielectric interfaces. The methodology is based on a two-dimensional topology optimization formulation based on the H-polarized scalar Helmholtz equation and finite-element m...
Improving adsorption dryer energy efficiency by simultaneous optimization and heat integration
Atuonwu, J.C.; Straten, G. van; Deventer, H.C. van; Boxtel, A.J.B. van
2011-01-01
Conventionally, energy-saving techniques in drying technology are sequential in nature. First, the dryer is optimized without heat recovery and then, based on the obtained process conditions, heat recovery possibilities are explored. This work presents a methodology for energy-efficient adsorption
O. Severyn; O. Shulika
2017-01-01
The results of optimization of gravimetric coefficients for indexes included in the integral criterion of estimation of the efficiency of transport-technological charts of cargo delivery are resulted. The values of gravimetric coefficients are determined on the basis of two methods of experimental researches: questioning of respondents among the specialists of motor transport production and imitation design.
International Nuclear Information System (INIS)
Santos Coelho, Leandro dos
2009-01-01
The reliability-redundancy optimization problems can involve the selection of components with multiple choices and redundancy levels that produce maximum benefits, and are subject to the cost, weight, and volume constraints. Many classical mathematical methods have failed in handling nonconvexities and nonsmoothness in reliability-redundancy optimization problems. As an alternative to the classical optimization approaches, the meta-heuristics have been given much attention by many researchers due to their ability to find an almost global optimal solutions. One of these meta-heuristics is the particle swarm optimization (PSO). PSO is a population-based heuristic optimization technique inspired by social behavior of bird flocking and fish schooling. This paper presents an efficient PSO algorithm based on Gaussian distribution and chaotic sequence (PSO-GC) to solve the reliability-redundancy optimization problems. In this context, two examples in reliability-redundancy design problems are evaluated. Simulation results demonstrate that the proposed PSO-GC is a promising optimization technique. PSO-GC performs well for the two examples of mixed-integer programming in reliability-redundancy applications considered in this paper. The solutions obtained by the PSO-GC are better than the previously best-known solutions available in the recent literature
Energy Technology Data Exchange (ETDEWEB)
Santos Coelho, Leandro dos [Industrial and Systems Engineering Graduate Program, LAS/PPGEPS, Pontifical Catholic University of Parana, PUCPR, Imaculada Conceicao, 1155, 80215-901 Curitiba, Parana (Brazil)], E-mail: leandro.coelho@pucpr.br
2009-04-15
The reliability-redundancy optimization problems can involve the selection of components with multiple choices and redundancy levels that produce maximum benefits, and are subject to the cost, weight, and volume constraints. Many classical mathematical methods have failed in handling nonconvexities and nonsmoothness in reliability-redundancy optimization problems. As an alternative to the classical optimization approaches, the meta-heuristics have been given much attention by many researchers due to their ability to find an almost global optimal solutions. One of these meta-heuristics is the particle swarm optimization (PSO). PSO is a population-based heuristic optimization technique inspired by social behavior of bird flocking and fish schooling. This paper presents an efficient PSO algorithm based on Gaussian distribution and chaotic sequence (PSO-GC) to solve the reliability-redundancy optimization problems. In this context, two examples in reliability-redundancy design problems are evaluated. Simulation results demonstrate that the proposed PSO-GC is a promising optimization technique. PSO-GC performs well for the two examples of mixed-integer programming in reliability-redundancy applications considered in this paper. The solutions obtained by the PSO-GC are better than the previously best-known solutions available in the recent literature.
Enhanced Particle Swarm Optimization Algorithm: Efficient Training of ReaxFF Reactive Force Fields.
Furman, David; Carmeli, Benny; Zeiri, Yehuda; Kosloff, Ronnie
2018-05-04
Particle swarm optimization is a powerful metaheuristic population-based global optimization algorithm. However, when applied to non-separable objective functions its performance on multimodal landscapes is significantly degraded. Here we show that a significant improvement in the search quality and efficiency on multimodal functions can be achieved by enhancing the basic rotation-invariant particle swarm optimization algorithm with isotropic Gaussian mutation operators. The new algorithm demonstrates a superior performance across several nonlinear, multimodal benchmark functions compared to the rotation-invariant Particle Swam Optimization (PSO) algorithm and the well-established simulated annealing and sequential one-parameter parabolic interpolation methods. A search for the optimal set of parameters for the dispersion interaction model in ReaxFF-lg reactive force field is carried out with respect to accurate DFT-TS calculations. The resulting optimized force field accurately describes the equations of state of several high-energy molecular crystals where such interactions are of crucial importance. The improved algorithm also presents a better performance compared to a Genetic Algorithm optimization method in the optimization of a ReaxFF-lg correction model parameters. The computational framework is implemented in a standalone C++ code that allows a straightforward development of ReaxFF reactive force fields.
Hayashibe, Mitsuhiro; Shimoda, Shingo
2014-01-01
A human motor system can improve its behavior toward optimal movement. The skeletal system has more degrees of freedom than the task dimensions, which incurs an ill-posed problem. The multijoint system involves complex interaction torques between joints. To produce optimal motion in terms of energy consumption, the so-called cost function based optimization has been commonly used in previous works.Even if it is a fact that an optimal motor pattern is employed phenomenologically, there is no evidence that shows the existence of a physiological process that is similar to such a mathematical optimization in our central nervous system.In this study, we aim to find a more primitive computational mechanism with a modular configuration to realize adaptability and optimality without prior knowledge of system dynamics.We propose a novel motor control paradigm based on tacit learning with task space feedback. The motor command accumulation during repetitive environmental interactions, play a major role in the learning process. It is applied to a vertical cyclic reaching which involves complex interaction torques.We evaluated whether the proposed paradigm can learn how to optimize solutions with a 3-joint, planar biomechanical model. The results demonstrate that the proposed method was valid for acquiring motor synergy and resulted in energy efficient solutions for different load conditions. The case in feedback control is largely affected by the interaction torques. In contrast, the trajectory is corrected over time with tacit learning toward optimal solutions.Energy efficient solutions were obtained by the emergence of motor synergy. During learning, the contribution from feedforward controller is augmented and the one from the feedback controller is significantly minimized down to 12% for no load at hand, 16% for a 0.5 kg load condition.The proposed paradigm could provide an optimization process in redundant system with dynamic-model-free and cost-function-free approach
Hayashibe, Mitsuhiro; Shimoda, Shingo
2014-01-01
A human motor system can improve its behavior toward optimal movement. The skeletal system has more degrees of freedom than the task dimensions, which incurs an ill-posed problem. The multijoint system involves complex interaction torques between joints. To produce optimal motion in terms of energy consumption, the so-called cost function based optimization has been commonly used in previous works.Even if it is a fact that an optimal motor pattern is employed phenomenologically, there is no evidence that shows the existence of a physiological process that is similar to such a mathematical optimization in our central nervous system.In this study, we aim to find a more primitive computational mechanism with a modular configuration to realize adaptability and optimality without prior knowledge of system dynamics.We propose a novel motor control paradigm based on tacit learning with task space feedback. The motor command accumulation during repetitive environmental interactions, play a major role in the learning process. It is applied to a vertical cyclic reaching which involves complex interaction torques.We evaluated whether the proposed paradigm can learn how to optimize solutions with a 3-joint, planar biomechanical model. The results demonstrate that the proposed method was valid for acquiring motor synergy and resulted in energy efficient solutions for different load conditions. The case in feedback control is largely affected by the interaction torques. In contrast, the trajectory is corrected over time with tacit learning toward optimal solutions.Energy efficient solutions were obtained by the emergence of motor synergy. During learning, the contribution from feedforward controller is augmented and the one from the feedback controller is significantly minimized down to 12% for no load at hand, 16% for a 0.5 kg load condition.The proposed paradigm could provide an optimization process in redundant system with dynamic-model-free and cost-function-free approach.
DEFF Research Database (Denmark)
2005-01-01
Sprogpsykologi beskæftiger sig med, hvordan sprog og mennesker hænger sammen, og hvilke følger sammenhængen får for vore forståelser af verden og os selv. Denne antologi henvender sig til den sproginteresserede, der ønsker at gå et lag dybere end sprogets grammatiske sider. Sprog er ikke kun et l...
Tilbagebetaling af sociale ydelser
DEFF Research Database (Denmark)
Hielmcrone, Nina Elisabeth von
konstateres, at der foreligger fejl og forsømmelser hos både modtager og myndighed. Dermed stilles der også spørgsmålstegn ved de såkaldt "objektive" tilbagebetalingsbestemmelser som f.x. i boligstøttelovens § 47 stk. 1 og 2. Bogen behandler desuden de mange og vanskelige fortolkningsproblemer, der...... knytter sig til anvendelsen af tilbagebetalingsbestemmelserne i de sociale love....
DEFF Research Database (Denmark)
Toft, Herdis
2008-01-01
Fokus i artiklen er den måde, hvorpå børn positionerer sig på i skolerummet, og på, hvordan børn gennem brug af it opbygger og integrerer digital kompetence forstået som færdigheder, kundskaber og holdninger, der skal sætte dem i stand til at agere i det lærende samfund. Med udgangspunkt i et Bou...
An Optimization Scheme for Water Pump Control in Smart Fish Farm with Efficient Energy Consumption
Directory of Open Access Journals (Sweden)
Israr Ullah
2018-06-01
Full Text Available Healthy fish production requires intensive care and ensuring stable and healthy production environment inside the farm tank is a challenging task. An Internet of Things (IoT based automated system is highly desirable that can continuously monitor the fish tanks with optimal resources utilization. Significant cost reduction can be achieved if farm equipment and water pumps are operated only when required using optimization schemes. In this paper, we present a general system design for smart fish farms. We have developed an optimization scheme for water pump control to maintain desired water level in fish tank with efficient energy consumption through appropriate selection of pumping flow rate and tank filling level. Proposed optimization scheme attempts to achieve a trade-off between pumping duration and flow rate through selection of optimized water level. Kalman filter algorithm is applied to remove error in sensor readings. We observed through simulation results that optimization scheme achieve significant reduction in energy consumption as compared to the two alternate schemes, i.e., pumping with maximum and minimum flow rates. Proposed system can help in collecting the data about the farm for long-term analysis and better decision making in future for efficient resource utilization and overall profit maximization.
Ariyarit, Atthaphon; Sugiura, Masahiko; Tanabe, Yasutada; Kanazaki, Masahiro
2018-06-01
A multi-fidelity optimization technique by an efficient global optimization process using a hybrid surrogate model is investigated for solving real-world design problems. The model constructs the local deviation using the kriging method and the global model using a radial basis function. The expected improvement is computed to decide additional samples that can improve the model. The approach was first investigated by solving mathematical test problems. The results were compared with optimization results from an ordinary kriging method and a co-kriging method, and the proposed method produced the best solution. The proposed method was also applied to aerodynamic design optimization of helicopter blades to obtain the maximum blade efficiency. The optimal shape obtained by the proposed method achieved performance almost equivalent to that obtained using the high-fidelity, evaluation-based single-fidelity optimization. Comparing all three methods, the proposed method required the lowest total number of high-fidelity evaluation runs to obtain a converged solution.
Analysis and Optimization of Wireless Power Transfer Efficiency Considering the Tilt Angle of a Coil
Directory of Open Access Journals (Sweden)
Wei Huang
2018-01-01
Full Text Available Wireless power transfer (WPT based on magnetic resonant coupling is a promising technology in many industrial applications. Efficiency of the WPT system usually depends on the tilt angle of the transmitter or the receiver coil. This work analyzes the effect of the tilt angle on the efficiency of the WPT system with horizontal misalignment. The mutual inductance between two coils located at arbitrary positions with tilt angles is calculated using a numerical analysis based on the Neumann formula. The efficiency of the WPT system with a tilted coil is extracted using an equivalent circuit model with extracted mutual inductance. By analyzing the results, we propose an optimal tilt angle to maximize the efficiency of the WPT system. The best angle to maximize the efficiency depends on the radii of the two coils and their relative position. The calculated efficiencies versus the tilt angle for various WPT cases, which change the radius of RX (r2 = 0.075 m, 0.1 m, 0.15 m and the horizontal distance (y = 0 m, 0.05 m, 0.1 m, are compared with the experimental results. The analytically extracted efficiencies and the extracted optimal tilt angles agree well with those of the experimental results.
DEFF Research Database (Denmark)
Harste, Gorm
2009-01-01
, at innovation af innovationen forsøges gennemført på en måde, hvor tiden kræves at forholde sig til sin egen tidslighed i form af fremtid, nutid, fortid og ikke mindst i form af samtidighed. I tiden skal vi iagttage, hvordan vi iagttager tiden. Vi dobbelt-koder tiden på samme måde, som forskning forsker i...... organisationssystemerne. De to typer systemer kan noget helt bestemt med fænomenet tid. De kan synkronisere. Analyseres organisationssystemer ser vi, imidlertid at innovation kræver ro. Stærkt innovative systemer er militærsystemet og kunstsystemet, der også inddrages, og hvor vi ser paradokset mellem innovation og...... involution. Tid er med et medium og ikke et lufttomt rum. Tid er end ikke en gasart, men udgør et solidt fluidum, som samfundet bader i og flyder i, konstant i bevægelse. Reformer forudsætter former, og innovation forudsætter involution. Kun sådan muliggøres evolution....
Optimal pitching axis location of flapping wings for efficient hovering flight.
Wang, Q; Goosen, J F L; van Keulen, F
2017-09-01
Flapping wings can pitch passively about their pitching axes due to their flexibility, inertia, and aerodynamic loads. A shift in the pitching axis location can dynamically alter the aerodynamic loads, which in turn changes the passive pitching motion and the flight efficiency. Therefore, it is of great interest to investigate the optimal pitching axis for flapping wings to maximize the power efficiency during hovering flight. In this study, flapping wings are modeled as rigid plates with non-uniform mass distribution. The wing flexibility is represented by a linearly torsional spring at the wing root. A predictive quasi-steady aerodynamic model is used to evaluate the lift generated by such wings. Two extreme power consumption scenarios are modeled for hovering flight, i.e. the power consumed by a drive system with and without the capacity of kinetic energy recovery. For wings with different shapes, the optimal pitching axis location is found such that the cycle-averaged power consumption during hovering flight is minimized. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to traditional wings used by most of flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. With the optimized pitching axis, flapping wings show higher pitching amplitudes and start the pitching reversals in advance of the sweeping reversals. These phenomena lead to higher lift-to-drag ratios and, thus, explain the lower power consumption. In addition, the optimized pitching axis provides the drive system higher potential to recycle energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when
Efficient approach for reliability-based optimization based on weighted importance sampling approach
International Nuclear Information System (INIS)
Yuan, Xiukai; Lu, Zhenzhou
2014-01-01
An efficient methodology is presented to perform the reliability-based optimization (RBO). It is based on an efficient weighted approach for constructing an approximation of the failure probability as an explicit function of the design variables which is referred to as the ‘failure probability function (FPF)’. It expresses the FPF as a weighted sum of sample values obtained in the simulation-based reliability analysis. The required computational effort for decoupling in each iteration is just single reliability analysis. After the approximation of the FPF is established, the target RBO problem can be decoupled into a deterministic one. Meanwhile, the proposed weighted approach is combined with a decoupling approach and a sequential approximate optimization framework. Engineering examples are given to demonstrate the efficiency and accuracy of the presented methodology
Efficiency optimization of wireless power transmission systems for active capsule endoscopes.
Zhiwei, Jia; Guozheng, Yan; Jiangpingping; Zhiwu, Wang; Hua, Liu
2011-10-01
Multipurpose active capsule endoscopes have drawn considerable attention in recent years, but these devices continue to suffer from energy limitations. A wireless power supply system is regarded as a practical way to overcome the power shortage problem in such devices. This paper focuses on the efficiency optimization of a wireless energy supply system with size and safety constraints. A mathematical programming model in which these constraints are considered is proposed for transmission efficiency, optimal frequency and current, and overall system effectiveness. To verify the feasibility of the proposed method, we use a wireless active capsule endoscope as an illustrative example. The achieved efficiency can be regarded as an index for evaluating the system, and the proposed approach can be used to direct the design of transmitting and receiving coils.
Efficiency optimization of wireless power transmission systems for active capsule endoscopes
International Nuclear Information System (INIS)
Zhiwei, Jia; Guozheng, Yan; Jiangpingping; Zhiwu, Wang; Hua, Liu
2011-01-01
Multipurpose active capsule endoscopes have drawn considerable attention in recent years, but these devices continue to suffer from energy limitations. A wireless power supply system is regarded as a practical way to overcome the power shortage problem in such devices. This paper focuses on the efficiency optimization of a wireless energy supply system with size and safety constraints. A mathematical programming model in which these constraints are considered is proposed for transmission efficiency, optimal frequency and current, and overall system effectiveness. To verify the feasibility of the proposed method, we use a wireless active capsule endoscope as an illustrative example. The achieved efficiency can be regarded as an index for evaluating the system, and the proposed approach can be used to direct the design of transmitting and receiving coils
AsséMat, Elie; Machnes, Shai; Tannor, David; Wilhelm-Mauch, Frank
In part I, we presented the theoretic foundations of the GOAT algorithm for the optimal control of quantum systems. Here in part II, we focus on several applications of GOAT to superconducting qubits architecture. First, we consider a control-Z gate on Xmons qubits with an Erf parametrization of the optimal pulse. We show that a fast and accurate gate can be obtained with only 16 parameters, as compared to hundreds of parameters required in other algorithms. We present numerical evidences that such parametrization should allow an efficient in-situ calibration of the pulse. Next, we consider the flux-tunable coupler by IBM. We show optimization can be carried out in a more realistic model of the system than was employed in the original study, which is expected to further simplify the calibration process. Moreover, GOAT reduced the complexity of the optimal pulse to only 6 Fourier components, composed with analytic wrappers.
A least squares approach for efficient and reliable short-term versus long-term optimization
DEFF Research Database (Denmark)
Christiansen, Lasse Hjuler; Capolei, Andrea; Jørgensen, John Bagterp
2017-01-01
The uncertainties related to long-term forecasts of oil prices impose significant financial risk on ventures of oil production. To minimize risk, oil companies are inclined to maximize profit over short-term horizons ranging from months to a few years. In contrast, conventional production...... optimization maximizes long-term profits over horizons that span more than a decade. To address this challenge, the oil literature has introduced short-term versus long-term optimization. Ideally, this problem is solved by a posteriori multi-objective optimization methods that generate an approximation...... the balance between the objectives, leaving an unfulfilled potential to increase profits. To promote efficient and reliable short-term versus long-term optimization, this paper introduces a natural way to characterize desirable Pareto points and proposes a novel least squares (LS) method. Unlike hierarchical...
An Optimal Design Method of Centrifugal Compressors in Consideration of the Efficiency and the Noise
International Nuclear Information System (INIS)
Ha, K. G.; Sung, S. M.; Kang, S. H.
2007-01-01
A centrifugal compressor is a principal part of the fuelcell vehicles, aircraft and home appliances. Therefore not only efficiency but also compact size and a low operation RPM for noise reducing turn into important criteria of centrifugal compressors design. But those criteria are in conflict each other often. In the case of a RPM in particular, it is profitable to lower the RPM for a noise reduction and an endurance. But for a compact size and a light weight, the reverse has a beneficial effect undoubtedly. So it is necessary to introduce a new optimization concept in the centrifugal compressor design. An one dimensional optimal design method for the centrifugal compressor considering a impeller, a vaneless diffuser and a volute at a time is described. The new optimization process and underlying design methods of centrifugal compressors and some optimal design results are included in the paper
Minimax robust power split in AF relays based on uncertain long-term CSI
Nisar, Muhammad Danish
2011-09-01
An optimal power control among source and relay nodes in presence of channel state information (CSI) is vital for an efficient amplify and forward (AF) based cooperative communication system. In this work, we study the optimal power split (power control) between the source and relay node in presence of an uncertainty in the CSI. The prime contribution is to solve the problem based on an uncertain long-term knowledge of both the first and second hop CSI (requiring less frequent updates), and under an aggregate network-level power constraint. We employ the minimax optimization methodology to arrive at the minimax robust optimal power split, that offers the best possible guarantee on the end-to-end signal to noise ratio (SNR). The derived closed form analytical expressions admit simple intuitive interpretations and are easy to implement in real-world AF relaying systems. Numerical results confirm the advantages of incorporating the presence of uncertainty into the optimization problem, and demonstrate the usefulness of the proposed minimax robust optimal power split. © 2011 IEEE.
Chang, Yuchao; Tang, Hongying; Cheng, Yongbo; Zhao, Qin; Yuan, Baoqing Li andXiaobing
2017-07-19
Routing protocols based on topology control are significantly important for improving network longevity in wireless sensor networks (WSNs). Traditionally, some WSN routing protocols distribute uneven network traffic load to sensor nodes, which is not optimal for improving network longevity. Differently to conventional WSN routing protocols, we propose a dynamic hierarchical protocol based on combinatorial optimization (DHCO) to balance energy consumption of sensor nodes and to improve WSN longevity. For each sensor node, the DHCO algorithm obtains the optimal route by establishing a feasible routing set instead of selecting the cluster head or the next hop node. The process of obtaining the optimal route can be formulated as a combinatorial optimization problem. Specifically, the DHCO algorithm is carried out by the following procedures. It employs a hierarchy-based connection mechanism to construct a hierarchical network structure in which each sensor node is assigned to a special hierarchical subset; it utilizes the combinatorial optimization theory to establish the feasible routing set for each sensor node, and takes advantage of the maximum-minimum criterion to obtain their optimal routes to the base station. Various results of simulation experiments show effectiveness and superiority of the DHCO algorithm in comparison with state-of-the-art WSN routing algorithms, including low-energy adaptive clustering hierarchy (LEACH), hybrid energy-efficient distributed clustering (HEED), genetic protocol-based self-organizing network clustering (GASONeC), and double cost function-based routing (DCFR) algorithms.
Energy Technology Data Exchange (ETDEWEB)
Iov, F.; Timbus, A.V.; Hansen, A.D.; Soerensen, P.; Blaabjerg, F.
2004-03-01
This report is a general overview of the results obtained in the project 'Electrical Design and Control. Simulation Platform to Model, Optimize and Design Wind Turbines'. The motivation for this research project is the ever-increasing wind energy penetration into the power network. Therefore, the project has the main goal to create a model database in different simulation tools for a system optimization of the wind turbine systems. Using this model database a simultaneous optimization of the aerodynamic, mechanical, electrical and control systems over the whole range of wind speeds and grid characteristics can be achieved. The report is structured in six chapters. First, the background of this project and the main goals as well as the structure of the simulation platform is given. The main topologies for wind turbines, which have been taken into account during the project, are briefly presented. Then, the considered simulation tools narrely: HAWC, DIgSILENT, Saber and Matlab/Simulink have been used in this simulation platform are described. The focus here is on the modelling and simulation time scale aspects. The abilities of these tools are complementary and they can together cover all the modelling aspects of the wind turbines e.g. mechanical loads, power quality, switching, control and grid faults. However, other simulation packages e.g PSCAD/EMTDC can easily be added in the simulation platform. New models and new Control algorithms for wind turbine systems have been developed and tested in these tools. All these models are collected in dedicated libraries in Matlab/Simulink as well as in Saber. Some simulation results from the considered tools are presented for MW wind turbines. These simulation results focuses on fixed-speed and variable speed/pitch wind turbines. A good agreement with the real behaviour of these systems is obtained for each simulation tool. These models can easily be extended to model different kinds of wind turbines or large wind
Introduktion af polte i PRRSV-besætninger
DEFF Research Database (Denmark)
Hoelstad, Bonnie Edahl; Sonne Kristensen, Charlotte; Qvist Pawlowski, Mia
karantæne. En optimal karantæne blev defineret som en stald, der ikke delte luftrum med øvrige staldafsnit, havde separat indgang og kørte alt ind/alt ud. På trods af at poltene ikke var viræmiske ved løbning, fører studiet ikke til ændringer i anbefalingerne vedrørende introduktion af polte i PRRS...
Chen, Zhongxian; Yu, Haitao; Wen, Cheng
2014-01-01
The goal of direct drive ocean wave energy extraction system is to convert ocean wave energy into electricity. The problem explored in this paper is the design and optimal control for the direct drive ocean wave energy extraction system. An optimal control method based on internal model proportion integration differentiation (IM-PID) is proposed in this paper though most of ocean wave energy extraction systems are optimized by the structure, weight, and material. With this control method, the heavy speed of outer heavy buoy of the energy extraction system is in resonance with incident wave, and the system efficiency is largely improved. Validity of the proposed optimal control method is verified in both regular and irregular ocean waves, and it is shown that IM-PID control method is optimal in that it maximizes the energy conversion efficiency. In addition, the anti-interference ability of IM-PID control method has been assessed, and the results show that the IM-PID control method has good robustness, high precision, and strong anti-interference ability. PMID:25152913
Chen, Zhongxian; Yu, Haitao; Wen, Cheng
2014-01-01
The goal of direct drive ocean wave energy extraction system is to convert ocean wave energy into electricity. The problem explored in this paper is the design and optimal control for the direct drive ocean wave energy extraction system. An optimal control method based on internal model proportion integration differentiation (IM-PID) is proposed in this paper though most of ocean wave energy extraction systems are optimized by the structure, weight, and material. With this control method, the heavy speed of outer heavy buoy of the energy extraction system is in resonance with incident wave, and the system efficiency is largely improved. Validity of the proposed optimal control method is verified in both regular and irregular ocean waves, and it is shown that IM-PID control method is optimal in that it maximizes the energy conversion efficiency. In addition, the anti-interference ability of IM-PID control method has been assessed, and the results show that the IM-PID control method has good robustness, high precision, and strong anti-interference ability.
Optimally efficient swimming in hyper-redundant mechanisms: control, design, and energy recovery
International Nuclear Information System (INIS)
Wiens, A J; Nahon, M
2012-01-01
Hyper-redundant mechanisms (HRMs), also known as snake-like robots, are highly adaptable during locomotion on land. Researchers are currently working to extend their capabilities to aquatic environments through biomimetic undulatory propulsion. In addition to increasing the versatility of the system, truly biomimetic swimming could also provide excellent locomotion efficiency. Unfortunately, the complexity of the system precludes the development of a functional solution to achieve this. To explore this problem, a rapid optimization process is used to generate efficient HRM swimming gaits. The low computational cost of the approach allows for multiple optimizations over a broad range of system conditions. By observing how these conditions affect optimal kinematics, a number of new insights are developed regarding undulatory swimming in robotic systems. Two key conditions are varied within the study, swimming speed and energy recovery. It is found that the swimmer mimics the speed control behaviour of natural fish and that energy recovery drastically increases the system's efficiency. Remarkably, this efficiency increase is accompanied by a distinct change in swimming kinematics. With energy recovery, the swimmer converges to a clearly anguilliform gait, without, it tends towards the carangiform mode. (paper)
Relevansen af Aristoteles' etik for konceptionen af eksistentiel terapi
DEFF Research Database (Denmark)
Dræby, Anders
Siden sin undfangelse i begyndelsen af det 20. århundrede har den eksistentielle terapi repræsenteret et filosofisk funderet alternativ til de former for terapeutisk praksis, der er funderet i den funktionalistiske medicinske metafysik. Anvendelse af elementer fra Aristoteles' etik muliggør en...... fremhævelse af den eksistentielle terapi som en praktisk eksistensfænomenologisk livskunst, hvis anliggende er en frembringelse af det enkelte menneskes muligheder fra det skjulte og ind i det uskjulte, så mennesket viser sig som det er ved sig selv...
