Auxiliary qubit selection: a physical synthesis technique for quantum circuits

Quantum circuit design flow consists of two main tasks: synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit objectives because of no information sharing between synthesis and physical design processes, we introduced the concept of “physical synthesis” for quantum circuit flow and proposed a technique for it. Following that concept, in this paper we propose a new technique for physical synthesis using auxiliary qubit selection to improve the latency of quantum circuits. Moreover, it will be shown that the auxiliary qubit selection technique can be seamlessly integrated into the previously introduced physical synthesis flow. Our experimental results show that the proposed technique decreases the average latency objective of quantum circuits by about 11% for the attempted benchmarks.     

Co-visibility and pedagogy: innovation and challenge at the High Museum of Art

Museum space is arranged not only to present but also to help understand displays. Patterns of visitor movement and the co-visibility of displays act as pedagogical media. This paper traces the recent history of the interior of the High Museum of Art, in Atlanta, and identifies radical transformations in the interaction between architectural setting, exhibition design and curatorial intention. The original 1983 second-floor layout, designed by Meier, created ‘rooms within rooms’, privileged cross views and provided a web of vistas cutting through spatial layers of displays and meandering paths of movement, even as the structural grid notated an abstract overall order. Thus, it supported comparisons and a multiplicity of points of view rather than a rigid classificatory scheme. Also, it challenged focused frontal viewing and hence traditional curatorial approaches.

The 1997 second-floor layout, by Scogin and Elam, masterfully deployed a formal exhibition language that resonated with Meier's architecture in order to implement a different curatorial programme, based on well-defined sequences of movement and controlled visual frames. The aim was not to impose an historical or stylistic classification, but rather to confront visitors with orchestrated assemblies of displays linking art to themes such as life, faith, the human figure or the city. In 2003, Lord Aeck and Sargent designed a new layout which reproduced the original ‘rooms within rooms’ implemented by Meier, whilst reducing the intricacy of internal subdivision and promoting less complex vistas. The evolution of interiors in Meier's original building stands in contrast to the simpler layout of Piano's 2005 extension for the High where architecture assumes the rôle of a more neutral and elegant background to the art works. These contrasts, their programmatic generators and their experiential consequences are documented and analysed as a case study in the pedagogical functions of museum space.     

Constrained optimal consensus in multi-agent systems with single- and double-integrator dynamics

ABSTRACT

This paper fully studies distributed optimal consensus problem in undirected dynamical networks. We consider a group of networked agents that are supposed to rendezvous at the optimal point of a collective convex objective function. Each agent has no knowledge about the global objective function and only has access to its own local objective function, which is a portion of the global one, and states information of agents within its neighbourhood set. In this setup, all agents coordinate with their neighbours to seek the consensus point that minimises the network's global objective function. In the current paper, we consider agents with single-integrator and double-integrator dynamics. Further, it is supposed that agents' movements are limited by some convex inequality constraints. In order to find the optimal consensus point under the described scenario, we combine the interior-point optimisation algorithm with a consensus protocol and propose a distributed control law. The associated convergence analysis based on Lyapunov stability analysis is provided.     

VAnDroid: A framework for vulnerability analysis of Android applications using a model-driven reverse engineering technique

Android is extensively used worldwide by mobile application developers. Android provides applications with a message passing system to communicate within and between them. Due to the risks associated with this system, it is vital to detect its unsafe operations and potential vulnerabilities. To achieve this goal, a new framework, called VAnDroid, based on Model Driven Reverse Engineering (MDRE), is presented that identifies security risks and vulnerabilities related to the Android application communication model. In the proposed framework, some security-related information included in an Android app is automatically extracted and represented as a domain-specific model. Then, it is used for analyzing security configurations and identifying vulnerabilities in the corresponding application. The proposed framework is implemented as an Eclipse-based tool, which automatically identifies the Intent Spoofing and Unauthorized Intent Receipt as two attacks related to the Android application communication model. To evaluate the tool, it has been applied to several real-world Android applications, including 20 apps from Google Play and 110 apps from the F-Droid repository. VAnDroid is also compared with several existing analysis tools, and it is shown that it has a number of key advantages over those tools specifically regarding its high correctness, scalability, and usability in discovering vulnerabilities. The results well indicate the effectiveness and capacity of the VAnDroid as a promising approach in the field of Android security.     

