3,232 research outputs found
The significance of neighborhood in Istanbul
Abstract The neighborhood is prominent in contemporary urban studies. One reason for choosing neighborhood as a unit of action is that the neighborhood provides an efficient scale within which to measure any change in target population’s circumstances. Neighborhood here is defined as the bundle of spatially based attributes associated with clusters of residences. This bundle of attributes is multidimensional consisting of everything from topography and structures and demography to social interactions. For most people, residence and the context in which it exists, that is to say neighborhood, is the largest consumption item of a lifetime. How much an individual’s needs and aspirations are met by his neighborhood is a concern for researchers and planners. This study expresses a belief in the value of the concept of place as part of the neighborhood question. There are now many established ways of looking at the neighborhood, as place, as network, as image, as property and as administrative unit. These all have something to offer individually and deserve continuing attention to help counteract some of the deficiencies of our contemporary society. In this study respondents from two districts of Istanbul are asked for their subjective assessments of a set of domains associated with neighborhood satisfaction. The neighborhoods are chosen to be one traditional and one modern context. The results indicate significant differences among the residents of traditional and modern neighborhoods. Keywords: Neighborhood satisfaction, context, subjective assessment, traditional, modern
Probably Approximately Correct MDP Learning and Control With Temporal Logic Constraints
We consider synthesis of control policies that maximize the probability of
satisfying given temporal logic specifications in unknown, stochastic
environments. We model the interaction between the system and its environment
as a Markov decision process (MDP) with initially unknown transition
probabilities. The solution we develop builds on the so-called model-based
probably approximately correct Markov decision process (PAC-MDP) methodology.
The algorithm attains an -approximately optimal policy with
probability using samples (i.e. observations), time and space that
grow polynomially with the size of the MDP, the size of the automaton
expressing the temporal logic specification, ,
and a finite time horizon. In this approach, the system
maintains a model of the initially unknown MDP, and constructs a product MDP
based on its learned model and the specification automaton that expresses the
temporal logic constraints. During execution, the policy is iteratively updated
using observation of the transitions taken by the system. The iteration
terminates in finitely many steps. With high probability, the resulting policy
is such that, for any state, the difference between the probability of
satisfying the specification under this policy and the optimal one is within a
predefined bound.Comment: 9 pages, 5 figures, Accepted by 2014 Robotics: Science and Systems
(RSS
Rydberg blockade with multivalent atoms: effect of Rydberg series perturbation on van der Waals interactions
We investigate the effect of series perturbation on the second order
dipole-dipole interactions between strontium atoms in and
Rydberg states as a means of engineering long-range
interactions between atoms in a way that gives an exceptional level of control
over the strength and the sign of the interaction by changing . We utilize
experimentally available data to estimate the importance of perturber states at
low , and find that van der Waals interaction between two strontium atoms in
the states shows strong peaks outside the usual hydrogenic
scaling. We identify this to be the result of the perturbation of
intermediate states by the and
states in the range. This demonstrates that divalent atoms in general
present a unique advantage for creating substantially stronger or weaker
interaction strengths than those can be achieved using alkali metal atoms due
to their highly perturbed spectra that can persist up to high-
Deception in Optimal Control
In this paper, we consider an adversarial scenario where one agent seeks to
achieve an objective and its adversary seeks to learn the agent's intentions
and prevent the agent from achieving its objective. The agent has an incentive
to try to deceive the adversary about its intentions, while at the same time
working to achieve its objective. The primary contribution of this paper is to
introduce a mathematically rigorous framework for the notion of deception
within the context of optimal control. The central notion introduced in the
paper is that of a belief-induced reward: a reward dependent not only on the
agent's state and action, but also adversary's beliefs. Design of an optimal
deceptive strategy then becomes a question of optimal control design on the
product of the agent's state space and the adversary's belief space. The
proposed framework allows for deception to be defined in an arbitrary control
system endowed with a reward function, as well as with additional
specifications limiting the agent's control policy. In addition to defining
deception, we discuss design of optimally deceptive strategies under
uncertainties in agent's knowledge about the adversary's learning process. In
the latter part of the paper, we focus on a setting where the agent's behavior
is governed by a Markov decision process, and show that the design of optimally
deceptive strategies under lack of knowledge about the adversary naturally
reduces to previously discussed problems in control design on partially
observable or uncertain Markov decision processes. Finally, we present two
examples of deceptive strategies: a "cops and robbers" scenario and an example
where an agent may use camouflage while moving. We show that optimally
deceptive strategies in such examples follow the intuitive idea of how to
deceive an adversary in the above settings
Linearized analysis versus optimization-based nonlinear analysis for nonlinear systems
For autonomous nonlinear systems stability and input-output properties in small enough (infinitesimally small) neighborhoods of (linearly) asymptotically stable equilibrium points can be inferred from the properties of the linearized dynamics. On the other hand, generalizations of the S-procedure and sum-of-squares programming promise a framework potentially capable of generating certificates valid over quantifiable, finite size neighborhoods of the equilibrium points. However, this procedure involves multiple relaxations (unidirectional implications). Therefore, it is not obvious if the sum-of-squares programming based nonlinear analysis can return a feasible answer whenever linearization based analysis does. Here, we prove that, for a restricted but practically useful class of systems, conditions in sum-of-squares programming based region-of-attraction, reachability, and input-output gain analyses are feasible whenever linearization based analysis is conclusive. Besides the theoretical interest, such results may lead to computationally less demanding, potentially more conservative nonlinear (compared to direct use of sum-of-squares formulations) analysis tools
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