Effects Of Changes In Parameters Research Articles

Effect of NS-DBD Actuator Parameters on the Aerodynamic Performance of a Flap Lifting Device

The flap lift device is an important part of the conventional configuration of aircrafts and has an important impact on the aerodynamic performance. In this paper, a high-efficiency, simple, and energy-saving nanosecond dielectric barrier discharge (DBD) plasma actuator is placed in the vicinity of the flap lift device to improve the aerodynamic performance of the flap by controlling the flow field. The two-dimensional airfoil GAW-1 and its 29% flap were selected as the research objects, and the nanosecond (NS) DBD actuators were fixed at different locations near the deflection angle of the 10°flap. The excitation frequency, pulse width, and energy density parameters of the pulse discharge were adjusted, and then, the effects of parameter changes on aerodynamic characteristics of the airfoil were studied by numerical simulation. The simulation results show that adjusting the excitation frequency on the aerodynamic drag is weak and that the effect on the aerodynamic lift is obvious. The increase of the discharge pulse width will have a more significant effect on the flow field, i.e., a proper increase of the discharge pulse width can achieve better drag reduction, and increase lift after a stall at a high angle of attack. Although the increase of discharge energy density can strengthen the pulse perturbation effect on the flow field, it also contributes to some adverse effects and has no obvious optimization effect on the control efficiency of lift increase and drag reduction.

Research Of Periodic Orbits And Chaos In Current Controlled Boost Converter

This paper investigates the periodic orbits and produced chaos produced in a current controlled boost converter using theory of one-dimensional piecewise-smooth maps, simulation and hardware. Initially the one-dimensional linear piecewise-smooth map with suitable parameters which can be used to represent the boost converter is derived. To achieve simulation results the converter is mathematically modelled such that the multi-dimensional system is converted into single-dimensional non-linear. The inductor current is taken as a sate variable. Therefore, the effect of parameter change has to observed and the qualitative change has to be observed and investigated. In this paper we choose to change current reference. The periodic orbits produced in the current are shown with the help of MATLAB Simulink model and the phase portrait is also plotted. Further the same results are validated with the help of hardware.

AN EPQ MODEL FOR DELAYED DETERIORATING ITEMS WITH RELIABILITY CONSIDERATION AND QUADRATIC DEMAND

In this paper, an EPQ model for delayed deteriorating items is developed where the demand before deterioration sets in is assumed to be different from that after deterioration sets in. There are three stages for the inventory system as follows: 1) the production build-up stage (0 ≤ t ≤ L1); 2) stage before deterioration sets in (L1 ≤ t ≤ L2); 3) stage after deterioration sets in (L3 ≤ t ≤ L). It is also assumed that the unit cost of production is directly proportional to the process reliability and inversely proportional to the rate of demand and shortages are not allowed. A numerical example is given to illustrate the developed model and sensitivity analysis carried out on the example to see the effect of parameter changes.

A continuous approximation approach for supply network design considering radio frequency identification adoption

The design and management of multiechelon supply networks is one of the most crucial and challenging problems that managers encounter. In this study, supply networks are designed for both single-item and multi-item cases by considering RFID adoption. To maximize total profits, the objective is to determine the following: (1) the locations of distribution centers, (2) the allocation of retail stores to distribution centers, (3) the replenishment cycle time at distribution centers, and (4) whether RFID was adopted. In this study, a continuous approximation model is developed and an algorithm for solving this problem is proposed. Numerical studies are adopted to demonstrate the solution procedure and the effects of changing parameters on decisions and profits. The results also show how RFID adoption affects the design of supply networks. This paper provides novel management implications that business managers can use as a reference.