Towards scalable synthesis of stochastic control systems

Formal synthesis approaches over stochastic systems have received significant attention in the past few years, in view of their ability to provide provably correct controllers for complex logical specifications in an automated fashion. Examples of complex specifications include properties expressed as formulae in linear temporal logic (LTL) or as automata on infinite strings. A general methodology to synthesize controllers for such properties resorts to symbolic models of the given stochastic systems. Symbolic models are finite abstractions of the given concrete systems with the property that a controller designed on the abstraction can be refined (or implemented) into a controller on the original system. Although the recent development of techniques for the construction of symbolic models has been quite encouraging, the general goal of formal synthesis over stochastic control systems is by no means solved. A fundamental issue with the existing techniques is the known “curse of dimensionality,” which is due to the need to discretize state and input sets. Such discretization generally results in an exponential complexity over the number of state and input variables in the concrete system. In this work we propose a novel abstraction technique for incrementally stable stochastic control systems, which does not require state-space discretization but only input set discretization, and that can be potentially more efficient (and thus scalable) than existing approaches. We elucidate the effectiveness of the proposed approach by synthesizing a schedule for the coordination of two traffic lights under some safety and fairness requirements for a road traffic model. Further we argue that this 5-dimensional linear stochastic control system cannot be studied with existing approaches based on state-space discretization due to the very large number of generated discrete states.     

On singular hybrid switched and impulsive systems

In this work, the problem of stability analysis for a class of singular hybrid switched and impulsive system (HSIS) is addressed. Corresponding to each subsystem, a hybrid switched and impulsive controller is designed and then the exponential stability property of the proposed singular HSIS is discussed for linear and nonlinear cases. Because switched systems without impulses are a special case of HSISs, the results are also given to switched system with synchronous and asynchronous controllers. The obtained results apply to control singular systems, and the introduced theorems allow knowing how the control must be designed. Two numerical examples are given to show the effectiveness of the proposed approaches. At first, by using MATLAB^® software, the proposed method is applied to a class of physiological processes of endocrine disruptor diethylstilbestrol models to illustrate the effectiveness of the results obtained here for the linear case. Thereafter, another numerical example is provided to support the presented theoretical results for the nonlinear case.     

Metal-Ion Type Effect on the Crystal Structure and Optical Properties of 2,2′-bipyridine Complexes of Pb(II) and Cd(II)

To investigate the effect of metal ion type on the crystal structure and optical and thermal behaviors of coordination compounds, two homometal and one heterometal 2,2′-bipyridine complexes of Pb(II) and Cd(II) have been synthesized and characterized by elemental analysis, PXRD, FT-IR and single crystal X-ray diffraction. Crystal structure analysis of heterometal coordination polymer, [Pb₂Cd(2,2′-bipy)₄(NO₃)₆]_n, displays the attendance of a centrosymmetric 1D coordination polymer that crystallizes in the triclinic system with the space group of \({\text{p}}_{1}^{ - }\). Thermal behavior of prepared coordination compounds was examined under air atmosphere by thermogravimetric analysis. The study of optical properties of compounds showed that metal ion type of coordination compounds is influential on their photophysical properties. Moreover, heterometal coordination polymer was doped into a PVK:PBD blend in two different concentrations as a light emitting material in the fabrication of two organic light-emitting diodes.     

Predictive Dynamic Model of Air Separation by Pressure Swing Adsorption

A general dynamic model is developed for separation of air over a carbon molecular sieve and a zeolite adsorbent for production of nitrogen and oxygen. The proposed model is validated using experimental data from working laboratory scale N₂–PSA and laboratory scale O₂–PSA systems. Simulations studies are performed to investigate the effect of changing various process variables, such as the duration of PSA steps, bed length and feed inlet velocity.