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Optimal Configuration (optimal + configuration)
Selected AbstractsOptimal Monetary Policy with Price and Wage RigiditiesECONOMIC NOTES, Issue 1 2006Massimiliano Marzo In this paper, I search for an optimal configuration of parameters for variants of the Taylor rule by using an accurate second-order welfare-based method within a fully microfounded dynamic stochastic model, with price and wage rigidities, without capital accumulation. A version of the model with distortionary taxation is also explicitly tested. The model is solved up to second-order solution. Optimal rules are obtained by maximizing a conditional welfare measure, differently from what has been done in the current literature. Optimal monetary policy functions turn out to be characterized by inflation targeting parameter lower than in empirical studies. In general, the optimal values for monetary policy parameters depend on the degree of nominal rigidities and on the role of fiscal policy. When nominal rigidities are higher, optimal monetary policy becomes more aggressive to inflation. With a tighter fiscal policy, optimal monetary policy turns out to be less aggressive to inflation. Impulse-response functions based on second-order model solution show a non-affine pattern when the economy is hit by shocks of different magnitude. [source] Power flow congestion relief by using customer-side energy storage systemsELECTRICAL ENGINEERING IN JAPAN, Issue 1 2007Ken Furusawa Abstract In recent years, energy storage systems have increasingly been expected as a means of load leveling of the annual load factor. Of course there is an effect of installing the energy storage systems at the substation. But some customers operate their storage system in an integrated way and it also has an effect of increasing the load factor. In this paper the authors proposed that the energy storage systems on the customer side be used for congestion relief on transmission networks. However, it is not clear which kind of customer has the effect of relieving transmission line congestion. First, this paper assumes the authors determine the optimal configuration of energy equipment including energy storage systems. We propose a new contract whereby electric utility subsidizes a part of the entrance cost of the energy storage systems and customers change the output pattern of energy storage according to the request of the electric utility. This paper evaluates the possibility that the contract gives merit to both the electric utility and the customer. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 36,45, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20299 [source] Service restoration method considering simultaneous disconnection of distributed generators by one-bank fault of distribution systemELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2008Hirotaka Takano Abstract Distributed generators (DGs) such as fuel cells and solar cells are going to be installed in the demand side of distribution systems. The DGs can reduce distribution loss by appropriate allocation. However, there are several problems installing DGs such as service restoration of distribution system with DGs and so on. When one bank fault of distribution substation occurs in distribution system, since DGs are simultaneously disconnected from the system, it is not easy to restore isolated load by one bank switching in distribution substation. Therefore, a service restoration method to determine restoration configuration and restoration procedures (switching procedure from normal configuration to restoration configuration) taking into account simultaneous disconnection of DGs is needed. In this paper, the authors propose a computation method to determine the optimal restoration configuration and the restoration procedure considering simultaneous disconnection of DGs by one bank fault of distribution system. In the proposed algorithm, after all of the restoration configuration candidates are effectively enumerated under the operational constraints, the optimal configuration to restore the isolated load is selected among enumerated configuration candidates. After determining the optimal restoration configuration, the optimal restoration procedures are obtained by greedy algorithm. Numerical simulations are carried out for a real scale system model with 237 sectionalizing switches (configuration candidates are 2237) and 21 DGs (total output is 5250 kW which is 3% of total load) in order to examine the validity of the proposed algorithm. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(8): 44,55, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10133 [source] Spatial metrics and methods for riverscapes: quantifying variability in riverine fish habitat patternsENVIRONMETRICS, Issue 5 2009Céline Le Pichon Abstract Defining the optimal configuration of all habitats required during a life cycle, called vital habitat, is a necessary step for effective management of riverine fishes and restoration of river habitats. Landscape ecology provides many metrics and methods to study the composition and configuration of habitats, but they need to be adapted for fishes in river environments or riverscapes. For example, hydrographic distance seems more appropriate than Euclidean distance for measuring distances between vital habitats in riverscapes. We adapted some metrics to assess habitats patterns of a threatened cyprinid species (Barbus barbus) for natural and artificial riverscapes of the Seine river, France. Composition metrics provided essential quantification of the relative abundance of the vital habitats, whereas configuration metrics were relevant to quantify their spatial arrangement and spatial relationships. Nearest-neighbor hydrographic distance was useful to evaluate the influence of flow variability in the natural riverscape, but was not relevant to discriminate the artificial riverscape from the natural one. Conversely, a proximity index revealed high fragmentation in the artificial riverscape. Spatial habitat relationships between feeding and resting habitats, evaluated with a moving window analysis, provided a map of daily activity patches and emphasized the gaps in the biological continuity of the riverscape. The spatial metrics and methods we adapted to the particularities of the Seine river allowed us to detect natural and artificial variability in fish habitat patterns. They should help in evaluating impacts of habitat alteration and isolation and prioritize preservation and restoration policies in human-impacted rivers. Copyright © 2008 John Wiley & Sons, Ltd. [source] Anticipating bipedalism: trabecular organization in the newborn iliumJOURNAL OF ANATOMY, Issue 6 2009Craig A. Cunningham Abstract Trabecular bone structural organization is considered to be predominantly influenced by localized temporal forces which act to maintain and remodel the trabecular architecture into a biomechanically optimal configuration. In the adult pelvis, the most significant remodelling forces are believed to be those generated during bipedal locomotion. However, during the fetal and neonatal period the pelvic complex is non-weight bearing and, as such, structural organization of iliac trabecular bone cannot reflect direct stance-related forces. In this study, micro-computed tomography scans from 28 neonatal ilia were analysed, using a whole bone approach, to investigate the trabecular characteristics present within specific volumes of interest relevant to density gradients highlighted in a previous radiographic study. Analysis of the structural indices bone volume fraction, trabecular thickness, trabecular spacing and trabecular number was carried out to quantitatively investigate structural composition. Quantification of the neonatal trabecular structure reinforced radiographic observations by highlighting regions of significant architectural form which grossly parallel architectural differences in the adult pattern but which have previously been attributed to stance-related forces. It is suggested that the seemingly organized rudimentary scaffold observed in the neonatal ilium may be attributable to other non-weight bearing anatomical interactions or even to a predetermined genetic blueprint. It must also be postulated that whilst the observed patterning may be indicative of a predetermined inherent template, early non-weight bearing and late stance-related locomotive influences may subsequently be superimposed upon this scaffolding and perhaps reinforced and likely remodelled at a later age. Ultimately, the analysis of this fundamental primary pattern has core implications for understanding the earliest changes in pelvic trabecular architecture and provides a baseline insight into future ontogenetic development and bipedal capabilities. [source] Enantioseparation via EIC-OSN: Process design and improvement of enantiomers resolvability and separation performanceAICHE JOURNAL, Issue 4 2010Issara Sereewatthanawut Abstract This article presents a mathematical model to assess and optimize the separation performance of an enantioselective inclusion complexation-organic solvent nanofiltration process. Enantiomer solubilities, feed concentrations, solvent compositions, permeate solvent volumes, and numbers of nanofiltrations were identified as key factors for process efficiency. The model was first tested by comparing calculated and experimental results for a nonoptimized process, and then, calculations were carried out to select the best operating conditions. An important finding was that the optimal configuration varied with the objective function selected, e.g., resolvability versus yield, with a boundary on product optical purity. The model also suggested that the process efficiency could benefit from diafiltration of the distomer and from the use of higher feed concentrations. However, the latter strategy would result in higher losses of eutomer. To address this drawback, a multistage process was evaluated using the verified process model. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Effects of alternative instrumentation strategies in adolescent idiopathic scoliosis: A biomechanical analysisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2009Martin Robitaille Abstract The recent advent of modern instrumentation systems has improved the correction of scoliosis, but complicated the surgical decision-making process, especially with the introduction of diverse spinal fixation devices, new preoperative corrective maneuvers, and the reevaluation of many rules concerning the selection of fusion levels and other guidelines for surgical correction. Our objective was to assess the biomechanical effects of different instrumentation strategies for the same scoliotic cases. Several instrumentation strategies suggested by a group of 32 experienced senior surgeons for five cases were individually simulated using a validated computer model implemented in a spine surgery simulator. The resulting geometric indices varied among the five cases (e.g., range of main thoracic Cobb angles: 5,17°, 16,29°, 25,44°, 15,34°, 16,32°; kyphosis: 22,33°, 20,54°, 33,55°, 24,49°, 29,46°; and lordosis: 10,52°, 24,38°, 26,54°, 8,28°, 34,53°). The average correction was better with pedicle screws (71%) than with hooks (51%) and hybrid constructs (67%). For the first time, to our knowledge, the effect of different instrumentation strategies was compared on the same patients, which is possible only with a surgery simulator. A large variability of instrumentation strategies existed among experienced surgeons and produced rather different results. This study questions the criteria for optimal configuration and standards to design the best surgical construct. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:104,113, 2009 [source] Structure and Function of Emergency Care Research Networks: Strengths, Weaknesses, and ChallengesACADEMIC EMERGENCY MEDICINE, Issue 10 2009Linda Papa MD Abstract The ability of emergency care research (ECR) to produce meaningful improvements in the outcomes of acutely ill or injured patients depends on the optimal configuration, infrastructure, organization, and support of emergency care research networks (ECRNs). Through the experiences of existing ECRNs, we can learn how to best accomplish this. A meeting was organized in Washington, DC, on May 28, 2008, to discuss the present state and future directions of clinical research networks as they relate to emergency care. Prior to the conference, at the time of online registration, participants responded to a series of preconference questions addressing the relevant issues that would form the basis of the breakout session discussions. During the conference, representatives from a number of existing ECRNs participated in discussions with the attendees and provided a description of their respective networks, infrastructure, and challenges. Breakout sessions provided the opportunity to further discuss the strengths and weaknesses of these networks and patterns of success with respect to their formation, management, funding, best practices, and pitfalls. Discussions centered on identifying characteristics