Neoliberal conservation in REDD+: The roles of market power and incentive designs

Market power relations and incentive designs are critical determinants affecting the success or failure of implementing the scheme of Reducing Emissions from Deforestation and Degradation (REDD+). This paper explores how market power differences in REDD + and incentive designs with different motivating objects affect the actors’ own emissions-reducing behavior. Guided by a theoretical framework that considers both market power and incentive designs, this paper examines the impacts of incentive designs and market power on the behavior of actors in REDD + by constructing game models. A numerical simulation is applied to examine the effects of parameter changes on the optimal strategies of each actor under different market-power structures and different incentive solutions. The results demonstrate the following. First, the incentives for landholders in REDD + are more conducive to affect actors’ efforts to reduce emissions than the incentives for the investor. Second, landholders, rather than investors, were found to obtain more market power due to the unequal market-power structure in REDD+, which will ultimately improve the landholders’ efforts to conserve forests and make a profit. At the same time, investors’ efforts and profits were also found not decline, despite the existence of the unequal market power. Third, the effects of market power and incentive designs on actors were found to be related to various REDD + factors, including opportunity costs, payments, the price of carbon credits, and the output elasticities of efforts. This paper further demonstrates that the incentive designs and market power have a more significant impact on landholders than on investors.

A green closed loop supply chain design using queuing system for reducing environmental impact and energy consumption

Abstract Due to increased environmental impacts and their important role in human life, reduction of impacts made by human has attracted more attention, recently. Green supply chains are among the most effective issues related to environmental impacts and increased number of studies in this area verifies this opinion. Transportation fleets transfer products between supply chain's centers and are one of the important factors which increase environmental impacts. Transportation fleets which transfer products between supply chain's centers are one of the important factors which increase environmental impacts while transferring products between centers and waiting in loading queue. Decreasing environmental impacts which are created by transportation fleets, from this point of view, is not investigated comprehensively in forward and reverse logistic supply chains. In order to deal with this gap, in this article a green supply chain with forward and reverse logistic consideration is designed and queuing system is used to optimize the transportation and waiting time of transportation fleets' network. This optimization model will lead to the reduction in environmental impacts. Our network consists of supplier, production system, distribution center, repair center, recycling center, disposal center, and collection center. Returned products from customers are collected in the collection center and transferred to other centers based on their type. Transportation fleets in the network are assumed to be customers of loading system in each center where each of these loading systems has a multi-server queuing system with finite sources. It is assumed that a sufficient number of servers are available in unloading centers, therefore, no queue will exist there. The proposed model will reduce the created environmental impacts and energy consumption of transportation fleets by determining loading, unloading and production rates, which affect waiting and transportation time. A numerical example is discussed for the NLP model in small size and solved with the exact methods. In addition, a meta-heuristics approach is employed to solve the large size of problem. Finally, the sensitivity analysis is performed to investigate the effects of change in parameters on model's decision variables and objective function.

Basin of Attraction and Limit Cycle Oscillation Amplitude of an Ankle-Hip Model of Balance on a Balance Board.

The study of upright posture (UP) stability is of relevance to estimating risk of falls, especially among people with neuromuscular deficits. Several studies have addressed this problem from a system dynamic approach based on parameter bifurcation analyses, which provide the region of stability (RoS) and the delimiting bifurcation curves (usually Hopf and pitchfork) in some parameter-spaces. In contrast, our goal is to determine the effect of parameter changes on the size of the basin of attraction (BoA) of the UP equilibrium and the amplitude of the limit cycle oscillations (LCOs) emerging from the Hopf bifurcations (HBs). The BoA is an indicator of the ability of the UP to maintain balance without falling, while LCOs may explain the sway motion commonly observed during balancing. In this study, a three degree-of-freedom model for a human balancing on a balance board (BB) was developed. Analysis of the model revealed the BoAs and the amplitude of the LCOs. Results show that physical parameters (time-delays and feedback control gains) have a large impact on the size of the BoA and the amplitude of the LCOs. Particularly, the size of the BoA increases when balancing on a rigid surface and decreases when either proprioceptive or combined visual and vestibular (V&V) feedback gain is too high. With respect to the LCOs, it is shown that they emerge from both the subcritical and supercritical HBs and increase their amplitudes as some parameters vary.

