Optimal Recovery Methods Research Articles

Cryogenic-membrane separation process for helium extraction and ethane co-production from natural gas

In order to address the defects of high energy consumption and low efficiency in the single cryogenic separation process for helium extraction, this paper integrate post-expansion nitrogen cycle refrigeration with membrane separation to establish a novel natural gas cryogenic-membrane helium recovery process. Based on four mainstream processes for ethane recovery from natural gas, an optimal ethane recovery method is selected and incorporated into the proposed cryogenic-membrane helium recovery process. The process is then simulated using ASPEN HYSYS software. The effects of operating parameters on critical equipment energy consumption, helium product concentration and ethane recovery were evaluated. The simulation results indicate that in the proposed helium recovery process, the concentration of refined helium reaches 99.6 %, and the ethane recovery rate is 90.13 %. Compared to the single helium extraction process, the total compressor energy consumption in our process is reduced by 23.10 %, and the integrated energy consumption is reduced by 20.4 %.

Radius of information for two intersected centered hyperellipsoids and implications in optimal recovery from inaccurate data

For objects belonging to a known model set and observed through a prescribed linear process, we aim at determining methods to recover linear quantities of these objects that are optimal from a worst-case perspective. Working in a Hilbert setting, we show that, if the model set is the intersection of two hyperellipsoids centered at the origin, then there is an optimal recovery method which is linear. It is specifically given by a constrained regularization procedure whose parameters can be precomputed by semidefinite programming. This general framework can be applied to several scenarios, including the two-space problem and problems involving ℓ2-inaccurate data. It can also be applied to the problem of recovery from ℓ1-inaccurate data. For the latter, we reach the conclusion of existence of an optimal recovery method which is linear, again given by constrained regularization, under a computationally verifiable sufficient condition.

On the construction of families of optimal recovery methods for linear operators

Предлагается некоторый подход к построению семейств оптимальных методов восстановления линейных операторов по неточно заданной информации. Предложенный метод построения применяется для восстановления производных по неточно заданным другим производным в многомерном случае и для восстановления решений уравнения теплопроводности по неточно заданным распределениям температур в некоторые моменты времени. Библиография: 25 наименований.

Recovery of analytic functions that is exact on subspaces of entire functions

A family of optimal recovery methods is developed for the recovery of analytic functions in a strip and their derivatives from inaccurately specified trace of the Fourier transforms of these functions on the real axis. In addition, the methods must be exact on some subspaces of entire functions. Bibliography: 12 titles.

Serum-based metabolomics reveals the mechanism of action of isorhynchophylline in the intervention of atherosclerosis in ApoE-/- mice.

Atherosclerosis (AS) is a chronic inflammatory disease with disorders of lipid metabolism. Metabolic disorders, inflammation and lipid deposition are prominent pathological features of atherosclerosis. Isorhynchophylline (IRN) has pharmacological effects such as protection of vascular endothelial cells, anti-inflammatory, anti-thrombotic, and anti-smooth muscle cell proliferation. However, it is unclear whether IRN is efficacious in atherosclerosis. In the present study, we verified the pharmacological efficacy and hepatoprotective effects of IRN in intervening in AS. LC-MS-based serum untargeted metabolomics was performed to search for potential biomarkers and related pathways in IRN-treated AS in ApoE-/- mice. Fifty-eight biomarkers were metabolically disturbed in the model mice compared to controls. Thirteen biomarkers showed optimal recovery methods after IRN-40 mg ml-1 intervention. We identified three metabolic pathways involved in IRN: glycerophospholipid metabolism, linoleic acid metabolism, and alpha-linolenic acid metabolism. These findings provide a research basis for the intervention of IRN in atherosclerosis.

On the construction of families of optimal recovery methods for linear operators

The paper proposes an approach for construction of families of optimal methods for the recovery of linear operators from inaccurately given information. The proposed method of construction is then applied to recover derivatives from inaccurately specified other derivatives in the multidimensional case and to recover solutions of the heat equation from inaccurately specified temperature distributions at some time instants.