DEFF Research Database (Denmark)
Gaspar, Jozsef; Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp
2017-01-01
-linear model based control to achieve optimal techno-economic performance. Accordingly, this work presents a computationally efficient and novel approach for solving a tray-by-tray equilibrium model and its implementation for open-loop optimal-control of a cryogenic distillation column. Here, the optimisation...... objective is to reduce the cost of compression in a volatile electricity market while meeting the production requirements, i.e. product flow rate and purity. This model is implemented in Matlab and uses the ThermoLib rigorous thermodynamic library. The present work represents a first step towards plant...
Directory of Open Access Journals (Sweden)
Lim, C. H.
2007-01-01
Full Text Available Production of Lactobacillus salivarius i 24, a probiotic strain for chicken, was studied in batch fermentation using 500 mL Erlenmeyer flask. Response surface method (RSM was used to optimize the medium for efficient cultivation of the bacterium. The factors investigated were yeast extract, glucose and initial culture pH. A polynomial regression model with cubic and quartic terms was used for the analysis of the experimental data. Estimated optimal conditions of the factors for growth of L. salivarius i 24 were; 3.32 % (w/v glucose, 4.31 % (w/v yeast extract and initial culture pH of 6.10.
Directory of Open Access Journals (Sweden)
Liang Tang
2010-01-01
Full Text Available A mathematical model for M/G/1-type queueing networks with multiple user applications and limited resources is established. The goal is to develop a dynamic distributed algorithm for this model, which supports all data traffic as efficiently as possible and makes optimally fair decisions about how to minimize the network performance cost. An online policy gradient optimization algorithm based on a single sample path is provided to avoid suffering from a “curse of dimensionality”. The asymptotic convergence properties of this algorithm are proved. Numerical examples provide valuable insights for bridging mathematical theory with engineering practice.
Ramrakhyani, A K; Mirabbasi, S; Mu Chiao
2011-02-01
Resonance-based wireless power delivery is an efficient technique to transfer power over a relatively long distance. This technique typically uses four coils as opposed to two coils used in conventional inductive links. In the four-coil system, the adverse effects of a low coupling coefficient between primary and secondary coils are compensated by using high-quality (Q) factor coils, and the efficiency of the system is improved. Unlike its two-coil counterpart, the efficiency profile of the power transfer is not a monotonically decreasing function of the operating distance and is less sensitive to changes in the distance between the primary and secondary coils. A four-coil energy transfer system can be optimized to provide maximum efficiency at a given operating distance. We have analyzed the four-coil energy transfer systems and outlined the effect of design parameters on power-transfer efficiency. Design steps to obtain the efficient power-transfer system are presented and a design example is provided. A proof-of-concept prototype system is implemented and confirms the validity of the proposed analysis and design techniques. In the prototype system, for a power-link frequency of 700 kHz and a coil distance range of 10 to 20 mm, using a 22-mm diameter implantable coil resonance-based system shows a power-transfer efficiency of more than 80% with an enhanced operating range compared to ~40% efficiency achieved by a conventional two-coil system.
Energy Technology Data Exchange (ETDEWEB)
Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Gray, Genetha Anne (Sandia National Laboratories, Livermore, CA); Castro, Joseph Pete Jr. (; .); Giunta, Anthony Andrew
2006-01-01
Many engineering application problems use optimization algorithms in conjunction with numerical simulators to search for solutions. The formulation of relevant objective functions and constraints dictate possible optimization algorithms. Often, a gradient based approach is not possible since objective functions and constraints can be nonlinear, nonconvex, non-differentiable, or even discontinuous and the simulations involved can be computationally expensive. Moreover, computational efficiency and accuracy are desirable and also influence the choice of solution method. With the advent and increasing availability of massively parallel computers, computational speed has increased tremendously. Unfortunately, the numerical and model complexities of many problems still demand significant computational resources. Moreover, in optimization, these expenses can be a limiting factor since obtaining solutions often requires the completion of numerous computationally intensive simulations. Therefore, we propose a multifidelity optimization algorithm (MFO) designed to improve the computational efficiency of an optimization method for a wide range of applications. In developing the MFO algorithm, we take advantage of the interactions between multi fidelity models to develop a dynamic and computational time saving optimization algorithm. First, a direct search method is applied to the high fidelity model over a reduced design space. In conjunction with this search, a specialized oracle is employed to map the design space of this high fidelity model to that of a computationally cheaper low fidelity model using space mapping techniques. Then, in the low fidelity space, an optimum is obtained using gradient or non-gradient based optimization, and it is mapped back to the high fidelity space. In this paper, we describe the theory and implementation details of our MFO algorithm. We also demonstrate our MFO method on some example problems and on two applications: earth penetrators and
International Nuclear Information System (INIS)
Brennan, Timothy J.
2010-01-01
Under conventional models, subsidizing energy efficiency requires electricity to be priced below marginal cost. Its benefits increase when electricity prices increase to finance the subsidy. With high prices, subsidies are counterproductive unless consumers fail to make efficiency investments when private benefits exceed costs. If the gain from adopting efficiency is only reduced electricity spending, capping revenues from energy sales may induce a utility to substitute efficiency for generation when the former is less costly. This goes beyond standard 'decoupling' of distribution revenues from sales, requiring complex energy price regulation. The models' results are used to evaluate tests in the 2002 California Standard Practice Manual for assessing demand-side management programs. Its 'Ratepayer Impact Measure' test best conforms to the condition that electricity price is too low. Its 'Total Resource Cost' and 'Societal Cost' tests resemble the condition for expanded decoupling. No test incorporates optimality conditions apart from consumer choice failure.
Gunnels, John; Lee, Jon; Margulies, Susan
2010-01-01
We provide a first demonstration of the idea that matrix-based algorithms for nonlinear combinatorial optimization problems can be efficiently implemented. Such algorithms were mainly conceived by theoretical computer scientists for proving efficiency. We are able to demonstrate the practicality of our approach by developing an implementation on a massively parallel architecture, and exploiting scalable and efficient parallel implementations of algorithms for ultra high-precision linear algebra. Additionally, we have delineated and implemented the necessary algorithmic and coding changes required in order to address problems several orders of magnitude larger, dealing with the limits of scalability from memory footprint, computational efficiency, reliability, and interconnect perspectives. © Springer and Mathematical Programming Society 2010.
Gunnels, John
2010-06-01
We provide a first demonstration of the idea that matrix-based algorithms for nonlinear combinatorial optimization problems can be efficiently implemented. Such algorithms were mainly conceived by theoretical computer scientists for proving efficiency. We are able to demonstrate the practicality of our approach by developing an implementation on a massively parallel architecture, and exploiting scalable and efficient parallel implementations of algorithms for ultra high-precision linear algebra. Additionally, we have delineated and implemented the necessary algorithmic and coding changes required in order to address problems several orders of magnitude larger, dealing with the limits of scalability from memory footprint, computational efficiency, reliability, and interconnect perspectives. © Springer and Mathematical Programming Society 2010.
DEFF Research Database (Denmark)
Broholm, Mette Martina; Janniche, Gry Sander; Damgaard, Ida
2014-01-01
Membrane Interface Probing (MIP) er et 'direct push' screeningsværktøj, som kan anvendes ved karakterisering af forurenede grunde. Karakterisering af kildeområder med chlorerede opløsningsmidler (som DNAPL) udgør et vigtigt led i udviklingen af den konceptuelle forståelse, som er essentiel...... for risikovurdering og valg af afværgestrategi. Integreret karakterisering med en række metoder for direkte såvel som indirekte dokumentation af DNAPL i moræneler, herunder MIP, er beskrevet i Kerrn-Jespersen et al. (2013). Det samlede DNAPL-karakteriseringsprojekt er beskrevet i detaljer i Janniche et al. (2013). En...... vurdering af anvendte detektorer for MIP er foretaget af Olsson (2013). Ved karakterisering af forurening med bl.a. chlorerede opløsningsmidler er der behov for en vurdering af forureningssammensætning og nedbrydning. Tilsvarende vurdering er nødvendig, når udviklingen af stimuleret reduktiv dechlorering...
Energiforbrug til opvarmning af bygninger
DEFF Research Database (Denmark)
Budde, J.; Pedersen, D.O.
Rapporten giver oplysninger om enhedsforbrug til varme og varmt brugsvand i forskellige typer af bygninger baseret på en analyse af et omfattende datamateriale. Formålet med undersøgelsen har været at ajourføre denne del af grundlaget for både landsdækkende og lokal varmeplanlægning i Danmark....
Automatic efficiency optimization of an axial compressor with adjustable inlet guide vanes
Li, Jichao; Lin, Feng; Nie, Chaoqun; Chen, Jingyi
2012-04-01
The inlet attack angle of rotor blade reasonably can be adjusted with the change of the stagger angle of inlet guide vane (IGV); so the efficiency of each condition will be affected. For the purpose to improve the efficiency, the DSP (Digital Signal Processor) controller is designed to adjust the stagger angle of IGV automatically in order to optimize the efficiency at any operating condition. The A/D signal collection includes inlet static pressure, outlet static pressure, outlet total pressure, rotor speed and torque signal, the efficiency can be calculated in the DSP, and the angle signal for the stepping motor which control the IGV will be sent out from the D/A. Experimental investigations are performed in a three-stage, low-speed axial compressor with variable inlet guide vanes. It is demonstrated that the DSP designed can well adjust the stagger angle of IGV online, the efficiency under different conditions can be optimized. This establishment of DSP online adjustment scheme may provide a practical solution for improving performance of multi-stage axial flow compressor when its operating condition is varied.
Toward Improved Rotor-Only Axial Fans—Part II: Design Optimization for Maximum Efficiency
DEFF Research Database (Denmark)
Sørensen, Dan Nørtoft; Thompson, M. C.; Sørensen, Jens Nørkær
2000-01-01
Numerical design optimization of the aerodynamic performance of axial fans is carried out, maximizing the efficiency in a designinterval of flow rates. Tip radius, number of blades, and angular velocity of the rotor are fixed, whereas the hub radius andspanwise distributions of chord length......, stagger angle, and camber angle are varied to find the optimum rotor geometry.Constraints ensure a pressure rise above a specified target and an angle of attack on the blades below stall. The optimizationscheme is used to investigate the dependence of maximum efficiency on the width of the design interval...
Stability Constrained Efficiency Optimization for Droop Controlled DC-DC Conversion System
DEFF Research Database (Denmark)
Meng, Lexuan; Dragicevic, Tomislav; Guerrero, Josep M.
2013-01-01
implementing tertiary regulation. Moreover, system dynamic is affected when shifting VRs. Therefore, the stability is considered in optimization by constraining the eigenvalues arising from dynamic state space model of the system. Genetic algorithm is used in searching for global efficiency optimum while....... As the efficiency of each converter changes with output power, virtual resistances (VRs) are set as decision variables for adjusting power sharing proportion among converters. It is noteworthy that apart from restoring the voltage deviation, secondary control plays an important role to stabilize dc bus voltage when...
Efficiency-optimized low-cost TDPAC spectrometer using a versatile routing/coincidence unit
International Nuclear Information System (INIS)
Renteria, M.; Bibiloni, A. G.; Darriba, G. N.; Errico, L. A.; Munoz, E. L.; Richard, D.; Runco, J.
2008-01-01
A highly efficient, reliable, and low-cost γ-γ TDPAC spectrometer, PACAr, optimized for 181 Hf-implanted low-activity samples, is presented. A versatile EPROM-based routing/coincidence unit was developed and implemented to be use with the memory-card-based multichannel analyzer hosted in a personal computer. The excellent energy resolution and very good overall resolution and efficiency of PACAr are analyzed and compare with advanced and already tested fast-fast and slow-fast PAC spectrometers.
Efficiency-optimized low-cost TDPAC spectrometer using a versatile routing/coincidence unit
Energy Technology Data Exchange (ETDEWEB)
Renteria, M., E-mail: renteria@fisica.unlp.edu.ar; Bibiloni, A. G.; Darriba, G. N.; Errico, L. A.; Munoz, E. L.; Richard, D.; Runco, J. [Universidad Nacional de La Plata, Departamento de Fisica, Facultad de Ciencias Exactas (Argentina)
2008-01-15
A highly efficient, reliable, and low-cost {gamma}-{gamma} TDPAC spectrometer, PACAr, optimized for {sup 181}Hf-implanted low-activity samples, is presented. A versatile EPROM-based routing/coincidence unit was developed and implemented to be use with the memory-card-based multichannel analyzer hosted in a personal computer. The excellent energy resolution and very good overall resolution and efficiency of PACAr are analyzed and compare with advanced and already tested fast-fast and slow-fast PAC spectrometers.
Optimization of the working process of the axial compressor according to the criterion of efficiency
Baturin, O. V.; Popov, G. M.; Goryachkin, E. S.; Novikova, Yu D.
2017-01-01
The paper shows search results of the optimal shape of low pressure compressor blades of the industrial gas turbine plant using methods of computational fluid dynamics and multicriteria methods of mathematical optimization. The essence of the methods is that an increase in compressor efficiency should be achieved by increasing the degree of compression up to 2%, and reducing the air flow to 8% relative to basic engine parameters. However, the compressor design elements should be retained as maximally unchanged as possible. During the work, the calculation model of the workflow in the test compressor has been developed and verified in the NUMECA software package, the automated algorithm of the blades shape change has been also developed using a small number of variables, while maintaining its stress-strain state. It allows reducing the number of changeable variables more than twofold. As the result of this study, the option of compressor performance was found, which can increase its efficiency by 1.3% (abs.).
Directory of Open Access Journals (Sweden)
JongHyup Lee
2016-08-01
Full Text Available For practical deployment of wireless sensor networks (WSN, WSNs construct clusters, where a sensor node communicates with other nodes in its cluster, and a cluster head support connectivity between the sensor nodes and a sink node. In hybrid WSNs, cluster heads have cellular network interfaces for global connectivity. However, when WSNs are active and the load of cellular networks is high, the optimal assignment of cluster heads to base stations becomes critical. Therefore, in this paper, we propose a game theoretic model to find the optimal assignment of base stations for hybrid WSNs. Since the communication and energy cost is different according to cellular systems, we devise two game models for TDMA/FDMA and CDMA systems employing power prices to adapt to the varying efficiency of recent wireless technologies. The proposed model is defined on the assumptions of the ideal sensing field, but our evaluation shows that the proposed model is more adaptive and energy efficient than local selections.
Lee, JongHyup; Pak, Dohyun
2016-01-01
For practical deployment of wireless sensor networks (WSN), WSNs construct clusters, where a sensor node communicates with other nodes in its cluster, and a cluster head support connectivity between the sensor nodes and a sink node. In hybrid WSNs, cluster heads have cellular network interfaces for global connectivity. However, when WSNs are active and the load of cellular networks is high, the optimal assignment of cluster heads to base stations becomes critical. Therefore, in this paper, we propose a game theoretic model to find the optimal assignment of base stations for hybrid WSNs. Since the communication and energy cost is different according to cellular systems, we devise two game models for TDMA/FDMA and CDMA systems employing power prices to adapt to the varying efficiency of recent wireless technologies. The proposed model is defined on the assumptions of the ideal sensing field, but our evaluation shows that the proposed model is more adaptive and energy efficient than local selections. PMID:27589743
Networks that optimize a trade-off between efficiency and dynamical resilience
International Nuclear Information System (INIS)
Brede, Markus; Vries, Bert J.M. de
2009-01-01
In this Letter we study networks that have been optimized to realize a trade-off between communication efficiency and dynamical resilience. While the first is related to the average shortest pathlength, we argue that the second can be measured by the largest eigenvalue of the adjacency matrix of the network. Best efficiency is realized in star-like configurations, while enhanced resilience is related to the avoidance of short loops and degree homogeneity. Thus crucially, very efficient networks are not resilient while very resilient networks lack in efficiency. Networks that realize a trade-off between both limiting cases exhibit core-periphery structures, where the average degree of core nodes decreases but core size increases as the weight is gradually shifted from a strong requirement for efficiency and limited resilience towards a smaller requirement for efficiency and a strong demand for resilience. We argue that both, efficiency and resilience are important requirements for network design and highlight how networks can be constructed that allow for both.
Operation optimization of a distributed energy system considering energy costs and exergy efficiency
International Nuclear Information System (INIS)
Di Somma, M.; Yan, B.; Bianco, N.; Graditi, G.; Luh, P.B.; Mongibello, L.; Naso, V.
2015-01-01
Highlights: • Operation optimization model of a Distributed Energy System (DES). • Multi-objective strategy to optimize energy cost and exergy efficiency. • Exergy analysis in building energy supply systems. - Abstract: With the growing demand of energy on a worldwide scale, improving the efficiency of energy resource use has become one of the key challenges. Application of exergy principles in the context of building energy supply systems can achieve rational use of energy resources by taking into account the different quality levels of energy resources as well as those of building demands. This paper is on the operation optimization of a Distributed Energy System (DES). The model involves multiple energy devices that convert a set of primary energy carriers with different energy quality levels to meet given time-varying user demands at different energy quality levels. By promoting the usage of low-temperature energy sources to satisfy low-quality thermal energy demands, the waste of high-quality energy resources can be reduced, thereby improving the overall exergy efficiency. To consider the economic factor as well, a multi-objective linear programming problem is formulated. The Pareto frontier, including the best possible trade-offs between the economic and exergetic objectives, is obtained by minimizing a weighted sum of the total energy cost and total primary exergy input using branch-and-cut. The operation strategies of the DES under different weights for the two objectives are discussed. The operators of DESs can choose the operation strategy from the Pareto frontier based on costs, essential in the short run, and sustainability, crucial in the long run. The contribution of each energy device in reducing energy costs and the total exergy input is also analyzed. In addition, results show that the energy cost can be much reduced and the overall exergy efficiency can be significantly improved by the optimized operation of the DES as compared with the
Efficient and Optimal Capital Accumulation under a Non Renewable Resource Constraint
Amigues, Jean-Pierre; Moreaux, Michel
2008-01-01
Usual resource models with capital accumulation focus upon simple one to one process transforming output either into some consumption good or into some capitalgood. We consider a bisectoral model where the capital good, labor and a non renewable resource are used to produce the consumption good and the capital good. Capitalaccumulation is an irreversible process and capital is depreciating over time. In thisframework we reconsider the usual results of the efficient and optimal growth theoryun...
Time efficient optimization of instance based problems with application to tone onset detection
Bauer, Nadja; Friedrichs, Klaus; Weihs, Claus
2016-01-01
A time efficient optimization technique for instance based problems is proposed, where for each parameter setting the target function has to be evaluated on a large set of problem instances. Computational time is reduced by beginning with a performance estimation based on the evaluation of a representative subset of instances. Subsequently, only promising settings are evaluated on the whole data set. As application a comprehensive music onset detection algorithm is introduce...
Asymptotic optimality and efficient computation of the leave-subject-out cross-validation
Xu, Ganggang
2012-12-01
Although the leave-subject-out cross-validation (CV) has been widely used in practice for tuning parameter selection for various nonparametric and semiparametric models of longitudinal data, its theoretical property is unknown and solving the associated optimization problem is computationally expensive, especially when there are multiple tuning parameters. In this paper, by focusing on the penalized spline method, we show that the leave-subject-out CV is optimal in the sense that it is asymptotically equivalent to the empirical squared error loss function minimization. An efficient Newton-type algorithm is developed to compute the penalty parameters that optimize the CV criterion. Simulated and real data are used to demonstrate the effectiveness of the leave-subject-out CV in selecting both the penalty parameters and the working correlation matrix. © 2012 Institute of Mathematical Statistics.
Directory of Open Access Journals (Sweden)
Guozhen Hu
2017-12-01
Full Text Available A loosely coupled inductive power transfer (IPT system for industrial track applications has been researched in this paper. The IPT converter using primary Inductor-Capacitor-Inductor (LCL network and secondary parallel-compensations is analyzed combined coil design for optimal operating efficiency. Accurate mathematical analytical model and expressions of self-inductance and mutual inductance are proposed to achieve coil parameters. Furthermore, the optimization process is performed combined with the proposed resonant compensations and coil parameters. The results are evaluated and discussed using finite element analysis (FEA. Finally, an experimental prototype is constructed to verify the proposed approach and the experimental results show that the optimization can be better applied to industrial track distributed IPT system.
Asymptotic optimality and efficient computation of the leave-subject-out cross-validation
Xu, Ganggang; Huang, Jianhua Z.
2012-01-01
Although the leave-subject-out cross-validation (CV) has been widely used in practice for tuning parameter selection for various nonparametric and semiparametric models of longitudinal data, its theoretical property is unknown and solving the associated optimization problem is computationally expensive, especially when there are multiple tuning parameters. In this paper, by focusing on the penalized spline method, we show that the leave-subject-out CV is optimal in the sense that it is asymptotically equivalent to the empirical squared error loss function minimization. An efficient Newton-type algorithm is developed to compute the penalty parameters that optimize the CV criterion. Simulated and real data are used to demonstrate the effectiveness of the leave-subject-out CV in selecting both the penalty parameters and the working correlation matrix. © 2012 Institute of Mathematical Statistics.
Optimizing cost-efficiency in mean exposure assessment--cost functions reconsidered.
Mathiassen, Svend Erik; Bolin, Kristian
2011-05-21
Reliable exposure data is a vital concern in medical epidemiology and intervention studies. The present study addresses the needs of the medical researcher to spend monetary resources devoted to exposure assessment with an optimal cost-efficiency, i.e. obtain the best possible statistical performance at a specified budget. A few previous studies have suggested mathematical optimization procedures based on very simple cost models; this study extends the methodology to cover even non-linear cost scenarios. Statistical performance, i.e. efficiency, was assessed in terms of the precision of an exposure mean value, as determined in a hierarchical, nested measurement model with three stages. Total costs were assessed using a corresponding three-stage cost model, allowing costs at each stage to vary non-linearly with the number of measurements according to a power function. Using these models, procedures for identifying the optimally cost-efficient allocation of measurements under a constrained budget were developed, and applied on 225 scenarios combining different sizes of unit costs, cost function exponents, and exposure variance components. Explicit mathematical rules for identifying optimal allocation could be developed when cost functions were linear, while non-linear cost functions implied that parts of or the entire optimization procedure had to be carried out using numerical methods.For many of the 225 scenarios, the optimal strategy consisted in measuring on only one occasion from each of as many subjects as allowed by the budget. Significant deviations from this principle occurred if costs for recruiting subjects were large compared to costs for setting up measurement occasions, and, at the same time, the between-subjects to within-subject variance ratio was small. In these cases, non-linearities had a profound influence on the optimal allocation and on the eventual size of the exposure data set. The analysis procedures developed in the present study can be used
Coaching af sygedagpengemodtagere
DEFF Research Database (Denmark)
Coop Henriksen, Annemette
SFI gennemførte i foråret 2008 til foråret 2009 en pilotundersøgelse om coaching. Undersøgelsen var designet som et lodtrækningsforsøg og omfattede 42 kvindelige sygedagpengemodtagere fra Rødovre Jobcenter, der var sygemeldt med psykiske lidelser i form af stress, depression eller udbrændthed eller...... med lidelser i bevægeapparatet. Undersøgelsen er bestilt og finansieret af Rødovre Jobcenter. I rapporten undersøges, om coaching kan bidrage til at bringe sygedagpengemodtagere i arbejde eller tættere på arbejdsmarkedet målt ved, om deltagerne får fx øget motivation, mere selvtillid, øget afklaring...... og færre symptomer på sygdom. Undersøgelsen viser, at gruppen, der har modtaget coaching, oplever en positiv udvikling i forhold til stress, depression og udbrændthed. Gruppen, der modtog coaching, har den tydeligste positive udvikling, men begge grupper har oplevet en helbredsmæssig fremgang i...
Directory of Open Access Journals (Sweden)
Stella Kafetzoglou
2015-08-01
Full Text Available Among the key aspects of the Internet of Things (IoT is the integration of heterogeneous sensors in a distributed system that performs actions on the physical world based on environmental information gathered by sensors and application-related constraints and requirements. Numerous applications of Wireless Sensor Networks (WSNs have appeared in various fields, from environmental monitoring, to tactical fields, and healthcare at home, promising to change our quality of life and facilitating the vision of sensor network enabled smart cities. Given the enormous requirements that emerge in such a setting—both in terms of data and energy—data aggregation appears as a key element in reducing the amount of traffic in wireless sensor networks and achieving energy conservation. Probabilistic frameworks have been introduced as operational efficient and performance effective solutions for data aggregation in distributed sensor networks. In this work, we introduce an overall optimization approach that improves and complements such frameworks towards identifying the optimal probability for a node to aggregate packets as well as the optimal aggregation period that a node should wait for performing aggregation, so as to minimize the overall energy consumption, while satisfying certain imposed delay constraints. Primal dual decomposition is employed to solve the corresponding optimization problem while simulation results demonstrate the operational efficiency of the proposed approach under different traffic and topology scenarios.
Kafetzoglou, Stella; Aristomenopoulos, Giorgos; Papavassiliou, Symeon
2015-08-11
Among the key aspects of the Internet of Things (IoT) is the integration of heterogeneous sensors in a distributed system that performs actions on the physical world based on environmental information gathered by sensors and application-related constraints and requirements. Numerous applications of Wireless Sensor Networks (WSNs) have appeared in various fields, from environmental monitoring, to tactical fields, and healthcare at home, promising to change our quality of life and facilitating the vision of sensor network enabled smart cities. Given the enormous requirements that emerge in such a setting-both in terms of data and energy-data aggregation appears as a key element in reducing the amount of traffic in wireless sensor networks and achieving energy conservation. Probabilistic frameworks have been introduced as operational efficient and performance effective solutions for data aggregation in distributed sensor networks. In this work, we introduce an overall optimization approach that improves and complements such frameworks towards identifying the optimal probability for a node to aggregate packets as well as the optimal aggregation period that a node should wait for performing aggregation, so as to minimize the overall energy consumption, while satisfying certain imposed delay constraints. Primal dual decomposition is employed to solve the corresponding optimization problem while simulation results demonstrate the operational efficiency of the proposed approach under different traffic and topology scenarios.
A Pareto-based multi-objective optimization algorithm to design energy-efficient shading devices
International Nuclear Information System (INIS)
Khoroshiltseva, Marina; Slanzi, Debora; Poli, Irene
2016-01-01
Highlights: • We present a multi-objective optimization algorithm for shading design. • We combine Harmony search and Pareto-based procedures. • Thermal and daylighting performances of external shading were considered. • We applied the optimization process to a residential social housing in Madrid. - Abstract: In this paper we address the problem of designing new energy-efficient static daylight devices that will surround the external windows of a residential building in Madrid. Shading devices can in fact largely influence solar gains in a building and improve thermal and lighting comforts by selectively intercepting the solar radiation and by reducing the undesirable glare. A proper shading device can therefore significantly increase the thermal performance of a building by reducing its energy demand in different climate conditions. In order to identify the set of optimal shading devices that allow a low energy consumption of the dwelling while maintaining high levels of thermal and lighting comfort for the inhabitants we derive a multi-objective optimization methodology based on Harmony Search and Pareto front approaches. The results show that the multi-objective approach here proposed is an effective procedure in designing energy efficient shading devices when a large set of conflicting objectives characterizes the performance of the proposed solutions.
