Flexible Transition Research Articles

Cationic Poly(ionic liquid) with Tunable Lower Critical Solution Temperature-Type Phase Transition.

A cationic polyelectrolyte based on the styrenic ionic liquid tributyl-4-vinylbenzylphosphonium pentanesulfonate was found to undergo a lower critical solution temperature (LCST)-type phase transition in aqueous solutions. This phase transition occurs in a wide temperature range in terms of polymer concentration as well as type and concentration of externally added salts. Anion exchange and salting out effects are responsible for the flexible phase transition temperature.

What is the shape of real exchange rate nonlinearity?

Evidence that real exchange rate dynamics can be described using models which exhibit nonlinear mean reversion has been mounting over the past decade. This article attempts to better understand the shape of real exchange rate nonlinearity through the use of the Smooth Transition Autoregressive (STAR) model and the newly proposed skewed generalized error transition function. The advantage of this transition function it that it nests popularly used transition functions through simple parameter constraints. This allows the use of nested model selection tests. It is shown that more flexible transition functions are preferred in many cases over the commonly used exponential transition function. The results suggest that most of the real exchange rates studied in this article are better described by discrete threshold models rather than STAR models.

Flexibility in Competency-Based Workplace Transition Programs: An Exploratory Study of Community Child and Family Health Nursing

Successful transition to practice programs that use competency-based assessment require the involvement of all staff, especially those undertaking the preceptor role. Qualitative data were collected using interview methods. Participants were 14 newly employed nurses and 7 preceptors in the child and family community health service in South Australia. Participant narratives were recorded electronically, transcribed, and thematically analyzed using the paradigm of critical social science. Five themes were identified that describe enablers as well as barriers to applying a flexible transition to practice program using competency-based assessment. These included flexibility in the program design, flexibility on the part of preceptors, flexibility to enable recognition of previous learning, flexibility in the assessment of competencies, and flexibility in workload. To ensure successful application of a transition to practice program using competency-based assessment, preceptors must understand the flexible arrangements built into the program design and have the confidence and competence to apply them.

Influence on the Stress of Pavement with Crack in Surface from Flexible Transition Layer under Dynamic Loading

After cracks appear in the surface layer, the stress mode of pavement structure transits from infinite continuum to limited size board, and the cracks become stress concentration areas. Based on the practical tire contact pressure and contact area, this paper establishes the C3D8R model by ABAQUS, to calculate and analyse the influence on the surface cracks extension from graded gravel transition layer under half-sinusoid load. Analysis shows that the graded gravel has excellent stress dissipation ability. Whether there are cracks in the surface layer, the graded gravel transition layer between asphalt surface layer and semi-rigid base layer could greatly reduce the tensile stresses in the bottom of semi-rigid base and subbase layers, improve the road bearing level, delay and avoid the cracks extension to deep road and prolong the road service life.

Influence on the Stress of Pavement with Crack in Base from Flexible Transition Layer under Dynamic Loading

After cracks appear in the semi-rigid base layer, the stress mode of pavement structure transits from infinite continuum to limited size board, and the cracks become stress concentration areas. Based on the practical tire contact pressure and contact area, this paper establishes the C3D8R model by ABAQUS, to calculate and analyse the influence on the base cracks extension from graded gravel transition layer under half-sinusoid load. Analysis shows that the graded gravel has excellent stress dissipation ability. Whether there are cracks in the base, the graded gravel transition layer between asphalt surface layer and semi-rigid base layer could greatly reduce the tensile stresses in the bottom of semi-rigid base and subbase layers, improve the road bearing level, delay and avoid the cracks extension to deep road and prolong the road service life.

Flexible and practical modeling of animal telemetry data: hidden Markov models and extensions

We discuss hidden Markov-type models for fitting a variety of multistate random walks to wildlife movement data. Discrete-time hidden Markov models (HMMs) achieve considerable computational gains by focusing on observations that are regularly spaced in time, and for which the measurement error is negligible. These conditions are often met, in particular for data related to terrestrial animals, so that a likelihood-based HMM approach is feasible. We describe a number of extensions of HMMs for animal movement modeling, including more flexible state transition models and individual random effects (fitted in a non-Bayesian framework). In particular we consider so-called hidden semi-Markov models, which may substantially improve the goodness of fit and provide important insights into the behavioral state switching dynamics. To showcase the expediency of these methods, we consider an application of a hierarchical hidden semi-Markov model to multiple bison movement paths.

