Vertical liquid controlled adiabatic waveguide coupler

A broadband vertical liquid controlled optical waveguide coupler (LCC) is demonstrated. The fabricated vertical LCC with silicon nitride (SiN) waveguides can switch light between 2 stacked photonic circuit layers with zero energy consumption in a steady switch state. In combination with low-loss interlayer waveguide crossovers they enable large scale non-volatile switch circuits with low loss. The fabricated vertical LCC has a loss less than 2.0 dB in bar state and less than 2.6 dB in cross state over the telecommunication wavelength range 1260 nm to 1630 nm. Interlayer waveguide crossovers with the same interlayer oxide thickness as the LCC have a loss less than 0.06 dB over the same wavelength range. The crosstalk of the LCC is less than 21 dB over the wavelength range 1500 nm to 1630 nm for both bar and cross state. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

A User Satisfaction Study of the London Congestion Charging e-Service

This research seeks to measure citizen satisfaction with the electronic London Congestion Charging (LCC) payment system offered by Transport For London (TFL) in the United Kingdom (UK). The paper reports on the findings of a survey of 500 users of the TFL LCC online payment system. Satisfaction is measured using the four dimensions from the COBRA framework 0that comprise the cost, opportunity, benefits and risk assessment constructs. The results show that most citizens using the LCC electronic service are satisfied with the service and that the service meets their essential needs. The paper also presents the results of qualitative feedback obtained from the participants that can be used to determine the areas that need further improvement in the current electronic LCC electronic-service (e-service) system and potential influences on user satisfaction

Decentralised Clinical Guidelines Modelling with Lightweight Coordination Calculus

Background: Clinical protocols and guidelines have been considered as a major means to ensure that cost-effective services are provided at the point of care. Recently, the computerisation of clinical guidelines has attracted extensive research interest. Many languages and frameworks have been developed. Thus far, however,an enactment mechanism to facilitate decentralised guideline execution has been a largely neglected line of research. It is our contention that decentralisation is essential to maintain a high-performance system in pervasive health care scenarios. In this paper, we propose the use of Lightweight Coordination Calculus (LCC) as a feasible solution. LCC is a light-weight and executable process calculus that has been used successfully in multi-agent systems, peer-to-peer (p2p) computer networks, etc. In light of an envisaged pervasive health care scenario, LCC, which represents clinical protocols and guidelines as message-based interaction models, allows information exchange among software agents distributed across different departments and/or hospitals. Results: We outlined the syntax and semantics of LCC; proposed a list of refined criteria against which the appropriateness of candidate clinical guideline modelling languages are evaluated; and presented two LCC interaction models of real life clinical guidelines. Conclusions: We demonstrated that LCC is particularly useful in modelling clinical guidelines. It specifies the exact partition of a workflow of events or tasks that should be observed by multiple "players" as well as the interactions among these "players". LCC presents the strength of both process calculi and Horn clauses pair of which can provide a close resemblance of logic programming and the flexibility of practical implementation

Linearized Coupled Cluster Correction on the Antisymmetric Product of 1 reference orbital Geminals

We present a Linearized Coupled Cluster (LCC) correction based on an Antisymmetric Product of 1 reference orbital Geminals (AP1roG) reference state. In our LCC ansatz, the cluster operator is restricted to double and to single and double excitations as in standard single-reference CC theory. The performance of the AP1roG-LCC models is tested for the dissociation of diatomic molecules (C$_2$ and F$_2$), spectroscopic constants of the uranyl cation (UO$_2^{2+}$), and the symmetric dissociation of the H$_{50}$ hydrogen chain. Our study indicates that an LCC correction based on an AP1roG reference function is more robust and reliable than corrections based on perturbation theory, yielding spectroscopic constants that are in very good agreement with theoretical reference data.Comment: 9 pages, 4 figure

Grounded: characterising the market exit of European low cost airlines

The aim of this paper is to undertake a comprehensive study of LCC market entry and exit in Europe between 1992 and 2012. In the 20 year period between 1992 and 2012, 43 low cost carriers (LCCs) have taken advantage of the progressive liberalisation of the European aviation market and commenced scheduled flight operations within the continent. Of these 43, only 10 remain operational, a failure rate of 77%. This paper contributes to extant literature on LCCs by examining the market entry, business practices, operating longevity and fate of failed operators to characterise European LCC market exit. Drawing on the findings of a detailed continental-wide study, the paper identifies that an airline’s start-up date, the nature and size of its operation and the size and composition of its aircraft fleet are key factors which influence LCC success and failure. The implications for both European and emerging LCC markets are discussed

Lagrange Coded Computing: Optimal Design for Resiliency, Security and Privacy

We consider a scenario involving computations over a massive dataset stored distributedly across multiple workers, which is at the core of distributed learning algorithms. We propose Lagrange Coded Computing (LCC), a new framework to simultaneously provide (1) resiliency against stragglers that may prolong computations; (2) security against Byzantine (or malicious) workers that deliberately modify the computation for their benefit; and (3) (information-theoretic) privacy of the dataset amidst possible collusion of workers. LCC, which leverages the well-known Lagrange polynomial to create computation redundancy in a novel coded form across workers, can be applied to any computation scenario in which the function of interest is an arbitrary multivariate polynomial of the input dataset, hence covering many computations of interest in machine learning. LCC significantly generalizes prior works to go beyond linear computations. It also enables secure and private computing in distributed settings, improving the computation and communication efficiency of the state-of-the-art. Furthermore, we prove the optimality of LCC by showing that it achieves the optimal tradeoff between resiliency, security, and privacy, i.e., in terms of tolerating the maximum number of stragglers and adversaries, and providing data privacy against the maximum number of colluding workers. Finally, we show via experiments on Amazon EC2 that LCC speeds up the conventional uncoded implementation of distributed least-squares linear regression by up to $13.43\times$, and also achieves a $2.36\times$-$12.65\times$ speedup over the state-of-the-art straggler mitigation strategies

The multi-disciplinary design study: A life cycle cost algorithm

The approach and results of a Life Cycle Cost (LCC) analysis of the Space Station Solar Dynamic Power Subsystem (SDPS) including gimbal pointing and power output performance are documented. The Multi-Discipline Design Tool (MDDT) computer program developed during the 1986 study has been modified to include the design, performance, and cost algorithms for the SDPS as described. As with the Space Station structural and control subsystems, the LCC of the SDPS can be computed within the MDDT program as a function of the engineering design variables. Two simple examples of MDDT's capability to evaluate cost sensitivity and design based on LCC are included. MDDT was designed to accept NASA's IMAT computer program data as input so that IMAT's detailed structural and controls design capability can be assessed with expected system LCC as computed by MDDT. No changes to IMAT were required. Detailed knowledge of IMAT is not required to perform the LCC analyses as the interface with IMAT is noninteractive

Electrochemical Energy Storage Subsystems Study, Volume 2

The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models are exercised to define baseline designs and costs. Then the major design and performance parameters are each varied to determine their influence on LCC around the baseline values