Pal, Partha S; Kar, R; Mandal, D; Ghoshal, S P
2015-11-01
This paper presents an efficient approach to identify different stable and practically useful Hammerstein models as well as unstable nonlinear process along with its stable closed loop counterpart with the help of an evolutionary algorithm as Colliding Bodies Optimization (CBO) optimization algorithm. The performance measures of the CBO based optimization approach such as precision, accuracy are justified with the minimum output mean square value (MSE) which signifies that the amount of bias and variance in the output domain are also the least. It is also observed that the optimization of output MSE in the presence of outliers has resulted in a very close estimation of the output parameters consistently, which also justifies the effective general applicability of the CBO algorithm towards the system identification problem and also establishes the practical usefulness of the applied approach. Optimum values of the MSEs, computational times and statistical information of the MSEs are all found to be the superior as compared with those of the other existing similar types of stochastic algorithms based approaches reported in different recent literature, which establish the robustness and efficiency of the applied CBO based identification scheme. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
Development of an Optimal Controller and Validation Test Stand for Fuel Efficient Engine Operation
Rehn, Jack G., III
There are numerous motivations for improvements in automotive fuel efficiency. As concerns over the environment grow at a rate unmatched by hybrid and electric automotive technologies, the need for reductions in fuel consumed by current road vehicles has never been more present. Studies have shown that a major cause of poor fuel consumption in automobiles is improper driving behavior, which cannot be mitigated by purely technological means. The emergence of autonomous driving technologies has provided an opportunity to alleviate this inefficiency by removing the necessity of a driver. Before autonomous technology can be relied upon to reduce gasoline consumption on a large scale, robust programming strategies must be designed and tested. The goal of this thesis work was to design and deploy an autonomous control algorithm to navigate a four cylinder, gasoline combustion engine through a series of changing load profiles in a manner that prioritizes fuel efficiency. The experimental setup is analogous to a passenger vehicle driving over hilly terrain at highway speeds. The proposed approach accomplishes this using a model-predictive, real-time optimization algorithm that was calibrated to the engine. Performance of the optimal control algorithm was tested on the engine against contemporary cruise control. Results indicate that the "efficient'' strategy achieved one to two percent reductions in total fuel consumed for all load profiles tested. The consumption data gathered also suggests that further improvements could be realized on a different subject engine and using extended models and a slightly modified optimal control approach.
International Nuclear Information System (INIS)
Rodriguez-Rodriguez, A.; Correa-Alfonso, C.M.; Lopez-Pino, N.; Padilla-Cabal, F.; D'Alessandro, K.; Corrales, Y.; Garcia-Alvarez, J. A.; Perez-Mellor, A.; Baly-Gil, L.; Machado, A.
2011-01-01
A highly detailed characterization of a 130 cm 3 n-type HPGe detector, employed in low - background gamma spectrometry measurements, was done. Precise measured data and several Monte Carlo (MC) calculations have been combined to optimize the detector parameters. HPGe crystal location inside the Aluminum end-cap as well as its dimensions, including the borehole radius and height, were determined from frontal and lateral scans. Additionally, X-ray radiography and Computed Axial Tomography (CT) studies were carried out to complement the information about detector features. Using seven calibrated point sources ( 241 Am, 133 Ba, 57,60 Co, 137 Cs, 22 Na and 152 Eu), photo-peak efficiency curves at three different source - detector distances (SDD) were obtained. Taking into account the experimental values, an optimization procedure by means of MC simulations (MCNPX 2.6 code) were performed. MC efficiency curves were calculated specifying the optimized detector parameters in the MCNPX input files. Efficiency calculation results agree with empirical data, showing relative deviations lesser 10%. (Author)
Toward efficient optimization of wind farm layouts: Utilizing exact gradient information
International Nuclear Information System (INIS)
Guirguis, David; Romero, David A.; Amon, Cristina H.
2016-01-01
Highlights: • A mathematical programming approach is proposed to solve the WFLO problem. • Differentiable mathematical models are developed to handle land-use constraints. • Test cases with significant land-use constraints are solved efficiently. • The proposed approach outperforms genetic algorithm. - Abstract: The Wind Farm Layout Optimization (WFLO) problem has attracted a lot of attention from researchers and industry practitioners, as it has been proven that better placement of wind turbines can increase the overall efficiency and the total revenue of a wind farm. Although the engineering wake models are commonly used for layout optimization, the literature seems to have settled on using metaheuristics and stochastic optimization methods. In the present study, we show the effectiveness of non-linear mathematical programming in solving continuous-variable WFLO problems by utilizing exact gradient information of the problem’s objective and constraints. Moreover, mathematical models for handling land-use constraints are developed to solve highly constrained practical problems. For demonstration purposes, the results were compared with those obtained by a genetic algorithm, using a set of test cases that have been frequently used in the WFLO literature. Additional test cases with higher dimensionality, significant land-availability constraints and higher wind farm turbine densities (i.e., turbines per square kilometer) are devised and solved to show the merits of the proposed approach. Our results show the superiority of mathematical programing in solving this problem, as evidenced by the resulting wind farm efficiency and the computational cost required to obtain the solutions.
Akhtar, Mahmuda; Hannan, M A; Begum, R A; Basri, Hassan; Scavino, Edgar
2017-03-01
Waste collection is an important part of waste management that involves different issues, including environmental, economic, and social, among others. Waste collection optimization can reduce the waste collection budget and environmental emissions by reducing the collection route distance. This paper presents a modified Backtracking Search Algorithm (BSA) in capacitated vehicle routing problem (CVRP) models with the smart bin concept to find the best optimized waste collection route solutions. The objective function minimizes the sum of the waste collection route distances. The study introduces the concept of the threshold waste level (TWL) of waste bins to reduce the number of bins to be emptied by finding an optimal range, thus minimizing the distance. A scheduling model is also introduced to compare the feasibility of the proposed model with that of the conventional collection system in terms of travel distance, collected waste, fuel consumption, fuel cost, efficiency and CO 2 emission. The optimal TWL was found to be between 70% and 75% of the fill level of waste collection nodes and had the maximum tightness value for different problem cases. The obtained results for four days show a 36.80% distance reduction for 91.40% of the total waste collection, which eventually increases the average waste collection efficiency by 36.78% and reduces the fuel consumption, fuel cost and CO 2 emission by 50%, 47.77% and 44.68%, respectively. Thus, the proposed optimization model can be considered a viable tool for optimizing waste collection routes to reduce economic costs and environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.
Overførsel af viden ved flytning af produktion
DEFF Research Database (Denmark)
Madsen, Erik Skov; Riis, Jens Ove; Wæhrens, Brian Vejrum
2010-01-01
Empiriske studier i tre industrielle virksomheder har afsløret, at selv virksomheder med mange års erfaring i at overføre produktion til andre lande hovedsagelig fokuserer på planlægning af den fysiske overflytning af produktionsudstyr og fokuserer på den eksplicitte viden, der er tilknyttet prod...
Real time PI-backstepping induction machine drive with efficiency optimization.
Farhani, Fethi; Ben Regaya, Chiheb; Zaafouri, Abderrahmen; Chaari, Abdelkader
2017-09-01
This paper describes a robust and efficient speed control of a three phase induction machine (IM) subjected to load disturbances. First, a Multiple-Input Multiple-Output (MIMO) PI-Backstepping controller is proposed for a robust and highly accurate tracking of the mechanical speed and rotor flux. Asymptotic stability of the control scheme is proven by Lyapunov Stability Theory. Second, an active online optimization algorithm is used to optimize the efficiency of the drive system. The efficiency improvement approach consists of adjusting the rotor flux with respect to the load torque in order to minimize total losses in the IM. A dSPACE DS1104 R&D board is used to implement the proposed solution. The experimental results released on 3kW squirrel cage IM, show that the reference speed as well as the rotor flux are rapidly achieved with a fast transient response and without overshoot. A good load disturbances rejection response and IM parameters variation are fairly handled. The improvement of drive system efficiency reaches up to 180% at light load. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
Geometric Design of Scalable Forward Scatterers for Optimally Efficient Solar Transformers.
Kim, Hye-Na; Vahidinia, Sanaz; Holt, Amanda L; Sweeney, Alison M; Yang, Shu
2017-11-01
It will be ideal to deliver equal, optimally efficient "doses" of sunlight to all cells in a photobioreactor system, while simultaneously utilizing the entire solar resource. Backed by the numerical scattering simulation and optimization, here, the design, synthesis, and characterization of the synthetic iridocytes that recapitulated the salient forward-scattering behavior of the Tridacnid clam system are reported, which presents the first geometric solution to allow narrow, precise forward redistribution of flux, utilizing the solar resource at the maximum quantum efficiency possible in living cells. The synthetic iridocytes are composed of silica nanoparticles in microspheres embedded in gelatin, both are low refractive index materials and inexpensive. They show wavelength selectivity, have little loss (the back-scattering intensity is reduced to less than ≈0.01% of the forward-scattered intensity), and narrow forward scattering cone similar to giant clams. Moreover, by comparing experiments and theoretical calculation, it is confirmed that the nonuniformity of the scatter sizes is a "feature not a bug" of the design, allowing for efficient, forward redistribution of solar flux in a micrometer-scaled paradigm. This method is environmentally benign, inexpensive, and scalable to produce optical components that will find uses in efficiency-limited solar conversion technologies, heat sinks, and biofuel production. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Shi, Shengchao; Li, Guangxia; An, Kang; Gao, Bin; Zheng, Gan
2017-09-04
This paper proposes novel satellite-based wireless sensor networks (WSNs), which integrate the WSN with the cognitive satellite terrestrial network. Having the ability to provide seamless network access and alleviate the spectrum scarcity, cognitive satellite terrestrial networks are considered as a promising candidate for future wireless networks with emerging requirements of ubiquitous broadband applications and increasing demand for spectral resources. With the emerging environmental and energy cost concerns in communication systems, explicit concerns on energy efficient resource allocation in satellite networks have also recently received considerable attention. In this regard, this paper proposes energy-efficient optimal power allocation schemes in the cognitive satellite terrestrial networks for non-real-time and real-time applications, respectively, which maximize the energy efficiency (EE) of the cognitive satellite user while guaranteeing the interference at the primary terrestrial user below an acceptable level. Specifically, average interference power (AIP) constraint is employed to protect the communication quality of the primary terrestrial user while average transmit power (ATP) or peak transmit power (PTP) constraint is adopted to regulate the transmit power of the satellite user. Since the energy-efficient power allocation optimization problem belongs to the nonlinear concave fractional programming problem, we solve it by combining Dinkelbach's method with Lagrange duality method. Simulation results demonstrate that the fading severity of the terrestrial interference link is favorable to the satellite user who can achieve EE gain under the ATP constraint comparing to the PTP constraint.
International Nuclear Information System (INIS)
Salari, Ehsan; Craft, David; Wala, Jeremiah
2012-01-01
To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called vmerge, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. vmerge begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the ‘ideal’ dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard vmerge algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the
Salari, Ehsan; Wala, Jeremiah; Craft, David
2012-09-07
To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called VMERGE, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. VMERGE begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the 'ideal' dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard VMERGE algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the merging
Extremely Efficient Design of Organic Thin Film Solar Cells via Learning-Based Optimization
Directory of Open Access Journals (Sweden)
Mine Kaya
2017-11-01
Full Text Available Design of efficient thin film photovoltaic (PV cells require optical power absorption to be computed inside a nano-scale structure of photovoltaics, dielectric and plasmonic materials. Calculating power absorption requires Maxwell’s electromagnetic equations which are solved using numerical methods, such as finite difference time domain (FDTD. The computational cost of thin film PV cell design and optimization is therefore cumbersome, due to successive FDTD simulations. This cost can be reduced using a surrogate-based optimization procedure. In this study, we deploy neural networks (NNs to model optical absorption in organic PV structures. We use the corresponding surrogate-based optimization procedure to maximize light trapping inside thin film organic cells infused with metallic particles. Metallic particles are known to induce plasmonic effects at the metal–semiconductor interface, thus increasing absorption. However, a rigorous design procedure is required to achieve the best performance within known design guidelines. As a result of using NNs to model thin film solar absorption, the required time to complete optimization is decreased by more than five times. The obtained NN model is found to be very reliable. The optimization procedure results in absorption enhancement greater than 200%. Furthermore, we demonstrate that once a reliable surrogate model such as the developed NN is available, it can be used for alternative analyses on the proposed design, such as uncertainty analysis (e.g., fabrication error.
International Nuclear Information System (INIS)
Pezzini, Paola; Gomis-Bellmunt, Oriol; Frau-Valenti, Joan; Sudria-Andreu, Antoni
2010-01-01
In transmission and distribution systems, the high number of installed transformers, a loss source in networks, suggests a good potential for energy savings. This paper presents how the Spanish Distribution regulation policy, Royal Decree 222/2008, affects the overall energy efficiency in distribution transformers. The objective of a utility is the maximization of the benefit, and in case of failures, to install a chosen transformer in order to maximize the profit. Here, a novel method to optimize energy efficiency, considering the constraints set by the Spanish Distribution regulation policy, is presented; its aim is to achieve the objectives of the utility when installing new transformers. The overall energy efficiency increase is a clear result that can help in meeting the requirements of European environmental plans, such as the '20-20-20' action plan.
Energy Technology Data Exchange (ETDEWEB)
Pezzini, Paola [Centre d' Innovacio en Convertidors Estatics i Accionaments (CITCEA-UPC), E.T.S. Enginyeria Industrial Barcelona, Universitat Politecnica Catalunya, Diagonal, 647, Pl. 2, 08028 Barcelona (Spain); Gomis-Bellmunt, Oriol; Sudria-Andreu, Antoni [Centre d' Innovacio en Convertidors Estatics i Accionaments (CITCEA-UPC), E.T.S. Enginyeria Industrial Barcelona, Universitat Politecnica Catalunya, Diagonal, 647, Pl. 2, 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Josep Pla, B2, Pl. Baixa, 08019 Barcelona (Spain); Frau-Valenti, Joan [ENDESA, Carrer Joan Maragall, 16 07006 Palma (Spain)
2010-12-15
In transmission and distribution systems, the high number of installed transformers, a loss source in networks, suggests a good potential for energy savings. This paper presents how the Spanish Distribution regulation policy, Royal Decree 222/2008, affects the overall energy efficiency in distribution transformers. The objective of a utility is the maximization of the benefit, and in case of failures, to install a chosen transformer in order to maximize the profit. Here, a novel method to optimize energy efficiency, considering the constraints set by the Spanish Distribution regulation policy, is presented; its aim is to achieve the objectives of the utility when installing new transformers. The overall energy efficiency increase is a clear result that can help in meeting the requirements of European environmental plans, such as the '20-20-20' action plan. (author)
Optimization design of hydroturbine rotors according to the efficiency-strength criteria
Bannikov, D. V.; Yesipov, D. V.; Cherny, S. G.; Chirkov, D. V.
2010-12-01
The hydroturbine runner designing [1] is optimized by efficient methods for calculation of head loss in entire flow-through part of the turbine and deformation state of the blade. Energy losses are found at modelling of the spatial turbulent flow and engineering semi-empirical formulae. State of deformation is determined from the solution of the linear problem of elasticity for the isolated blade at hydrodynamic pressure with the method of boundary elements. With the use of the proposed system, the problem of the turbine runner design with the capacity of 640 MW providing the preset dependence of efficiency on the turbine work mode (efficiency criterion) is solved. The arising stresses do not exceed the critical value (strength criterion).
Optimization of Multi-layer Active Magnetic Regenerator towards Compact and Efficient Refrigeration
DEFF Research Database (Denmark)
Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein
2016-01-01
Magnetic refrigerators can theoretically be more efficient than current vapor compression systems and use no vapor refrigerants with global warming potential. The core component, the active magnetic regenerator (AMR) operates based on the magnetocaloric effect of magnetic materials and the heat r....... In addition, simulations are carried out to investigate the potential of applying nanofluid in future magnetic refrigerators.......Magnetic refrigerators can theoretically be more efficient than current vapor compression systems and use no vapor refrigerants with global warming potential. The core component, the active magnetic regenerator (AMR) operates based on the magnetocaloric effect of magnetic materials and the heat...... their Curie temperature. Simulations are implemented to investigate how to layer the FOPT materials for obtaining higher cooling capacity. Moreover, based on entropy generation minimization, optimization of the regenerator geometry and related operating parameters is presented for improving the AMR efficiency...
An Optimal Balance between Efficiency and Safety of Urban Drainage Networks
Seo, Y.
2014-12-01
Urban drainage networks have been developed to promote the efficiency of a system in terms of drainage time so far. Typically, a drainage system is designed to drain water from developed areas promptly as much as possible during floods. In this regard, an artificial drainage system have been considered to be more efficient compared to river networks in nature. This study examined artificial drainage networks and the results indicate they can be less efficient in terms of network configuration compared with river networks, which is counter-intuitive. The case study of 20 catchments in Seoul, South Korea shows that they have wide range of efficiency in terms of network configuration and consequently, drainage time. This study also demonstrates that efficient drainage networks are more sensitive to spatial and temporal rainfall variation such as rainstorm movement. Peak flows increase more than two times greater in effective drainage networks compared with inefficient and highly sinuous drainage networks. Combining these results, this study implies that the layout of a drainage network is an important factor in terms of efficient drainage and also safety in urban catchments. Design of an optimal layout of the drainage network can be an alternative non-structural measures that mitigate potential risks and it is crucial for the sustainability of urban environments.
Enhancement of the efficiency of the Open Cycle Phillips Optimized Cascade LNG process
International Nuclear Information System (INIS)
Fahmy, M.F.M.; Nabih, H.I.; El-Nigeily, M.
2016-01-01
Highlights: • Expanders replaced JT valves in the Phillips Optimized Cascade liquefaction process. • Improvement in plant liquefaction efficiency was evaluated in presence of expanders. • Comparison of the different optimum cases for the liquefaction process was presented. - Abstract: This study aims to improve the performance of the Open Cycle Phillips Optimized Cascade Process for the production of liquefied natural gas (LNG) through the replacement of Joule–Thomson (JT) valves by expanders. The expander has a higher thermodynamic efficiency than the JT valve. Moreover, the produced shaft power from the expander is integrated into the process. The study is conducted using the Aspen HYSYS-V7 simulation software for simulation of the Open Cycle Phillips Optimized Cascade Process having the JT valves. Simulation of several proposed cases in which expanders are used instead of JT valves at different locations in the process as at the propane cycle, ethylene cycle, methane cycle and the upstream of the heavies removal column is conducted. The optimum cases clearly indicate that expanders not only produce power, but also offer significant improvements in the process performance as shown by the total plant power consumption, LNG production, thermal efficiency, plant specific power and CO_2 emissions reduction. Results also reveal that replacing JT valves by expanders in the methane cycle has a dominating influence on all performance criteria and hence, can be considered as the main key contributor affecting the Phillips Optimized Cascade Process leading to a notable enhancement in its efficiency. This replacement of JT valves by liquid expanders at different locations of the methane cycle encounters power savings in the range of 4.92–5.72%, plant thermal efficiency of 92.64–92.97% and an increase in LNG production of 5.77–7.04%. Moreover, applying liquid expanders at the determined optimum cases for the different cycles, improves process performance and
Sidler, Dominik; Cristòfol-Clough, Michael; Riniker, Sereina
2017-06-13
Replica-exchange enveloping distribution sampling (RE-EDS) allows the efficient estimation of free-energy differences between multiple end-states from a single molecular dynamics (MD) simulation. In EDS, a reference state is sampled, which can be tuned by two types of parameters, i.e., smoothness parameters(s) and energy offsets, such that all end-states are sufficiently sampled. However, the choice of these parameters is not trivial. Replica exchange (RE) or parallel tempering is a widely applied technique to enhance sampling. By combining EDS with the RE technique, the parameter choice problem could be simplified and the challenge shifted toward an optimal distribution of the replicas in the smoothness-parameter space. The choice of a certain replica distribution can alter the sampling efficiency significantly. In this work, global round-trip time optimization (GRTO) algorithms are tested for the use in RE-EDS simulations. In addition, a local round-trip time optimization (LRTO) algorithm is proposed for systems with slowly adapting environments, where a reliable estimate for the round-trip time is challenging to obtain. The optimization algorithms were applied to RE-EDS simulations of a system of nine small-molecule inhibitors of phenylethanolamine N-methyltransferase (PNMT). The energy offsets were determined using our recently proposed parallel energy-offset (PEOE) estimation scheme. While the multistate GRTO algorithm yielded the best replica distribution for the ligands in water, the multistate LRTO algorithm was found to be the method of choice for the ligands in complex with PNMT. With this, the 36 alchemical free-energy differences between the nine ligands were calculated successfully from a single RE-EDS simulation 10 ns in length. Thus, RE-EDS presents an efficient method for the estimation of relative binding free energies.
Virkelighedsflugt og masser af sex
DEFF Research Database (Denmark)
Lorentzen, Rasmus Fink
2011-01-01
I artiklen laves en læsning af ungdomsromanen "6" (2010) af Ronni Andersen. Dernæst udfoldes en række litteraturpædagogiske forslag tilen undervisning i romanen i skolens ældste klasser. Arbejdsforslagene er baseret på en kompetencetilgang til danskfaget og rummer fire værksteder hvor eleverne sk...
DEFF Research Database (Denmark)
Bonde, Lisbeth
2015-01-01
En fodrejse fra Assisi til Rom i Frans af Assisis fodspor sætter gang i tankerne og giver anledning til nye ideer......En fodrejse fra Assisi til Rom i Frans af Assisis fodspor sætter gang i tankerne og giver anledning til nye ideer...
Ledelse af forandringer i folkeskolen
DEFF Research Database (Denmark)
Kjer, Mikkel; Rosdahl, Anders
2016-01-01
Dette notat bygger på kvalitative interview på seks folkeskoler i efteråret 2015. Skolerne ligger i forskellige egne af landet og i landområder, mindre og store byer. Skolerne er af forskellig størrelse, og deres elevgrundlag, dvs. forældrenes sociale baggrund, varierer også. Notatet bygger primæ...
Forhastet regulering af de store
DEFF Research Database (Denmark)
Thomsen, Steen
2013-01-01
Christiansborg gennemfører sandsynligvis en markant skærpet regulering af de store finansielle virksomheder. Det vil virke kontraktivt og medvirke til erhvervslivets kredittørke.......Christiansborg gennemfører sandsynligvis en markant skærpet regulering af de store finansielle virksomheder. Det vil virke kontraktivt og medvirke til erhvervslivets kredittørke....
Masser af information uden betydning
DEFF Research Database (Denmark)
Brier, Søren
en diskussion af informationsteorien i Tor Nørretranders "Mærk verden" og en skitse til et alternativ baseret på anden ordens kybernetik og semiotik......en diskussion af informationsteorien i Tor Nørretranders "Mærk verden" og en skitse til et alternativ baseret på anden ordens kybernetik og semiotik...
Anbefalinger til organisering af uddannelserne
DEFF Research Database (Denmark)
Andersen, Lars; Andersen, Lars Døvling; Hornemann, Birte C.
2009-01-01
Notatet sammenfatter de diskussioner, som det af fakulteterne nedsatte udvalg vedrørende nye undervisnings- og eksamensformer har haft, og de anbefalinger til en omlægning af vores uddannelsessystem, som udvalget har valgt at give. Notatet er samtidig en begyndelse på en erfaringsudveksling om ny...
Modeller af komplicerede systemer
DEFF Research Database (Denmark)
Mortensen, J.
emphasizes their use in relation to technical systems. All the presented models, with the exception of the types presented in chapter 2, are non-theoretical non-formal conceptual network models. Two new model types are presented: 1) The System-Environment model, which describes the environments interaction...... with conceptual modeling in relation to process control. It´s purpose is to present classify and exemplify the use of a set of qualitative model types. Such model types are useful in the early phase of modeling, where no structured methods are at hand. Although the models are general in character, this thesis......This thesis, "Modeller af komplicerede systemer", represents part of the requirements for the Danish Ph.D.degree. Assisting professor John Nørgaard-Nielsen, M.Sc.E.E.Ph.D. has been principal supervisor and professor Morten Lind, M.Sc.E.E.Ph.D. has been assisting supervisor. The thesis is concerned...
Health Information in Somali (Af-Soomaali )
... and Wound Healing - Af-Soomaali (Somali) Bilingual PDF Health Information Translations Fasting Blood Sugar Test - Af-Soomaali (Somali) Bilingual PDF Health Information Translations GTT (Glucose Tolerance Test) - Af-Soomaali ( ...
18.4%-Efficient Heterojunction Si Solar Cells Using Optimized ITO/Top Electrode.
Kim, Namwoo; Um, Han-Don; Choi, Inwoo; Kim, Ka-Hyun; Seo, Kwanyong
2016-05-11
We optimize the thickness of a transparent conducting oxide (TCO) layer, and apply a microscale mesh-pattern metal electrode for high-efficiency a-Si/c-Si heterojunction solar cells. A solar cell equipped with the proposed microgrid metal electrode demonstrates a high short-circuit current density (JSC) of 40.1 mA/cm(2), and achieves a high efficiency of 18.4% with an open-circuit voltage (VOC) of 618 mV and a fill factor (FF) of 74.1% as result of the shortened carrier path length and the decreased electrode area of the microgrid metal electrode. Furthermore, by optimizing the process sequence for electrode formation, we are able to effectively restore the reduction in VOC that occurs during the microgrid metal electrode formation process. This work is expected to become a fundamental study that can effectively improve current loss in a-Si/c-Si heterojunction solar cells through the optimization of transparent and metal electrodes.
Directory of Open Access Journals (Sweden)
Naghma Khatoon
2017-01-01
Full Text Available Mobility awareness and energy efficiency are two indispensable optimization problems in mobile ad hoc networks (MANETs where nodes move unpredictably in any direction with restricted battery life, resulting in frequent change in topology. These constraints are widely studied to increase the lifetime of such networks. This paper focuses on the problems of mobility as well as energy efficiency to develop a clustering algorithm inspired by multiagent stochastic parallel search technique of particle swarm optimization. The election of cluster heads takes care of mobility and remaining energy as well as the degree of connectivity for selecting nodes to serve as cluster heads for longer duration of time. The cluster formation is presented by taking multiobjective fitness function using particle swarm optimization. The proposed work is experimented extensively in the NS-2 network simulator and compared with the other existing algorithms. The results show the effectiveness of our proposed algorithm in terms of network lifetime, average number of clusters formed, average number of reclustering required, energy consumption, and packet delivery ratio.