Effect of annealing on phase separation and mechanical properties of epoxy/ATBN adhesive

Amine-terminated butadiene acrylonitrile (ATBN) was applied as curing agents for diglycidyl ether of bisphenol A epoxy resin without any accelerating agent. ATBN weight percentage of 59–82wt% was used, so that the soft ATBN domains in the cured samples formed a continuous phase, while the hard epoxy domains formed a discontinuous phase. Mechanical properties were tested in the means of strain-stress and adhesive strength. The results showed that the samples had excellent toughness at temperatures above the flexible segment glass transition temperature (Tg1), and it was well maintained after annealing at 150°C. However, adhesive strength of the annealed sample decreased dramatically when the testing temperature was close to the rigid segment glass transition temperature (Tg2). It was observed that (Tg2) decreased and phase separation became weaker after the annealing. Real-time Fourier transform infrared (FTIR) measurement indicated that this phenomenon was related to the disassociation of hydrogen bonding within the hard domain caused by the increased mixing of the hard segments into the soft domains by the high temperature annealing. It was confirmed by transmission electronic microscope (TEM) test.

Study on Acc/Dec Algorithm Based on Piecewise Polynomial in CNC

In order to improve the stability of feed movement in high speed CNC system, the feedrate planning algorithm based on piece-wise polynomial function was proposed. The flexible transition of feedrate was realized through maintaining linear continuous jerk. The principle of the proposed algorithm was introduced and the method to generate smooth motion profile based on the proposed algorithm was presented. The rapidity, stability and tracking accuracy of the feedrate planning algorithm to linearity, S curve and the proposed one were analyzed. The proposed algorithm is simple and it can be applied in acceleration/deceleration before interpolation in high speed feed movement to improve the stability of it. The proposed algorithm was applied in multi-contour high speed processing and the result indicated that it could improve the stability of large-scale parts motion.

A SOM-based hybrid linear-neural model for short-term load forecasting

In this paper, a short-term load forecasting method is considered, which is based upon a flexible smooth transition autoregressive (STAR) model. The described model is a linear model with time varying coefficients, which are the outputs of a single hidden layer feedforward neural network. The hidden layer is responsible for partitioning the input space into multiple sub-spaces through multivariate thresholds and smooth transition between the sub-spaces. In this paper, we propose a new method to smartly initialize the weights of the hidden layer of the neural network before its training. A self-organizing map (SOM) network is applied to split the historical data dynamics into clusters, and the Ho–Kashyap algorithm is then used to obtain the separating planes' equations. Applied to the electricity markets, the proposed method is better able to model the smooth transitions between the different regimes, which are present in the load demand series because of market effects and season effects. We use data from three electricity markets to compare the prediction accuracy of the proposed method with traditional benchmarks and other recent models, and find our results to be competitive.

Study of NiAl<SUB>2</SUB>O<SUB>4</SUB> Spinel Coating with Flexible Transition Layer

Study of NiAl<SUB>2</SUB>O<SUB>4</SUB> Spinel Coating with Flexible Transition Layer

Mechanisms of the Knoevenagel hetero Diels–Alder sequence in multicomponent reactions to dihydropyrans: experimental and theoretical investigations into the role of water

The role of water in a multicomponent domino reaction (MCR) involving styrene, 2,4-pentanedione, and formaldehyde was studied. Whereas anhydrous conditions produced no reaction, the MCR successfully proceeded in the presence of water, affording the targeted dihydropyran derivatives with good yield. The mechanism of this MCR (Knoevenagel hetero Diels-Alder sequence) was studied with and without explicit water molecules using the SMD continuum solvation model in combination with the B3LYP density functional and the 6-311++G** basis set to compute the water and acetone (aprotic organic solvent) solution Gibbs free energies. In the Knoevenagel step, we found that water acted as a proton relay to favor the formation of more flexible six-membered ring transition state structures both in concerted (direct H(2)O elimination) and stepwise (keto-enol tautomerization and dehydration) pathways. The inclusion of a water molecule in our model resulted in a significant decrease (-8.5 kcal mol(-1)ΔG(water)(‡)) of the direct water elimination activation barrier. Owing to the presence of water, all chemical steps involved in the MCR mechanism had activation free energies barriers lower than 39 kcal mol(-1) at 25 °C in aqueous solvent (<21 kcal mol(-1) ZPE corrected electronic energies barriers). Consequently, the MCR proceeded without the assistance of any catalyst.