On Recovery of the Singular Differential Laplace—Bessel Operator from the Fourier–Bessel Transform

This paper is devoted to the problem of the best recovery of a fractional power of the B-elliptic operator of a function on R+N by its Fourier–Bessel transform known approximately on a convex set with the estimate of the difference between Fourier–Bessel transform of the function and its approximation in the metric L∞. The optimal recovery method has been found. This method does not use the Fourier–Bessel transform values beyond a ball centered at the origin.

Optimal Recovery Methods Exact on Trigonometric Polynomials for the Solution of the Heat Equation

Optimal Recovery Methods Exact on Trigonometric Polynomials for the Solution of the Heat Equation

Системний підхід до формування показників якості відновлених деталей

The paper considers the technological process of parts restoration as a system of interrelated elements that can influence the formation of quality indicators of restored parts. It is established that the technological process has all the necessary properties that are required for systems. However, modern methods and criteria used in the design of the technological process of parts recovery focus on the selection of the optimal recovery method, which is only part of the technological process. Therefore, the paper sets the goal of presenting the technological process of restoration as a system of interconnections between individual elements that allow to purposefully influence the quality indicators of restored parts. The main hierarchical levels of technological design of part recovery are defined. In turn, the technological process of restoration as a whole is presented in the form of functions of connections between individual elements of the subsystem. This made it possible to present the overall structure of the technological process of restoring worn parts as a system. Taking into account the peculiarities of the system's functioning, an approach is proposed, according to which all elements of the system have an impact on the formation of quality indicators of the restored parts. The functional links between quality indicators and elements of the technological process at different levels of evaluation are established. The main ways to ensure the required quality indicators through the elements of the technological process are determined: methods, equipment, materials, modes, equipment, etc. The proposed approach to the formation of quality indicators of remanufactured parts makes it possible to study the cause-and-effect relationships between the parameters of technological processes and quality indicators of remanufactured parts, as well as to establish ways to improve them. The ways to ensure the quality of remanufactured parts at the main stages of the product life cycle are shown.

Optimal Recovery Methods Exact on Trigonometric Polynomials for the Solution of the Heat Equation

Рассматривается задача оптимального восстановления решения уравнения теплопроводности на торе $\mathbb T$ по конечному набору неточно заданных коэффициентов Фурье начальной температуры. При этом на методы накладываются условия точности на подпространствах тригонометрических полиномов фиксированной степени. Библиография: 13 названий.

Optimal Container Migration/Re-Instantiation in Hybrid Computing Environments

End-users and service providers have recently favored lower latency services. Edge computing has improved user quality of service (QoS) guarantees through the reduced geographical distance, decreased use of the network backbone, and flexible placement of the container hosting edge devices. The under-utilized isolated edge computing idling nodes are significant for service providers, especially for Internet of Things (IoT) applications. However, the nodes’ minimal maintenance remains a hindrance due to related increased failures. Orchestrating over the edge alongside core environments allows tolerant services and more demanding ones to coexist without impacting the user experience. Therefore, the orchestrator’s second priority is achieving and maintaining the QoS through optimal recovery method selection by either migrating the live containers or re-instantiating them. This paper proposes an Optimal Container Migration/Re-Instantiation (OC-MRI) model to optimize the orchestration methods focusing on downtime, container dependencies, and latency requirements. Next, we introduce a real-time heuristic-based solution, Edge Computing-enabled Container Migration/Re-Instantiation (EC2-MRI). Both models are bench-marked alongside staple greedy approaches. Simulation results showcase the lowest latencies and downtime with the OC-MRI model. Furthermore, the EC2-MRI model shows comparable results to the optimal model with minimal lag.

On optimal recovery of values of linear operators from information known with a stochastic error

The optimal recovery of values of linear operators is considered for classes of elements the information on which is known with a stochastic error. Linear optimal recovery methods are constructed that, in general, do not use all the available information for the measurements. As a consequence, an optimal method is described for recovering a function from a finite set of its Fourier coefficients specified with a stochastic error. Bibliography: 14 titles.