Investigation of thermal conductivity property of plasmonic nanofluids based on gold nanorods prepared by seed-mediated growth method

In this paper, nanofluids were prepared based on gold nanorods in basic fluid, water, by single-stage chemical reduction and in different volume fractions and the used gold nanorods were synthesized by seed-mediated growth method in different dimensional ratios. The properties of the prepared nanoparticles, including crystalline size, aspect ratio, surface properties, nanoparticle purity, shape and morphology of nanostructures were investigated using x-ray diffraction, UV-vis spectroscopy, FT-IR, and transmitted electron microscopy. The effect of changing parameters of Nano rod dimensions, changes in Nano rod volume fraction in water and also the effect of temperature on the nanofluid thermal conductivity coefficient were investigated using transient hot wire method. The results showed that reducing the aspect ratio, increasing the volume fraction and increasing the temperature increase the thermal conductivity. In fact, results show that an increase in the nanorods aspect ratio with a constant volume fraction of 1:50 of gold in water nanorod and at room temperature leads to a decrease in the thermal conductivity of the nanofluid. Also, increasing the two parameters of volume fraction and temperature significantly increases the thermal conductivity coefficient.

Dynamic analysis of dissemination model of innovation ability of enterprise R&D personnel

In the competitive global economy, innovation is widely regarded as one of the most critical factors affecting the development and growth of enterprises. It is important to consider the generation, evolution and dissemination of innovation ability. In this paper, it is assumed that innovation can spread among R&D (research and development) population in the way a special “infectious disease” does. On the basis of this assumption, a quantitative model is established to describe the mechanism of innovation ability among R&D population and corresponding influencing factors have been displayed to have a further understanding of innovation ability disseminating. Meanwhile, we analyze the local and global stability of innovation-free equilibrium and innovation-existence equilibrium and calculate the basic reproduction number of our model. Then we discuss the effect of parameter changes on the dissemination of innovation ability and analyzed the parameter sensitivity of the model with numerical simulations. Finally, some suggestions are given on how to better understand the dissemination of innovation ability in an effort to improve the innovation ability of enterprises.

Industrial optimization of multi-effect desalination equipment for olefin complex

This research consists of a brief overview of some methods used to produce freshwater and how they work, the obvious points of performance, and the advantages and disadvantages of each of these methods. The effects of change in operation parameters on the performance as well as thermal energy consumption of sample MED–TVC (MED with thermal vapor compression) are investigated. This article represents the result of experimental and actual changes provided by process engineering department in Kavian Petrochemical Company (11th Olefin) to find best operating conditions for system stability. The most significant reason to opt these MED units is the internal steam source (5 * 140 ton h−1 boilers) which is located inside the complex’s battery limit making the control of operational variables more accessible. Also, the performance of the system and thermodynamic and thermo-hydraulic equations have been studied carefully. By writing a solving algorithm for the governing equations and implementing it in the MATLAB software, a conceptual design of the system has been considered. By using the written program, the effect of change in parameters such as inlet steam pressure, seawater temperature, feed water temperature, inlet seawater flow, the performance ratio on the steam consumption has been reviewed. Although most of the above-mentioned changes cannot be implemented after the system designing, changes in the steam consumption that is generated inside the complex have been investigated and the results have been communicated to the operation department through the process engineering department to modify the system.

Current Change Rate Influences Sensorimotor Cortical Excitability During Neuromuscular Electrical Stimulation.

