general constraints
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Author(s):  
О. V. Bulygina

Today the knowledge–intensive industry development is carried out by the programs that combine a set of innovation and investment projects aimed at achieving a single goal and implemented in general constraints. The presence of a larger number of project characteristics (in particular, terms, resources, performers, etc.), which must be taken into account when forming the composition of the program, leads to the formulation of the problem of multicriteria optimization. As its solution, it is proposed to use an algorithm of bacterial optimization, supplemented by a procedure for forming initial positions using fuzzy logic methods.


Aerospace ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 8
Author(s):  
Akshay Gangadhar ◽  
Murugaiah Manikandan ◽  
Dushhyanth Rajaram ◽  
Dimitri Mavris

In recent years, hybrid airships have been identified as promising alternatives for high altitude, long endurance missions. In this study, a design methodology to study the feasibility of a winged hybrid airship powered by solar energy is presented. The proposed methodology involves five disciplines of the airship, viz., geometry, aerodynamics, environment, energy and structures that have been coupled in order to develop an optimum design which incorporates the maximum advantages of the modules. A total of fourteen design variables have been finalized, which are required to carry out the sizing of the envelope, wing, and solar panel layout. The Particle Swarm Optimization (PSO) algorithm is implemented to carry out optimization of a user-defined fitness function for given user-defined operating conditions. The optimization study is subjected to general constraints of weight balance and energy balance. Optimal solutions have been obtained for two different configurations. These are—conventional airship and winged hybrid airship. The solutions have been obtained for four different days of the year, in order to analyse any potential benefits and pitfalls of the two configurations for the varying conditions over the course of one year. The results obtained are generally found to be in excellent agreement with the imposed constraints. The winged hybrid airship configuration was found to have offered no significant benefits in comparison to the conventional configuration. The analysis of the key parameters and data values readily supports this conclusion.


Author(s):  
Young-San Lin ◽  
Hai Nguyen ◽  
Thành Nguyen ◽  
Kemal Altinkemer
Keyword(s):  

Synthese ◽  
2021 ◽  
Author(s):  
Marvin Backes

AbstractIn ordinary discourse we often attribute beliefs not just to individuals but also to groups. But can groups really have genuine beliefs? This paper considers but ultimately rejects one of the main arguments in support of the claim that groups can be genuine believers – the Argument From Interpretationism – and concludes that we have good reasons to be sceptical about the existence of group beliefs. According to the Argument From Interpretationism, roughly speaking, groups qualify as genuine believers because we can interpret (or predict) their behaviour in much the same way that we can interpret (or predict) the behaviour of individuals. While this argument may seem initially attractive, I argue that it is ultimately unsuccessful. In particular, I argue that the argument is unsuccessful even if one is generally sympathetic towards interpretationism. The reason for this, as we will see, is that a number of problems arise when we try to apply the interpretationist strategy – originally formulated with individual subjects in mind – to plural subjects or groups. In showing why the Argument From Interpretationism fails, the paper also brings into focus some more general constraints on the scope and applicability of interpretationism.


2021 ◽  
pp. 1-47
Author(s):  
Sebastian Bücking

Abstract This paper addresses the grammar of PP-like free relatives (= PP-FRs) such as the locative clause in Bello schläft, wo Grace schläft ‘Bello is sleeping where Grace is sleeping’. The most prominent compositional analysis of PP-FRs is developed by Caponigro (2004), Caponigro and Pearl (2009), and Hall and Caponigro (2010). They derive PP-FRs from a stacked CP-structure that is based on silent prepositions and a nominal treatment of wh-words such as where. I first take issue with this analysis by means of a detailed discussion of subordinate clauses introduced by wo ‘where’ in German. Specifically, I show that wo-clauses do not involve silent prepositions, and that both wo and wo-clauses have a prepositional instead of a nominal nature. Second, I sketch a surface-oriented alternative approach to PP-FRs that dispenses with silent prepositions and assigns the prepositional nature of PP-like wh-words a key role in the derivation. Specifically, I propose that the fronting of PP-like wh-words in free relatives licenses an abstraction over predicates (instead of entities) and a corresponding type shifting. The new analysis is related to analyses of corresponding subordinate headed relative and interrogative clauses. Furthermore, it is confronted with potential general constraints on higher-order abstraction as argued for, in particular, by Poole (2017).


2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Dominic V. Else ◽  
Ryan Thorngren ◽  
T. Senthil

Author(s):  
O. D. Street ◽  
D. Crisan

Spearheaded by the recent efforts to derive stochastic geophysical fluid dynamics models, we present a general framework for introducing stochasticity into variational principles through the concept of a semi-martingale driven variational principle and constraining the component variables to be compatible with the driving semi-martingale. Within this framework and the corresponding choice of constraints, the Euler–Poincaré equation can be easily deduced. We show that the deterministic theory is a special case of this class of stochastic variational principles. Moreover, this is a natural framework that enables us to correctly characterize the pressure term in incompressible stochastic fluid models. Other general constraints can also be incorporated as long as they are compatible with the driving semi-martingale.


2021 ◽  
Author(s):  
Ricardo Sánchez-Martín ◽  
José I. Querejeta ◽  
Jordi Voltas ◽  
Juan Pedro Ferrio ◽  
Iván Prieto ◽  
...  
Keyword(s):  

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Nima Afkhami-Jeddi ◽  
Henry Cohn ◽  
Thomas Hartman ◽  
Amirhossein Tajdini

Abstract We study the torus partition functions of free bosonic CFTs in two dimensions. Integrating over Narain moduli defines an ensemble-averaged free CFT. We calculate the averaged partition function and show that it can be reinterpreted as a sum over topologies in three dimensions. This result leads us to conjecture that an averaged free CFT in two dimensions is holographically dual to an exotic theory of three-dimensional gravity with U(1)c×U(1)c symmetry and a composite boundary graviton. Additionally, for small central charge c, we obtain general constraints on the spectral gap of free CFTs using the spinning modular bootstrap, construct examples of Narain compactifications with a large gap, and find an analytic bootstrap functional corresponding to a single self-dual boson.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Aleix Gimenez-Grau ◽  
Pedro Liendo

Abstract We apply the numerical conformal bootstrap to correlators of Coulomb and Higgs branch operators in 4d$$ \mathcal{N} $$ N = 2 superconformal theories. We start by revisiting previous results on single correlators of Coulomb branch operators. In particular, we present improved bounds on OPE coefficients for some selected Argyres-Douglas models, and compare them to recent work where the same cofficients were obtained in the limit of large r charge. There is solid agreement between all the approaches. The improved bounds can be used to extract an approximate spectrum of the Argyres-Douglas models, which can then be used as a guide in order to corner these theories to numerical islands in the space of conformal dimensions. When there is a flavor symmetry present, we complement the analysis by including mixed correlators of Coulomb branch operators and the moment map, a Higgs branch operator which sits in the same multiplet as the flavor current. After calculating the relevant superconformal blocks we apply the numerical machinery to the mixed system. We put general constraints on CFT data appearing in the new channels, with particular emphasis on the simplest Argyres-Douglas model with non-trivial flavor symmetry.


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