Directory of Open Access Journals (Sweden)
Eleonora Sforza
Full Text Available Biofuels from algae are highly interesting as renewable energy sources to replace, at least partially, fossil fuels, but great research efforts are still needed to optimize growth parameters to develop competitive large-scale cultivation systems. One factor with a seminal influence on productivity is light availability. Light energy fully supports algal growth, but it leads to oxidative stress if illumination is in excess. In this work, the influence of light intensity on the growth and lipid productivity of Nannochloropsis salina was investigated in a flat-bed photobioreactor designed to minimize cells self-shading. The influence of various light intensities was studied with both continuous illumination and alternation of light and dark cycles at various frequencies, which mimic illumination variations in a photobioreactor due to mixing. Results show that Nannochloropsis can efficiently exploit even very intense light, provided that dark cycles occur to allow for re-oxidation of the electron transporters of the photosynthetic apparatus. If alternation of light and dark is not optimal, algae undergo radiation damage and photosynthetic productivity is greatly reduced. Our results demonstrate that, in a photobioreactor for the cultivation of algae, optimizing mixing is essential in order to ensure that the algae exploit light energy efficiently.
Directory of Open Access Journals (Sweden)
Álvaro Gutiérrez
2011-11-01
Full Text Available Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the Distributed Bees Algorithm (DBA, previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA’s control parameters by means of a Genetic Algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots’ distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce.
Anmeldelse af World Drug Report 2005
DEFF Research Database (Denmark)
Møller, Kim
2005-01-01
Internationale udfordringer i spændingsfeltet mellem organiseret kriminalitet og narkotika. Værdien af det illegale narkotikamarked. Skabelsen af et Illicit Drug Index. Ny organisationsstruktur bag udgivelsen af denne WDR. Udgivelsesdato: December......Internationale udfordringer i spændingsfeltet mellem organiseret kriminalitet og narkotika. Værdien af det illegale narkotikamarked. Skabelsen af et Illicit Drug Index. Ny organisationsstruktur bag udgivelsen af denne WDR. Udgivelsesdato: December...
Gao, Ya; Cheng, Wenchi; Zhang, Hailin
2017-08-23
Energy harvesting, which offers a never-ending energy supply, has emerged as a prominent technology to prolong the lifetime and reduce costs for the battery-powered wireless sensor networks. However, how to improve the energy efficiency while guaranteeing the quality of service (QoS) for energy harvesting based wireless sensor networks is still an open problem. In this paper, we develop statistical delay-bounded QoS-driven power control policies to maximize the effective energy efficiency (EEE), which is defined as the spectrum efficiency under given specified QoS constraints per unit harvested energy, for energy harvesting based wireless sensor networks. For the battery-infinite wireless sensor networks, our developed QoS-driven power control policy converges to the Energy harvesting Water Filling (E-WF) scheme and the Energy harvesting Channel Inversion (E-CI) scheme under the very loose and stringent QoS constraints, respectively. For the battery-finite wireless sensor networks, our developed QoS-driven power control policy becomes the Truncated energy harvesting Water Filling (T-WF) scheme and the Truncated energy harvesting Channel Inversion (T-CI) scheme under the very loose and stringent QoS constraints, respectively. Furthermore, we evaluate the outage probabilities to theoretically analyze the performance of our developed QoS-driven power control policies. The obtained numerical results validate our analysis and show that our developed optimal power control policies can optimize the EEE over energy harvesting based wireless sensor networks.
Chen, Zhenning; Shao, Xinxing; Xu, Xiangyang; He, Xiaoyuan
2018-02-01
The technique of digital image correlation (DIC), which has been widely used for noncontact deformation measurements in both the scientific and engineering fields, is greatly affected by the quality of speckle patterns in terms of its performance. This study was concerned with the optimization of the digital speckle pattern (DSP) for DIC in consideration of both the accuracy and efficiency. The root-mean-square error of the inverse compositional Gauss-Newton algorithm and the average number of iterations were used as quality metrics. Moreover, the influence of subset sizes and the noise level of images, which are the basic parameters in the quality assessment formulations, were also considered. The simulated binary speckle patterns were first compared with the Gaussian speckle patterns and captured DSPs. Both the single-radius and multi-radius DSPs were optimized. Experimental tests and analyses were conducted to obtain the optimized and recommended DSP. The vector diagram of the optimized speckle pattern was also uploaded as reference.
Optimal Cross-Layer Design for Energy Efficient D2D Sharing Systems
Alabbasi, Abdulrahman
2016-11-23
In this paper, we propose a cross-layer design, which optimizes the energy efficiency of a potential future 5G spectrum-sharing environment, in two sharing scenarios. In the first scenario, underlying sharing is considered. We propose and minimize a modified energy per good bit (MEPG) metric, with respect to the spectrum sharing user’s transmission power and media access frame length. The cellular users, legacy users, are protected by an outage probability constraint. To optimize the non-convex targeted problem, we utilize the generalized convexity theory and verify the problem’s strictly pseudoconvex structure. We also derive analytical expressions of the optimal resources. In the second scenario, we minimize a generalized MEPG function while considering a probabilistic activity of cellular users and its impact on the MEPG performance of the spectrum sharing users. Finally, we derive the associated optimal resource allocation of this problem. Selected numerical results show the improvement of the proposed system compared with other systems.
Intelligent styring af dynamisk LED belysning
DEFF Research Database (Denmark)
Thorseth, Anders; Corell, Dennis Dan; Hansen, Søren Stentoft
Denne slutrapport giver en kort beskrivelse af arbejdet, der er udført af DTU Fotonik i projektet ”Intelligent styring af dynamisk LED belysning” støttet af EUDP. Arbejdet er udført i perioden 2011‐2012 i samarbejde med Lighten.......Denne slutrapport giver en kort beskrivelse af arbejdet, der er udført af DTU Fotonik i projektet ”Intelligent styring af dynamisk LED belysning” støttet af EUDP. Arbejdet er udført i perioden 2011‐2012 i samarbejde med Lighten....
Nyttigt bidrag til professionalisering af revisionsudvalg
DEFF Research Database (Denmark)
Thomsen, Steen
2009-01-01
Anmeldelse af: KPMG. 2009, Audit Committee Institute. Revisionsudvalg i Praksis. 2. reviderede udgave.......Anmeldelse af: KPMG. 2009, Audit Committee Institute. Revisionsudvalg i Praksis. 2. reviderede udgave....
Peng, Ting; Sun, Xiaochun; Mumm, Rita H
2014-01-01
Multiple trait integration (MTI) is a multi-step process of converting an elite variety/hybrid for value-added traits (e.g. transgenic events) through backcross breeding. From a breeding standpoint, MTI involves four steps: single event introgression, event pyramiding, trait fixation, and version testing. This study explores the feasibility of marker-aided backcross conversion of a target maize hybrid for 15 transgenic events in the light of the overall goal of MTI of recovering equivalent performance in the finished hybrid conversion along with reliable expression of the value-added traits. Using the results to optimize single event introgression (Peng et al. Optimized breeding strategies for multiple trait integration: I. Minimizing linkage drag in single event introgression. Mol Breed, 2013) which produced single event conversions of recurrent parents (RPs) with ≤8 cM of residual non-recurrent parent (NRP) germplasm with ~1 cM of NRP germplasm in the 20 cM regions flanking the event, this study focused on optimizing process efficiency in the second and third steps in MTI: event pyramiding and trait fixation. Using computer simulation and probability theory, we aimed to (1) fit an optimal breeding strategy for pyramiding of eight events into the female RP and seven in the male RP, and (2) identify optimal breeding strategies for trait fixation to create a 'finished' conversion of each RP homozygous for all events. In addition, next-generation seed needs were taken into account for a practical approach to process efficiency. Building on work by Ishii and Yonezawa (Optimization of the marker-based procedures for pyramiding genes from multiple donor lines: I. Schedule of crossing between the donor lines. Crop Sci 47:537-546, 2007a), a symmetric crossing schedule for event pyramiding was devised for stacking eight (seven) events in a given RP. Options for trait fixation breeding strategies considered selfing and doubled haploid approaches to achieve homozygosity
Efficiency optimization of a photovoltaic water pumping system for irrigation in Ouargla, Algeria
Louazene, M. L.; Garcia, M. C. Alonso; Korichi, D.
2017-02-01
This work is technical study to contribute to the optimization of pumping systems powered by solar energy (clean) and used in the field of agriculture. To achieve our goals, we studied the techniques that must be entered on a photovoltaic system for maximum energy from solar panels. Our scientific contribution in this research is the realization of an efficient photovoltaic pumping system for irrigation needs. To achieve this and extract maximum power from the PV generator, two axes have been optimized: 1. Increase in the uptake of solar radiation by choice an optimum tilt angle of the solar panels, and 2. it is necessary to add an adaptation device, MPPT controller with a DC-DC converter, between the source and the load.
Directory of Open Access Journals (Sweden)
Mariana B. Laborde
2015-03-01
Full Text Available A healthy dehydrated food of high nutritional-quality and added-value was developed: low-calories raisin obtained by an ultrasonic assisted combined-dehydration with two-stage osmotic treatment (D3S complemented by drying. Pink Red Globe grape produced at Mendoza (Argentina, experienced a substitution of sugar by natural sweetener Stevia in two osmotic stages under different conditions (treatment with/without ultrasound; sweetener concentration 18, 20, 22% w/w; time 35, 75, 115 minutes, evaluating soluble solids (SS, moisture (M, total polyphenols (PF, antioxidant efficiency (AE and sugar profile. The multiple optimization of the process by response surface methodology and desirability analysis, allowed to minimize M, maximize SS (Stevia incorporation, and preserve the maximum amount of PF. After the first stage, the optimal treatment reduced the majority sugars of the grape in 32% (sucrose, glucose, and the 57% at the end of the dehydration process.
Optimization of ultrasonic array inspections using an efficient hybrid model and real crack shapes
Energy Technology Data Exchange (ETDEWEB)
Felice, Maria V., E-mail: maria.felice@bristol.ac.uk [Department of Mechanical Engineering, University of Bristol, Bristol, U.K. and NDE Laboratory, Rolls-Royce plc., Bristol (United Kingdom); Velichko, Alexander, E-mail: p.wilcox@bristol.ac.uk; Wilcox, Paul D., E-mail: p.wilcox@bristol.ac.uk [Department of Mechanical Engineering, University of Bristol, Bristol (United Kingdom); Barden, Tim; Dunhill, Tony [NDE Laboratory, Rolls-Royce plc., Bristol (United Kingdom)
2015-03-31
Models which simulate the interaction of ultrasound with cracks can be used to optimize ultrasonic array inspections, but this approach can be time-consuming. To overcome this issue an efficient hybrid model is implemented which includes a finite element method that requires only a single layer of elements around the crack shape. Scattering Matrices are used to capture the scattering behavior of the individual cracks and a discussion on the angular degrees of freedom of elastodynamic scatterers is included. Real crack shapes are obtained from X-ray Computed Tomography images of cracked parts and these shapes are inputted into the hybrid model. The effect of using real crack shapes instead of straight notch shapes is demonstrated. An array optimization methodology which incorporates the hybrid model, an approximate single-scattering relative noise model and the real crack shapes is then described.
Efficiency Optimization Control of IPM Synchronous Motor Drives with Online Parameter Estimation
Directory of Open Access Journals (Sweden)
Sadegh Vaez-Zadeh
2011-04-01
Full Text Available This paper describes an efficiency optimization control method for high performance interior permanent magnet synchronous motor drives with online estimation of motor parameters. The control system is based on an input-output feedback linearization method which provides high performance control and simultaneously ensures the minimization of the motor losses. The controllable electrical loss can be minimized by the optimal control of the armature current vector. It is shown that parameter variations except at near the nominal conditions have undesirable effect on the controller performance. Therefore, a parameter estimation method based on the second method of Lyapunov is presented which guarantees the stability and convergence of the estimation. The extensive simulation results show the feasibility of the proposed controller and observer and their desirable performances.
DEFF Research Database (Denmark)
Bjerre-Harpøth, Vibeke; Damgaard, Birthe Marie
2013-01-01
Et forsøg har vist, at køer på lavt energiniveau i goldperioden var fysiologisk sundere og havde mindre risiko for at udvikle stofskiftesygdomme end køer på et højt energiniveau. Forsøget viste også, at køer på et normalt energiniveau i senlaktationen gav mere mælk i den efterfølgende laktation e...
Efficient 3D porous microstructure reconstruction via Gaussian random field and hybrid optimization.
Jiang, Z; Chen, W; Burkhart, C
2013-11-01
Obtaining an accurate three-dimensional (3D) structure of a porous microstructure is important for assessing the material properties based on finite element analysis. Whereas directly obtaining 3D images of the microstructure is impractical under many circumstances, two sets of methods have been developed in literature to generate (reconstruct) 3D microstructure from its 2D images: one characterizes the microstructure based on certain statistical descriptors, typically two-point correlation function and cluster correlation function, and then performs an optimization process to build a 3D structure that matches those statistical descriptors; the other method models the microstructure using stochastic models like a Gaussian random field and generates a 3D structure directly from the function. The former obtains a relatively accurate 3D microstructure, but computationally the optimization process can be very intensive, especially for problems with large image size; the latter generates a 3D microstructure quickly but sacrifices the accuracy due to issues in numerical implementations. A hybrid optimization approach of modelling the 3D porous microstructure of random isotropic two-phase materials is proposed in this paper, which combines the two sets of methods and hence maintains the accuracy of the correlation-based method with improved efficiency. The proposed technique is verified for 3D reconstructions based on silica polymer composite images with different volume fractions. A comparison of the reconstructed microstructures and the optimization histories for both the original correlation-based method and our hybrid approach demonstrates the improved efficiency of the approach. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.
Optimal sampling plan for clean development mechanism energy efficiency lighting projects
International Nuclear Information System (INIS)
Ye, Xianming; Xia, Xiaohua; Zhang, Jiangfeng
2013-01-01
Highlights: • A metering cost minimisation model is built to assist the sampling plan for CDM projects. • The model minimises the total metering cost by the determination of optimal sample size. • The required 90/10 criterion sampling accuracy is maintained. • The proposed metering cost minimisation model is applicable to other CDM projects as well. - Abstract: Clean development mechanism (CDM) project developers are always interested in achieving required measurement accuracies with the least metering cost. In this paper, a metering cost minimisation model is proposed for the sampling plan of a specific CDM energy efficiency lighting project. The problem arises from the particular CDM sampling requirement of 90% confidence and 10% precision for the small-scale CDM energy efficiency projects, which is known as the 90/10 criterion. The 90/10 criterion can be met through solving the metering cost minimisation problem. All the lights in the project are classified into different groups according to uncertainties of the lighting energy consumption, which are characterised by their statistical coefficient of variance (CV). Samples from each group are randomly selected to install power meters. These meters include less expensive ones with less functionality and more expensive ones with greater functionality. The metering cost minimisation model will minimise the total metering cost through the determination of the optimal sample size at each group. The 90/10 criterion is formulated as constraints to the metering cost objective. The optimal solution to the minimisation problem will therefore minimise the metering cost whilst meeting the 90/10 criterion, and this is verified by a case study. Relationships between the optimal metering cost and the population sizes of the groups, CV values and the meter equipment cost are further explored in three simulations. The metering cost minimisation model proposed for lighting systems is applicable to other CDM projects as
Demayo, Trevor Nat
Criteria pollutant regulations, climate change concerns, and energy conservation efforts are placing strict constraints in the design and operation of advanced, stationary combustion systems. To ensure minimal pollutant emissions and maximal efficiency at every instant of operation while preventing reaction blowout, combustion systems need to react and adapt in real-time to external changes. This study describes the development, demonstration, and evaluation of a multivariable feedback control system, designed to maximize the performance of natural gas-fired combustion systems. A feedback sensor array was developed to monitor reaction stability and measure combustion performance as a function of NOx, CO, and O, emissions. Acoustic and UV chemiluminescent emissions were investigated for use as stability indicators. Modulated signals of CH* and CO2* chemiluminescence were found to correlate well with the onset of lean blowout. A variety of emissions sensors were tested and evaluated, including conventional CEMS', micro-fuel cells, a zirconia NOx transducer, and a rapid response predictive NOx sensor based on UV flame chemiluminescence. A dual time-scale controller was designed to actively optimize operating conditions by maximizing a multivariable performance function J using a linear direction set search algorithm. The controller evaluated J under slow, quasi steady-state conditions, while dynamically monitoring the reaction zone at high speed for pre-blowout instabilities or boundary condition violations. To establish the input control parameters, two burner systems were selected: a 30 kW air-swirl, generic research burner, and a 120 kW scaled, fuel-staged, industrial boiler burner. The parameters, chosen to most affect burner performance, consisted of air swirl intensity and excess air for the generic burner, and fuel-staging and excess air for the boiler burner. A set of optimization parameters was also established to ensure efficient and deterministic
Optimizing efficiency on conventional transformer based low power AC/DC standby power supplies
DEFF Research Database (Denmark)
Nielsen, Nils
2004-01-01
This article describes the research results for simple and cheap methods to reduce the idle- and load-losses in very low power conventional transformer based power supplies intended for standby usage. In this case "very low power" means 50 Hz/230 V-AC to 5 V-DC@1 W. The efficiency is measured...... on two common power supply topologies designed for this power level. The two described topologies uses either a series (or linear) or a buck regulation approach. Common to the test power supplies is they either are using a standard cheap off-the-shelf transformer, or one, which are loss optimized by very...
Optimization of E-DCH channel power ratios to maximize link level efficiency
DEFF Research Database (Denmark)
Zarco, Carlos Ruben Delgado; Malone, Jaime Tito; Wigard, Jeroen
2006-01-01
For the WCDMA/HSUPA concept, a key to ensuring high spectral efficiency is to correctly adjust the transmission power ratios among the data and control channels. This paper provides optimal values for the power ratio between the Enhanced-Dedicated Physical Data Channel (E-DPDCH) and the Dedicated...... rate (typical values ranging from 8.1 to 9.9 dB) and the RSN target (maintaining or decreasing their value as the target increases). These results show that it is more link efficient to increase the DPCCH transmission power with the bit rate (and the E-DPDCH's by applying the power ratio) than...... to maintain a constant DPCCH transmission power and just increase the EDPDCH to DPCCH power ratio....
Modellering af elforbrug til netanalyse
DEFF Research Database (Denmark)
Østergaard, Jacob
I denne rapport undersøges mulighederne for at etablere en model for elforbruget, der kan anvendes ved analyser af det østdanske transmissionsnet. Rapporten henvender sig til ingeniører og beslutningstagere, der ønsker viden om betydningen af en nøjagtig elforbrugsmodel og om mulighederne for i p...... simuleringsresultater med mindre usikkerhed, og der opnås en integration mellem eksisterende systemer, idet data fra en række systemer bl.a. Panda, elforbrugsprognoser, elforbrugspaneler og stationsprognoser kan udnyttes til etableringen af en model....
International Nuclear Information System (INIS)
Sheng, Shiqi; Tu, Z C
2013-01-01
A unified χ-criterion for heat devices (including heat engines and refrigerators), which is defined as the product of the energy conversion efficiency and the heat absorbed per unit time by the working substance (de Tomás et al 2012 Phys. Rev. E 85 010104), is optimized for tight-coupling heat engines and refrigerators operating between two heat baths at temperatures T c and T h ( > T c ). By taking a new convention on the thermodynamic flux related to the heat transfer between two baths, we find that for a refrigerator tightly and symmetrically coupled with two heat baths, the coefficient of performance (i.e., the energy conversion efficiency of refrigerators) at maximum χ asymptotically approaches √(ε C ) when the relative temperature difference between two heat baths ε C -1 ≡(T h -T c )/T c is sufficiently small. Correspondingly, the efficiency at maximum χ (equivalent to maximum power) for a heat engine tightly and symmetrically coupled with two heat baths is proved to be η C /2+η C 2 /8 up to the second order term of η C ≡ (T h − T c )/T h , which reverts to the universal efficiency at maximum power for tight-coupling heat engines operating between two heat baths at small temperature difference in the presence of left–right symmetry (Esposito et al 2009 Phys. Rev. Lett. 102 130602). (fast track communication)
Efficient 3D multi-region prostate MRI segmentation using dual optimization.
Qiu, Wu; Yuan, Jing; Ukwatta, Eranga; Sun, Yue; Rajchl, Martin; Fenster, Aaron
2013-01-01
Efficient and accurate extraction of the prostate, in particular its clinically meaningful sub-regions from 3D MR images, is of great interest in image-guided prostate interventions and diagnosis of prostate cancer. In this work, we propose a novel multi-region segmentation approach to simultaneously locating the boundaries of the prostate and its two major sub-regions: the central gland and the peripheral zone. The proposed method utilizes the prior knowledge of the spatial region consistency and employs a customized prostate appearance model to simultaneously segment multiple clinically meaningful regions. We solve the resulted challenging combinatorial optimization problem by means of convex relaxation, for which we introduce a novel spatially continuous flow-maximization model and demonstrate its duality to the investigated convex relaxed optimization problem with the region consistency constraint. Moreover, the proposed continuous max-flow model naturally leads to a new and efficient continuous max-flow based algorithm, which enjoys great advantages in numerics and can be readily implemented on GPUs. Experiments using 15 T2-weighted 3D prostate MR images, by inter- and intra-operator variability, demonstrate the promising performance of the proposed approach.
Optimization of phenol biodegradation by efficient bacteria isolated from petrochemical effluents
Directory of Open Access Journals (Sweden)
M. Shahriari Moghadam
2016-05-01
Full Text Available Phenol is an environmental pollutant present in industrial wastewaters such as refineries, coal processing and petrochemicals products. In this study three phenol degrading bacteria from Arak Petrochemical Complex effluent were isolated which consume phenol. Molecular analysis was used to identify bacteria and isolated bacteria were identified as Rhodococcus pyridinivorans (NS1, Advenella faeciporci (NS2 and Pseudomonas aeroginosa (NS3. Among the isolated strains, NS1 had the highest ability to degrade phenol. In order to observe the best yield in phenol biodegradation using NS1, optimization was performed using one factor at a time of experimental design to investigate the effect of four factors, including pH, temperature, phosphate and urea concentration. The optimal biodegradation condition through or tho pathway was pH = 8, urea = 1 g/L, temperature = 30°C and K2HPO4 = 0.5 g/L. Under the suggested condition, a biodegradation efficiency of 100% was achieved. Moreover, NS1 has shown growth and phenol degradation in concentrations between 250 to 2000 mg/L. In a nutshell, the results revealed thatphenol efficiently consumed by NS1 as the sole carbon source. Obviously, the isolate strain may be seen as an important tool in the bioremediation of wastewater effluent, petrochemical complex.
Optimization model for school transportation design based on economic and social efficiency
Energy Technology Data Exchange (ETDEWEB)
Heddebaut, O.; Ciommo, F. di
2016-07-01
The purpose of this paper is to design a model that allows to suggest new planning proposals on school transport, so that greater efficiency operational will be achieved. It is a multi-objective optimization problem including the minimization of the cost of busing and minimizes the total travel time of all students. The foundation of the model is the planning routes made by bus due to changes in the starting time in schools, so the buses are able to perform more than one route. The methodology is based on the School Bus Routing Problem, so that routes from different schools within a given time window are connected, and within the restrictions of the problem, the system costs are minimized. The proposed model is programmed to be applied in any generic case. This is a multi-objective problem, in which there will be several possible solutions, depending on the weight to be assigned to each of the variables involved, economic point of view versus social point of view. Therefore, the proposed model is helpful for policy planning school transportation, supporting the decision making under conditions of economic and social efficiency. The model has been applied in some schools located in an area of Cantabria (Spain), resulting in 71 possible optimal options that minimize the cost of school transport between 2,7% and 35,1% regarding to the current routes of school transport, with different school start time and minimum travel time for students. (Author)
International Nuclear Information System (INIS)
Sewsynker-Sukai, Yeshona; Faloye, Funmilayo; Kana, Evariste Bosco Gueguim
2016-01-01
In view of the looming energy crisis as a result of depleting fossil fuel resources and environmental concerns from greenhouse gas emissions, the need for sustainable energy sources has secured global attention. Research is currently focused towards renewable sources of energy due to their availability and environmental friendliness. Biofuel production like other bioprocesses is controlled by several process parameters including pH, temperature and substrate concentration; however, the improvement of biofuel production requires a robust process model that accurately relates the effect of input variables to the process output. Artificial neural networks (ANNs) have emerged as a tool for modelling complex, non-linear processes. ANNs are applied in the prediction of various processes; they are useful for virtual experimentations and can potentially enhance bioprocess research and development. In this study, recent findings on the application of ANN for the modelling and optimization of biohydrogen, biogas, biodiesel, microbial fuel cell technology and bioethanol are reviewed. In addition, comparative studies on the modelling efficiency of ANN and other techniques such as the response surface methodology are briefly discussed. The review highlights the efficiency of ANNs as a modelling and optimization tool in biofuel process development
A Building Energy Efficiency Optimization Method by Evaluating the Effective Thermal Zones Occupancy
Directory of Open Access Journals (Sweden)
Franco Cotana
2012-12-01
Full Text Available Building energy efficiency is strongly linked to the operations and control systems, together with the integrated performance of passive and active systems. In new high quality buildings in particular, where these two latter aspects have been already implemented at the design stage, users’ perspective, obtained through post-occupancy assessment, has to be considered to reduce whole energy requirement during service life. This research presents an innovative and low-cost methodology to reduce buildings’ energy requirements through post-occupancy assessment and optimization of energy operations using effective users’ attitudes and requirements as feedback. As a meaningful example, the proposed method is applied to a multipurpose building located in New York City, NY, USA, where real occupancy conditions are assessed. The effectiveness of the method is tested through dynamic simulations using a numerical model of the case study, calibrated through real monitoring data collected on the building. Results show that, for the chosen case study, the method provides optimized building energy operations which allow a reduction of primary energy requirements for HVAC, lighting, room-electricity, and auxiliary supply by about 21%. This paper shows that the proposed strategy represents an effective way to reduce buildings’ energy waste, in particular in those complex and high-efficiency buildings that are not performing as well as expected during the concept-design-commissioning stage, in particular due to the lack of feedback after the building handover.
Stilp, Christian E.; Kluender, Keith R.
2012-01-01
To the extent that sensorineural systems are efficient, redundancy should be extracted to optimize transmission of information, but perceptual evidence for this has been limited. Stilp and colleagues recently reported efficient coding of robust correlation (r = .97) among complex acoustic attributes (attack/decay, spectral shape) in novel sounds. Discrimination of sounds orthogonal to the correlation was initially inferior but later comparable to that of sounds obeying the correlation. These effects were attenuated for less-correlated stimuli (r = .54) for reasons that are unclear. Here, statistical properties of correlation among acoustic attributes essential for perceptual organization are investigated. Overall, simple strength of the principal correlation is inadequate to predict listener performance. Initial superiority of discrimination for statistically consistent sound pairs was relatively insensitive to decreased physical acoustic/psychoacoustic range of evidence supporting the correlation, and to more frequent presentations of the same orthogonal test pairs. However, increased range supporting an orthogonal dimension has substantial effects upon perceptual organization. Connectionist simulations and Eigenvalues from closed-form calculations of principal components analysis (PCA) reveal that perceptual organization is near-optimally weighted to shared versus unshared covariance in experienced sound distributions. Implications of reduced perceptual dimensionality for speech perception and plausible neural substrates are discussed. PMID:22292057
Directory of Open Access Journals (Sweden)
Xiaoxiao Xu
2012-03-01
Full Text Available The subcritical Organic Rankine Cycle (ORC with 28 working fluids for waste heat recovery is discussed in this paper. The effects of the temperature of the waste heat, the critical temperature of working fluids and the pinch temperature difference in the evaporator on the optimal evaporation temperature (OET of the ORC have been investigated. The second law efficiency of the system is regarded as the objective function and the evaporation temperature is optimized by using the quadratic approximations method. The results show that the OET will appear for the temperature ranges investigated when the critical temperatures of working fluids are lower than the waste heat temperatures by 18 ± 5 K under the pinch temperature difference of 5 K in the evaporator. Additionally, the ORC always exhibits the OET when the pinch temperature difference in the evaporator is raised under the fixed waste heat temperature. The maximum second law efficiency will decrease with the increase of pinch temperature difference in the evaporator.