Neuromuscular electrical stimulation (NMES) is frequently used in rehabilitation therapy to improve motor recovery. To optimize the stimulatory effect of NMES, the parameters of NMES, including stimulation mode, location, current intensity, and duration, among others have been investigated; however, these studies mainly focused on the effects of changing parameters in the current plateau stage of the NMES cycle, while the impacts on other stages, such as the current rising stage, have yet to be investigated. In this article, we studied the electroencephalograph (EEG) effects during NMES, with different rates of current change in the rising stage, and stable current intensity in the plateau stage. EEG signals (64-channel) were collected from 28 healthy subjects, who were administered with high, medium, or low current change rate (CCR) NMES through a right-hand wrist extensor. Time-frequency analysis and brain source analysis, using the LORETA method, were used to investigate neural activity in sensorimotor cortical areas. The strengths of cortical activity induced by different CCR conditions were compared. NMES with a high CCR activated the sensorimotor cortex, despite the NMES current intensity in the plateau stage lower than the motor threshold. Reduction of the Alpha 2 band (10–13 Hz) event related spectral power (ERSP) during NMES stimulation was significantly enhanced by increasing CCR (p < 0.05). LORETA-based source analysis demonstrated that, in addition to typical sensory areas, such as primary somatosensory cortex (S1), sensorimotor areas including primary motor cortex (M1), premotor cortex (PMC), and somatosensory association cortex (SAC) were all activated by within threshold NMES. Furthermore, compared with the low CCR condition, cortical activity was significantly enhanced in the S1, M1, and PMC areas under high CCR conditions. This study shows CCR in the NMES rising stage can affect EEG responses in the sensorimotor cortex and suggests that CCR is an important parameter applicable to the optimization of NMES treatment.

Simulation modeling and interface parameter design of the semi‐physical braking intelligent test system

AbstractIn order to adapt to the improvement of freight train braking technology, it is a good method to establish a semi‐physical braking intelligent test system, and the core technology of modeling and interface that supports the system is especially critical. Based on the above background, this paper is focus on the simulation modeling that reflects the braking performance characteristics of freight trains and designs the interface system that can be connected with the test equipment. Based on the analysis of the state equations of pressure gas during the braking process and the characteristics of fluid changes, this paper deduces a modular digital model of the braking machine that reflects the structural factors and the influencing factors of the process of fluid transfer. Then it combines the specific braking tests to verify the significance of the model and the effect of parameter changes on braking performance. The experimental results show the accuracy and feasibility of the modeling process, which provides a reference model establishing method and a research idea for the establishment of a more completed set of freight train braking system mathematical model. The design and implementation of this part of the technology also provide an important basis for the control part of the entire semi‐physical braking intelligent test system.

The Impact of Government Policy on Food Pricing Using Game Theory

In this research, a model based on the theory of competitive games using Nash equilibrium and in the presence of a retailer for the purpose of food pricing was presented in terms of state competition and policy. Considering the effects of government competition and policy on the issue, we are trying to make a model more in line with real-world conditions and used by managers and practitioners in the food industry. Ultimately, the sensitivity analysis plant production costs were taken and the effect of changes in parameters on the variables of the research was measured. Keywords : pricing, food products, competition, government policy, game theory. DOI : 10.7176/IEL/9-4-06 Publication date :May 31 st 2019

A numerical approach for a discrete Markov model for progressing drug resistance of cancer

The presence of treatment-resistant cells is an important factor that limits the efficacy of cancer therapy, and the prospect of resistance is considered the major cause of the treatment strategy. Several recent studies have employed mathematical models to elucidate the dynamics of generating resistant cancer cells and attempted to predict the probability of emerging resistant cells. The purpose of this paper is to present numerical approach to compute the number of resistant cells and the emerging probability of resistance. Stochastic model was designed and developed a method to approximately but efficiently compute the number of resistant cells and the probability of resistance. To model the progression of cancer, a discrete-state, two-dimensional Markov process whose states are the total number of cells and the number of resistant cells was employed. Then exact analysis and approximate aggregation approaches were proposed to calculate the number of resistant cells and the probability of resistance when the cell population reaches detection size. To confirm the accuracy of computed results of approximation, relative errors between exact analysis and approximation were computed. The numerical values of our approximation method were very close to those of exact analysis calculated in the range of small detection size M = 500, 100, and 1500. Then computer simulation was performed to confirm the accuracy of computed results of approximation when the detection size was M = 10000,30000,50000,100000 and 1000000. All the numerical results of approximation fell between the upper level and the lower level of 95% confidential intervals and our method took less time to compute over a broad range of cell size. The effects of parameter change on emerging probabilities of resistance were also investigated by computed values using approximation method. The results showed that the number of divisions until the cell population reached the detection size is important for emerging the probability of resistance. The next step of numerical approach is to compute the emerging probabilities of resistance under drug administration and with multiple mutation. Another effective approximation would be necessary for the analysis of the latter case.