Cognitive Radio for aeronautical air-ground communications

The system of air-ground communications is one of the most fundamental elements of air traffic control in the National Airspace System (NAS). The current air-ground voice communications systems are using the more than 50-year-old analog voice transmission technology in the licensed air traffic management VHF spectrum band. The limited spectrum is allocated statically based on air traffic control organization and geographic locations. With the increasing use of data applications for air-ground communications, the demand to effectively use the limited spectrum has increased. There are several proposed approaches to solve the projected saturated spectrum in the future. However, these approaches do not address the current practice of static spectrum allocation, which this author anticipates will be a major bottleneck for effective use of the limited spectrum. The current static channel assignment creates inefficient use of the limited spectrum. Regardless of whether a channel is used, it is permanently assigned to the particular geographical areas and organizations. This prevents other users from using the channels when the channels are idle. Also, this static allocation of the spectrum constrains the reassignment of channels and creates a long transition period for moving the existing analog system to a new digital system. The emerging Cognitive Radio (CR) technology provides the opportunity to address the static allocation of spectrum issue and offer a more flexible transition approach for updating the legacy air-ground radio system. The emerging CR technology provides the sensing of surrounding environment, allowing the radio to adapt to the environment accordingly. Built on software-defined radio (SDR) technology, CR is able to employ these features with the cognitive engine and the aid of several sensors. The cognitive engine carries out these tasks by obtaining all available information from sources such as sensors, protocol layers, a policy engine, and its own hardware, and then interprets, reasons, and makes the optimum decision to adapt. Integrated with ground radio stations and centralized management systems, the CR can dynamically use the available channels based on its actual location, environment condition, and, therefore, maximize the use of the limited spectrum.

Moving gradients

We describe a method for plausible interpolation of images, with a wide range of applications like temporal up-sampling for smooth playback of lower frame rate video, smooth view interpolation, and animation of still images. The method is based on the intuitive idea, that a given pixel in the interpolated frames traces out a path in the source images. Therefore, we simply move and copy pixel gradients from the input images along this path. A key innovation is to allow arbitrary (asymmetric) transition points , where the path moves from one image to the other. This flexible transition preserves the frequency content of the originals without ghosting or blurring, and maintains temporal coherence. Perhaps most importantly, our framework makes occlusion handling particularly simple. The transition points allow for matches away from the occluded regions, at any suitable point along the path. Indeed, occlusions do not need to be handled explicitly at all in our initial graph-cut optimization. Moreover, a simple comparison of computed path lengths after the optimization, allows us to robustly identify occluded regions, and compute the most plausible interpolation in those areas. Finally, we show that significant improvements are obtained by moving gradients and using Poisson reconstruction.

How to find exculpatory and inculpatory evidence using a circular digital forensics process model

With raising the number of cyber crimes, the need of having a proper digital forensic process also increases. Although digital forensics is practiced in recent years, there is still a big gap between previously suggested digital forensics processes and what is really needed to be done in real cases. Some problems with current processes are lack of flexible transition between phases, not having a clear method or a complete scenario for addressing reliable evidence, and not paying enough attention to management aspects and team roles. This article provides a process model by paying special attention to the team roles and management aspects as well as both exculpatory and inculpatory evidence.

The 18-month well-baby visit: A commentary

The 18-month well-baby visit: A commentary

Between labour market and retirement pension - flexible transition as a new paradigm for ageing societies?