Zhang, Minliang; Chen, Qian; Tao, Tianyang; Feng, Shijie; Hu, Yan; Li, Hui; Zuo, Chao
2017-08-21
Temporal phase unwrapping (TPU) is an essential algorithm in fringe projection profilometry (FPP), especially when measuring complex objects with discontinuities and isolated surfaces. Among others, the multi-frequency TPU has been proven to be the most reliable algorithm in the presence of noise. For a practical FPP system, in order to achieve an accurate, efficient, and reliable measurement, one needs to make wise choices about three key experimental parameters: the highest fringe frequency, the phase-shifting steps, and the fringe pattern sequence. However, there was very little research on how to optimize these parameters quantitatively, especially considering all three aspects from a theoretical and analytical perspective simultaneously. In this work, we propose a new scheme to determine simultaneously the optimal fringe frequency, phase-shifting steps and pattern sequence under multi-frequency TPU, robustly achieving high accuracy measurement by a minimum number of fringe frames. Firstly, noise models regarding phase-shifting algorithms as well as 3-D coordinates are established under a projector defocusing condition, which leads to the optimal highest fringe frequency for a FPP system. Then, a new concept termed frequency-to-frame ratio (FFR) that evaluates the magnitude of the contribution of each frame for TPU is defined, on which an optimal phase-shifting combination scheme is proposed. Finally, a judgment criterion is established, which can be used to judge whether the ratio between adjacent fringe frequencies is conducive to stably and efficiently unwrapping the phase. The proposed method provides a simple and effective theoretical framework to improve the accuracy, efficiency, and robustness of a practical FPP system in actual measurement conditions. The correctness of the derived models as well as the validity of the proposed schemes have been verified through extensive simulations and experiments. Based on a normal monocular 3-D FPP hardware system
Optimized efficiency of all-electric ships by dc hybrid power systems
Zahedi, Bijan; Norum, Lars E.; Ludvigsen, Kristine B.
2014-06-01
Hybrid power systems with dc distribution are being considered for commercial marine vessels to comply with new stringent environmental regulations, and to achieve higher fuel economy. In this paper, detailed efficiency analysis of a shipboard dc hybrid power system is carried out. An optimization algorithm is proposed to minimize fuel consumption under various loading conditions. The studied system includes diesel engines, synchronous generator-rectifier units, a full-bridge bidirectional converter, and a Li-Ion battery bank as energy storage. In order to evaluate potential fuel saving provided by such a system, an online optimization strategy for fuel consumption is implemented. An Offshore Support Vessel (OSV) is simulated over different operating modes using the online control strategy. The resulted consumed fuel in the simulation is compared to that of a conventional ac power system, and also a dc power system without energy storage. The results show that while the dc system without energy storage provides noticeable fuel saving compared to the conventional ac system, optimal utilization of the energy storage in the dc system results in twice as much fuel saving.
Directory of Open Access Journals (Sweden)
Ricardo Soto
2016-01-01
Full Text Available The Machine-Part Cell Formation Problem (MPCFP is a NP-Hard optimization problem that consists in grouping machines and parts in a set of cells, so that each cell can operate independently and the intercell movements are minimized. This problem has largely been tackled in the literature by using different techniques ranging from classic methods such as linear programming to more modern nature-inspired metaheuristics. In this paper, we present an efficient parallel version of the Migrating Birds Optimization metaheuristic for solving the MPCFP. Migrating Birds Optimization is a population metaheuristic based on the V-Flight formation of the migrating birds, which is proven to be an effective formation in energy saving. This approach is enhanced by the smart incorporation of parallel procedures that notably improve performance of the several sorting processes performed by the metaheuristic. We perform computational experiments on 1080 benchmarks resulting from the combination of 90 well-known MPCFP instances with 12 sorting configurations with and without threads. We illustrate promising results where the proposal is able to reach the global optimum in all instances, while the solving time with respect to a nonparallel approach is notably reduced.
Schumann, Marcel; Armen, Roger S
2013-05-30
Molecular docking of small-molecules is an important procedure for computer-aided drug design. Modeling receptor side chain flexibility is often important or even crucial, as it allows the receptor to adopt new conformations as induced by ligand binding. However, the accurate and efficient incorporation of receptor side chain flexibility has proven to be a challenge due to the huge computational complexity required to adequately address this problem. Here we describe a new docking approach with a very fast, graph-based optimization algorithm for assignment of the near-optimal set of residue rotamers. We extensively validate our approach using the 40 DUD target benchmarks commonly used to assess virtual screening performance and demonstrate a large improvement using the developed side chain optimization over rigid receptor docking (average ROC AUC of 0.693 vs. 0.623). Compared to numerous benchmarks, the overall performance is better than nearly all other commonly used procedures. Furthermore, we provide a detailed analysis of the level of receptor flexibility observed in docking results for different classes of residues and elucidate potential avenues for further improvement. Copyright © 2013 Wiley Periodicals, Inc.
A tool for efficient, model-independent management optimization under uncertainty
White, Jeremy; Fienen, Michael N.; Barlow, Paul M.; Welter, Dave E.
2018-01-01
To fill a need for risk-based environmental management optimization, we have developed PESTPP-OPT, a model-independent tool for resource management optimization under uncertainty. PESTPP-OPT solves a sequential linear programming (SLP) problem and also implements (optional) efficient, “on-the-fly” (without user intervention) first-order, second-moment (FOSM) uncertainty techniques to estimate model-derived constraint uncertainty. Combined with a user-specified risk value, the constraint uncertainty estimates are used to form chance-constraints for the SLP solution process, so that any optimal solution includes contributions from model input and observation uncertainty. In this way, a “single answer” that includes uncertainty is yielded from the modeling analysis. PESTPP-OPT uses the familiar PEST/PEST++ model interface protocols, which makes it widely applicable to many modeling analyses. The use of PESTPP-OPT is demonstrated with a synthetic, integrated surface-water/groundwater model. The function and implications of chance constraints for this synthetic model are discussed.
An optimization method of VON mapping for energy efficiency and routing in elastic optical networks
Liu, Huanlin; Xiong, Cuilian; Chen, Yong; Li, Changping; Chen, Derun
2018-03-01
To improve resources utilization efficiency, network virtualization in elastic optical networks has been developed by sharing the same physical network for difference users and applications. In the process of virtual nodes mapping, longer paths between physical nodes will consume more spectrum resources and energy. To address the problem, we propose a virtual optical network mapping algorithm called genetic multi-objective optimize virtual optical network mapping algorithm (GM-OVONM-AL), which jointly optimizes the energy consumption and spectrum resources consumption in the process of virtual optical network mapping. Firstly, a vector function is proposed to balance the energy consumption and spectrum resources by optimizing population classification and crowding distance sorting. Then, an adaptive crossover operator based on hierarchical comparison is proposed to improve search ability and convergence speed. In addition, the principle of the survival of the fittest is introduced to select better individual according to the relationship of domination rank. Compared with the spectrum consecutiveness-opaque virtual optical network mapping-algorithm and baseline-opaque virtual optical network mapping algorithm, simulation results show the proposed GM-OVONM-AL can achieve the lowest bandwidth blocking probability and save the energy consumption.
Qi, Xin; Ju, Guohao; Xu, Shuyan
2018-04-10
The phase diversity (PD) technique needs optimization algorithms to minimize the error metric and find the global minimum. Particle swarm optimization (PSO) is very suitable for PD due to its simple structure, fast convergence, and global searching ability. However, the traditional PSO algorithm for PD still suffers from the stagnation problem (premature convergence), which can result in a wrong solution. In this paper, the stagnation problem of the traditional PSO algorithm for PD is illustrated first. Then, an explicit strategy is proposed to solve this problem, based on an in-depth understanding of the inherent optimization mechanism of the PSO algorithm. Specifically, a criterion is proposed to detect premature convergence; then a redistributing mechanism is proposed to prevent premature convergence. To improve the efficiency of this redistributing mechanism, randomized Halton sequences are further introduced to ensure the uniform distribution and randomness of the redistributed particles in the search space. Simulation results show that this strategy can effectively solve the stagnation problem of the PSO algorithm for PD, especially for large-scale and high-dimension wavefront sensing and noisy conditions. This work is further verified by an experiment. This work can improve the robustness and performance of PD wavefront sensing.
Imani, Rana; Emami, Shahriar Hojjati; Faghihi, Shahab
2015-02-01
A method for carboxylation of graphene oxide (GO) with chloroacetic acid that precisely optimizes and controls the efficacy of the process for bioconjugation applications is proposed. Quantification of COOH groups on nano-graphene oxide sheets (NGOS) is performed by novel colorimetric methylene blue (MB) assay. The GO is synthesized and carboxylated by chloroacetic acid treatment under strong basic condition. The size and morphology of the as-prepared NGOS are characterized by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effect of acid to base molar ratio on the physical, chemical, and morphological properties of NGOS is analyzed by Fourier-transformed infrared spectrometry (FTIR), UV-Vis spectroscopy, X-ray diffraction (XRD), AFM, and zeta potential. For evaluation of bioconjugation efficacy, the synthesized nano-carriers with different carboxylation ratios are functionalized by octaarginine peptide sequence (R8) as a biomolecule model containing amine groups. The quantification of attached R8 peptides to graphene nano-sheets' surface is performed with a colorimetric-based assay which includes the application of 2,4,6-Trinitrobenzene sulfonic acid (TNBS). The results show that the thickness and lateral size of nano-sheets are dramatically decreased to 0.8 nm and 50-100 nm after carboxylation process, respectively. X-ray analysis shows the nano-sheets interlaying space is affected by the alteration of chloroacetic acid to base ratio. The MB assay reveals that the COOH groups on the surface of NGOS are maximized at the acid to base ratio of 2 which is confirmed by FTIR, XRD, and zeta potential. The TNBS assay also shows that bioconjugation of the optimized carboxylated NGOS sample with octaarginine peptide is 2.5 times more efficient compared to bare NGOS. The present work provides evidence that treatment of GO by chloroacetic acid under an optimized condition would create a functionalized high surface
Rating af banker og banksystemer
DEFF Research Database (Denmark)
Grosen, Anders
2010-01-01
Banksystemer over hele verdenen er med nød og næppe blevet reddet af diverse statslige hjælpepakker. Derfor er der i disse år øget fokus på banker og banksystemers rating. Denne interesse bliver ikke mindre af, at de statslige garantier til bankerne i mange lande udløber i de kommende år. Rating ...
Analyse og design af produktionssystemer
DEFF Research Database (Denmark)
Johansen, John; Riis, Jens Ove; Arlbjørn, Jan Stentoft
lys, men til vores store glæde og overraskelse har vi erfaret, at dele af materialet stadigvæk er anvendt på en del ingeniør- og økonomiuddannelser i Danmark. Nogle af de tanker og metoder som blev udviklet i ViPSprogrammet har overlevet og opfattes fortsat som relevante og anvendelige også til...
International Nuclear Information System (INIS)
Nabavi-Pelesaraei, Ashkan; Hosseinzadeh-Bandbafha, Homa; Qasemi-Kordkheili, Peyman; Kouchaki-Penchah, Hamed; Riahi-Dorcheh, Farshid
2016-01-01
In this study a non-parametric method of DEA (Data Envelopment Analysis) and MOGA (Multi-Objective Genetic Algorithm) were used to estimate the energy efficiency and greenhouse gas emissions reduction of wheat farmers in Ahvaz county of Iran. Data were collected using a face-to-face questionnaire method from 39 farmers. The results showed that based on constant returns to scale model, 41.02% of wheat farms were efficient, though based on variable returns to scale model it was 53.23%. The average of technical, pure technical and scale efficiency of wheat farms were 0.94, 0.95 and 0.98, respectively. By following the recommendations of this study, 3640.90 MJ ha"−"1 could be saved (9.13% of total input energy). Moreover, 42 optimal units were found by MOGA. The total energy required and GHG (greenhouse gas) emissions of the best generation of MOGA were about 23105 MJ ha"−"1 and 340 kgCO_2_e_q_. ha"−"1, respectively. The results revealed that the total energy required of MOGA was less than DEA, significantly. Also, the GHG emissions of present, DEA and MOGA farms were about 903, 837 and 340 kgCO_2_e_q_. ha"−"1, respectively. - Highlights: • We analyze the energy efficiency and GHG emissions of wheat production in Iran. • The technical and pure technical efficiencies were 0.94 and 0.95 respectively. • DEA can be saved total energy and GHG emissions 9.13% and 7.28% respectively. • MOGA can be reduced total energy and GHG emissions more than DEA significantly.
Directory of Open Access Journals (Sweden)
Belošević Srđan V.
2016-01-01
Full Text Available Pulverized coal-fired power plants should provide higher efficiency of energy conversion, flexibility in terms of boiler loads and fuel characteristics and emission reduction of pollutants like nitrogen oxides. Modification of combustion process is a cost-effective technology for NOx control. For optimization of complex processes, such as turbulent reactive flow in coal-fired furnaces, mathematical modeling is regularly used. The NOx emission reduction by combustion modifications in the 350 MWe Kostolac B boiler furnace, tangentially fired by pulverized Serbian lignite, is investigated in the paper. Numerical experiments were done by an in-house developed three-dimensional differential comprehensive combustion code, with fuel- and thermal-NO formation/destruction reactions model. The code was developed to be easily used by engineering staff for process analysis in boiler units. A broad range of operating conditions was examined, such as fuel and preheated air distribution over the burners and tiers, operation mode of the burners, grinding fineness and quality of coal, boiler loads, cold air ingress, recirculation of flue gases, water-walls ash deposition and combined effect of different parameters. The predictions show that the NOx emission reduction of up to 30% can be achieved by a proper combustion organization in the case-study furnace, with the flame position control. Impact of combustion modifications on the boiler operation was evaluated by the boiler thermal calculations suggesting that the facility was to be controlled within narrow limits of operation parameters. Such a complex approach to pollutants control enables evaluating alternative solutions to achieve efficient and low emission operation of utility boiler units. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in
DEFF Research Database (Denmark)
Introduktion til Kants Kritik af dømmekraften bestående af otte artikler, der følger værkets egen tematiske opbygning......Introduktion til Kants Kritik af dømmekraften bestående af otte artikler, der følger værkets egen tematiske opbygning...
Bilag til forskningsoversigt - Effekterne af Cooperative Learning
DEFF Research Database (Denmark)
Larsen, Lea Lund
Ved en opsamling af de empiriske studier vedrørende effekten af CL inden for voksenundervisningsfeltet ses en overvægt af studier, som rapporterer en positiv effekt af CL i forhold til de voksne lærendes faglige udbytte. En meta-analyse over 168 amerikanske undersøgelser på universitetsniveau vis...
Beregning af luftlydisolation mellem to rum
DEFF Research Database (Denmark)
Donovan, A.
Meddelelsen bringer resultaterne af en forundersøgelse af to beregningsmetoder. Den ene metode belyses nærmere gennem nogle forenklede eksempler, der viser omfanget af regnearbejdet og peger på nogle af de vanskeligheder det vil indebære at opstille en praktisk anvendelig beregningsmetode....
På sporet af de gyldne opskrifter?
DEFF Research Database (Denmark)
Poulfelt, Flemming
2015-01-01
Børsen Ledelse. Markedet for kogebøger er stort. For der produceres hvert år et hav nye af slagsen. Nogle udgives af kendte kokke, nogle af særlige eksperter inden for kost og motion, og andre af personer, der har en ægte interesse inden for gastronomi og mad. På ledelsesområdet findes en...
Udvikling af systemleverancer, parametri og BIM
DEFF Research Database (Denmark)
Kortegaard, Per
2016-01-01
Seminaret rummede indlæg fra både nogle af projektets tidligere ph.d.-studerende og forskellige kompetente professionelle personer fra forskellige grene af praksis. Seminaret gav samlet et fint billede af status indenfor udviklingen af systemleverancer og deres anvendelse i relation til BIM...
DEFF Research Database (Denmark)
Hermansen, Jonathan
2017-01-01
Denne bog gennemgår alle surveyarbejdets faser og giver en praktisk indføring i •design af undersøgelsen og udvælgelse af stikprøver, •formulering af spørgeskemaer samt indsamling og kodning af data, •metoder til at analysere resultaterne....
DEFF Research Database (Denmark)
Greve, Carsten
2013-01-01
Transportdebatten: En mulig finansiering af fremtidige infrastrukturprojekter kunne være OPP. Danmark bør tage ved lære af erfaringer fra Canada.......Transportdebatten: En mulig finansiering af fremtidige infrastrukturprojekter kunne være OPP. Danmark bør tage ved lære af erfaringer fra Canada....
Fremtidens biblioteksbetjening af børn
DEFF Research Database (Denmark)
Høyrup, Helene
2008-01-01
Rapporten er resultatet af et tværministerielt udvalgsarbejde nedsat af Kulturministeriet. Kommissoriet har været at nytænke biblioteksbetjeningen af børn, så den passer til vidensamfundet. Udvalgsarbejdet munder ud i ti bud for fremtidens biblioteksbetjening af børn....
Regulering af det psykiske arbejdsmiljø
DEFF Research Database (Denmark)
Nielsen, Klaus T.
nationale informationer om reguleringen af det psykiske arbejdsmiljø. Rapport er bygget op med ◊ et internationalt overblik over regulering af psykisk arbejdsmiljø ◊ en bredere diskussion af reguleringens dilemmaer ◊ en gennemgang af den aktuelle danske udvikling ◊ udfordringerne på området...
DEFF Research Database (Denmark)
Henze-Pedersen, Sofie; Kohl, Katrine Syppli; Oldrup, Helene
(MultifunC), som allerede havde vist lovende resultater i Norge og Sverige. I 2011 og 2012 åbnede to danske MultifunC-institutioner derfor i henholdsvis København og Aarhus. Denne rapport undersøger, hvordan implementeringen af MultifunC-programmet er forløbet i Danmark. Undersøgelsen viser, at ingen af de...... to danske institutioner lykkedes med at implementere MultifunC tilfredsstillende i løbet af implementeringsperioden. Det har fx været vanskeligt at implementere det tætte tværfaglige samarbejde mellem medarbejdere med forskellige fagprofessionelle baggrunde, som behandlingsprogrammet indebærer. Det har...... desuden været særdeles vanskeligt for de danske MultifunC-institutioner at få etableret det eksterne samarbejde med de sociale myndigheder i kommunerne, politiet, skoler og praktiksteder samt fritidstilbud i nærområdet, som også er en væsentlig del af behandlingsprogrammet. Undersøgelsen af finansieret af...
Design and Optimization of a 3-Coil Inductive Link for Efficient Wireless Power Transmission.
Kiani, Mehdi; Jow, Uei-Ming; Ghovanloo, Maysam
2011-07-14
Inductive power transmission is widely used to energize implantable microelectronic devices (IMDs), recharge batteries, and energy harvesters. Power transfer efficiency (PTE) and power delivered to the load (PDL) are two key parameters in wireless links, which affect the energy source specifications, heat dissipation, power transmission range, and interference with other devices. To improve the PTE, a 4-coil inductive link has been recently proposed. Through a comprehensive circuit based analysis that can guide a design and optimization scheme, we have shown that despite achieving high PTE at larger coil separations, the 4-coil inductive links fail to achieve a high PDL. Instead, we have proposed a 3-coil inductive power transfer link with comparable PTE over its 4-coil counterpart at large coupling distances, which can also achieve high PDL. We have also devised an iterative design methodology that provides the optimal coil geometries in a 3-coil inductive power transfer link. Design examples of 2-, 3-, and 4-coil inductive links have been presented, and optimized for 13.56 MHz carrier frequency and 12 cm coupling distance, showing PTEs of 15%, 37%, and 35%, respectively. At this distance, the PDL of the proposed 3-coil inductive link is 1.5 and 59 times higher than its equivalent 2- and 4-coil links, respectively. For short coupling distances, however, 2-coil links remain the optimal choice when a high PDL is required, while 4-coil links are preferred when the driver has large output resistance or small power is needed. These results have been verified through simulations and measurements.
Nacelle Chine Installation Based on Wind-Tunnel Test Using Efficient Global Optimization
Kanazaki, Masahiro; Yokokawa, Yuzuru; Murayama, Mitsuhiro; Ito, Takeshi; Jeong, Shinkyu; Yamamoto, Kazuomi
Design exploration of a nacelle chine installation was carried out. The nacelle chine improves stall performance when deploying multi-element high-lift devices. This study proposes an efficient design process using a Kriging surrogate model to determine the nacelle chine installation point in wind-tunnel tests. The design exploration was conducted in a wind-tunnel using the JAXA high-lift aircraft model at the JAXA Large-scale Low-speed Wind Tunnel. The objective was to maximize the maximum lift. The chine installation points were designed on the engine nacelle in the axial and chord-wise direction, while the geometry of the chine was fixed. In the design process, efficient global optimization (EGO) which includes Kriging model and genetic algorithm (GA) was employed. This method makes it possible both to improve the accuracy of the response surface and to explore the global optimum efficiently. Detailed observations of flowfields using the Particle Image Velocimetry method confirmed the chine effect and design results.
Optimization of the Efficiency of a Neutron Detector to Measure (α, n) Reaction Cross-Section
Perello, Jesus; Montes, Fernando; Ahn, Tony; Meisel, Zach; Joint InstituteNuclear Astrophysics Team
2015-04-01
Nucleosynthesis, the origin of elements, is one of the greatest mysteries in physics. A recent particular nucleosynthesis process of interest is the charge-particle process (cpp). In the cpp, elements form by nuclear fusion reactions during supernovae. This process of nuclear fusion, (α,n), will be studied by colliding beam elements produced and accelerated at the National Superconducting Cyclotron Laboratory (NSCL) to a helium-filled cell target. The elements will fuse with α (helium nuclei) and emit neutrons during the reaction. The neutrons will be detected for a count of fused-elements, thus providing us the probability of such reactions. The neutrons will be detected using the Neutron Emission Ratio Observer (NERO). Currently, NERO's efficiency varies for neutrons at the expected energy range (0-12 MeV). To study (α,n), NERO's efficiency must be near-constant at these energies. Monte-Carlo N-Particle Transport Code (MCNP6), a software package that simulates nuclear processes, was used to optimize NERO configuration for the experiment. MCNP6 was used to simulate neutron interaction with different NERO configurations at the expected neutron energies. By adding additional 3He detectors and polyethylene, a near-constant efficiency at these energies was obtained in the simulations. With the new NERO configuration, study of the (α,n) reactions can begin, which may explain how elements are formed in the cpp. SROP MSU, NSF, JINA, McNair Society.
Directory of Open Access Journals (Sweden)
Modesto Pérez-Sánchez
2017-10-01
Full Text Available Analyses of possible synergies between energy recovery and water management are essential for achieving sustainable advances in the performance of pressurized irrigation networks. Nowadays, the use of micro hydropower in water systems is being analysed to improve the overall energy efficiency. In this line, the present research is focused on the proposal and development of a novel optimization strategy for increasing the energy efficiency in pressurized irrigation networks by energy recovering. The recovered energy is maximized considering different objective functions, including feasibility index: the best energy converter must be selected, operating in its best efficiency conditions by variation of its rotational speed, providing the required flow in each moment. These flows (previously estimated through farmers’ habits are compared with registered values of flow in the main line with very suitable calibration results, getting a Nash–Sutcliffe value above 0.6 for different time intervals, and a PBIAS index below 10% in all time interval range. The methodology was applied to a Vallada network obtaining a maximum recovered energy of 58.18 MWh/year (41.66% of the available energy, improving the recovered energy values between 141 and 184% when comparing to energy recovery considering a constant rotational speed. The proposal of this strategy shows the real possibility of installing micro hydropower machines to improve the water–energy nexus management in pressurized systems.
International Nuclear Information System (INIS)
Kamalzare, Mahmoud; Johnson, Erik A; Wojtkiewicz, Steven F
2014-01-01
Designing control strategies for smart structures, such as those with semiactive devices, is complicated by the nonlinear nature of the feedback control, secondary clipping control and other additional requirements such as device saturation. The usual design approach resorts to large-scale simulation parameter studies that are computationally expensive. The authors have previously developed an approach for state-feedback semiactive clipped-optimal control design, based on a nonlinear Volterra integral equation that provides for the computationally efficient simulation of such systems. This paper expands the applicability of the approach by demonstrating that it can also be adapted to accommodate more realistic cases when, instead of full state feedback, only a limited set of noisy response measurements is available to the controller. This extension requires incorporating a Kalman filter (KF) estimator, which is linear, into the nominal model of the uncontrolled system. The efficacy of the approach is demonstrated by a numerical study of a 100-degree-of-freedom frame model, excited by a filtered Gaussian random excitation, with noisy acceleration sensor measurements to determine the semiactive control commands. The results show that the proposed method can improve computational efficiency by more than two orders of magnitude relative to a conventional solver, while retaining a comparable level of accuracy. Further, the proposed approach is shown to be similarly efficient for an extensive Monte Carlo simulation to evaluate the effects of sensor noise levels and KF tuning on the accuracy of the response. (paper)
An efficient inverse radiotherapy planning method for VMAT using quadratic programming optimization.
Hoegele, W; Loeschel, R; Merkle, N; Zygmanski, P
2012-01-01
The purpose of this study is to investigate the feasibility of an inverse planning optimization approach for the Volumetric Modulated Arc Therapy (VMAT) based on quadratic programming and the projection method. The performance of this method is evaluated against a reference commercial planning system (eclipse(TM) for rapidarc(TM)) for clinically relevant cases. The inverse problem is posed in terms of a linear combination of basis functions representing arclet dose contributions and their respective linear coefficients as degrees of freedom. MLC motion is decomposed into basic motion patterns in an intuitive manner leading to a system of equations with a relatively small number of equations and unknowns. These equations are solved using quadratic programming under certain limiting physical conditions for the solution, such as the avoidance of negative dose during optimization and Monitor Unit reduction. The modeling by the projection method assures a unique treatment plan with beneficial properties, such as the explicit relation between organ weightings and the final dose distribution. Clinical cases studied include prostate and spine treatments. The optimized plans are evaluated by comparing isodose lines, DVH profiles for target and normal organs, and Monitor Units to those obtained by the clinical treatment planning system eclipse(TM). The resulting dose distributions for a prostate (with rectum and bladder as organs at risk), and for a spine case (with kidneys, liver, lung and heart as organs at risk) are presented. Overall, the results indicate that similar plan qualities for quadratic programming (QP) and rapidarc(TM) could be achieved at significantly more efficient computational and planning effort using QP. Additionally, results for the quasimodo phantom [Bohsung et al., "IMRT treatment planning: A comparative inter-system and inter-centre planning exercise of the estro quasimodo group," Radiother. Oncol. 76(3), 354-361 (2005)] are presented as an example
Tuning the Music: Acoustic Force Spectroscopy (AFS) 2.0
Kamsma, D.; Creyghton, R.; Sitters, G.; Wuite, G.J.L.; Peterman, E.J.G.
