Optimal Consumption Research Articles

Performance prediction and multi-objective optimization for the Atkinson cycle engine using eXtreme Gradient Boosting

In this study, substantial efforts have been done to enhance both the economy and nitrogen dioxide (NOx) emission characteristics of an Atkinson cycle engine (ACE). The integrated simulation model was meticulously formulated and calibrated utilizing GT-Power software based on test data, and four machine learning (ML) models were developed to predict the performance of the ACE. On this basic, the improved multi-objective hybrid particle swarm optimization (IMHPSO) algorithm was proposed to conduct comprehensive optimization of ACE performance. The results highlight the superior prediction performance and generalization ability of the eXtreme Gradient Boosting (XGBoost) model, attaining an average coefficient of determination (R2) of 0.9978 and 0.9966 on the train and test sets, respectively. The IMHPSO algorithm exhibited efficient convergence, uniform distribution and rich diversity across five benchmark test problems, effectively mitigating issues related to local optima and premature convergence. The Optimal Brake Specific Fuel Consumption (BSFC) solution is chosen as the preferred optimized scheme and realizes significant reductions of 8.5 % for BSFC and 96.1 % for NOx emissions, which experiences a remarkable increase of over 1300 times in computational efficiency compared to the GT-Power model. These findings provide theoretical basis, data support and novel insights for multi-objective optimization of ACE performance.

Sodium and water dynamics in the progression of chronic kidney disease: mechanisms and clinical significance.

Lifestyle modifications can postpone the progression of chronic kidney disease toward its terminal stage.This mini-review aims to explore the impact of salt and water intake on the progression of chronic kidney disease (CKD) and provide insights into the optimal consumption levels to preserve the glomerular filtration rate. We reviewed relevant literature to examine the association between salt and water consumption and CKD progression. Our analysis includes discussions on the pathophysiology, findings from clinical trials, and recommended intake guidelines. Sodium intake, often linked to cardiovascular risk and CKD progression, has shown a complex J-shaped association in some studies, leading to uncertainty about the ideal salt intake level. Sodium and fluid retention are key factors contributing to hypertension, a well-established risk factor for CKD progression. Low-sodium diets have demonstrated promise in reducing blood pressure and enhancing the effects of renin-angiotensin-aldosterone system inhibitors in non-dialysis CKD patients. However, a debate persists regarding the independent effect of salt restriction on CKD progression. Despite medical recommendations, salt consumption remains high among CKD patients. Additionally, the role of water consumption in CKD remains controversial despite its established benefits for CKD prevention in the general population. Lifestyle modifications involving salt and water intake can influence the progression of CKD. While low-sodium diets have shown potential for mitigating hypertension and proteinuria in non-dialysis CKD patients, their independent impact on CKD progression warrants further investigation. The role of water consumption in CKD remains uncertain, and there is a need for additional research in this area. Clinicians should consider individualized dietary recommendations for CKD patients to help preserve the glomerular filtration rate and improve overall outcomes.

Optimal Consumption and Portfolio Rules with Dynamic Adjustment of Consumption Bounds

Optimal Consumption and Portfolio Rules with Dynamic Adjustment of Consumption Bounds

Constrained Optimal Fuel Consumption of HEV: A Constrained Reinforcement Learning Approach

Constrained Optimal Fuel Consumption of HEV: A Constrained Reinforcement Learning Approach

Optimal investment and consumption with forward preferences and uncertain parameters

Optimal investment and consumption with forward preferences and uncertain parameters

Portfolio Optimization Strategy Based on Risk Diffusion Model in Emerging Industry Development

