Equivalent Minimum Research Articles

A novel equivalent consumption minimization strategy for hybrid electric vehicle powered by fuel cell, battery and supercapacitor

The aim of this paper is to present a sequential quadratic programming (SQP) based equivalent consumption minimum strategy (ECMS) (SECMS) for fuel cell hybrid electric vehicle (FCHEV) powered by fuel cell, battery and supercapacitor. In order to decrease hydrogen consumption and increase the durability of power sources, fuel cell is chosen as the main power source and supplies steady current, battery is designed as the main energy buffer and the replacement of fuel cell failure and supercapacitor is operated to supply peak power. Low energy density of supercpacitor lets its equivalent hydrogen consumption be taken as zero for many ECMS researches. This simplification leads to suboptimal fuel economy and complex of control system. SECMS considers hydrogen consumption of three power sources into objective function to solve this problem. A rule based control strategy (RBCS) and an hybrid ECMS operating mode control strategy (OMCS) (HEOS) are also designed to compare with SECMS. An experimental test bench is built to validate the comparative study of three strategies. The results show that compared with RBCS and HEOS, hydrogen consumption of SECMS decreases of 2.16% and 1,47% respectively and it also has the most smooth fuel cell current, which means a lowest fuel cell degradation.

A Pontryagin Minimum Principle-Based Adaptive Equivalent Consumption Minimum Strategy for a Plug-in Hybrid Electric Bus on a Fixed Route

When developing a real-time energy management strategy for a plug-in hybrid electric vehicle, it is still a challenge for the Equivalent Consumption Minimum Strategy to achieve near-optimal energy consumption, because the optimal equivalence factor is not readily available without the trip information. With the help of realistic speeding profiles sampled from a plug-in hybrid electric bus running on a fixed commuting line, this paper proposes a convenient and effective approach of determining the equivalence factor for an adaptive Equivalent Consumption Minimum Strategy. Firstly, with the adaptive law based on the feedback of battery SOC, the equivalence factor is described as a combination of the major component and tuning component. In particular, the major part defined as a constant is applied to the inherent consistency of regular speeding profiles, while the second part including a proportional and integral term can slightly tune the equivalence factor to satisfy the disparity of daily running cycles. Moreover, Pontryagin’s Minimum Principle is employed and solved by using the shooting method to capture the co-state dynamics, in which the Secant method is introduced to adjust the initial co-state value. And then the initial co-state value in last shooting is taken as the optimal stable constant of equivalence factor. Finally, altogether ten successive driving profiles are selected with different initial SOC levels to evaluate the proposed method, and the results demonstrate the excellent fuel economy compared with the dynamic programming and PMP method.

Ending Too-Big-To-Fail: Progress Since the Crisis, the Importance of Loss-Absorbing Capacity and the UK Approach to Resolution

In 2008 the largest cross-border banks were too big to fail and had to be bailed out, inappropriately penalising taxpayers and rewarding bank investors. This paper reviews the major progress since then in seeking to end ‘too-big-to-fail’. This has involved several strands: the development of resolution regimes; the negotiation and agreement of cooperative resolution strategies for global systemically-important banks (G-SIBs); the identification of barriers to resolvability; and paving the way to removing those barriers. A crucial aspect of this is requiring all banks to have sufficient loss-absorbing capacity to ensure their orderly resolution. Following adoption by the G20 of the Financial Stability Board’s standard on total loss-absorbing capacity (TLAC), the UK authorities have recently published their policy on TLAC and its Bank Recovery and Resolution Directive equivalent Minimum Requirement for Own Funds and Eligible Liabilities (MREL)—the minimum requirement for own funds and eligible liabilities. The provisions link both the quantum and quality of TLAC or MREL resources to the preferred resolution strategy, whether that is bail-in, partial transfer or liquidation, on a case-by-case basis. This ensures that a one-size-fits-all approach is not taken to resolution of different types of bank. The UK rules also provide a degree of flexibility to UK banks in meeting their MRELs, both by specifying appropriate transitional arrangements and by making the final requirements subject to review by the UK authorities. This will take into account any changes to the UK regulatory environment in coming years and the actual experience of UK banks in raising loss-absorbing resources.