2016-01-01
AFS is a recently introduced high-throughput single-molecule technique that allows studying structural and mechanochemical properties of many biomolecules in parallel. To further improve the method, we developed a modelling tool to optimize the layer thicknesses, and a calibration method to
Energy Technology Data Exchange (ETDEWEB)
1994-04-01
The first aim was to identify the barriers to energy efficient projecting and related purchasing in businesses and to suggest means to remove these barriers. It is stated that if energy consumption is taken into consideration in the first planning phase and before making purchases, energy-saving can be achieved at a reasonable investment. Examples are given to illustrate this point. As a result of interviews and discussions with involved persons, it was found that constraints are not only economical but also take the form of lack of sufficient time, procrastination on the part of decision-makers, lack of relevant information and a certain reluctance to experiment with new ideas. A three-phased decision process is suggested. It was found that energy-saving was not always given very high priority. Consultants should point out the relation between energy saving and environmental protection. Training and campaigning activities are essential. Consultants should be able to produce documentation to prove their theories on energy saving within industry. An effective organisation of consultancy services is essential. Clients` attitudes to energy savings must be influenced. A sequence of practical goals should be set up during the planning process. Cost-benefit analyses were carried out in relation to seven of the suggested plans for breaking down the barriers to energy-effective projecting. (AB) (16 refs.)
On the efficiency of a randomized mirror descent algorithm in online optimization problems
Gasnikov, A. V.; Nesterov, Yu. E.; Spokoiny, V. G.
2015-04-01
A randomized online version of the mirror descent method is proposed. It differs from the existing versions by the randomization method. Randomization is performed at the stage of the projection of a subgradient of the function being optimized onto the unit simplex rather than at the stage of the computation of a subgradient, which is common practice. As a result, a componentwise subgradient descent with a randomly chosen component is obtained, which admits an online interpretation. This observation, for example, has made it possible to uniformly interpret results on weighting expert decisions and propose the most efficient method for searching for an equilibrium in a zero-sum two-person matrix game with sparse matrix.
Using Markov Chains and Multi-Objective Optimization for Energy-Efficient Context Recognition
Directory of Open Access Journals (Sweden)
Vito Janko
2017-12-01
Full Text Available The recognition of the user’s context with wearable sensing systems is a common problem in ubiquitous computing. However, the typically small battery of such systems often makes continuous recognition impractical. The strain on the battery can be reduced if the sensor setting is adapted to each context. We propose a method that efficiently finds near-optimal sensor settings for each context. It uses Markov chains to simulate the behavior of the system in different configurations and the multi-objective genetic algorithm to find a set of good non-dominated configurations. The method was evaluated on three real-life datasets and found good trade-offs between the system’s energy expenditure and the system’s accuracy. One of the solutions, for example, consumed five-times less energy than the default one, while sacrificing only two percentage points of accuracy.
Using Markov Chains and Multi-Objective Optimization for Energy-Efficient Context Recognition.
Janko, Vito; Luštrek, Mitja
2017-12-29
The recognition of the user's context with wearable sensing systems is a common problem in ubiquitous computing. However, the typically small battery of such systems often makes continuous recognition impractical. The strain on the battery can be reduced if the sensor setting is adapted to each context. We propose a method that efficiently finds near-optimal sensor settings for each context. It uses Markov chains to simulate the behavior of the system in different configurations and the multi-objective genetic algorithm to find a set of good non-dominated configurations. The method was evaluated on three real-life datasets and found good trade-offs between the system's energy expenditure and the system's accuracy. One of the solutions, for example, consumed five-times less energy than the default one, while sacrificing only two percentage points of accuracy.
Using Markov Chains and Multi-Objective Optimization for Energy-Efficient Context Recognition †
Janko, Vito
2017-01-01
The recognition of the user’s context with wearable sensing systems is a common problem in ubiquitous computing. However, the typically small battery of such systems often makes continuous recognition impractical. The strain on the battery can be reduced if the sensor setting is adapted to each context. We propose a method that efficiently finds near-optimal sensor settings for each context. It uses Markov chains to simulate the behavior of the system in different configurations and the multi-objective genetic algorithm to find a set of good non-dominated configurations. The method was evaluated on three real-life datasets and found good trade-offs between the system’s energy expenditure and the system’s accuracy. One of the solutions, for example, consumed five-times less energy than the default one, while sacrificing only two percentage points of accuracy. PMID:29286301
Research on optimization of combustion efficiency of thermal power unit based on genetic algorithm
Zhou, Qiongyang
2018-04-01
In order to improve the economic performance and reduce pollutant emissions of thermal power units, the characteristics of neural network in establishing boiler combustion model are analyzed based on the analysis of the main factors affecting boiler efficiency by using orthogonal method. In addition, on the basis of this model, the genetic algorithm is used to find the best control amount of the furnace combustion in a certain working condition. Through the genetic algorithm based on real number encoding and roulette selection is concluded: the best control quantity at a condition of furnace combustion can be combined with the boiler combustion system model for neural network training. The precision of the neural network model is further improved, and the basic work is laid for the research of the whole boiler combustion optimization system.
Betydning af centraliseret behandling
DEFF Research Database (Denmark)
Højgaard, Liselotte
2006-01-01
hospital organizations. Centralization with a focus on efficiency and low cost, as well as decentralization combined with the loss of university hospital functions, will further challenge the conditions of clinical research already seen worldwide and also experienced in Denmark....
Optimal production of renewable hydrogen based on an efficient energy management strategy
International Nuclear Information System (INIS)
Ziogou, Chrysovalantou; Ipsakis, Dimitris; Seferlis, Panos; Bezergianni, Stella; Papadopoulou, Simira; Voutetakis, Spyros
2013-01-01
This work presents the development of a flexible energy management strategy (EMS) for a renewable hydrogen production unit through water electrolysis with solar power. The electricity flow of the unit is controlled by a smart microgrid and the overall unattended operation is achieved by a supervisory control system. The proposed approach formalizes the knowledge regarding the system operation using a finite-state machine (FSM) which is subsequently combined with a propositional-based logic to describe the transitions among various process states. The operating rules for the integrated system are derived by taking into account both the operating constraints and the interaction effects among the individual subsystems in a systematic way. Optimal control system parameter values are obtained so that a system performance criterion incorporating efficient and economic operation is satisfied. The resulted EMS has been deployed to the industrial automation system that monitors and controls a small-scale experimental solar hydrogen production unit. The overall performance of the proposed EMS in the experimental unit has been evaluated over short-term and long-term operating periods resulting in smooth and efficient hydrogen production. - Highlights: • Development of an energy management strategy based on a finite-state machine and propositional-based reasoning. • Deployment of the energy-aware algorithm to an autonomous renewable hydrogen production unit. • Supervisory control of the electricity flow by a smart microgrid using an industrial automation system. • Unattended operation and remote monitoring incorporating subsystem interactions in a systematic way. • Optimal hydrogen production regardless of the weather conditions through water electrolysis with solar power
Madani, N.; Kimball, J. S.; Running, S. W.
2014-12-01
Remote sensing based light use efficiency (LUE) models, including the MODIS (MODerate resolution Imaging Spectroradiometer) MOD17 algorithm are commonly used for regional estimation and monitoring of vegetation gross primary production (GPP) and photosynthetic carbon (CO2) uptake. A common model assumption is that plants in a biome matrix operate at their photosynthetic capacity under optimal climatic conditions. A prescribed biome maximum light use efficiency parameter defines the maximum photosynthetic carbon conversion rate under prevailing climate conditions and is a large source of model uncertainty. Here, we used tower (FLUXNET) eddy covariance measurement based carbon flux data for estimating optimal LUE (LUEopt) over a North American domain. LUEopt was first estimated using tower observed daily carbon fluxes, meteorology and satellite (MODIS) observed fraction of photosynthetically active radiation (FPAR). LUEopt was then spatially interpolated over the domain using empirical models derived from independent geospatial data including global plant traits, surface soil moisture, terrain aspect, land cover type and percent tree cover. The derived LUEopt maps were then used as primary inputs to the MOD17 LUE algorithm for regional GPP estimation; these results were evaluated against tower observations and alternate MOD17 GPP estimates determined using Biome-specific LUEopt constants. Estimated LUEopt shows large spatial variability within and among different land cover classes indicated from a sparse North American tower network. Leaf nitrogen content and soil moisture are two important factors explaining LUEopt spatial variability. GPP estimated from spatially explicit LUEopt inputs shows significantly improved model accuracy against independent tower observations (R2 = 0.76; Mean RMSE plant trait information can explain spatial heterogeneity in LUEopt, leading to improved GPP estimates from satellite based LUE models.
An efficient global energy optimization approach for robust 3D plane segmentation of point clouds
Dong, Zhen; Yang, Bisheng; Hu, Pingbo; Scherer, Sebastian
2018-03-01
Automatic 3D plane segmentation is necessary for many applications including point cloud registration, building information model (BIM) reconstruction, simultaneous localization and mapping (SLAM), and point cloud compression. However, most of the existing 3D plane segmentation methods still suffer from low precision and recall, and inaccurate and incomplete boundaries, especially for low-quality point clouds collected by RGB-D sensors. To overcome these challenges, this paper formulates the plane segmentation problem as a global energy optimization because it is robust to high levels of noise and clutter. First, the proposed method divides the raw point cloud into multiscale supervoxels, and considers planar supervoxels and individual points corresponding to nonplanar supervoxels as basic units. Then, an efficient hybrid region growing algorithm is utilized to generate initial plane set by incrementally merging adjacent basic units with similar features. Next, the initial plane set is further enriched and refined in a mutually reinforcing manner under the framework of global energy optimization. Finally, the performances of the proposed method are evaluated with respect to six metrics (i.e., plane precision, plane recall, under-segmentation rate, over-segmentation rate, boundary precision, and boundary recall) on two benchmark datasets. Comprehensive experiments demonstrate that the proposed method obtained good performances both in high-quality TLS point clouds (i.e., http://SEMANTIC3D.NET)
The Fuzzy Logic Method to Efficiently Optimize Electricity Consumption in Individual Housing
Directory of Open Access Journals (Sweden)
Sébastien Bissey
2017-10-01
Full Text Available Electricity demand shifting and reduction still raise a huge interest for end-users at the household level, especially because of the ongoing design of a dynamic pricing approach. In particular, end-users must act as the starting point for decreasing their consumption during peak hours to prevent the need to extend the grid and thus save considerable costs. This article points out the relevance of a fuzzy logic algorithm to efficiently predict short term load consumption (STLC. This approach is the cornerstone of a new home energy management (HEM algorithm which is able to optimize the cost of electricity consumption, while smoothing the peak demand. The fuzzy logic modeling involves a strong reliance on a complete database of real consumption data from many instrumented show houses. The proposed HEM algorithm enables any end-user to manage his electricity consumption with a high degree of flexibility and transparency, and “reshape” the load profile. For example, this can be mainly achieved using smart control of a storage system coupled with remote management of the electric appliances. The simulation results demonstrate that an accurate prediction of STLC gives the possibility of achieving optimal planning and operation of the HEM system.
Wei, Xiuyan; Song, Xinyue; Dong, Dong; Keyhani, Nemat O; Yao, Lindan; Zang, Xiangyun; Dong, Lili; Gu, Zijian; Fu, Delai; Liu, Xingzhong; Qiu, Junzhi; Guan, Xiong
2016-07-01
The insect pathogenic fungus Aschersonia placenta is a highly effective pathogen of whiteflies and scale insects. However, few genetic tools are currently available for studying this organism. Here we report on the conditions for the production of transformable A. placenta protoplasts using an optimized protocol based on the response surface method (RSM). Critical parameters for protoplast production were modelled by using a Box-Behnken design (BBD) involving 3 levels of 3 variables that was subsequently tested to verify its ability to predict protoplast production (R(2) = 0.9465). The optimized conditions resulted in the highest yield of protoplasts ((4.41 ± 0.02) × 10(7) cells/mL of culture, mean ± SE) when fungal cells were treated with 26.1 mg/mL of lywallzyme for 4 h of digestion, and subsequently allowed to recover for 64.6 h in 0.7 mol/L NaCl-Tris buffer. The latter was used as an osmotic stabilizer. The yield of protoplasts was approximately 10-fold higher than that of the nonoptimized conditions. Generated protoplasts were transformed with vector PbarGPE containing the bar gene as the selection marker. Transformation efficiency was 300 colonies/(μg DNA·10(7) protoplasts), and integration of the vector DNA was confirmed by PCR. The results show that rational design strategies (RSM and BBD methods) are useful to increase the production of fungal protoplasts for a variety of downstream applications.
Optimal Tradable Credits Scheme and Congestion Pricing with the Efficiency Analysis to Congestion
Directory of Open Access Journals (Sweden)
Ge Gao
2015-01-01
Full Text Available We allow for three traffic scenarios: the tradable credits scheme, congestion pricing, and no traffic measure. The utility functions of different modes (car, bus, and bicycle are developed by considering the income’s impact on travelers’ behaviors. Their purpose is to analyze the demand distribution of different modes. A social optimization model is built aiming at maximizing the social welfare. The optimal tradable credits scheme (distribution of credits, credits charging, and the credit price, congestion pricing fees, bus frequency, and bus fare are obtained by solving the model. Mode choice behavior under the tradable credits scheme is also studied. Numerical examples are presented to demonstrate the model’s availability and explore the effects of the three schemes on traffic system’s performance. Results show congestion pricing would earn more social welfare than the other traffic measures. However, tradable credits scheme will give travelers more consumer surplus than congestion pricing. Travelers’ consumer surplus with congestion pricing is the minimum, which injures the travelers’ benefits. Tradable credits scheme is considered the best scenario by comparing the three scenarios’ efficiency.
Lin, Wushao; Bi, Lei; Liu, Dong; Zhang, Kejun
2017-08-21
The extinction efficiencies of atmospheric particles are essential to determining radiation attenuation and thus are fundamentally related to atmospheric radiative transfer. The extinction efficiencies can also be used to retrieve particle sizes or refractive indices through particle characterization techniques. This study first uses the Debye series to improve the accuracy of high-frequency extinction formulae for spheroids in the context of Complex angular momentum theory by determining an optimal number of edge-effect terms. We show that the optimal edge-effect terms can be accurately obtained by comparing the results from the approximate formula with their counterparts computed from the invariant imbedding Debye series and T-matrix methods. An invariant imbedding T-matrix method is employed for particles with strong absorption, in which case the extinction efficiency is equivalent to two plus the edge-effect efficiency. For weakly absorptive or non-absorptive particles, the T-matrix results contain the interference between the diffraction and higher-order transmitted rays. Therefore, the Debye series was used to compute the edge-effect efficiency by separating the interference from the transmission on the extinction efficiency. We found that the optimal number strongly depends on the refractive index and is relatively insensitive to the particle geometry and size parameter. By building a table of optimal numbers of edge-effect terms, we developed an efficient and accurate extinction simulator that has been fully tested for randomly oriented spheroids with various aspect ratios and a wide range of refractive indices.
Brug af alternativ isolering i forbindelse med renovering af ældre etageejendomme
DEFF Research Database (Denmark)
Hansen, Ernst Jan de Place
2003-01-01
Resume af rapport om praktiske erfaringer med brug af alternative isoleringsmaterialer i en renoveringsopgave, udarbejdet af Byfornyelse København m.fl. under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"...
Energy Technology Data Exchange (ETDEWEB)
Imani, Rana; Emami, Shahriar Hojjati, E-mail: semami@aut.ac.ir [Amirkabir University of Technology, Department of Biomedical Engineering (Iran, Islamic Republic of); Faghihi, Shahab, E-mail: shahabeddin.faghihi@mail.mcgill.ca, E-mail: sfaghihi@nigeb.ac.ir [National Institute of Genetic Engineering and Biotechnology, Tissue Engineering and Biomaterials Division (Iran, Islamic Republic of)
2015-02-15
A method for carboxylation of graphene oxide (GO) with chloroacetic acid that precisely optimizes and controls the efficacy of the process for bioconjugation applications is proposed. Quantification of COOH groups on nano-graphene oxide sheets (NGOS) is performed by novel colorimetric methylene blue (MB) assay. The GO is synthesized and carboxylated by chloroacetic acid treatment under strong basic condition. The size and morphology of the as-prepared NGOS are characterized by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effect of acid to base molar ratio on the physical, chemical, and morphological properties of NGOS is analyzed by Fourier-transformed infrared spectrometry (FTIR), UV–Vis spectroscopy, X-ray diffraction (XRD), AFM, and zeta potential. For evaluation of bioconjugation efficacy, the synthesized nano-carriers with different carboxylation ratios are functionalized by octaarginine peptide sequence (R8) as a biomolecule model containing amine groups. The quantification of attached R8 peptides to graphene nano-sheets’ surface is performed with a colorimetric-based assay which includes the application of 2,4,6-Trinitrobenzene sulfonic acid (TNBS). The results show that the thickness and lateral size of nano-sheets are dramatically decreased to 0.8 nm and 50–100 nm after carboxylation process, respectively. X-ray analysis shows the nano-sheets interlaying space is affected by the alteration of chloroacetic acid to base ratio. The MB assay reveals that the COOH groups on the surface of NGOS are maximized at the acid to base ratio of 2 which is confirmed by FTIR, XRD, and zeta potential. The TNBS assay also shows that bioconjugation of the optimized carboxylated NGOS sample with octaarginine peptide is 2.5 times more efficient compared to bare NGOS. The present work provides evidence that treatment of GO by chloroacetic acid under an optimized condition would create a functionalized high
International Nuclear Information System (INIS)
Imani, Rana; Emami, Shahriar Hojjati; Faghihi, Shahab
2015-01-01
A method for carboxylation of graphene oxide (GO) with chloroacetic acid that precisely optimizes and controls the efficacy of the process for bioconjugation applications is proposed. Quantification of COOH groups on nano-graphene oxide sheets (NGOS) is performed by novel colorimetric methylene blue (MB) assay. The GO is synthesized and carboxylated by chloroacetic acid treatment under strong basic condition. The size and morphology of the as-prepared NGOS are characterized by scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effect of acid to base molar ratio on the physical, chemical, and morphological properties of NGOS is analyzed by Fourier-transformed infrared spectrometry (FTIR), UV–Vis spectroscopy, X-ray diffraction (XRD), AFM, and zeta potential. For evaluation of bioconjugation efficacy, the synthesized nano-carriers with different carboxylation ratios are functionalized by octaarginine peptide sequence (R8) as a biomolecule model containing amine groups. The quantification of attached R8 peptides to graphene nano-sheets’ surface is performed with a colorimetric-based assay which includes the application of 2,4,6-Trinitrobenzene sulfonic acid (TNBS). The results show that the thickness and lateral size of nano-sheets are dramatically decreased to 0.8 nm and 50–100 nm after carboxylation process, respectively. X-ray analysis shows the nano-sheets interlaying space is affected by the alteration of chloroacetic acid to base ratio. The MB assay reveals that the COOH groups on the surface of NGOS are maximized at the acid to base ratio of 2 which is confirmed by FTIR, XRD, and zeta potential. The TNBS assay also shows that bioconjugation of the optimized carboxylated NGOS sample with octaarginine peptide is 2.5 times more efficient compared to bare NGOS. The present work provides evidence that treatment of GO by chloroacetic acid under an optimized condition would create a functionalized high
Optimization of nanoparticle structure for improved conversion efficiency of dye solar cell
Energy Technology Data Exchange (ETDEWEB)
Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my [Centre of Innovative Nanostructure and Nanodevices, Universiti Teknologi PETRONAS, Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Zaine, Siti Nur Azella, E-mail: ct.azella@gmail.com.my [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Seri Iskandar, 31750 Tronoh, Perak (Malaysia)
2014-10-24
Heavy dye loading and the ability to contain the light within the thin layer (typically ∼12 μm) are the requirement needed for the photoelectrode material in order to enhance the harvesting efficiency of dye solar cell. This can be realized by optimizing the particle size with desirable crystal structure. The paper reports the investigation on the dependency of the dye loading and light scattering on the properties of nanostructured photoelectrode materials by comparing 4 different samples of TiO{sub 2} in the form of nanoparticles and micron-sized TiO{sub 2} aggregates which composed of nanocrystallites. Their properties were evaluated by using scanning electron microscopy, X-ray diffraction and UVVis spectroscopy while the performance of the fabricated test cells were measured using universal photovoltaic test system (UPTS) under 1000 W/cm{sup 2} intensity of radiation. Nano sized particles provide large surface area which allow for greater dye adsorption but have no ability to retain the incident light in the TiO{sub 2} film. In contrast, micron-sized particles in the form of aggregates can generate light scattering allowing the travelling distance of the light to be extended and increasing the interaction between the photons and dye molecules adsorb on TiO{sub 2}nanocrystallites. This resulted in an improvement in the conversion efficiency of the aggregates that demonstrates the close relation between light scattering effect and the structure of the photolectrode film.
Development and optimization of an efficient qPCR system for olive authentication in edible oils.
Alonso-Rebollo, Alba; Ramos-Gómez, Sonia; Busto, María D; Ortega, Natividad
2017-10-01
The applicability of qPCR in olive-oil authentication depends on the DNA obtained from the oils and the amplification primers. Therefore, four olive-specific amplification systems based on the trnL gene were designed (A-, B-, C- and D-trnL systems). The qPCR conditions, primer concentration and annealing temperature, were optimized. The systems were tested for efficiency and sensitivity to select the most suitable for olive oil authentication. The selected system (D-trnL) demonstrated specificity toward olive in contrast to other oleaginous species (canola, soybean, sunflower, maize, peanut and coconut) and showed high sensitivity in a broad linear dynamic range (LOD and LOQ: 500ng - 0.0625pg). This qPCR system enabled detection, with high sensitivity and specificity, of olive DNA isolated from oils processed in different ways, establishing it as an efficient method for the authentication of olive oil regardless of its category. Copyright © 2017 Elsevier Ltd. All rights reserved.
Decreasing-Rate Pruning Optimizes the Construction of Efficient and Robust Distributed Networks.
Directory of Open Access Journals (Sweden)
Saket Navlakha
2015-07-01
Full Text Available Robust, efficient, and low-cost networks are advantageous in both biological and engineered systems. During neural network development in the brain, synapses are massively over-produced and then pruned-back over time. This strategy is not commonly used when designing engineered networks, since adding connections that will soon be removed is considered wasteful. Here, we show that for large distributed routing networks, network function is markedly enhanced by hyper-connectivity followed by aggressive pruning and that the global rate of pruning, a developmental parameter not previously studied by experimentalists, plays a critical role in optimizing network structure. We first used high-throughput image analysis techniques to quantify the rate of pruning in the mammalian neocortex across a broad developmental time window and found that the rate is decreasing over time. Based on these results, we analyzed a model of computational routing networks and show using both theoretical analysis and simulations that decreasing rates lead to more robust and efficient networks compared to other rates. We also present an application of this strategy to improve the distributed design of airline networks. Thus, inspiration from neural network formation suggests effective ways to design distributed networks across several domains.
Energy Technology Data Exchange (ETDEWEB)
Arumugam, Kamesh [Old Dominion Univ., Norfolk, VA (United States)
2017-05-01
Efficient parallel implementations of scientific applications on multi-core CPUs with accelerators such as GPUs and Xeon Phis is challenging. This requires - exploiting the data parallel architecture of the accelerator along with the vector pipelines of modern x86 CPU architectures, load balancing, and efficient memory transfer between different devices. It is relatively easy to meet these requirements for highly structured scientific applications. In contrast, a number of scientific and engineering applications are unstructured. Getting performance on accelerators for these applications is extremely challenging because many of these applications employ irregular algorithms which exhibit data-dependent control-ow and irregular memory accesses. Furthermore, these applications are often iterative with dependency between steps, and thus making it hard to parallelize across steps. As a result, parallelism in these applications is often limited to a single step. Numerical simulation of charged particles beam dynamics is one such application where the distribution of work and memory access pattern at each time step is irregular. Applications with these properties tend to present significant branch and memory divergence, load imbalance between different processor cores, and poor compute and memory utilization. Prior research on parallelizing such irregular applications have been focused around optimizing the irregular, data-dependent memory accesses and control-ow during a single step of the application independent of the other steps, with the assumption that these patterns are completely unpredictable. We observed that the structure of computation leading to control-ow divergence and irregular memory accesses in one step is similar to that in the next step. It is possible to predict this structure in the current step by observing the computation structure of previous steps. In this dissertation, we present novel machine learning based optimization techniques to address
Power and efficiency optimization for combined Brayton and inverse Brayton cycles
International Nuclear Information System (INIS)
Zhang Wanli; Chen Lingen; Sun Fengrui
2009-01-01
A thermodynamic model for open combined Brayton and inverse Brayton cycles is established considering the pressure drops of the working fluid along the flow processes and the size constraints of the real power plant using finite time thermodynamics in this paper. There are 11 flow resistances encountered by the gas stream for the combined Brayton and inverse Brayton cycles. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, combustion inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances control the air flow rate and the net power output. The relative pressure drops associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle. The analytical formulae about the relations between power output, thermal conversion efficiency, and the compressor pressure ratio of the top cycle are derived with the 11 pressure drop losses in the intake, compression, combustion, expansion, and flow process in the piping, the heat transfer loss to the ambient, the irreversible compression and expansion losses in the compressors and the turbines, and the irreversible combustion loss in the combustion chamber. The performance of the model cycle is optimized by adjusting the compressor inlet pressure of the bottom cycle, the air mass flow rate and the distribution of pressure losses along the flow path. It is shown that the power output has a maximum with respect to the compressor inlet pressure of the bottom cycle, the air mass flow rate or any of the overall pressure drops, and the maximized power output has an additional maximum with respect to the compressor pressure
Directory of Open Access Journals (Sweden)
Endang Tri Margawati
2017-12-01
Full Text Available One of small accessory genes between pol and env is tat gene encoding TAT protein. This research was aimed to optimize the expression of Jembrana TAT (JTAT protein with preparing Escherichia coli (E. coli in advance using adopted methods of M1 (MgCl2 + CaCl2 and M2 (CaCl2 + Glycerol. The best transformation efficiency resulting from a better transformation method was used to subsequent expression of JTAT protein. A synthetic tat gene encoding protein JTAT was previously cloned into pBT-hisC. Concentration of 200; 400; 600 µM IPTG was induced to a small volume culture (200 ml; OD600 = 4, incubated for 3 h. Pellets were harvested by centrifugation (4000 rpm; 4 °C; 15 min. Buffer B (10 mM Immidazole was added into pellets, lysed by freeze-thaw followed by sonication. Supernatant was collected by centrifugation (10,000 rpm; 4 °C; 20 min and purified using Ni-NTA Agarose resin, released by elution buffer (E containing 400 mM Immidazole to collect purified protein twice (E1, E2. The protein was characterized by SDS-PAGE and Western Blot (WB, quantified (at λ595 nm with BSA standard method in prior. The result showed that transformation efficiency was better in M2 (2.53 × 106 than M1 (3.10 × 105. The JTAT protein was expressed at a right size of 11.8 kDa. Concentration of 200 µM IPTG produced a significantly better protein yield (1.500 ± 0.089 mg/ml; P < 0.05 than 600 µM IPTG (0.896 ± 0.052 mg/ml and not different to 400 µM IPTG (1.298 ± 0.080 mg/ml. This research indicated that transformation efficiency needs to be taken account in prior of optimization of the protein expression.