Quantum Game Application to Recovery Problem in Mobile Database

Mobile Computing (MC) is a relatively new concept in the world of distributed computing that is rapidly gaining traction. Due to the dynamic nature of mobility and the limited bandwidth available on wireless networks, this new computing environment for mobile devices presents significant challenges in terms of fault-tolerant system development. As a consequence, traditional fault-tolerance techniques are inherently inapplicable to these systems. External circumstances often expose mobile systems to failures in communication or data storage. In this article, a quantum game theory-based recovery model is proposed in the case of a mobile host’s failure. Several of the state-of-the-art recovery protocols are selected and analyzed in order to identify the most important variables influencing the recovery mechanism, such as the number of processes, the time needed to send messages, and the number of messages logged-in time. Quantum game theory is then adapted to select the optimal recovery method for the given environment variables using the proposed utility matrix of three players. Game theory is the study of mathematical models of situations in which intelligent rational decision-makers face conflicting interests (alternative recovery procedures). The purpose of this study is to present an adaptive algorithm based on quantum game theory for selecting the most efficient context-aware computing recovery procedure. The transition from a classical to a quantum domain is accomplished in the proposed model by treating strategies as a Hilbert space rather than a discrete set and then allowing for the existence of linear superpositions between classical strategies; this naturally increases the number of possible strategic choices available to each player from a numerable to a continuous set. Numerical data are provided to demonstrate feasibility.

Velocity obstacle–based conflict resolution and recovery method

ABSTRACTConsidering the shortcomings of current methods for real-time resolution of two-aircraft flight conflicts, a geometric optimal conflict resolution and recovery method based on the velocity obstacle method for two aircraft and a cooperative conflict resolution method for multiple aircraft are proposed. The conflict type was determined according to the relative position and velocity of the aircraft, and a corresponding conflict mitigation strategy was selected. A resolution manoeuvre and a recovery manoeuvre were performed. On the basis of a two-aircraft conflict resolution model, a multi-aircraft cooperative conflict resolution game was constructed to identify an optimal solution for maximising group welfare. The solution and recovery method is simple and effective, and no new flight conflicts are introduced during track recovery. For multi-aircraft conflict resolution, an equilibrium point that maximises the welfare function of the group was identified, and thus, an optimal strategy for multi-aircraft conflict resolution was obtained.

Influence of oil field production life on optimal CO2 flooding strategies: Insight from the microscopic displacement efficiency

We investigate the influence of the microscopic displacement processes on optimal gas flooding strategies. We couple a 1-D compositional reservoir model with an economic model of the flooding to assess profitability of the strategies. In general, we aim at the net present value maximization, although the oil recovery and CO2 storage efficiencies are also estimated. Under certain assumptions, we reduce the number of parameters controlling selection of optimal strategy to just a few dimensionless quantities characterizing both physical and economic processes. We show that the production life of oil fields should not be fixed in optimization studies, especially at low oil prices. A significantly larger net present value can be achieved by varying the reservoir lifetime in addition to the injection rates and volumes and other well controls. Herewith, the optimal strategy can differ from that in the case of a presumed production time. We conclude that waterflooding is the optimal recovery method if the injection rate is low, whereas gas (WAG) flooding applied as a primary method and followed by waterflooding is most optimal for large injection rates. Gas flooding applied as the tertiary recovery method is most optimal for an intermediate range of the rates. In the latter case, gas injection should begin much earlier than water breaks through to producing wells. Finally, we investigate how oil price influences the range of parameters suitable for gas injection.

Polar coded probabilistic shaping PAM8 based on many-to-one mapping for short-reach optical interconnection.