Geometrically nonlinear analysis of Timoshenko piezoelectric nanobeams with flexoelectricity effect based on Eringen's differential model

• Extended theory of piezoelectricity is used to investigate flexoelectricity effect on vibrational behavior of nanobeam. • The von-Kármán strain–displacement relationship, electric Gibbs free energy and Hamilton's principle are employed. • Multiple scales method is used to obtain a closed form solution of derived nonlinear governing equations of motion. • The effects of changes in parameters on free vibration and postbuckling behavior of nanobeam are discussed comprehensively. • Theoretical range of flexoelectricity constant is estimated through buckling analysis . This study analyzes the nonlinear free vibration and post-buckling of nanobeams with flexoelectric effect based on Eringen's differential model. The nanobeam is modeled based on Timoshenko beam's theory. The von-Kármán strain–displacement relation together with the electrical Gibbs free energy and Hamilton's principle are employed to derive equations of motion. The nonlinear free vibration frequencies are obtained for pinned–pinned (P–P) and clamped–clamped (C–C) boundary conditions. Multiple scales method is employed to obtain the closed-form solution for the nonlinear governing equations. By employing this methodology, the natural frequencies of nanobeams are obtained and their post-buckling behavior is examined. The influence of nonlocal parameter, amplitude ratio, and input voltage on the top surface and flexoelectricity constant on nonlinear free vibration and post-buckling characteristics of nanobeam is investigated. In this paper, it is concluded that the flexoelectricity has a significant effect on free vibration of the beams in nano-scale and its effect has to be considered in designing nano-electro-mechanical systems (NEMS) such as nano- generators and nano-sensors.

Parameter sensitivity analysis for biochemical reaction networks.

Biochemical reaction networks describe the chemical interactions occurring between molecular populations inside the living cell. These networks can be very noisy and complex and they often involve many variables and even more parameters. Parameter sensitivity analysis that studies the effects of parameter changes to the behaviour of biochemical networks can be a powerful tool in unravelling their key parameters and interactions. It can also be very useful in designing experiments that study these networks and in addressing parameter identifiability issues. This article develops a general methodology for analysing the sensitivity of probability distributions of stochastic processes describing the time-evolution of biochemical reaction networks to changes in their parameter values. We derive the coefficients that efficiently summarise the sensitivity of the probability distribution of the network to each parameter and discuss their properties. The methodology is scalable to large and complex stochastic reaction networks involving many parameters and can be applied to oscillatory networks. We use the two-dimensional Brusselator system as an illustrative example and apply our approach to the analysis of the Drosophila circadian clock. We investigate the impact of using stochastic over deterministic models and provide an analysis that can support key decisions for experimental design, such as the choice of variables and time-points to be observed.

STATE OF THE ART IN SIMULATION-BASED OPTIMIZATION APPROACHES FOR VEHICLE ROUTING PROBLEMS ALONG MANUFACTURING SUPPLY CHAINS