Optical Fiber Photoacoustic Gas Sensor With Graphene Nano-Mechanical Resonator as the Acoustic Detector

We report an all-optical fiber photoacoustic gas sensor with a graphene nano-mechanical resonator as the acoustic detector. The acoustic detector is a Fabry–Perot interferometer formed by attaching a 100-nm-thick, 2.5-mm-diameter multilayer graphene diaphragm to a hollow cavity at the end of a single-mode optical fiber. By operating at one of the mechanical resonances of the diaphragm, the sensitivity for acoustic detection is enhanced and a noise equivalent minimum detectable pressure of 2.11 μPa/Hz1/2 at 10.1 kHz is demonstrated. Detection of acetylene gas is demonstrated with a distributed feedback semiconductor laser tuned to the P(9) absorption line of acetylene and a lower detection limit of 119.8 parts-per-billion (ppb) is achieved with 123.9-mW pump power. Theoretical analysis shows that by increasing the Q-factor of the resonator, which may be achieved by operating at low gas pressures, ppb level gas detection is possible. The all-fiber photoacoustic gas sensor is immune to electromagnetic interference, safe in flammable and explosive environment, and would be ideally suited for remote, space-limited applications and for multipoint detection in a multiplexed fiber optic sensor network.

Deep kernel learning in core vector machines

In machine learning literature, deep learning methods have been moving toward greater heights by giving due importance in both data representation and classification methods. The recently developed multilayered arc-cosine kernel leverages the possibilities of extending deep learning features into the kernel machines. Even though this kernel has been widely used in conjunction with support vector machines (SVM) on small-size datasets, it does not seem to be a feasible solution for the modern real-world applications that involve very large size datasets. There are lot of avenues where the scalability aspects of deep kernel machines in handling large dataset need to be evaluated. In machine learning literature, core vector machine (CVM) is being used as a scaling up mechanism for traditional SVMs. In CVM, the quadratic programming problem involved in SVM is reformulated as an equivalent minimum enclosing ball problem and then solved by using a subset of training sample (Core Set) obtained by a faster \((1+\epsilon )\) approximation algorithm. This paper explores the possibilities of using principles of core vector machines as a scaling up mechanism for deep support vector machine with arc-cosine kernel. Experiments on different datasets show that the proposed system gives high classification accuracy with reasonable training time compared to traditional core vector machines, deep support vector machines with arc-cosine kernel and deep convolutional neural network.

An Extreme-Value Event Approach for Frequency-Domain Performance Reliability

With time and usage, systems become less reliable as performance measures continuously degrade. In frequency-domain design, a sufficiently large number of performance measures are selected at discrete frequencies to act as surrogates for the frequency bands. Over discretized life-time, the system failure event grows into an ever larger number of highly correlated elementary failure events in terms of both frequency and time. This paper replaces the complex system failure event with an equivalent minimum extreme-value event: it is shown that this single event retains all of the original correlation information and is invariant to the number of elemental events. The novelty of the new and elegant approach is that it standardizes the failure probability evaluation via one-dimensional pdfs at either selected times, or importantly, selected frequencies. Further, pdfs of the frequencies causing failure over life-time are shown to be a useful design tool. The pdfs are easily represented by sampling techniques. Error analysis identifies three errors and the paper gives strategies to control. Case studies of an analogue filter show the proposed methodology has engineering applications. The impact of the proposed methodology is two-fold: it presents a standard way to assess and manage the uncertainty in the degradation process, and it provides a launching platform for timely design optimization.