that promote or inhibit successful networks and their interactivity, productivity, and expansion. Here the authors describe the current state of ECRNs and identify the strengths, weaknesses, and potential pitfalls of research networks. The most commonly cited strengths of population- or disease-based research networks identified in the preconference survey were access to larger numbers of patients; involvement of physician experts in the field, contributing to high-level study content; and the collaboration among investigators. The most commonly cited weaknesses were studies with too narrow a focus and restrictive inclusion criteria, a vast organizational structure with a risk of either too much or too little central organization or control, and heterogeneity of institutional policies and procedures among sites. Through the survey and structured discussion process involving multiple stakeholders, the authors have identified strengths and weaknesses that are consistent across a number of existing ECRNs. By leveraging the strengths and addressing the weaknesses, strategies can be adopted to enhance the scientific value and productivity of these networks and give direction to future ECRNs. [source] Optimal design of interconnected bioreactors: New resultsAICHE JOURNAL, Issue 6 2003Jérôme Harmand The optimal design of two interconnected continuous stirred bioreactors in which a single reaction occurs is presented. The term "optimal" should be understood here as the minimum of the total volume of the reactors required to perform a given conversion rate, given a quantity of matter to be converted per time unit. In determining the optimal volume, it is assumed that the input flow may be distributed among the tanks and also that a recirculation loop can be used. The analysis of the optimal configurations is investigated, and the concept of "steady-state equivalent biological system" is highlighted. The class of growth functions for which the results of this study hold is quite wide and includes, in particular, Monod, Haldane, and Aiba kinetics. [source] Study of the transport properties of a molecular junction as a function of the distance between the leadsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2007Víctor M. García-Suárez Abstract We consider a model of a molecular junction made of BDT (benzene dithiol) molecule trapped between two Au(100) leads. Using the ab initio approach implemented in the SIESTA package we look for the optimal configurations of the molecule as a function of the distance between the leads. We find that for distances long enough the energy of the system is minimized when the molecule is bonded asymmetrically, i.e. chemisorbed to one of the leads, whereas for distances shorter than 12 Å the energy is minimized when the molecule sits in the middle between the leads. We discuss possible consequences of the above findings for the transport properties of the junction. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mass peak shape improvement of a quadrupole mass filter when operating with a rectangular wave power supplyRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Chan Luo Numeric experiments were performed to study the first and second stability regions and find the optimal configurations of a quadrupole mass filter constructed of circular quadrupole rods with a rectangular wave power supply. The ion transmission contours were calculated using ion trajectory simulations. For the first stability region, the optimal rod set configuration and the ratio r/r0 is 1.110,1.115; for the second stability region, it is 1.128,1.130. Low-frequency direct current (DC) modulation with the parameters of m,=,0.04,0.16 and ,,=,,/,,=,1/8,1/14 improves the mass peak shape of the circular rod quadrupole mass filter at the optimal r/r0 ratio of 1.130. The amplitude modulation does not improve mass peak shape. Copyright © 2009 John Wiley & Sons, Ltd. [source] The interaction between model resolution, observation resolution and observation density in data assimilation: A one-dimensional studyTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 582 2002Z.-Q. Liu Abstract In this paper, the optimal configurations of model resolution, observation resolution and observation density are investigated in a simple one-dimensional framework. In this context, the representativeness error is formalized and estimated before being used in the analysis-error formulation. Some optimal and suboptimal assimilation-schemes, differing from different approximations of observation-error covariance and observation operator, are compared. The optimal observation-extent is determined as a function of model resolution. Increasing the observation density is usually beneficial, except for suboptimal schemes similar to the ones used in operational practice. The impact of thinning the observations with correlated error is also studied from a suboptimal viewpoint. Copyright © 2002 Royal Meteorological Society [source] The concept of the gas turbine-based hybrid vehicle: system, design and configuration issuesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2006Roberto Capata Abstract The object of this study is a theoretical and experimental analysis of a new hybrid propulsion system for a passenger sedan in which the thermal engine is a small gas turbine set. Some preliminary results on the possibility of replacing the conventional ICE of a hybrid ,series' configuration by a turbogas were presented and discussed in previous papers by the same authors: several possible designs were examined under both a thermodynamic and an operative point of view. This paper presents a summary of the project and constitutes an attempt to put things in a proper engineering perspective: the technical feasibility of the project is assessed via a calculation of the required mission loads, a preliminary design of the most important elements of the propulsive system, the choice of the mission control strategy and the implementation of a numerical system simulator. The experiments that provided a verification for the assumed component efficiencies were carried out, in cooperation with the Research Centre of ENEA-Casaccia, on an ELLIOTT TA-45 group. Our results, though only preliminary, allow for a direct comparison between a GT-hybrid vehicle and a modern diesel car, and indicate that the GT-hybrid may be actually a competitor for the FC-powered vehicle concept. Our ,optimal' configuration is a combination of a 100 kg battery pack and two turbogas set of 5 and 16 kW, respectively. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||