Abstract In this paper, we first sort out the formula of the premium principle and the algorithm of the diffusion model and then study the strategy problem about optimal investment consumption and insurance purchase when investors invest in new developing industries under the risk diffusion model. In real financial markets, there are two types of uncertainty regarding asset prices: normal fluctuations and abnormal shocks. The risk diffusion model is used to plan the optimal investment strategy based on this basis. In the end, three tests are executed, including two numerical simulations and one investment analysis that determines the investor’s age. The computational results show that the optimal strategy in the first set of simulations is the 56% increase in investment volume A(x) at the parameter σ = 0.1. The standard deviation of the investor’s objective in the second set of simulations is 9.287%, and the investor’s assets invested in risky securities should be 1.071. In the third set of tests, as the investor’s age increases, the value of the investor’s investment in risky assets continues to decline from 2.0 after 30 years, and by the time it reaches 40 years, it is already close to 0.25, and there is a continued decline, converging to 0. Investors can invest in providing effective reference data by investing in the portfolio optimization strategy in this paper, which predicts stock market volatility and vibration.

Działanie antykorozyjne wybranych odczynników na korozję stali węglowej w wodzie złożowej zawierającej siarkowodór

For the first time, the impact of the composition of gossypol resin and IB-1 reagent, prepared in a 3:1 ratio and conventionally named HS-1, on the corrosion rate in hydrogen sulfide formation water has been investigated under laboratory conditions. Concentrations of 20, 40, 60, 80 mg/l of the new composition were used. During the experiments, a formation water sample taken from well No. 1082 of “Bibiheybatneft” OGPD, SOCAR, served as the electrochemical corrosion medium for the study. To conduct a comparative analysis, gossypol resin, IB-1 inhibitor, and HS-1 composition were used. Concentrations of 50, 100, 150, 200 mg/l of gossypol resin and 10, 15, 20, and 25 mg/l of IB-1 inhibitor were employed in the experiments. Numerous laboratory experiments revealed that the optimal consumption rate for the HS-1 inhibitor is 100 mg/l, for gossypol resin it is 200 mg/l, and for the IB-1 inhibitor it is 25 mg/l. These experiments were conducted under dynamic conditions over six hours. It was determined that the newly developed HS-1 composition offers superior protection in an aggressive medium containing hydrogen sulfide compared to its constituent components, gossypol resin, and IB-1 inhibitor. Specifically, as the concentration of gossypol resin in formation water increases from 50 to 200 mg/l, the corrosion protection effect ranges from 60–82%. When the concentration of IB-1 inhibitor varies between 10–25 mg/l in a hydrogen sulfide medium, the protection effect lies between 65-90%. In the aggressive medium of hydrogen sulfide formation water, increasing the concentration of the new HS-1 composition from 30–80 mg/l results in an enhancement of its electrochemical corrosion protection effect, ranging from 74–98%. Upon analyzing the results of numerous laboratory experiments, it was found that the optimal consumption rate of gossypol resin for corrosion protection in an aggressive medium with hydrogen sulfide is 200 mg/l, the consumption rate of IB-1 inhibitor is 25 mg/l, and for the HS-1 composition is 80 mg/l. The corrosion rates for gossypol resin in the concentrations of 50, 100, 150, 200 mg/l is 1.72, 1.38, 1.12, 0.78 g/m2 · h and retardation coefficient is 2.50, 3.10, 3.84, 5.51, respectively. Corrosion rate of IB-1 inhibitor concentration in the amount of 10, 15, 20, and 25 mg/l is 1.5, 1.12, 0.78, 0.43, and retardation coefficient is 2.86, 3.84, 5.51, 10.0, respectively. The corrosion rates for the new HS-1 composition at concentrations of 20, 40, 60, 80 mg/l is 1.12, 0.73, 0.34, 0.08, and the retardation coefficient is 3.84, 5.89, 12.64, 53.75, respectively. Comparing the corrosion rate values obtained for all three reagents with the corrosion rate for hydrogen sulphide formation water shows that new HS-1 composition has a higher effectiveness compared to its constituent components.