An unconstrained mathematical description for conduction heat transfer problems with linear temperature-dependent thermal conductivity

This work presents a systematic modeling for conduction heat transfer problems in which the thermal conductivity is assumed a linear function of the temperature. In general, the mathematical descriptions arising from a linear relationship between thermal conductivity and temperature give rise to more than one solution, some of them without physical sense. In this work a convenient mathematical representation is proposed, avoiding physically inadmissible solutions.A conduction heat transfer problem in which the thermal conductivity decreases linearly with the temperature in a given interval is considered in this work. A physically equivalent alternative form, valid for any absolute temperature is proposed, giving rise to an unrestricted mathematical modeling and circumventing the need of a posterior choice for establishing the solution with physical meaning.An equivalent minimum principle for the problem is presented, showing that the extremum of a proposed functional corresponds to the solution of the problem.

Existence, uniqueness and construction of the solution of the energy transfer problem in a rigid and non-convex blackbody with temperature-dependent thermal conductivity

In this paper, we study the steady-state (coupled) conduction–radiation heat transfer phenomenon in a non-convex opaque blackbody with temperature-dependent thermal conductivity. The mathematical description consists of a nonlinear partial differential equation subjected to a nonlinear boundary condition involving an integral operator that is inherently associated with the non-convexity of the body. The unknown is the absolute temperature distribution. The problem is rewritten with the aid of a Kirchhoff transformation, giving rise to linear partial differential equation and a new unknown. An iterative procedure is proposed for constructing the solution of the problem by means of a sequence of problems, each of them with an equivalent minimum principle. Proofs of convergence as well as existence and uniqueness of the solution are presented. An error estimate, for each element of the sequence, is presented too.

On-line experiments on rapid detection of radionuclides based on sequential Bayesian analysis

A rapid detection method based on sequential Bayesian analysis provides a new perspective on national security in preventing the smuggling and illegal transportation of nuclear materials. In this paper, a sequential Bayesian analysis system, which mainly consists of a LaBr3(Ce) scintillator detector, a pulse analyzer based on a field-programmable gate array technique, and a sequential Bayesian analysis processor, is developed to directly validate the feasibility of sequential Bayesian analysis. The detection ability of 60Co, 137Cs, 133Ba, and 152Eu for a specific radioactivity is studied and quantified using the maximum detection distance and the equivalent minimum detection activity.

Path Optimality Conditions for Minimum Spanning Tree Problem with Uncertain Edge Weights

This paper investigates the uncertain minimum spanning tree (UMST) problem where the edge weights are assumed to be uncertain variables. In order to propose effective solving methods for the UMST problem, path optimality conditions as well as some equivalent definitions for two commonly used types of UMST, namely, uncertain expected minimum spanning tree (expected UMST) and uncertain α-minimum spanning tree (α-UMST), are discussed. It is shown that both the expected UMST problem and the α-UMST problem can be transformed into an equivalent classical minimum spanning tree problem on a corresponding deterministic graph, which leads to effective algorithms with low computational complexity. Furthermore, the notion of uncertain most minimum spanning tree (most UMST) is initiated for an uncertain graph, and then the equivalent relationship between the α-UMST and the most UMST is proved. Numerical examples are presented as well for illustration.

Comparative study on constructal optimizations of rectangular fins heat sink based on entransy dissipation rate minimization and maximum thermal resistance minimization

Constructal optimization of a rectangular fin heat sink with two-dimensional heat transfer model is carried out through using numerical simulation by finite element method, in which the minimized maximum thermal resistance and the minimized equivalent thermal resistance based on entransy dissipation are taken as the optimization objectives, respectively. The optimal constructs based on the two objectives are compared. The influences of a global parameter (a) which integrates convective heat transfer coefficient, overall area occupied by fin and its thermal conductivity, and the volume fraction (φ), on the minimized maximum thermal resistance, the minimized equivalent thermal resistances and their corresponding optimal constructs are analyzed. The results show that there does not exist optimal thickness of fins for the two objectives when the shape of the heat sink is fixed, and the optimal constructs based on the two objectives are different when the shape of the heat sinks can be changed freely. Besides, the global parameter has no influence on the optimal constructs based on the two objectives, but the volume fraction does. The increases of the global parameter and the volume fraction reduce the minimum values of the maximum thermal resistance and the equivalent thermal resistance, but the degrees are different. The reduce degree of the global parameter to the minimized equivalent thermal resistance is larger than that to the minimized maximum thermal resistance. The minimized equivalent thermal resistance and the minimized maximum thermal resistance are reduced by 40.03% and 41.42% for a= 0.5, respectively, compared with those for a = 0.3. However, the reduce degree of the volume fraction to the minimized maximum thermal resistance is larger than that to the minimized equivalent thermal resistance. The minimized equivalent thermal resistance and the minimized maximum thermal resistance are reduced by 59.69% and 32.80% for φ= 0.4, respectively, compared with those for φ= 0.3. As a whole, adjusting the parameters of the heat sink to make the equivalent thermal resistance minimum can make the local limit performance good enough at the same time; however, the overall average heat dissipation performance of the heat sink becomes worse when the parameters of the heat sink are adjusted to make the maximum thermal resistance minimum. Thus, it is more reasonable to take the equivalent thermal resistance minimization as the optimization objective when the heat sink is optimized.

