Modeling the AgInSbTe Memristor

The AgInSbTe memristor shows gradual resistance tuning characteristics, which makes it a potential candidate to emulate biological plastic synapses. The working mechanism of the device is complex, and both intrinsic charge-trapping mechanism and extrinsic electrochemical metallization effect are confirmed in the AgInSbTe memristor. Mathematical model of the AgInSbTe memristor has not been given before. We propose the flux-voltage controlled memristor model. With piecewise linear approximation technique, we deliver the flux-voltage controlled memristor model of the AgInSbTe memristor based on the experiment data. Our model fits the data well. The flux-voltage controlled memristor model and the piecewise linear approximation method are also suitable for modeling other kinds of memristor devices based on experiment data

Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles

As the integration of wind generation displaces conventional plants, system inertia provided by rotating mass declines, causing concerns over system frequency stability. This paper implements an advanced stochastic scheduling model with inertia-dependent fast frequency response requirements to investigate the challenges on the primary frequency control in the future Great Britain electricity system. The results suggest that the required volume and the associated cost of primary frequency response increase significantly along with the increased capacity of wind plants. Alternative measures (e.g. electric vehicles) have been proposed to alleviate these concerns. Therefore, this paper also analyses the benefits of primary frequency response support from electric vehicles in reducing system operation cost, wind curtailment and carbon emissions

Assessment and simulation of evacuation in large railway stations

Evacuation systems in buildings are frequently assessed to improve emergency response processes. This paper proposes a method to evaluate the performance of different evacuation modes, and determine a rational mode for large railway stations. We developed a simulation for the evaluation of fire safety in large buildings based on an analytic hierarchy process (AHP) method. This approach includes AHP-based exploration and simulation-based refinement. We considered a typical railway station for validation, conducted a field survey to collect the data, and calculated the influencing factors based on expert opinion. The influencing factors were further processed based on the principles of a hierarchical model. The relative weights of the influencing factors were calculated through a series of pairwise comparisons using the AHP. Further, we applied factor refinement based on the evacuation simulations to determine the degree and status of influence of each factor. The influence of external factors was generally stronger than that of the internal factors. Among them, the building component characteristics and people’s physiological capabilities were the core of the evacuation assessment in large railway stations. Additionally, the exit width, seat layout, visibility, speed, and reaction capabilities were crucial to the evacuation process. The proposed method is practical as it demands limited computations to provide useful information, such as a priority ranking of each influencing factor, for the evaluation process

Acoustic environment of comprehensive activity spaces in nursing homes: A case study in Harbin, China

Nursing homes are places where the elderly conduct their daily activities, and frequent gatherings of nursing home residents may lead to a complicated acoustic environment in which elderly people may have declining ability to function. This study explores the acoustic environment of an activity hall in a nursing home in Harbin, China and assesses the elderly residents’ perception of and preference towards sounds by using site observation, sound measurements, and a questionnaire. The results showed that the elderly evaluated the activity hall’s acoustic environment as poor. When the reverberation time in the hall exceeded four seconds or the sound pressure level exceeded 65 dB(A), their subjective evaluation of the comfort of the acoustic environment declined. Overall, the participants evaluated background and foreground music positively, liked to participate in music-related activities, were not bothered by mechanical sounds, and disliked speech sounds. They preferred (near-) silent activities, while the evaluation of activities with low-dB(A) and high-dB(A) depended on the degree of participation and personal preference. During activities in the activity hall, participators’ acoustic evaluation was generally more positive than that of the onlookers, and music-related activity sounds (singing and dancing) were perceived as more comfortable than vocal activity sounds (playing chess and cards). The results also show that the acoustic environment evaluation is associated with social background factors. This study may help improve the elderly’s quality of life in nursing homes by providing a reference for the construction and design of elderly facilities

In an Attempt to Introduce Long-range Interactions into Small-world Networks

Distinguishing the long-range bonds with the regular ones, the critical temperature of the spin-lattice Guassian model built on two typical Small-world Networks (SWNs) is studied. The results show much difference from the classical case, and thus may induce some more accurate discussion on the critical properties of the spin-lattice systems combined with the SWNs.Comment: 4 pages, 3 figures, 18 referenc