Capital income jumps and wealth distribution

Compared to the distributions of earnings, the distributions of wealth in the US and many other countries are strikingly concentrated on the top and skewed to the right. To explain the income and wealth inequality, we provide a tractable heterogeneous‐agent model with incomplete markets in continuous time. We separate illiquid capital assets from liquid bond assets and introduce jump risks to capital income, which are crucial for generating a thicker tail of the wealth distribution than that of the labor income distribution. Under recursive utility, we derive optimal consumption and wealth in closed form and show that the stationary wealth distribution has an exponential right tail that closely approximates a power‐law distribution. Our calibrated model can match the income and wealth distributions in the US data including the extreme right tail of the wealth distribution.

A long-term optimal consumption and investment problem with partial information

A long-term optimal consumption and investment problem with partial information

Determination of vitamin D serum levels in women receiving vitamin supplementation: The PERSIAN Guilan Cohort Study

Background: Vitamin D is a basic nutrient and plays a very crucial role in preventing various diseases, so it is known as an indicator of health and survival. Objective: This study was conducted to determine the serum level of vitamin D in women receiving vitamin supplementation in Persian Guilan cohort study (PGCS). Methods: In this analytic cross-sectional study that was conducted on PERSIAN Guilan cohort, 614 subjects from 5633 women aged 35 to 70 years old who were taking vitamin D supplements were selected through census method. Required data were collected in two sections of demographic and social characteristics and serum measurement 25-hydroxy vitamin D3 at three levels of deficient (<10), insufficient (10-20) and sufficient (>20 ng/ml). Data analysis was done using descriptive and inferential statistics. P <0.05 was considered statistically significant. Results: The mean age of people was 50.3±8.7 years, of which 5.2 % of the subjects had vitamin D deficiency, 29.5% had insufficient serum level and 65.4% subjects with sufficient serum levels. Based on the results, there was a significant relationship between employment status, place of residence and housing area with vitamin D level (P<0.05), and non-employed persons (P=0.044), living in the city (P=0.002) and a residential house with a higher area (P=0.014) had higher levels of vitamin D. There was no significant association between serum vitamin D levels with age, body mass index, marital status, alcohol consumption, level of education and how to take vitamin D supplementation. Conclusion: In the present study, about one third of vitamin consumers did not have a sufficient serum level despite taking the supplement, so it is expected that the country's health system, health officials, and policymakers pay attention to the education program of optimum consumption as well as appropriate prescription of vitamin D supplement.

Two-Stage Approach for Demand Side Management in Multi-Smart Grids

In the face of escalating electricity demand driven by technological advancements and a growing population, efficient management becomes imperative. This study explores demand-side management (DSM) within smart grids (SGs) to minimize customer bills, alleviate peak loads, and mitigate losses. The research employs diverse strategies and compares their effectiveness, focusing on optimal load consumption across smart microgrids. Key contributions include a DSM strategy for cost reduction, efficient peak load reduction, and active power loss minimization in smart microgrids. The proposed approach is validated through simulations, with results contributing to real-world SG implementation. The study highlights a 23.4% and 31.6% cost saving for residential and commercial customers, respectively, and emphasizes the significance of load management in enhancing operational efficiency and cost-effectiveness within the energy hub framework. The research provides valuable insights for developing advanced consumption management strategies, ensuring energy efficiency and sustainability in future power systems.

Development of a foam composition for use in wells with potential risks of sanding

Considerable petroleum reserves of Azerbaijan are confined to fields, the layers of which are mainly structured of incompetent rocks. Well operation is accompanied by the destruction of the bottom-hole formation zone, and, as a consequence, sand production, which leads to a drop in oil production. Sand production leads to the formation of sand plugs in wells, which makes it difficult for fluid to flow from the formation to the well. In this regard, new foam and foam-polymer compositions for washing sand plugs in sand-producing wells have been developed and studied. The advantage of the developed foam systems as flushing liquids in order to ensure optimal consumption of surfactants and aluminum nanoparticles is considered. Considering that the problem of sanding in the fields of Azerbaijan is very relevant, the developed foam compositions are widely used. Keywords: Oil well; Bottom – hole; Appearance; Sand pluq; Foam compositions; Polimer; Aluminum nanoparticles.