Acoustic climate in the environment of the selected road sections in Poland

Traffic noise is an inherent element of contemporary societies’ life. Its volume systematically increases as the car number is growing and the road network is developed. Traffic noise, especially road-induced noise, is so widespread in our environment that it is hard to isolate ourselves from it. This paper presents the results of acoustic climate studies conducted in the vicinity of selected road sections in Poland: national road DK8 in the vicinity of Budzisko and Augustow, S8 road near Wyszkow and at the final stretch of DK 8 in the vicinity of Kudowa-Zdroj. The studies also covered two areas adjacent to A1 motorway in the vicinity of Kamionek and Pelplin and next to road DK 91, which runs in parallel to A1 motorway. Acoustic climate studies were also carried out along A4 motorway and national road DK 94 in the vicinity of Lewin Brzeski. Measurements were made along the Buszyce–Magnuszewice profile. Noise measurements were made on a total of 11 profiles. The analysis covered certain features of the acoustic climate (equivalent sound level, its maximum and minimum values and duration of noise of a given level). Acoustic climate features were compared with data on traffic intensity and vehicle type structure along the road sections under analysis. The paper also discusses sound propagation in the vicinity of transport routes and the impact of local environment characteristics (landscape relief and humidity) on noise propagation. Possible noise level reduction means to be applied in the vicinity of roads are also discussed.

Quantifying the Combined Effect of Radiation Therapy and Hyperthermia in Terms of Equivalent Dose Distributions

To develop a method to quantify the therapeutic effect of radiosensitization by hyperthermia; to this end, a numerical method was proposed to convert radiation therapy dose distributions with hyperthermia to equivalent dose distributions without hyperthermia. Clinical intensity modulated radiation therapy plans were created for 15 prostate cancer cases. To simulate a clinically relevant heterogeneous temperature distribution, hyperthermia treatment planning was performed for heating with the AMC-8 system. The temperature-dependent parameters α (Gy(-1)) and β (Gy(-2)) of the linear-quadratic model for prostate cancer were estimated from the literature. No thermal enhancement was assumed for normal tissue. The intensity modulated radiation therapy plans and temperature distributions were exported to our in-house-developed radiation therapy treatment planning system, APlan, and equivalent dose distributions without hyperthermia were calculated voxel by voxel using the linear-quadratic model. The planned average tumor temperatures T90, T50, and T10 in the planning target volume were 40.5°C, 41.6°C, and 42.4°C, respectively. The planned minimum, mean, and maximum radiation therapy doses were 62.9 Gy, 76.0 Gy, and 81.0 Gy, respectively. Adding hyperthermia yielded an equivalent dose distribution with an extended 95% isodose level. The equivalent minimum, mean, and maximum doses reflecting the radiosensitization by hyperthermia were 70.3 Gy, 86.3 Gy, and 93.6 Gy, respectively, for a linear increase of α with temperature. This can be considered similar to a dose escalation with a substantial increase in tumor control probability for high-risk prostate carcinoma. A model to quantify the effect of combined radiation therapy and hyperthermia in terms of equivalent dose distributions was presented. This model is particularly instructive to estimate the potential effects of interaction from different treatment modalities.