Optimized efficiency in InP nanowire solar cells with accurate 1D analysis
Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas
2018-01-01
Semiconductor nanowire arrays are a promising candidate for next generation solar cells due to enhanced absorption and reduced material consumption. However, to optimize their performance, time consuming three-dimensional (3D) opto-electronics modeling is usually performed. Here, we develop an accurate one-dimensional (1D) modeling method for the analysis. The 1D modeling is about 400 times faster than 3D modeling and allows direct application of concepts from planar pn-junctions on the analysis of nanowire solar cells. We show that the superposition principle can break down in InP nanowires due to strong surface recombination in the depletion region, giving rise to an IV-behavior similar to that with low shunt resistance. Importantly, we find that the open-circuit voltage of nanowire solar cells is typically limited by contact leakage. Therefore, to increase the efficiency, we have investigated the effect of high-bandgap GaP carrier-selective contact segments at the top and bottom of the InP nanowire and we find that GaP contact segments improve the solar cell efficiency. Next, we discuss the merit of p-i-n and p-n junction concepts in nanowire solar cells. With GaP carrier selective top and bottom contact segments in the InP nanowire array, we find that a p-n junction design is superior to a p-i-n junction design. We predict a best efficiency of 25% for a surface recombination velocity of 4500 cm s-1, corresponding to a non-radiative lifetime of 1 ns in p-n junction cells. The developed 1D model can be used for general modeling of axial p-n and p-i-n junctions in semiconductor nanowires. This includes also LED applications and we expect faster progress in device modeling using our method.
New sensorless, efficient optimized and stabilized v/f control for pmsm machines
Jafari, Seyed Hesam
With the rapid advances in power electronics and motor drive technologies in recent decades, permanent magnet synchronous machines (PMSM) have found extensive applications in a variety of industrial systems due to its many desirable features such as high power density, high efficiency, and high torque to current ratio, low noise, and robustness. In low dynamic applications like pumps, fans and compressors where the motor speed is nearly constant, usage of a simple control algorithm that can be implemented with least number of the costly external hardware can be highly desirable for industry. In recent published works, for low power PMSMs, a new sensorless volts-per-hertz (V/f) controlling method has been proposed which can be used for PMSM drive applications where the motor speed is constant. Moreover, to minimize the cost of motor implementation, the expensive rotor damper winding was eliminated. By removing the damper winding, however, instability problems normally occur inside of the motor which in some cases can be harmful for a PMSM drive. As a result, to address the instability issue, a stabilizing loop was developed and added to the conventional V/f. By further studying the proposed sensorless stabilized V/f, and calculating power loss, it became known that overall motor efficiency still is needed to be improved and optimized. This thesis suggests a new V/f control method for PMSMs, where both efficiency and stability problems are addressed. Also, although in nearly all recent related research, methods have been applied to low power PMSM, for the first time, in this thesis, the suggested method is implemented for a medium power 15 kW PMSM. A C2000 F2833x Digital Signal Processor (DSP) is used as controller part for the student custom built PMSM drive, but instead of programming the DSP in Assembly or C, the main control algorithm was developed in a rapid prototype software environment which here Matlab Simulink embedded code library is used.
Directory of Open Access Journals (Sweden)
Junhao Luo
2018-05-01
Full Text Available As a key factor in the design of a voltage-adjustable LLC resonant converter, frequency regulation range is very important to the optimization of magnetic components and efficiency improvement. This paper presents a novel optimal design method for LLC resonant converters, which can narrow the frequency variation range and ensure high efficiency under the premise of a required gain achievement. A simplified gain model was utilized to simplify the calculation and the expected efficiency was initially set as 96.5%. The restricted area of parameter optimization design can be obtained by taking the intersection of the gain requirement, the efficiency requirement, and three restrictions of ZVS (Zero Voltage Switch. The proposed method was verified by simulation and experiments of a 150 W prototype. The results show that the proposed method can achieve ZVS from full-load to no-load conditions and can reach 1.6 times the normalized voltage gain in the frequency variation range of 18 kHz with a peak efficiency of up to 96.3%. Moreover, the expected efficiency is adjustable, which means a converter with a higher efficiency can be designed. The proposed method can also be used for the design of large-power LLC resonant converters to obtain a wide output voltage range and higher efficiency.
Directory of Open Access Journals (Sweden)
E. D. Nikitina
2016-08-01
Full Text Available Optimal values of phytohormones in the differential nutrient medium providing the efficient realization of morphogenetic potencies of four spring bread wheat varieties (Skala, Spectr, Zarnitsa and Zhnitsa from immature embryo cultures have been determined. For callus induction explants 1.5 – 1.7 mmin size were used, which were subsequently passed to the medium by Linsmaier&Skoog possessing 0.8 % of agar, 3 % of sucrose and 2.0 mg l-1 dichlorophenoxyacetic acid (2,4-D. Cell cultures were incubated in darkness at the temperature 26±1 °С. 30 – 35 days after in accordance with the scheme of complete factorial experiment of 32 type calli were passed to differential medium supplemented with 2,4-D at levels 0.5; 2.5; 4.0 mg l-1 and with kinetin (6-furfurylaminopurine at levels 0.5; 2.25 and 4.0 mg l-1. Number of replications for each of 9 variants was four. As a result, 20 mathematic models (4 varieties × 5 stages of regeneration designed as polynomial quadric equation were obtained. On the ground of the analysis of models it was established that optimal values for factors are not equal both for cultures of genotypes analyzed and for different regeneration stages. For callus tissues of Skala and Spectr an optimal value of kinetin for all regeneration stages was 0.5 mg l-1 except for the frequency of morphogenesis. Optimal values of 2,4-D for the same varieties were within 2.3 – 3.2 mg l-1. For cell cultures of Zarnitsa and Zhnitsa recommended concentration intervals made up 1.3 – 2.2 mg l-1 on kinetin except for the frequency of rhizogenesis, and 1.9 – 2.7 on 2,4-D. The level of exogenous phytohormones necessary for stem differentiation was lower than the one for root formation. The dependence of morphogenesis results on the hormonal status of the explant has been discussed.
Forebyggelse af proteseinfektioner
DEFF Research Database (Denmark)
Jørgensen, Peter Holmberg; Gromov, Kirill; Søballe, Kjeld
2007-01-01
Prosthetic infection is a feared complication to surgery with alloplastics and has a high degree of comorbidity. Prophylaxis is concentrated on commonly-accepted hygienic behaviour, optimization of the patient's general health status, peri-operative antibiotics (one dose before surgery and three...... doses during the first 24 hours postoperatively) and antibiotic loaded cement. Laminary flow reduces the risk of prosthesis infection but there is no clear evidence of any effect to concomitant antibiotic prophylaxis. Udgivelsesdato: 2007-Nov-26...
Forebyggelse af proteseinfektioner
DEFF Research Database (Denmark)
Jørgensen, Peter Holmberg; Gromov, Kirill; Søballe, Kjeld
2007-01-01
Prosthetic infection is a feared complication to surgery with alloplastics and has a high degree of comorbidity. Prophylaxis is concentrated on commonly-accepted hygienic behaviour, optimization of the patient's general health status, peri-operative antibiotics (one dose before surgery and three...... doses during the first 24 hours postoperatively) and antibiotic loaded cement. Laminary flow reduces the risk of prosthesis infection but there is no clear evidence of any effect to concomitant antibiotic prophylaxis....
DEFF Research Database (Denmark)
Frederiksen, Signe; Lausten, Mette
Siden starten af 1990’erne har Danmark sendt over 30.000 soldater og andet personel på internationale missioner – langt de fleste til Eks-Jugoslavien, Afghanistan og Irak. Denne undersøgelse handler om de børn, hvis fædre har været udsendt på militære missioner i udlandet. For hvordan håndterer...... spørgsmål er fokus for undersøgelsen. Undersøgelsen bygger på en spørgeskemaundersøgelse blandt børn af veteraner på henholdsvis 7, 11 og 15 år. Undersøgelsen er gennemført for og i samarbejde med Veterancentrets Videncenter, som er en del af Forsvarsministeriets Personalestyrelse....
Styring af international transfer pricing
DEFF Research Database (Denmark)
Reuther, Peter; Rossing, Christian Plesner
2011-01-01
Nærværende artikel introducerer international transfer pricing, dels som et skatteretligt fænomen og dels som et værktøj til planlægning og økonomisk styring af koncernforbundne selskaber i en multinational virksomhed (MNV). Med udgangspunkt i en case-analyse af MNV’en gives der et konkret eksempel...... på hvordan transfer pricing håndteres i praksis. Artiklens formål er at give et praktisk eksempel på at transfer pricing handler om at efterleve regler, ikke omgå dem. På baggrund af case-analysen argumenteres der for, at såvel akademikere som praktikere bør tage virksomhedens tilgang til...... international transfer pricing i betragtning, når økonomiske styringssystemer i en MNV skal anvendes til planlægning og opfølgning....
ANTICOAGULANT TREATMENT OF AF: FOCUS ON THE WARFARIN DOSAGE
Directory of Open Access Journals (Sweden)
Y. Kovbasniuk
2015-10-01
Summary Authors analyzed the results of some studies of AF and warfarin dosing. Than investigation of 75 patient with AF (permanent type was performed. According to demographic, anthropometric data and related conditions (diabetes mellitus type 2, myocardial infarction, acute cerebrovascular ischemia, pulmonary embolism, alcohol abuse - drinking more than one ounce of ≥3 weekly predictive model of warfarin dosing was developed: warfarin dose = 0.097 * BMI - 0.03 * AGE + 0.30 *ASS.Status+ 0.02 *WC+ 1, 88. After testing of final model authors concluded what derived formula was representative, to determine the optimal dose of warfarin given to patient based on demographic characteristics. Considering all of the abovementioned, this model can be recommended for use determining the treatment strategy in patients with AF. Keywords: anticoagulant treatment, warfarin, atrial fibrillation.
Strategi til udbredelse og udvikling af aquaponik
Bartholin, Aline; Nielsen, Per
2014-01-01
Denne rapport omhandler, hvorledes aquaponik i fremtiden skal udbredes med henblik på at produktionsmetoden bliver en del af den etablerede fødevaresektor. Ud fra et interview med PlanteLaboratoriet som er en del af foreningen Akvaponisk Selskab, samt observationer af en workshop afholdt af PlanteLaboratoriet forsøger vi at kortlægge den førte strategi til udbredelse og udvikling af aquaponik, samt undersøge hvorledes aquaponik som innovation bliver taget imod af mulige adoptere. Empirien sam...
Kortlægning af evalueringer og undersøgelser af vejledning knyttet til vejledning af unge i UU-regi
DEFF Research Database (Denmark)
Skovhus, Randi Boelskifte; thomsen, rie
2013-01-01
Kortlægning af evalueringer og undersøgelser af vejledning knyttet til vejledning af unge i UU-regi 2004-2013. Et arbejdspapir......Kortlægning af evalueringer og undersøgelser af vejledning knyttet til vejledning af unge i UU-regi 2004-2013. Et arbejdspapir...
Logning af teledata i lyset af Tele2-dommen
DEFF Research Database (Denmark)
Lentz, Lene Wacher
2017-01-01
De danske teleudbydere har siden 2007 været underlagt en pligt efter logningsbekendtgørelsen til at registrere data om al telekommunikation for at sikre at data er tilgængelige ved en eventuel senere efterforskning. Logningspligten må nu revideres og i vidt omfang afvikles som følge af EU-domstol...
Undersøgelse af kommunernes administration af bygningsreglementets elevatorkrav
DEFF Research Database (Denmark)
Grangaard, Sidse
Denne rapport undersøger kommunernes praksis omkring administrationen af bygningsreglementets krav om elevator ved nybyggeri og ombygning. Blandt de 26 kommuner, der har deltaget i undersøgelsen, var der generelt konsensus om at stille krav om elevator ved nybyggeri. Kommunerne modtager kun meget...
Betydningen af pesticider for forekomsten af vilde bier
DEFF Research Database (Denmark)
Bruus, Marianne; Dupont, Yoko Luise; Grant, Ruth
Både i Danmark og andre steder er der observeret en nedgang i de insekter, der bestøver landmandens afgrøder og de vilde planter. Tilbagegangen falder sammen med, at landbrugsdriften er blevet mere intensiv, og anvendelsen af pesticider er øget. Vi ved imidlertid ikke, hvilken rolle pesticiderne ...
Forekomst af resistente bakterier og forbrug af antibiotika til hunde
DEFF Research Database (Denmark)
Pedersen, Karl; Pedersen, Kristina; Jensen, Helene
2007-01-01
), Pasteurella multocida (n=25), Bordetella bronchiseptica (n=14), Proteus spp. (n=29), og E. coli (n=449). I undersøgelsen anvendtes data fra VetStat databasen. Størstedelen af de antibiotika, der bruges til hunde er bredspektrede. Penicilliner med udvidet spektrum, cephalosporiner samt sulphonamider...
Transkateterlukning af venstre atriums aurikel til forebyggelse af apoplexia cerebri
DEFF Research Database (Denmark)
Loupis, Anastasia M; De Backer, Ole; Ihlemann, Nikolaj
2014-01-01
In patients with atrial fibrillation (AF) and increased risk of stroke, oral anticoagulation (OAC) is the standard treatment for stroke prevention - however, this therapy also carries a high risk of bleeding. Percutaneous closure of the left atrial appendage (LAA) has been suggested to be an alte...
Directory of Open Access Journals (Sweden)
J.-M. Beckers
2014-10-01
Full Text Available We present a method in which the optimal interpolation of multi-scale processes can be expanded into a succession of simpler interpolations. First, we prove how the optimal analysis of a superposition of two processes can be obtained by different mathematical formulations involving iterations and analysis focusing on a single process. From the different mathematical equivalent formulations, we then select the most efficient ones by analyzing the behavior of the different possibilities in a simple and well-controlled test case. The clear guidelines deduced from this experiment are then applied to a real situation in which we combine large-scale analysis of hourly Spinning Enhanced Visible and Infrared Imager (SEVIRI satellite images using data interpolating empirical orthogonal functions (DINEOF with a local optimal interpolation using a Gaussian covariance. It is shown that the optimal combination indeed provides the best reconstruction and can therefore be exploited to extract the maximum amount of useful information from the original data.
Mbagwu, Chukwuka Chijindu
High speed, air-breathing hypersonic vehicles encounter a varied range of engine and operating conditions traveling along cruise/ascent missions at high altitudes and dynamic pressures. Variations of ambient pressure, temperature, Mach number, and dynamic pressure can affect the combustion conditions in conflicting ways. Computations were performed to understand propulsion tradeoffs that occur when a hypersonic vehicle travels along an ascent trajectory. Proper Orthogonal Decomposition methods were applied for the reduction of flamelet chemistry data in an improved combustor model. Two operability limits are set by requirements that combustion efficiency exceed selected minima and flameout be avoided. A method for flameout prediction based on empirical Damkohler number measurements is presented. Operability limits are plotted that define allowable flight corridors on an altitude versus flight Mach number performance map; fixed-acceleration ascent trajectories were considered for this study. Several design rules are also presented for a hypersonic waverider with a dual-mode scramjet engine. Focus is placed on ''vehicle integration" design, differing from previous ''propulsion-oriented" design optimization. The well-designed waverider falls between that of an aircraft (high lift-to-drag ratio) and a rocket (high thrust-to-drag ratio). 84 variations of an X-43-like vehicle were run using the MASIV scramjet reduced order model to examine performance tradeoffs. Informed by the vehicle design study, variable-acceleration trajectory optimization was performed for three constant dynamic pressures ascents. Computed flameout operability limits were implemented as additional constraints to the optimization problem. The Michigan-AFRL Scramjet In-Vehicle (MASIV) waverider model includes finite-rate chemistry, applied scaling laws for 3-D turbulent mixing, ram-scram transition and an empirical value of the flameout Damkohler number. A reduced-order modeling approach is justified
Bayiz, Yagiz Efe; Ghanaatpishe, Mohammad; Fathy, Hosam; Cheng, Bo
2018-03-20
In this work, a multi-objective optimization framework is developed for optimizing low-Reynolds number (Re) hovering flight. This framework is then applied to compare the efficiency of rigid revolving and flapping wings with rectangular shape under varying Re and Rossby number (Ro, or aspect ratio). The proposed framework is capable of generating sets of optimal solutions and Pareto fronts for maximizing lift coefficient and minimizing power coefficient in dimensionless space, which explicitly reveal the trade off between lift generation and power consumption. The results indicate that revolving wings are more efficient if the required average lift coefficient CL is low (< 1 for Re = 100 and < 1.6 for Re = 8000), while flapping wings are more efficient in achieving higher CL. Using dimensionless power loading as the single objective performance measure to be maximized, rotary flight is more efficient than flapping wings for Re > 100 regardless of the amount of energy storage assumed in the flapping-wing actuation mechanism, while flapping flight becomes more efficient for Re < 100. It is observed that wings with low Ro perform better if higher CL is needed, whereas higher Ro cases are more efficient at CL < 0.9 region. However, for the selected geometry and Re, the efficiency is weakly dependent on Ro if the dimensionless power loading is maximized. © 2018 IOP Publishing Ltd.
DEFF Research Database (Denmark)
Meng, Lexuan; Dragicevic, Tomislav; Quintero, Juan Carlos Vasquez
2015-01-01
This paper proposes a hierarchical control scheme which applies optimization method into DC microgrids in order to improve the system overall efficiency while considering the State-of-Charge (SoC) balancing at the same time. Primary droop controller, secondary voltage restoration controller...... and tertiary optimization tool formulate the complete hierarchical control system. Virtual resistances are taken as the decision variables for achieving the objective. simulation results are presented to verify the proposed approach....
International Nuclear Information System (INIS)
Tzolakis, G.; Papanikolaou, P.; Kolokotronis, D.; Samaras, N.; Tourlidakis, A.; Tomboulides, A.
2012-01-01
Since most of the world's electric energy production is mainly based on fossil fuels and need for better efficiency of the energy conversion systems is imminent, mathematical programming algorithms were applied for the simulation and optimization of a detailed model of an existing lignite-fired power plant in Kozani, Greece (KARDIA IV). The optimization of its overall thermal efficiency, using as control variables the mass flow rates of the steam turbine extractions and the fuel consumption, was performed with the use of the simulation and optimization software gPROMS. The power plant components' mathematical models were imported in software by the authors and the results showed that further increase to the overall thermal efficiency of the plant can be achieved (a 0.55% absolute increase) through reduction of the HP turbine's and increase of the LP turbine's extractions mass flow rates and the parallel reduction of the fuel consumption by 2.05% which also results to an equivalent reduction of the greenhouse gasses. The setup of the mathematical model and the flexibility of gPROMS, make this software applicable to various power plants. - Highlights: ► Modeling and simulation of the flue gases circuit of a specific plant. ► Designing of modules in gPROMS FO (Foreign Objects). ► Simulation of the complete detailed plant with gPROMS. ► Optimization using a non-linear optimization algorithm of the plant's efficiency.
Bloom, Guillaume; Larat, Christian; Lallier, Eric; Lee-Bouhours, Mane-Si Laure; Loiseaux, Brigitte; Huignard, Jean-Pierre
2011-02-10
We have designed a high-efficiency array generator composed of subwavelength grooves etched in a GaAs substrate for operation at 4.5 μm. The method used combines rigorous coupled wave analysis with an optimization algorithm. The optimized beam splitter has both a high efficiency (∼96%) and a good intensity uniformity (∼0.2%). The fabrication error tolerances are numerically calculated, and it is shown that this subwavelength array generator could be fabricated with current electron beam writers and inductively coupled plasma etching. Finally, we studied the effect of a simple and realistic antireflection coating on the performance of the beam splitter.
Optimizing MRI Logistics: Prospective Analysis of Performance, Efficiency, and Patient Throughput.
Beker, Kevin; Garces-Descovich, Alejandro; Mangosing, Jason; Cabral-Goncalves, Ines; Hallett, Donna; Mortele, Koenraad J
2017-10-01
The objective of this study is to optimize MRI logistics through evaluation of MRI workflow and analysis of performance, efficiency, and patient throughput in a tertiary care academic center. For 2 weeks, workflow data from two outpatient MRI scanners were prospectively collected and stratified by value added to the process (i.e., value-added time, business value-added time, or non-value-added time). Two separate time cycles were measured: the actual MRI process cycle as well as the complete length of patient stay in the department. In addition, the impact and frequency of delays across all observations were measured. A total of 305 MRI examinations were evaluated, including body (34.1%), neurologic (28.9%), musculoskeletal (21.0%), and breast examinations (16.1%). The MRI process cycle lasted a mean of 50.97 ± 24.4 (SD) minutes per examination; the mean non-value-added time was 13.21 ± 18.77 minutes (25.87% of the total process cycle time). The mean length-of-stay cycle was 83.51 ± 33.63 minutes; the mean non-value-added time was 24.33 ± 24.84 minutes (29.14% of the total patient stay). The delay with the highest frequency (5.57%) was IV or port placement, which had a mean delay of 22.82 minutes. The delay with the greatest impact on time was MRI arthrography for which joint injection of contrast medium was necessary but was not accounted for in the schedule (mean delay, 42.2 minutes; frequency, 1.64%). Of 305 patients, 34 (11.15%) did not arrive at or before their scheduled time. Non-value-added time represents approximately one-third of the total MRI process cycle and patient length of stay. Identifying specific delays may expedite the application of targeted improvement strategies, potentially increasing revenue, efficiency, and overall patient satisfaction.
Energy Technology Data Exchange (ETDEWEB)
Sevcik, Petr
2009-07-01
The Kaplan turbine has the best theoretical efficiency chart in the total range of operation. In order to achieve these good properties, the turbine has to be adjusted optimally. In general, these settings are performed by the manufacturer of turbines during commissioning. In practice one often meets Kaplan turbines where the scenery does not correspond to the optimal control line. The author of the contribution under consideration reports on possible causes for these errors and also methods of how this scenery can be optimized cost-effectively and how to minimize power losses.
Weber-Krüger, Mark; Gelbrich, Götz; Stahrenberg, Raoul; Liman, Jan; Kermer, Pawel; Hamann, Gerhard F; Seegers, Joachim; Gröschel, Klaus; Wachter, Rolf
2014-10-01
Detecting paroxysmal atrial fibrillation (AF) in patients with ischemic strokes presenting in sinus rhythm is challenging because episodes are often short, occur randomly, and are frequently asymptomatic. If AF is detected, recurrent thromboembolism can be prevented efficiently by oral anticoagulation. Numerous uncontrolled studies using various electrocardiogram (ECG) devices have established that prolonged ECG monitoring increases the yield of AF detection, but most established procedures are time-consuming and costly. The few randomized trials are mostly limited to cryptogenic strokes. The optimal method, duration, and patient selection remain unclear. Repeated prolonged continuous Holter ECG monitoring to detect paroxysmal AF within an unspecific stroke population may prove to be a widely applicable, effective secondary prevention strategy. Find-AFRANDOMISED is a randomized and controlled prospective multicenter trial. Four hundred patients 60 years or older with manifest (symptoms ≥24 hours or acute computed tomography/magnetic resonance imaging lesion) and acute (symptoms ≤7 days) ischemic strokes will be included at 4 certified stroke centers in Germany. Those with previously diagnosed AF/flutter, indications/contraindications for oral anticoagulation, or obvious causative blood vessel pathologies will be excluded. Patients will be randomized 1:1 to either enhanced and prolonged Holter ECG monitoring (10 days at baseline and after 3 and 6 months) or standard of care (≥24-hour continuous ECG monitoring, according to current stroke guidelines). All patients will be followed up for at least 12 months. The primary end point is newly detected AF (≥30 seconds) after 6 months, confirmed by an independent adjudication committee. We plan to complete recruitment in autumn 2014. First results can be expected by spring 2016. Copyright © 2014 Mosby, Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Luman Zhao
2015-01-01
Full Text Available A thrust allocation method was proposed based on a hybrid optimization algorithm to efficiently and dynamically position a semisubmersible drilling rig. That is, the thrust allocation was optimized to produce the generalized forces and moment required while at the same time minimizing the total power consumption under the premise that forbidden zones should be taken into account. An optimization problem was mathematically formulated to provide the optimal thrust allocation by introducing the corresponding design variables, objective function, and constraints. A hybrid optimization algorithm consisting of a genetic algorithm and a sequential quadratic programming (SQP algorithm was selected and used to solve this problem. The proposed method was evaluated by applying it to a thrust allocation problem for a semisubmersible drilling rig. The results indicate that the proposed method can be used as part of a cost-effective strategy for thrust allocation of the rig.
Ledelse af ledelse i udviklingssamtaler
DEFF Research Database (Denmark)
Ryberg, Birgit
2012-01-01
Hvem sætter dagsorden for udvikling? Udviklingssamtaler er præget af forskellige ledende interessser, der ikke blot konkurrerer om at vinde indflydelse, men også skaber tvetydigheder og doublebind, som ledere og medarbejdere må forholde sig til....
Kvalifikation af skattesubjekter og traktatbeskyttelse
DEFF Research Database (Denmark)
Bolander, Jane
2014-01-01
Artiklen er baseret på generalrapporten og den danske nationalrapport om emnet “Qualification of taxable entities and treaty protection”, der er udarbejdet til IFA-kongressen 2014 i Mumbai. Artiklen opsummerer konklusionerne fra generalrapportens komparative studier, og forhold af særlig dansk...
Afgivelse af formue til trusts
DEFF Research Database (Denmark)
Feldthusen, Rasmus Kristian
2009-01-01
Kravet om at en stifter skal have foretaget en "uigenkaldelig og effektiv udskillelse" for at dansk skatteret vil anerkende at der foreligger en trust vurderes. Kravet er senest lagt til grund i SKM 2009.249 SR. Forfatteren opfordrer til, at SKAT i stedet foretager en konkret vurdering af selve...
Digitalisering af det eksisterende byggeri
DEFF Research Database (Denmark)
Sørensen, Nils Lykke; Øien, Turid Borgestrand
2010-01-01
Digitalisering af det eksisterende byggeri er en vanskelig og uendelig opgave. Det giver kun mening at digitalisere eksisterende byggeri, når man har et konkret behov, og da kun at indhente og lagre de informationer, som man strategisk eller konkret har behov for. Erhvervs og Byggestyrelsen har i...
Evaluering af Animationsbaseret Sketching Workshop
DEFF Research Database (Denmark)
Vistisen, Peter; Hautopp, Heidi
2017-01-01
Formålet med workshoppen var at styrke forskere fra Ild-Lab i at anvende animationsbaseret sketching og prototyping i deres undervisning således, at undervisningen understøtter designbaserede tilgange, der er mere produkt- og teknologiorienteret. På denne led kan vi styrke materialiseringen af hu...