A novel solar tower assisted pulverized coal power system considering solar energy cascade utilization: Performance analysis and multi-objective optimization

Solar-assisted pulverized coal power systems offer higher solar energy utilization efficiency, enabling pulverized coal power plants to rapidly achieve energy-saving and emission-reduction targets. This study proposes the incorporation of two solar heaters to create a new solar tower assisted pulverized coal power (STPCP) system for the cascade utilization of solar energy. A comprehensive performance analysis, considering both power-boosting (PB) and fuel-saving (FS) operation modes, has been conducted. The multi-objective particle swarm optimization method is then applied to optimize the system from both thermal and economic perspectives. The findings demonstrate that in FS mode, annual coal consumption decreases by 24.35 × 103 tons, while in PB mode, annual power generation increases by 94.12 GWh. The optimization analysis demonstrates that the optimal cost of electricity (COE) and annual standard coal consumption rate in PB mode are 1.4 × 10−4 USD/kWh and 4.3 g/kWh lower than those in FS mode. Additionally, as the solar field cost declines, the optimal COE and annual standard coal consumption rate gradually decrease. While, increasing coal prices result in higher optimal COE, but lower optimal annual standard coal consumption rate. Based on this study, it can be inferred that the STPCP system shows promising prospects in the future.

Ethanol vapor ameliorates chilling injury and maintains postharvest quality by increasing antioxidant capacity of hardy kiwifruit (Actinidia arguta)

Hardy kiwifruit (Actinidia arguta) stored at room temperature has a limited shelf life, and improper low-temperature storage can cause chilling injury. To address this issue, we applied ethanol vapor pre-treatment at concentrations of 250, 500, and 1000 μL L−1 and evaluated postharvest quality under low-temperature conditions (1 ± 1 °C). Our research revealed that lower concentrations of ethanol vapor (250–500 μL L−1) effectively mitigated chilling injury, delayed adverse physiological changes, such as superficial scald, softening, and rot, and enhanced the antioxidant system of A. arguta fruit. Ethanol treatment increased the activity of antioxidant enzymes like peroxidase, superoxide dismutase, and glutathione reductase while maintaining higher levels of non-enzymatic antioxidants like total phenolics, total flavonoids, ascorbic acid, and glutathione. It also improved the antioxidant capacity as assessed by various methods. Principal component analysis and overall scores demonstrated that ethanol vapor treatment significantly improved A. arguta fruit's antioxidant capacity and postharvest quality, extending the optimal consumption period by 14 d. This highlights ethanol's potential application in preserving A. arguta fruit's postharvest quality and enhancing its antioxidant capacity.

Hyperbolic discounting and state‐dependent commitment

AbstractIn a stochastic economy with uninsurable endowment risk, we establish a condition under which hyperbolic‐discounting consumers commit to a future consumption path using both illiquid assets and borrowing constraints as commitment devices. There is the possibility that a state‐dependent commitment can be adopted as an equilibrium consumption strategy. On a path leading to low future endowment, the current self can commit to its own optimal consumption path, which is undesirable for future selves. In contrast, along the path with a high future endowment, the current self cannot make a commitment and must accept a consumption allocation that future selves will revise. Thus, depending on what stochastic state will arise, people cannot fully utilize the available commitment devices in risky situations.

Optimal annuitization and asset allocation under linear habit formation

This paper studies the optimal consumption-investment-annuitization problem for a retiree with linear consumption habits. We explore the effect of consumption habits on the decision to annuitize when annuities are purchased as a lump sum. The problem is formulated as a combined stopping-control problem. We derive optimal annuitization time, investment, and consumption strategies by a generalized dual method and habit reduction method. We investigate the influence of various factors on the annuitization time and derive optimal annuitization time, which is a barrier strategy. The numerical simulations reveal several interesting results. Our results demonstrate that risk aversion, subjective hazard rate, and consumption habits all play a role in shaping annuitization decisions. Furthermore, we offer a new explanation for the rarity of voluntary annuitization among retirees.