SU-F-500-04: Motion Mitigation in Active Scanning Proton Therapy for Lung Cancer: A 4D Monte Carlo Study

Purpose: To study the efficacy of various rescanning techniques and gating in the mitigation of motion interplay effects in hypofractioned lung treatments employing actively scanned protons. Methods: 5 lung cancer patients with varying tumor size (21.1–82.3cc) and motion amplitude (2.9– 30.6mm) were simulated employing 4D Monte Carlo simulations and deformable image registration. We investigated 2 different spot sizes (σ∼12mm and ∼3mm), 3 different rescanning techniques (layered, volumetric, breath‐sampled volumetric) and respiratory gating. Changes in the resulting dose distribution in the target were determined using equivalent uniform dose (EUD), dose homogeneity, minimum and mean dose, in the lung through V5, V20 and mean lung dose (MLD). Results: For patients with motion amplitudes <20mm, rescanning successfully maintains EUD within the target. For the large spot size 2 paintings are sufficient, while at least 6 are required for the small spot size. Rescanning also reduces the dependence on the initial breathing phase. The average variation of the EUD with initial breathing phase is reduced from 4% without rescanning to 2.5% for 2x‐and 0.7% for 10x‐rescanning. Breath‐sampling the timing of the paintings is effective, leading to EUDs that are, on average, 5.3% higher than for the same number of consecutive rescans. Volumetric rescanning is sensitive to synchronization effects with the breathing cycle, reducing its effectiveness in 4 out of 50 scenarios studied, while no such effects were observed for layered rescanning. Rescanning has no significant effect on normal lung V 20 , V 5 and MLD, though it reduces maximum lung dose by 2.2Gy(RBE) on average. Gating improves normal lung sparing, reducing V20 and MLD by up to 10% and 7.4Gy(RBE). Conclusion: Rescanning offers the possibility to mitigate interplay effects in the target up to a motion of 20mm in this patient cohort. Gating performs similar or better, additionally significantly sparing lung tissue. This project was supported by the National Cancer Institute Grant No. R01 CA111590

Effects of hydrodynamic interaction on the equivalent conductivity minimum of electrolyte solutions in solvents of low dielectric constant

Brownian dynamics simulation on model electrolyte solutions in our previous work [T. Yamaguchi et al., J. Chem. Phys. 134, 244506 (2011)] is extended to include the hydrodynamic interaction between ions, in order to examine its effects on ionic mobility in solvents of low dielectric constant. The effects of the hydrodynamic interaction are rather small as a whole, and the equivalent conductivity minimum is observed in systems with the hydrodynamic interaction. The hydrodynamic interaction increases the self-diffusion coefficient while decreases the equivalent conductivity, thereby increases the deviation from the Nernst-Einstein relationship. Based on the analysis of the time-dependent ionic mobilities, these changes are elucidated in terms of the electrophoretic and relaxation effects. It is also demonstrated that the concentration dependence of the ionic mobilities with the hydrodynamic interaction is reproduced fairly well by a theoretical calculation.

An intrinsic fiber ring laser based sensor with saturable absorber

A novel configuration of fiber ring laser acoustic sensor, which adopts single-mode fiber as sensing element, is proposed and demonstrated. Linewidth less than 1 kHz is achieved by introducing a segment of erbium-doped fiber in the reflecting arm as saturable absorber. A polarization independent unbalanced Michelson interrogation interferometer and phase generated carrier demodulation technique are adopted to recover signal. Experiments demonstrate that the phase sensitivity is 0.018 rad/nm in good linearity and equivalent minimum detect able length change reaches 19.1 pm.