Udredning af xerostomi og hyposalivation
DEFF Research Database (Denmark)
Pedersen, Anne Marie Lynge; Dynesen, Anja Weirsøe; Jensen, Siri Beier
2011-01-01
Mundtørhed kræver grundig undersøgelse Xerostomi er ofte associeret til betydelig nedsat spytsekretion, men kan forekomme, uden at der objektivt kan påvises nedsat spytsekretion. Udredning af patienter, som klager over mundtørhed, bør således altid inkludere en omhyggelig anamnese, en detaljeret ...
Danskernes brug af nyhedsmedier 2018
DEFF Research Database (Denmark)
Schrøder, Kim Christian; Ørsten, Mark; Eberholst, Mads Kæmsgaard
Hvis der er ét begreb, der i 2018 er blevet slået fast med syvtommersøm i den offentlige debat verden over, så er det ’fake news’! Bekymringen over fænomenet er vokset eksplosivt, samtidig med at det er blevet mere og mere uklart, hvad ’fake news’ egentlig dækker over. I dette års analyse af...... brugen af nyhedsmedier sætter Reuters Institute Digital News Report, og også denne specialrapport om Danmark, analytisk fokus på ’fake news’ og kaster lys over borgernes opfattelse af fænomenet på en måde, så vi får nuancerne i det komplekse begreb med. Et andet emne, der er blevet diskuteret...... for fake news og egne oplevelser af fake news, og danskernes viden om, hvordan nyheder bliver lavet (nyheds-literacy)....
Overholdelse af kravene i bygningsreglementet
DEFF Research Database (Denmark)
Christensen, Toke Haunstrup; Jensen, Jesper Ole; Gram-Hanssen, Kirsten
Denne rapport undersøger, hvorvidt bestemmelserne i bygningsreglementet BR10 omkring energieffektivisering ved renoveringen af bygninger bliver overholdt. Der fokuseres især på parcelhuse, da problemet med manglende overholdelse menes at være størst her, ligesom potentialet for energibesparelser...
Ledelsesroller i globalisering af cleantech
DEFF Research Database (Denmark)
Knudsen, Poul Frøjk; Tambo, Torben
2011-01-01
nyeste teknologier, globalisering af salg, installation og produktion, og at vækstdagsordenen er blevet fastholdt. Den globale satsning på cleantech sætter disse ledelsesmæssige kvaliteter under pres. Dette studie ser på en mellemstor komponentleverandør til vindindustrien, og dennes kamp...
Virksomhedernes opfattelse af arbejdsmarkedets "restgrupper"
DEFF Research Database (Denmark)
Larsen, Christian Albrekt
2010-01-01
Artiklen beskriver, hvorledes danske arbejdsgivere opfatter ældre ledige, ledige indvandrere og ledige med lang forudgående ledighed. Det teoretiske udgangspunkt er, at arbejdsmarkedets fundamentale informationsproblemer fører til brug af statistisk diskrimination og frygt for «lemons». Analyserne...
På sporet af fremtidens konkurrenceevne
DEFF Research Database (Denmark)
Boje Rasmussen, Martin Møller
2013-01-01
Michael Porter og Harvard Business School står bag nyt banebrydende initiativ, Social Progress Index, som måler et samfunds evne til at skabe livskvalitet for borgerne. Dette aktualiserer debatten om udviklingen af helt nye konkurrencemodeller. Der er tale om et valg mellem tre forskellige typer...
Broderick, Shaun R.; Jones, Michelle L.
2013-01-01
Virus-induced gene silencing (VIGS) is used to down-regulate endogenous plant genes. VIGS efficiency depends on viral proliferation and systemic movement throughout the plant. Although tobacco rattle virus (TRV)-based VIGS has been successfully used in petunia (Petunia × hybrida), the protocol has not been thoroughly optimized for efficient and uniform gene down-regulation in this species. Therefore, we evaluated six parameters that improved VIGS in petunia. Inoculation of mechanically wounde...
Thermal and Performance Analysis of a Gasification Boiler and Its Energy Efficiency Optimization
Directory of Open Access Journals (Sweden)
Jan Valíček
2017-07-01
Full Text Available The purpose of this study was to determine a method for multi-parametric output regulation of a gasification boiler especially designed for heating or for hot water heating in buildings. A new method of regulation is offered, namely more parametric regulation via proportional-integral-derivative (PID controllers that are capable of controlling the calculated values of pressure, temperature and fan speed. These values of pressure, temperature and fan speed are calculated in a completely new way, and calculations of setpoints for determination of optimal parameters lead to an increase in boilers efficiency and power output. Results of measurements show that changes at the mouth of the stack draft due atmospheric influences occur in times with high intensity and high frequency, while power parameters, or boiler power output amplitudes and fan speed automatically “copy” those changes proportionally due to instantaneous fan speed changes. The proposed method of regulation of the gasification boiler power output according to the technical solution enables a simple, cheap, express and continuous maintenance of high power output at low concentrations of the exhaust gases of the gasification boilers from the viewpoint of the boiler user, as well as from the perspective of development and production it allows a continuous control monitoring of these parameters.
Li, Kai; Qin, Jin-Cheng; Liu, Chen-Guang; Bai, Feng-Wu
2016-12-01
Jerusalem artichoke (JA) is a potential energy crop for biorefinery due to its unique agronomic traits such as resistance to environmental stresses and high biomass yield in marginal lands. Although JA tubers have been explored for inulin extraction and biofuels production, there is little concern on its stalk (JAS). In this article, the pretreatment of JAS by alkaline hydrogen peroxide was optimized using the response surface methodology to improve sugars yield and reduce chemicals usage. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the structures of the pretreated JAS to evaluate the effectiveness of the pretreatment. Furthermore, the feeding of the pretreated JAS and cellulase was performed for high solid uploading (up to 30%) to increase ethanol titer, and simultaneous saccharification and fermentation with 55.6g/L ethanol produced, 36.5% more than that produced through separate hydrolysis and fermentation, was validated to be more efficient. Copyright © 2016 Elsevier Ltd. All rights reserved.
Zeng, Xueqiang; Luo, Gang
2017-12-01
Machine learning is broadly used for clinical data analysis. Before training a model, a machine learning algorithm must be selected. Also, the values of one or more model parameters termed hyper-parameters must be set. Selecting algorithms and hyper-parameter values requires advanced machine learning knowledge and many labor-intensive manual iterations. To lower the bar to machine learning, miscellaneous automatic selection methods for algorithms and/or hyper-parameter values have been proposed. Existing automatic selection methods are inefficient on large data sets. This poses a challenge for using machine learning in the clinical big data era. To address the challenge, this paper presents progressive sampling-based Bayesian optimization, an efficient and automatic selection method for both algorithms and hyper-parameter values. We report an implementation of the method. We show that compared to a state of the art automatic selection method, our method can significantly reduce search time, classification error rate, and standard deviation of error rate due to randomization. This is major progress towards enabling fast turnaround in identifying high-quality solutions required by many machine learning-based clinical data analysis tasks.
Yang, Leyun; Xu, Yu; Chen, Yong; Ying, Hanjie
2018-01-01
New secretion vectors containing the synthetic signal sequence (OmpA’) was constructed for the secretory production of recombinant proteins in Escherichia coli. The E. coli Phospholipase D structural gene (Accession number:NC_018658) fused to various signal sequence were expressed from the Lac promoter in E. coli Rosetta strains by induction with 0.4mM IPTG at 28°C for 48h. SDS-PaGe analysis of expression and subcellular fractions of recombinant constructs revealed the translocation of Phospholipase D (PLD) not only to the medium but also remained in periplasm of E. coli with OmpA’ signal sequence at the N-terminus of PLD. Thus the study on the effects of various surfactants on PLD extracellular production in Escherichia coli in shake flasks revealed that optimal PLD extracellular production could be achieved by adding 0.4% Triton X-100 into the medium. The maximal extracellular PLD production and extracellular enzyme activity were 0.23mg ml-1 and 16U ml-1, respectively. These results demonstrate the possibility of efficient secretory production of recombinant PLD in E. coli should be a potential industrial applications.
Escartin, Terenz R.; Nano, Tomi F.; Cunningham, Ian A.
2016-03-01
The detective quantum efficiency (DQE), expressed as a function of spatial frequency, describes the ability of an x-ray detector to produce high signal-to-noise ratio (SNR) images. While regulatory and scientific communities have used the DQE as a primary metric for optimizing detector design, the DQE is rarely used by end users to ensure high system performance is maintained. Of concern is that image quality varies across different systems for the same exposures with no current measures available to describe system performance. Therefore, here we conducted an initial DQE measurement survey of clinical x-ray systems using a DQE-testing instrument to identify their range of performance. Following laboratory validation, experiments revealed that the DQE of five different systems under the same exposure level (8.0 μGy) ranged from 0.36 to 0.75 at low spatial frequencies, and 0.02 to 0.4 at high spatial frequencies (3.5 cycles/mm). Furthermore, the DQE dropped substantially with decreasing detector exposure by a factor of up to 1.5x in the lowest spatial frequency, and a factor of 10x at 3.5 cycles/mm due to the effect of detector readout noise. It is concluded that DQE specifications in purchasing decisions, combined with periodic DQE testing, are important factors to ensure patients receive the health benefits of high-quality images for low x-ray exposures.
Moss and peat hydraulic properties are optimized to maximise peatland water use efficiency
Kettridge, Nicholas; Tilak, Amey; Devito, Kevin; Petrone, Rich; Mendoza, Carl; Waddington, Mike
2016-04-01
Peatland ecosystems are globally important carbon and terrestrial surface water stores that have formed over millennia. These ecosystems have likely optimised their ecohydrological function over the long-term development of their soil hydraulic properties. Through a theoretical ecosystem approach, applying hydrological modelling integrated with known ecological thresholds and concepts, the optimisation of peat hydraulic properties is examined to determine which of the following conditions peatland ecosystems target during this development: i) maximise carbon accumulation, ii) maximise water storage, or iii) balance carbon profit across hydrological disturbances. Saturated hydraulic conductivity (Ks) and empirical van Genuchten water retention parameter α are shown to provide a first order control on simulated water tensions. Across parameter space, peat profiles with hypothetical combinations of Ks and α show a strong binary tendency towards targeting either water or carbon storage. Actual hydraulic properties from five northern peatlands fall at the interface between these goals, balancing the competing demands of carbon accumulation and water storage. We argue that peat hydraulic properties are thus optimized to maximise water use efficiency and that this optimisation occurs over a centennial to millennial timescale as the peatland develops. This provides a new conceptual framework to characterise peat hydraulic properties across climate zones and between a range of different disturbances, and which can be used to provide benchmarks for peatland design and reclamation.
Using Animal Instincts to Design Efficient Biomedical Studies via Particle Swarm Optimization.
Qiu, Jiaheng; Chen, Ray-Bing; Wang, Weichung; Wong, Weng Kee
2014-10-01
Particle swarm optimization (PSO) is an increasingly popular metaheuristic algorithm for solving complex optimization problems. Its popularity is due to its repeated successes in finding an optimum or a near optimal solution for problems in many applied disciplines. The algorithm makes no assumption of the function to be optimized and for biomedical experiments like those presented here, PSO typically finds the optimal solutions in a few seconds of CPU time on a garden-variety laptop. We apply PSO to find various types of optimal designs for several problems in the biological sciences and compare PSO performance relative to the differential evolution algorithm, another popular metaheuristic algorithm in the engineering literature.
International Nuclear Information System (INIS)
Gimelli, A.; Luongo, A.; Muccillo, M.
2017-01-01
Highlights: • Multi-objective optimization method for ORC design has been addressed. • Trade-off between electric efficiency and overall heat exchangers area is evaluated. • The heat exchangers area was used as objective function to minimize the plant cost. • MDM was considered as organic working fluid for the thermodynamic cycle. • Electric efficiency: 14.1–18.9%. Overall heat exchangers area: 446–1079 m 2 . - Abstract: Multi-objective optimization could be, in the industrial sector, a fundamental strategic approach for defining the target design specifications and operating parameters of new competitive products for the market, especially in renewable energy and energy savings fields. Vector optimization mostly enabled the determination of a set of optimal solutions characterized by different costs, sizes, efficiencies and other key features. The designer can subsequently select the solution with the best compromise between the objective functions for the specific application and constraints. In this paper, a multi-objective optimization problem addressing an Organic Rankine Cycle system is solved with consideration for the electric efficiency and overall heat exchangers area as quantities that should be optimized. In fact, considering that the overall capital cost of the ORC system is dominated by the cost of the heat exchangers rather than that of the pump and turbine, this area is related to the cost of the plant and so it was used to indirectly optimize the economic system performance. For this reason, although cost data have not been used, the heat exchangers area was used as a second objective function to minimize the plant cost. Pareto optimal solutions highlighted a trade-off between the two conflicting objective functions. Octamethyltrisiloxane (MDM) was considered organic working fluid, while the following input parameters were used as decision variables: minimum and maximum pressure of the thermodynamic cycle; superheating and subcooling
Sygeplejestuderendes brug af portfolio i klinisk undervisning
DEFF Research Database (Denmark)
Hjorth, Anne Charlotte Overgaard; Bruhn, Helle
2014-01-01
Brugen af portfolio var mangelfuld, men et udviklingsprojekt i samarbejde med den kommunale sygepleje motiverede både sygeplejestuderende og kliniske vejledere til at anvende læringsdelen af portfolio aktivt.......Brugen af portfolio var mangelfuld, men et udviklingsprojekt i samarbejde med den kommunale sygepleje motiverede både sygeplejestuderende og kliniske vejledere til at anvende læringsdelen af portfolio aktivt....
Udviklingen af rumopfattelsen 1600-2000
DEFF Research Database (Denmark)
Brock, Steen
2010-01-01
Hovedtræk af rumopfattelsens idehistorie fra Descartes til Wittgenstein med speciel vægt på Kant, værkbegrebet, modelbegrebet og den fænomenologiske opfattelse af rummet som handlingens sted......Hovedtræk af rumopfattelsens idehistorie fra Descartes til Wittgenstein med speciel vægt på Kant, værkbegrebet, modelbegrebet og den fænomenologiske opfattelse af rummet som handlingens sted...
Chen, Allen Kuan-Liang; Chew, Yi Kong; Tan, Hong Yu; Reuveny, Shaul; Weng Oh, Steve Kah
2015-02-01
Large amounts of human mesenchymal stromal cells (MSCs) are needed for clinical cellular therapy. In a previous publication, we described a microcarrier-based process for expansion of MSCs. The present study optimized this process by selecting suitable basal media, microcarrier concentration and feeding regime to achieve higher cell yields and more efficient medium utilization. MSCs were expanded in stirred cultures on Cytodex 3 microcarriers with media containing 10% fetal bovine serum. Process optimization was carried out in spinner flasks. A 2-L bioreactor with an automated feeding system was used to validate the optimized parameters explored in spinner flask cultures. Minimum essential medium-α-based medium supported faster MSC growth on microcarriers than did Dulbecco's modified Eagle's medium (doubling time, 31.6 ± 1.4 vs 42 ± 1.7 h) and shortened the process time. At microcarrier concentration of 8 mg/mL, a high cell concentration of 1.08 × 10(6) cells/mL with confluent cell concentration of 4.7 × 10(4)cells/cm(2) was achieved. Instead of 50% medium exchange every 2 days, we have designed a full medium feed that is based on glucose consumption rate. The optimal medium feed that consisted of 1.5 g/L glucose supported MSC growth to full confluency while achieving the low medium usage efficiency of 3.29 mL/10(6)cells. Finally, a controlled bioreactor with the optimized parameters achieved maximal confluent cell concentration with 16-fold expansion and a further improved medium usage efficiency of 1.68 mL/10(6)cells. We have optimized the microcarrier-based platform for expansion of MSCs that generated high cell yields in a more efficient and cost-effective manner. This study highlighted the critical parameters in the optimization of MSC production process. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
Identifikation af referencevandløb til implementering af vandrammedirektivet i Danmark
DEFF Research Database (Denmark)
Kristensen, Esben Astrup; Baattrup-Pedersen, Annette; Skriver, Jens
Definition og beskrivelse af referencetilstanden er centralt for implementering af vandrammedirektivet, da bedømmelse af den økologiske tilstand sker som afvigelsen fra den upåvirkede referencetilstand. I denne rapport præsenteres analyser af danske, udenlandske og historiske data med det formål...
Aspekter af integrationsindsatsen i 6 kommuner
DEFF Research Database (Denmark)
Rosdahl, Anders
Dette arbejdspapir præsenterer resultaterne af en mindre kvalitativ undersøgelse af kommuners indsats for at bringe nyankomne flygtninge og indvandrere i beskæftigelse. Undersøgelsen er en opfølgning på en kvantitativ benchmarkanalyse, som er gennemført af Amternes og Kommunernes Forskningsinstit...
Registrering af biometriske og biologiske personoplysninger
DEFF Research Database (Denmark)
Blume, Peter Erik; Herrmann, Janne Rothmar
2009-01-01
Med udgangspunkt i menneskeretsdomstolens Marper dom drøftes i artiklen indretningen af dansk rets regler om registrering af fingeraftryk og dna-profil med tilhørende biologisk materiale, og om dommen nødvendiggør ændringer af disse regler....
Delegation af lovgivningsmagt: risiko for ringere regulering?
DEFF Research Database (Denmark)
Pedersen, Morten Jarlbæk; Christensen, Geert Laier; Ravn, Jacob
2016-01-01
kortsigtetede, politiske incitamenter. Samtidig underlægges delegation ikke samme grad af kvalitetskontrolmekanismer som almindelig lovgivning; dette kunne ellers kompensere for den mere politiserede delegation. En øget brug af bekendtgørelser kan derfor betyde en stigende risiko for regulering af lavere...
Registrering og Benchmarking af Modus 2 Forskning
DEFF Research Database (Denmark)
Duus, Henrik Johannsen; Jørgensen, Jens E.
2004-01-01
Fremvæksten af modus 2 forskning stiller krav om en revurdering af højere læreanstalters evaluerings- og meriteringspraksis. Den endimensionale prioritering af modus 1 forskning såvel som dennes ligeså endimensionale evaluering via publikationer må afvises som utidssvarende. Som en konsekvens her...
Energioptimering af bæredygtighedscertificeringsprocesserne
DEFF Research Database (Denmark)
Christensen, Dorthe Holmberg; Carlsen, Mads; Alon, Shlomo Nevo
2014-01-01
Større fokus på bæredygtighedscertificeringer som DGNB har yderligere øget kompleksiteten af designet af bygninger. Introduktionen af teknologier som building information modelling (BIM) og proces metoder som integreret design proces (IDP) kan hjælpe med at reducere kompleksiteten og bedre...
DEFF Research Database (Denmark)
Schleicher, Marianne
2014-01-01
på teori dels af Michel Foucault om, hvordan kultur sikrer sin egen overlevelse ved at indsamle viden om bl.a. kroppe med henblik på at regulere brugen af dem, dels af Judith Butler, der bl.a. forklarer, hvordan kultur trods alt er åben for såkaldt subversion, idet det bidrager til at udvide og...
Magtens repræsentation af danskhed
DEFF Research Database (Denmark)
Madsen, Carsten
2016-01-01
Med udgangspunkt i Maurice Charlands begreb om konstitutiv retorik og Jacques Derridas dekonstruktion af repræsentationslogik foretager artiklen en kritisk analyse og fortolkning af repræsentationen af dansk nationalidentitet, sådan som den kommer til udtryk i Dronning Margrethes nytårstaler...
DEFF Research Database (Denmark)
Sørensen, Inga
Bogen fokuserer på prøveatgning af grundvand og drikkevand til forskellige formål såsom undersøgelse af forurenede grunde, grundvandsmonitering samt produktion af drikkevand. Da grundvand i sagens natur findes under jordoverfladen, beskriver bogen også væsentlige forhold om hydrogeologi og...
Modelanalyser af mobilitet og miljø
DEFF Research Database (Denmark)
Christensen, Linda; Gudmundsson, Henrik
Begrebet bæredygtig transport diskuteres og ved hjælp af persontrafikmodellen ALTRANS belyses mulighederne for at fremme bæredygtig udvikling gennem en række scenarier. Desuden præsenteres en mere detaljeret analyse af ændringer i CO2-belastningen ved forbedring af den kollektive trafiks servicen...
Hærdeteknologi og Holdbarhed af Betonkonstruktioner
DEFF Research Database (Denmark)
Sørensen, Eigil V.
Kurset Hærdeteknologi og Holdbarhed af Betonkonstruktioner afholdes i 1. og 2. periode af forårssemesteret 2006. Kurset sigter på at give de studerende en grundlæggende forståelse af, hvorledes man designer og udfører holdbare betonkonstruktioner....
DEFF Research Database (Denmark)
Neumann, Katrine; Buse, Katja Strøm; Hjulsager, Charlotte Kristiane
2018-01-01
Mængden af PCV2-virus i poolede serumprøver kan anvendes til at finde grise med meget PCV2-virus, hvorimod mængden af PCV2-virus i spyt og fæces er velegnede til at vurdere tilstedeværelsen af eller tidspunktet for en begyndende PCV2-infektion...
DEFF Research Database (Denmark)
Neumann, Katrine; Buse, Katja Strøm; Hjulsager, Charlotte Kristiane
Mængden af PCV2-virus i poolede serumprøver kan anvendes til at finde grise med meget PCV2-virus, hvorimod mængden af PCV2-virus i spyt og fæces er velegnede til at vurdere tilstedeværelsen af eller tidspunktet for en begyndende PCV2-infektion...
Phan, Thanh Duoc; Lim, James; Tanyimboh, Tiku T.; Sha, Wei
2013-01-01
The design optimization of a cold-formed steel portal frame building is considered in this paper. The proposed genetic algorithm (GA) optimizer considers both topology (i.e., frame spacing and pitch) and cross-sectional sizes of the main structural members as the decision variables. Previous GAs in the literature were characterized by poor convergence, including slow progress, that usually results in excessive computation times and/or frequent failure to achieve an optimal or near-optimal sol...
DEFF Research Database (Denmark)
Baldini, Mattia; Klinge Jacobsen, Henrik
2016-01-01
the improvements made in the energy saving field. Indeed, little attention has been paid to implement energy efficiency measures, which has resulted in scenarios where expedients for a wise use of energy (e.g. energy savings and renewables share) are unbalanced. The aim of this paper is to review and evaluate...... international experiences on finding the optimal trade-off between efficiency improvements and additional renewable energy supply. A critical review of each technique, focusing on purposes, methodology and outcomes, is provided along with a review of tools adopted for the analyses. The models are categorized...... trade-off between renewables and energy efficiency measures in energy-systems under different objectives....
Energy Technology Data Exchange (ETDEWEB)
Strohmer, F.
2014-07-01
The profitability of nuclear power plants is worldwide challenged by low electricity prices. One hand low cost shale gas is offering a low price electricity production , other hand additional taxes on fuel are reducing the operating income of nuclear power stations. The optimization of cooling towers can help to increase the efficiency and profit of a nuclear power plant. (Author)
DEFF Research Database (Denmark)
Radzisheuskaya, Aliaksandra; Shlyueva, Daria; Müller, Iris
2016-01-01
CRISPR interference (CRISPRi) represents a newly developed tool for targeted gene repression. It has great application potential for studying gene function and mapping gene regulatory elements. However, the optimal parameters for efficient single guide RNA (sgRNA) design for CRISPRi are not fully...
Optimization of an Efficient and Sustainable Sonogashira Cross-Coupling Protocol
Walter, Philipp E.
2012-12-01
Cross coupling reactions are a well-established tool in modern organic synthesis and play a crucial role in the synthesis of a high number of organic compounds. Their importance is highlighted by the Nobel Prize in chemistry to Suzuki, Heck and Negishi in 2010. The increasing importance of sustainability requirements in chemical production has furthermore promoted the development of cross-coupling protocols that comply with the principles of “Green Chemistry”1. The Sonogashira reaction is today the most versatile and powerful way to generate aryl alkynes, a moiety recurring in many pharmaceutical and natural products. Despite many improvements to the original reaction, reports on generally applicable protocols that work under sustainable conditions are scarce. Our group recently reported an efficient protocol for a copperfree Sonogashira cross-coupling at low temperature, in aqueous medium and with no addition of organic solvents or additives2. The goal of this work was to further investigate the effects of different reaction parameters on the catalytic activity in order to optimize the protocol. Limitations of the protocol were tested in respect to reaction temperature, heating method, atmosphere, base type and amount, catalyst loading, reaction time and work up procedure. The reaction worked successfully under air and results were not affected by the presence of oxygen in the water phase. Among a variety of bases tested, triethylamine was confirmed to give the best results and its required excess could be reduced from nine to four equivalents. Catalyst loading could also be reduced by up to 90%: Good to near quantitative yields for a broad range of substrates were achieved using a catalyst concentration of 0.25mol% and 5 eq of Et3N at 50°C while more reactive substrates could be coupled with a catalyst concentration as low as 0.025mol%. Filtration experiments showed the possibility of a simplified work up procedure and a protocol completely free of organic
Henten, van E.J.; Buwalda, F.; Zwart, de H.F.; Gelder, de A.; Hemming, J.
2006-01-01
Sweet pepper production is characterized by large fluctuations in fruit yield in time. These fluctuations have a detrimental effect on the operational planning of labor at nursery level as well as on the efficiency of the supply chain. At the same time, the dependence of temperate zone greenhouse
Produktion og afsætning af nicheprodukter
DEFF Research Database (Denmark)
Jensen, Jonas Baungaard; Hansen, Henning Otte
2016-01-01
. Egnsmærker opnår generelt en merpris på 20-30 pct. Det er dog bemærkelsesværdigt, at landmanden “kun” har omkring 13 pct. af forbrugerkronen på Lammefjords-kartofler. Her er der tale om unikke produkter, hvor det i praksis udelukkende er landmanden og landmandens placering og produktion, som skaber de unikke...
Lima Passos, Valéria; Tan, Frans E S; Winkens, Bjorn; Berger, Martijn P F
2009-01-01
Comparative studies between the one- and two-color microarrays provide supportive evidence for similarities of results on differential gene expression. So far, no design comparisons between the two platforms have been undertaken. With the objective of comparing optimal designs of one- and two-color microarrays in their statistical efficiencies, techniques of design optimization were applied within a mixed model framework. A- and D-optimal designs for the one- and two-color platforms were sought for a 3 x 3 factorial experiment. The results suggest that the choice of the platform will not affect the "subjects to groups" allocation, being concordant in the two designs. However, under financial constraints, the two-color arrays are expected to have a slight upper hand in terms of efficiency of model parameters estimates, once the price of arrays is more expensive than that of subjects. This statement is especially valid for microarray studies envisaging class comparisons.
Design optimization for permanent magnet machine with efficient slot per pole ratio
Potnuru, Upendra Kumar; Rao, P. Mallikarjuna
2018-04-01
This paper presents a methodology for the enhancement of a Brush Less Direct Current motor (BLDC) with 6Poles and 8slots. In particular; it is focused on amulti-objective optimization using a Genetic Algorithmand Grey Wolf Optimization developed in MATLAB. The optimization aims to maximize the maximum output power value and minimize the total losses of a motor. This paper presents an application of the MATLAB optimization algorithms to brushless DC (BLDC) motor design, with 7 design parameters chosen to be free. The optimal design parameters of the motor derived by GA are compared with those obtained by Grey Wolf Optimization technique. A comparative report on the specified enhancement approaches appearsthat Grey Wolf Optimization technique has a better convergence.