Increasing the pensionable age due to rising life expectancy meets strong political resistance. For health and labour market reasons it will always be impossible for some to achieve full pension eligibility directly from employment. Even if early retirement options are not restricted the scope for an accumulation of earnings to fund an early pension is often narrowly defined. Consequently, it is impossible for early retirees to compensate for the reductions in the pension they receive. Contrary to the general tendency to increase the pensionable age an alternative reform proposal is currently under discussion in German social policy circles. This involves free choice of retirement at age 60; unlimited accumulation of additional pension entitlements whilst earning; actuarial deductions for early retirement; and consideration of life expectancy in making adjustments to pension awards. This solution relieves the public pension system financially, raises the attractiveness of senior citizens on the labour market, offers the opportunity for a self-determined transition from work to retirement and reduces political resistance to pension reform. The effect on the labour market for senior citizens remains to be examined.

Bayesian semi parametric multi-state models

Multi-state models provide a unified framework for the description of the evolution of discrete phenomena in continuous time. One particular example is Markov processes which can be characterised by a set of time-constant transition intensities between the states. In this paper, we will extend such parametric approaches to semiparametric models with flexible transition intensities based on Bayesian versions of penalised splines. The transition intensities will be modelled as smooth functions of time and can further be related to parametric as well as nonparametric covariate effects. Covariates with time-varying effects and frailty terms can be included in addition. Inference will be conducted either fully Bayesian (using Markov chain Monte Carlo simulation techniques) or empirically Bayesian (based on a mixed model representation). A counting process representation of semiparametric multi-state models provides the likelihood formula and also forms the basis for model validation via martingale residual processes. As an application, we will consider human sleep data with a discrete set of sleep states such as REM and non-REM phases. In this case, simple parametric approaches are inappropriate since the dynamics underlying human sleep are strongly varying throughout the night and individual-specific variation has to be accounted for using covariate information and frailty terms.

Identification of age‐structured models: Cell cycle phase transitions

A methodology is developed that determines age-specific transition rates between cell cycle phases during balanced growth by utilizing age-structured population balance equations. Age-distributed models are the simplest way to account for varied behavior of individual cells. However, this simplicity is offset by difficulties in making observations of age distributions, so age-distributed models are difficult to fit to experimental data. Herein, the proposed methodology is implemented to identify an age-structured model for human leukemia cells (Jurkat) based only on measurements of the total number density after the addition of bromodeoxyuridine partitions the total cell population into two subpopulations. Each of the subpopulations will temporarily undergo a period of unbalanced growth, which provides sufficient information to extract age-dependent transition rates, while the total cell population remains in balanced growth. The stipulation of initial balanced growth permits the derivation of age densities based on only age-dependent transition rates. In fitting the experimental data, a flexible transition rate representation, utilizing a series of cubic spline nodes, finds a bimodal G(0)/G(1) transition age probability distribution best fits the experimental data. This resolution may be unnecessary as convex combinations of more restricted transition rates derived from normalized Gaussian, lognormal, or skewed lognormal transition-age probability distributions corroborate the spline predictions, but require fewer parameters. The fit of data with a single log normal distribution is somewhat inferior suggesting the bimodal result as more likely. Regardless of the choice of basis functions, this methodology can identify age distributions, age-specific transition rates, and transition-age distributions during balanced growth conditions.

利用微纳光纤倏逝场实现的双色原子波导和一维光学晶格

We propose a two-color scheme of atom waveguides and one-dimensional (1D) optical lattices using evanescent wave fields of different transverse modes around an optical micro/nano-fiber. The atom guide potential can be produced when the optical fiber carries a red-detuned light with TE01 mode and a blue-detuned light with HE11 mode, and the 1D optical lattice potential can be produced when the red-detuned light is transformed to the superposition of the TE01 mode and HE11 mode. The two trapping potentials can be transformed to each other for accurately controlling mode transformation for the red-detuned light. This might provide a new approach to realize flexible transition between the guiding and trapping states of atoms.

Two-colour atom guide and 1D optical lattice using evanescent fields of high-order transverse modes

We propose a two-colour scheme of atom guide and 1D optical lattice using evanescent light fields of TE00 and TE01 transverse modes in an optical waveguide. The optical waveguide carries red-detuned light and blue-detuned light, with both modes far from resonance. The atom guide and 1D optical lattice potentials can be transformed to each other by using a Mach–Zehnder interferometer to accurately control mode transformation. This might provide a new approach to realize flexible transition between the guiding and trapping states of atoms.