Development and evaluation of smart irrigation system to enhance the water use efficiency

<p>For this purpose, a moisture sensor device was designed and constructed in February and March 2019 to determine the appropriate time to stop irrigation in furrow irrigation. Testing the device in the laboratory and its application in the Farm of the Campus of Agriculture and Natural Resources, University of Tehran (Mohammad Shahr), Iran, from April to July 2019. The purpose of this study was to evaluate the performance of a smart sensor of soil moisture to determine the optimum depth of installation and recording of soil moisture at 10, 30, and 50 cm depths and different length ratios in furrow irrigation. Initially, calibration of the device was carried out on field soil, and based on the obtained validation, the device was transferred to the field. To achieve the goals of optimum depth of installation and optimum length, 36-meter furrows with a distance of 0.75 m were created in the field. Sensitive lengths in furrows with 0.5 L, 0.75 L, and 0.85 L ratios were selected as the starting points. The results showed that in the calibration and validation phases, the R<sup>2</sup> values were 0.93 and 0.95, respectively, and in the calibration and validation stages, the value of nRMSE was 80 and 13.81%, indicating good model training in the calibration stage. Also, the average RE parameter in estimating soil moisture was 2.74%, indicating the high accuracy of the device in estimating soil moisture. The results also showed that if the device was installed at a depth of 30 cm from the soil surface of the furrow and at 75% from the beginning of the field, the depth and runoff losses would be minimal and irrigation adequacy would be best compared to other depths and lengths. It is expected that with optimal water consumption and timely interruption of irrigation, deep losses and runoff will be avoided, and with low water consumption, the productivity of crops will increase.</p>

Optimal consumption for recursive preferences with local substitution — the case of certainty

We characterize optimal consumption policies in a recursive intertemporal utility framework with local substitution. We establish existence, uniqueness, and a version of the Kuhn–Tucker theorem. The structure of optimal consumption plans is described explicitly for a large class of aggregators. For Epstein-Zin preferences, the solution coincides with the solution of the corresponding time-additive preferences.

A Dynamic Model for an Optimal Consumption Tax Rate

Following Ramsey, the existing literature on optimal taxation only compares the pre and the post-tax market equilibriums in order to account for the efficiency losses. However, when the government imposes an ad valorem tax on the consumer, the buyer's price jumps to the pre-tax equilibrium price plus the amount of the tax, and the supply and the demand of the taxed commodity then adjust over time to bring the new post-tax market equilibrium. The existing literature does not take into account the efficiency losses during the adjustment process while computing the optimal ad valorem taxes. This paper shows how adjustment process influences the optimal ad valorem taxes, minimizing the efficiency losses (output and/ or consumption lost) during the dynamic adjustment process as well as the post-tax market equilibrium. (JEL H20, H21, H22)

Equilibrium multi-agent model with heterogeneous views on fundamental risks

This paper investigates an equilibrium-based multi-agent optimal consumption and portfolio problem incorporating uncertainties on fundamental risks, where multiple agents have heterogeneous (conservative, neutral, aggressive) views on the risks represented by Brownian motions. Each agent maximizes its expected utility on consumption under its subjective probability measure. Specifically, we formulate the individual optimization problem as a sup–sup–inf problem, which is an optimal consumption and portfolio problem with a choice of a probability measure. Moreover, we provide an expression of the state-price density process in a market equilibrium, which derives the representations of the interest rate and the market price of risk. To the best of our knowledge, this is the first attempt to investigate the multi-agent model with heterogeneous views on the risks by considering a market equilibrium and solving sup–sup–inf problems on the choice of a probability measure. We emphasize that the setting, where each agent has heterogeneous views on different risks, incorporates a special case where each agent has only conservative or neutral views on risks with different degrees of conservativeness. Also, the setting includes the case where the agents have aggressive views on risks, commonly observed as bullish sentiments in the financial markets in the monetary easing after the global financial crisis and particularly in the COVID-19 pandemic. Finally, we present numerical examples of the interest rate model, which show how heterogeneous views of the multiple agents on the risks affect the shape of the yield curve.