Theoretical Investigation into Electronic Structures and Charge Transfer Properties of π‐Conjugated System with Different Combinations of Thiophene and Vinyl/Butadiene

Abstract A series of combinations of thiophene and vinyl/butadiene were investigated by ab initio and DFT methods to explore their electronic structures and charge transfer properties. The results show that increasing thiophene ring and vinyl number is a rational strategy to raise the HOMO energy levels and lower the LUMO energy levels. Moving the vinyl from the periphery to the core has the slight effect on the HOMO and LUMO energy levels. Furthermore, replacing the middle vinyl and end‐capped vinyl of 3b (T5V4) with the butadiene can lower LUMO energy levels and then facilitate the electron injection. Above all, the close hole and electron reorganization energies (λh and λe) are observed from these compounds. However, the λes are smaller than their respective λhs in some compounds, which is relatively rare in organic materials. Especially, the promising ambipolar material 3c (T5B4) is recommended theoretically for possessing the equivalent minimum λh (0.24 eV) and λe (0.24 eV). The absorption wavelengths exhibit red shifts with the increasing of the thiophene ring and the vinyl number under the same configuration, which correspond to the reverse order of ΔEH‐L and Eg. The linear relationships are found between experimental lowest singlet excited energies (Eexp) with theoretical values ΔEH‐L and Eg.

Corneal Collagen Cross-Linking Before Ferrara Intrastromal Corneal Ring Implantation for the Treatment of Progressive Keratoconus

To evaluate the safety, efficacy, and stability of sequential corneal collagen cross-linking (CXL) and Ferrara intrastromal corneal ring segment (FR) implantation in selected patients with progressive keratoconus. This prospective study involved 9 eyes with progressive keratoconus and a preoperative cylinder value equal to or greater than 5 diopters (D) diagnosed between June 2007 and October 2008. Preoperative and postoperative (6 months after the CXL procedure and 6 months after the FR implantation) biomicroscopy examinations, distance uncorrected and best-corrected visual acuities, refractive error, and topographic maps were evaluated and compared. Mean uncorrected visual acuity was 1.11 logarithm of the minimal angle of resolution (logMAR) preoperatively and 0.75 logMAR at 6 months after CXL (P = 0.03) and 0.23 logMAR at 6 months after FR implantation (P < 0.001). Mean best-corrected visual acuity was 0.26 logMAR preoperatively and 0.24 logMAR at 6 months after CXL (P = 0.87) and 0.12 logMAR at 6 months after FR (P = 0.05). Statistically significant reductions in the mean spherical equivalent (4.38 D; P < 0.001) and mean maximum (5.58 D; P < 0.001) and minimum (4.17 D; P < 0.001) keratometry values were present at 6 months after FR. FR implantation after CXL is a safe and efficacious treatment option for managing selected patients with progressive keratoconus. Good results in terms of visual acuity, postoperative residual refractive error, and keratometry values were obtained. Longer follow-up would be valuable to confirm the stability of these results.

Amplitude‐phase constraints based blind and semi‐blind channel estimation for OFDM systems

ABSTRACTIn this paper, a new blind channel estimation method for orthogonal frequency division multiplexing systems is presented. The proposed approach based on the amplitude‐phase constraints of the channel frequency response first estimates the channel amplitude‐frequency response, and then calculates the channel‐frequency response of the equivalent minimum phase system by its amplitude‐frequency response. The zeros of the actual system and its equivalent minimum phase system are symmetric about the unit circle, and the symmetric relationships are easily determined according to the finite alphabet property of information symbols. A semi‐blind estimation method based on the blind estimation method is also proposed in this paper, and it greatly reduces the numerical complexity of the blind method. Unlike existing statistical blind channel estimators, the proposed method requires short data records especially for phase‐shift keying modulation. Compared with the existing finite alphabet based method, the proposed method has a lower numerical complexity. Comparison of the proposed method with training based estimation method, which is presented by computer simulations, show the effectiveness of the proposed method. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Minimum Distance Analysis of a Certain Class of 2-D ISI Channels

We perform a minimum distance analysis of a class of two-dimensional intersymbol interference (ISI) channels applicable to multitrack magnetic recording and orthogonal frequency division multiplex transmission systems. Exact minimum distance for a wide class of ISI responses is derived. The fundamental analytical technique is to transform the channel into an equivalent minimum phase channel. The results improve upon the prior work of Soljanin and Georghiades.