790,722 research outputs found
D-optimal matrices of orders 118, 138, 150, 154 and 174
We construct supplementary difference sets (SDS) with parameters
, , , and
. These SDSs give D-optimal designs (DO-designs) of
two-circulant type of orders 118,138,150,154 and 174. Until now, no DO-designs
of orders 138,154 and 174 were known. While a DO-design (not of two-circulant
type) of order 150 was constructed previously by Holzmann and Kharaghani, no
such design of two-circulant type was known. The smallest undecided order for
DO-designs is now 198. We use a novel property of the compression map to speed
up some computations.Comment: 14 pages. arXiv admin note: substantial text overlap with
arXiv:1409.596
Recikliranje ekspandiranog polistirena kao uÄinkovitog adsorbensa naftalena iz vodene otopine
Batch adsorption process factors [contact time (20â150 min), adsorbent dosage (0.5â1.5 g), adsorbate concentration (5â30 mg lâ1), and agitation rate (100â250 rpm)] were optimised based on D-optimal Design under the Response Surface Methodology (RSM) of the Design-Expert Software (7.6.8) for the removal of naphthalene from aqueous solution using adsorbent developed from Acetylated Waste Expanded Polystyrene (AWEPs). The maximum adsorption capacity (5.6608 mg gâ1) achieved was well fitted to Dubinin-Radushkevich Isotherm (R2 = 0.9949). The SSE (< 0.05) and ARE (< 4.0 %) indicated pseudo-second-order as the most suitable model. This research has demonstrated the effectiveness of the WEPs for the removal of naphthalene from the aqueous solution.
This work is licensed under a Creative Commons Attribution 4.0 International License.Ć arĆŸni faktori procesa adsorpcije [vrijeme kontakta (20 â 150 min), doziranje adsorbenta (0,5 â 1,5 g), koncentracija adsorbata (5â30 mg lâ1) i brzina mijeĆĄanja (100â250 minâ1)] optimizirani su na temelju D-optimalnog dizajna primjenom metodologije odzivne povrĆĄine (RSM) programa Design-Expert (7.6.8) za uklanjanje naftalena iz vodene otopine pomoÄu adsorbenta razvijenog iz acetiliranog otpadnog ekspandiranog polistirena (AWEP). Ostvareni maksimalni adsorpcijski kapacitet (5,6608 mg gâ1) dobro je prilagoÄen izotermi Dubinin-Radushkevich (R2 = 0,9949). SSE (< 0,05) i ARE (< 4,0 %) oznaÄili su pseudo-drugi red kao najprikladniji model. Ovo istraĆŸivanje pokazalo je uÄinkovitost WEP-a za uklanjanje naftalena iz vodene otopine.
Ovo djelo je dano na koriĆĄtenje pod licencom Creative Commons Imenovanje 4.0 meÄunarodna
Optimized Multipactor-Resistant Wedge-Shaped Waveguide Bandpass Filters
[EN] Wedge-shaped waveguides present a certain advantage
with respect to rectangular waveguides regarding their
resistance to multipactor discharges. In this paper, the optimal
configuration for the wedge geometry is investigated based on
theoretical results, on a precise multipactor prediction tool, and
on previous experience. In addition, design rules are presented,
which allow us to achieve for wedge-shaped filters electrical
performances comparable to the ones of rectangular waveguide
filters, while at the same time improving the multipactor-free
power range. As a proof of concept, two three-pole bandpass
filters with equivalent electrical characteristic of 150-MHz bandwidth,
centered at 12 GHz (Ku band), and the same Q factor have
been designed, manufactured, and tested. The first design is based
on conventional rectangular waveguide technology, while the
second one has non-parallel broadside walls (wedge-shaped cross
section). The multipactor power threshold and RF performance
of the filters have been measured in order to validate the
improvements achievable employing wedge-shaped resonators.This work was supported by the Ministerio de Ciencia e Innovacion, Spain, under Research Project TEC2010-21520-C04-01/TCM.Hueso GonzĂĄlez, J.; Raboso GarcĂa-Baquero, D.; Ernst, C.; Schmitt, D.; Boria Esbert, VE.; Gimeno Martinez, B.; Taroncher Calduch, M.... (2013). Optimized Multipactor-Resistant Wedge-Shaped Waveguide Bandpass Filters. IEEE TRANSACTIONS ON PLASMA SCIENCE. 41(8):2135-2144. https://doi.org/10.1109/TPS.2013.2253134S2135214441
Optimal design of dilution experiments under volume constraints
The paper develops methods to construct a one-stage optimal design of
dilution experiments under the total available volume constraint typical for
bio-medical applications. We consider various design criteria based on the
Fisher information both is Bayesian and non-Bayasian settings and show that the
optimal design is typically one-atomic meaning that all the dilutions should be
of the same size. The main tool is variational analysis of functions of a
measure and the corresponding steepest descent type numerical methods. Our
approach is generic in the sense that it allows for inclusion of additional
constraints and cost components, like the cost of materials and of the
experiment itself.Comment: 29 pages, 10 figure
The application of multi-objective robust design methods in ship design