In this paper, a polar coded probabilistic shaping (PS) 8-ary pulse amplitude modulation (PAM8) based on many-to-one (MTO) mapping is investigated for short-reach optical interconnection. By ingeniously assigning parity bits to ambiguities positions, no extra PS redundancy and no complex distribution matcher are required in the scheme comparing to traditional probabilistic amplitude shaping (PAS). The noise distributions after different transmission distances are studied and an optimal clock recovery method for PS signal is proposed to degrade the impact of severe eye skew effect on BER performance. The experimental results show that up to 1.2 dB and 0.8 dB shaping gains are respectively achieved over back-to-back (BTB) and 2-km standard single mode fiber (SSMF) transmission. With the help of the proposed optimal clock recovery method in the PS scheme, the shaping gain is improved from 0.15 dB to 0.4 dB after 10-km transmission. Moreover, compared to low-density parity-check (LDPC) code, the polar coded PS-PAM8 can provide an additional coding gain of 2.2 dB with code length of 256, which proves the performance superiority of polar code in short code length. Therefore, the proposed polar coded PS-PAM8 with low complexity and satisfactory BER performance is believed to be an alternative solution for the cost-sensitive short-reach optical interconnection.

A novel technique of paper mill sludge conversion to bioethanol toward sustainable energy production: Effect of fiber recovery on the saccharification hydrolysis and fermentation

A new process for the production of bioethanol from paper mill sludge (PMS) is described in this work. PMS biomass feedstock was processed via the simultaneous saccharification and fermentation (SSF) with and without accelerants. The enzymatic hydrolysis and fermentation were first evaluated, and the energy demand was 2.2 MJ/L of produced ethanol. When the enzymatic hydrolysis and fermentation were combined, the energy demand was reduced to 1.0 MJ/L ethanol, the sugars production increased, and the overall capital cost of the process decreased. The sugar yield was improved by adding accelerant and selecting the optimal fiber recovery method. The accelerant improved the enzymatic hydrolysis via a pathing/bridging mechanism. The SSF with the chemical fiber recovery method coupled with accelerant addition would be the best process configuration. Upon this combination, the glucose profile was enhanced from 9.8 g/L to 17.0 g/L. The sludge fiber conversion by SSF was improved by selecting an efficient fiber recovery method combined with the accelerant addition. SSF in chemical fiber recovery with accelerant addition was the best process by a 10% improvement of ethanol yield. The proposed process configuration offers a lower cost and sustainable process and contributes to the circular economy of zero waste discharges.

Recovery of the Operator $$\boldsymbol{\Delta}_{\boldsymbol{B}}$$ from Its Incomplete Fourier–Bessel Image

In this paper we consider optimal recovery of the B-elliptic operator with its powers of a smooth function from the Fourier–Bessel transform given on some convex subset. We construct a series of optimal recovery methods. It turns out that information about the Fourier–Bessel transform outside of some ball with the center at zero is superfluous, optimal methods do not use it. The methods themselves differ in the way they process available information.

Optimal Recovery Method of the Solution of a One-Dimensional Wave Equation at Time Τ From Inaccurate Data at t=0 And t = T

The article deals with the problem of optimal recovery of the solution of the wave equation at some time instant by known, but given with some error, functions determining the shape of the string at times t and T. The goal of the paper is to construct an optimal recovery method for the solution of the wave equation from inaccurate data. An important assumption used in the work is the possibility of representing the solution in the form of a Fourier series. The main solution method is the introduction of an auxiliary extremal problem for a conditional extremum, the solution of which determines the optimal recovery method. The result of the work is to find the optimal recovery method among all possible methods. The solution of the restoration problem and the value of the error of optimal recovery are obtained. Cases are indicated when it is possible to reduce the amount of initial information required for solving the problem.

Optimal Recovery Methods for Solutions of the Dirichlet Problem that are Exact on Subspaces of Spherical Harmonics

We consider the optimal recovery problem for the solution of the Dirichlet problem for the Laplace equation in the unit d-dimensional ball on a sphere of radius ρ from a finite collection of inaccurately specified Fourier coefficients of the solution on a sphere of radius r, 0 < r < ρ < 1. The methods are required to be exact on certain subspaces of spherical harmonics.