Non-Abelian Proca model based on the improved BFT formalism

We present the newly improved Batalin-Fradkin-Tyutin (BFT) Hamiltonian formalism and the generalization to the Lagrangian formulation, which provide the much more simple and transparent insight to the usual BFT method, with application to the non-Abelian Proca model which has been an difficult problem in the usual BFT method. The infinite terms of the effectively first class constraints can be made to be the regular power series forms by ingenious choice of $X_{\alpha \beta}$ and $\omega^{\alpha \beta}$-matrices. In this new method, the first class Hamiltonian, which also needs infinite correction terms is obtained simply by replacing the original variables in the original Hamiltonian with the BFT physical variables. Remarkably all the infinite correction terms can be expressed in the compact exponential form. We also show that in our model the Poisson brackets of the BFT physical variables in the extended phase space are the same structure as the Dirac brackets of the original phase space variables. With the help of both our newly developed Lagrangian formulation and Hamilton's equations of motion, we obtain the desired classical Lagrangian corresponding to the first class Hamiltonian which can be reduced to the generalized St\"uckelberg Lagrangian which is non-trivial conjecture in our infinitely many terms involved in Hamiltonian and Lagrangian.Comment: Notable improvements in Sec. I

Predictions on the Development Dimensions of Provincial Tourism Discipline Based on the Artificial Neural Network BP Model

As the tourism industry has gradually become the strategic mainstay industry of the national economy, the scope of the tourism discipline has developed rigorously. This paper makes a predictive study on the development of the scope of Guangdong provincial tourism discipline based on the artificial neural network BP model in order to find out how the branch of tourism studies can better adapt to the development of the tourism industry. The research findings indicate that the BP model can be applied to the predictions of the scope of the tourism discipline and provide a quantitative basis for decision making with regard to the spatial layout and optimal allocation of the tourism discipline

BRST Quantization of the Proca Model based on the BFT and the BFV Formalism

The BRST quantization of the Abelian Proca model is performed using the Batalin-Fradkin-Tyutin and the Batalin-Fradkin-Vilkovisky formalism. First, the BFT Hamiltonian method is applied in order to systematically convert a second class constraint system of the model into an effectively first class one by introducing new fields. In finding the involutive Hamiltonian we adopt a new approach which is more simpler than the usual one. We also show that in our model the Dirac brackets of the phase space variables in the original second class constraint system are exactly the same as the Poisson brackets of the corresponding modified fields in the extended phase space due to the linear character of the constraints comparing the Dirac or Faddeev-Jackiw formalisms. Then, according to the BFV formalism we obtain that the desired resulting Lagrangian preserving BRST symmetry in the standard local gauge fixing procedure naturally includes the St\"uckelberg scalar related to the explicit gauge symmetry breaking effect due to the presence of the mass term. We also analyze the nonstandard nonlocal gauge fixing procedure.Comment: 29 pages, plain Latex, To be published in Int. J. Mod. Phys.

Amniotic fluid embolism as a cause of maternal mortality in China between 1996 and 2013: A population-based retrospective study

© 2016 The Author(s). Background: To analyse the maternal mortality ratio, demographic and pregnancy related details in women who suffered a fatal amniotic fluid embolism (AFE) in China. Methods: A retrospective population based study using data collected as part of the National Maternal Mortality Surveillance System between 1996 and 2013. Data were collected onto a standardised form from women whose cause of death was listed as being secondary to AFE. Results: Records were available for 640 deaths. Over the 17 year period the maternal mortality ratio for AFE decreased from 4.4 per 100,000 births (95 % confidence interval (CI):2.72-6.12) to 1.9 per 100,000 births (95 % CI:1.35-2.54). Over the same period the proportion of maternal deaths secondary to AFE increased from 6.8 to 12.5 %. The mean age of women who died was 30.1 years and the onset of the AFE occurred prior to delivery in 39 %. The most prominent presenting features included premonitory symptoms (29 %), acute fetal compromise (28 %), maternal haemorrhage (16 %) and shortness of breath (15 %). Conclusions: Maternal mortality secondary to AFE has decreased in China, however at a slower rate than mortality secondary to other conditions. Active surveillance is recommended to assess case fatality rates, risk factors and other lessons specific to this population