When designing large complex vessels, the evaluation of a particular design can be both complicated and time consuming. Designers often resort to the use of concept design models enabling both a reduction in complexity and time for evaluation. Various optimisation methods are then typically used to explore the design space facilitating the selection of optimum or near optimum designs. It is now possible to incorporate considerations of seakeeping, stability and costs at the earliest stage in the ship design process. However, to ensure that reliable results are obtained, the models used are generally complex and computationally expensive. Methods have been developed which avoid the necessity to carry out an exhaustive search of the complete design space. One such method is described which is concerned with the application of the theory of Design Of Experiments (DOE) enabling the design space to be efficiently explored. The objective of the DOE stage is to produce response surfaces which can then be used by an optimisation module to search the design space. It is assumed that the concept exploration tool whilst being a simplification of the design problem, is still sufficiently complicated to enable reliable evaluations of a particular design concept. The response surface is used as a representation of the concept exploration tool, and by it's nature can be used to rapidly evaluate a design concept hence reducing concept exploration time. While the methodology has a wide applicability in ship design and production, it is illustrated by its application to the design of a catamaran with respect to seakeeping. The paper presents results exploring the design space for the catamaran. A concept is selected which is robust with respect to the Relative Bow Motion (RBM), the heave, pitch and roll at any particular waveheading. The design space is defined by six controllable design parameters; hull length, breadth to draught ratio, distance between demihull centres, coefficient of waterplane, longitudinal centre of floatation, longitudinal centre of buoyancy, and by one noise parameter, the waveheading. A Pareto-optimal set of solutions is obtained using RBM, heave, pitch and roll as criteria. The designer can then select from this set the design which most closely satisfies their requirements. Typical solutions are shown to yield average reductions of over 25% in the objective functions when compared to earlier results obtained using conventional optimisation methods
Low-thrust trajectories design for the European Student Moon Orbiter mission
The following paper presents the mission analysis studies performed for the phase A of the solar electric propulsion option of the European Student Moon Orbiter (ESMO) mission. ESMO is scheduled to be launched in 2011, as an auxiliary payload on board of Ariane 5. Hence the launch date will be imposed by the primary payload. A method to efficiently assess wide launch windows for the Earth-Moon transfer is presented here. Sets of spirals starting from the GTO were propagated forward with a continuous tangential thrust until reaching an apogee of 280,000 km. Concurrently, sets of potential Moon spirals were propagated backwards from the lunar orbit injection. The method consists of ranking all the admissible lunar spiral-down orbits that arrive to the target orbit with a simple tangential thrust profile after a capture through the L1 Lagrange point. The 'best' lunar spiral is selected for each Earth spiral. Finally,comparing the value of the ranking function for each launch date, the favourable and unfavourable launch windows are identified
Rethinking Location Privacy for Unknown Mobility Behaviors
Location Privacy-Preserving Mechanisms (LPPMs) in the literature largely
consider that users' data available for training wholly characterizes their
mobility patterns. Thus, they hardwire this information in their designs and
evaluate their privacy properties with these same data. In this paper, we aim
to understand the impact of this decision on the level of privacy these LPPMs
may offer in real life when the users' mobility data may be different from the
data used in the design phase. Our results show that, in many cases, training
data does not capture users' behavior accurately and, thus, the level of
privacy provided by the LPPM is often overestimated. To address this gap
between theory and practice, we propose to use blank-slate models for LPPM
design. Contrary to the hardwired approach, that assumes known users' behavior,
blank-slate models learn the users' behavior from the queries to the service
provider. We leverage this blank-slate approach to develop a new family of
LPPMs, that we call Profile Estimation-Based LPPMs. Using real data, we
empirically show that our proposal outperforms optimal state-of-the-art
mechanisms designed on sporadic hardwired models. On non-sporadic location
privacy scenarios, our method is only better if the usage of the location
privacy service is not continuous. It is our hope that eliminating the need to
bootstrap the mechanisms with training data and ensuring that the mechanisms
are lightweight and easy to compute help fostering the integration of location
privacy protections in deployed systems
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