Transport execution influences directly the operational performance of distributed production systems. In order to attain efficiency, many decisions have to be taken, such as, (i) the choice of best route which minimizes travelling distance, (ii) the definition of proper scheduling, which improves the displacement timing, and (iii) the selection of transportation mode. Transport routing and scheduling present stochastic characteristics which can be described as functions of probability. In the recent literature, it has been suggested that complex stochastic problems can be solved using simulation-based optimization approaches (SBO). SBO combines the power of optimization heuristics with the advantages of simulation models which can evaluate the effect of parameter changes even on very complex systems. Since it is capable of capturing the relationships and interactions among various entities and subsequently identifying a good design or solution, SBO might represent a powerful support to decision-making in complex and stochastic situations such as transport routing and scheduling in distributed production systems. Furthermore, transport systems are highly dynamic, which have to adapt permanently to a variety of oscillations such as unpredictable demand, urgent requests of high priority, or disturbances such as vehicle crashes. On the technological frontier, the availability of system state data is facilitated by the introduction of cyber-physical systems and industry 4.0 concepts and technologies. Thereof, a new approach that employs the newly available data, enabling real-time revision of transport routing and scheduling as operations take place, embodies a research opportunity with potential practical impact. This paper aims to report the state of the art regarding SBO approaches applied to vehicle routing and scheduling problems with pick-up and delivery (VRPPD). The paper substantiate the relevance of developing new approaches for vehicle routing and scheduling along distributed manufacturing supply chains, which embrace the new possibilities created by the widespread employment of cyber-physical systems.

Rumor spreading model with the different attitudes towards rumors

Rumor spreading has a profound influence on people’s well-being and social stability. There are many factors influencing rumor spreading. In this paper, we recommended an assumption that among the common mass there are three attitudes towards rumors: to like rumor spreading, to dislike rumor spreading, and to be hesitant (or neutral) to rumor spreading. Based on such an assumption, a Susceptible–Hesitating–Affected–Resistant(SHAR) model is established, which considered individuals’ different attitudes towards rumor spreading. We also analyzed the local and global stability of rumor-free equilibrium and rumor-existence equilibrium, calculated the basic reproduction number of our model. With numerical simulations, we illustrated the effect of parameter changes on rumor spreading, analyzing the parameter sensitivity of the model. The results of the theoretical analysis and numerical simulations illustrated the conclusions of this study. People having different attitudes towards rumors may play different roles in the process of rumor spreading. It was surprising to find, in our research, that people who hesitate to spread rumors have a positive effect on the spread of rumors.

Economic design of control charts with multiple assignable causes under Burr XII shock model

ABSTRACTThe economic design of control charts depends on the process shock model distribution and due to difficulties from both theoretical and practical aspects, one of the proper alternatives may be the Burr XII (Burr) distribution which is quite flexible and its hazard rate can be fixed, increasing, decreasing, single mode or even U-shaped. Yet, in Burr distribution context, only one assignable cause model were considered where more realistic approach may be to consider multiple assignable causes. Thus, in this paper, an economic design of the control charts under the Burr shock model and multiple assignable causes were considered and compared with three types of prior distribution for the mean shift parameter. Also, a numerical example and a sensitivity analysis for more illustration and studying the effect of changing parameters of the shock model distribution on the optimum values of proposed design models were conducted, respectively. The results indicate that when the prior distribution is of negative exponential distribution, the multiple assignable cause models under Burr XII (Burr) distribution have minimum loss-cost.

Investment strategy for underground gas storage facilities based on real option model considering gas market reform in China

Natural gas is expected to play a much more important role in China's energy supply, however, the lack of underground gas storage facilities becomes a serious barrier for its market penetration. Therefore, gas market reform is expected to be incentive for developing gas storage facilities. In the present study, a real option model was proposed to analyse the optimal investment strategy (investment timing and value) for underground gas storage facilities with/without the consideration of gas market reform. Uncertainties in gas market, government incentives and technological improvements were considered. The obtained results showed that it was not optimal for immediate investment in underground gas storage in China, and that to implement gas market reform would greatly contribute to gas storage construction. With the consideration of gas market reform, the investment of underground gas storage would be executed at 2026 with an investment value of 0.33RMB/m3 if there were no government incentive, while to invest in 2030 would be the best decision without the consideration of gas market reform, and the investment value is only 0.05 RMB/m3. Through a sensitivity analysis, the effects of changes in parameters related to gas market, government incentives and technological improvements on the investment strategy were investigated. The conclusions can provide useful information for gas storage enterprise decision-makers on whether and when to invest underground gas storage facilities in China considering uncertainties.