Optimal Strategy Research Articles

Optimal Arrangements of Renewable Energy Systems for Promoting the Decarbonization of Desalination Plants

In this research, a renewable energy hybrid system (PV-Wind) is modeled to compare different design options based on their economic and technical features. The energy requirements of a Reversible Osmosis desalination plant located on the island of Tenerife with a water production capacity of up to 20,000 m3/day was considered. The system is connected to the electricity grid. The HOMER software, version 2.75 was used to produce optimum strategies for renewable energy. The assumptions input into the model were: the technical specifications of the devices, electricity demand of the desalination plant, as well as the solar radiation and the wind speed potentials. Numerous arrangements were considered by the software, version 2.75. The optimal results were obtained based on the use of renewable energy. The data used in the study were recorded in Tenerife in the Canary Islands. The experience of this research could be transferred to other Atlantic islands with similar renewable energy sources (specifically the wind) and water scarce conditions.

The Size Differences of Breast Cancer and Benign Tumors Measured by Two-Dimensional Ultrasound and Contrast-Enhanced Ultrasound.

Ultrasound (US) imaging has been observed to underestimate tumor size in clinical practice. This study aims to compare the size measurements of breast cancer and benign tumors using two-dimensional ultrasound (2DUS) and contrast-enhanced ultrasound (CEUS). The study included 42 clinically confirmed breast cancer and 47 benign breast tumors. Two experienced physicians independently measured the maximal longitudinal and transverse diameters of the masses in 2DUS and CEUS. All analyses were performed in R (4.2.2) and GraphPad Prism 6. The maximal longitudinal and transverse diameters of breast cancer measured by CEUS were 26.61 ± 0.21% and 26.24 ± 0.19% larger compared with 2DUS, and benign breast tumors had an 11.74 ± 0.21% and 11.06 ± 0.14% increase in size compared with 2DUS. The area under the curve (AUC) of the receiver operating characteristic curve (ROC) for the difference between 2DUS and CEUS was 0.870 for longitudinal diameters (95% CI: 0.795-0.945, sensitivity 0.842, specificity 0.783, threshold value 0.215), and 0.863 for transverse diameters (95% CI: 0.785-0.942, sensitivity 0.667, specificity 0.936, threshold value 0.203). The size measurements of both breast cancer and benign tumors were larger in CEUS compared with 2DUS, with CEUS measurements of breast cancer being more pronounced than those of benign breast tumors. These findings suggest that CEUS may provide a more precise assessment of tumor size, which is crucial for determining optimal treatment strategies and improving patient outcomes in breast cancer management.

A Review of Central Bank Digital Currency: Current Status and Changing Trends

Since the emergence of the Central Bank Digital Currency (CBDC), which digitally represents the legal currency of the country in which it is created, significant developments have been experienced in the global financial environment as a result of the changes brought about by the innovations. Although CBDCs offer various advantages, such as cost reduction, financial inclusion, and increasing the efficiency of payment systems, they may create some disadvantages, such as the risk of dysfunctionalization of the banking sector or decreasing the level of security. At this point, it is necessary to be aware of the possible risks it may create and to develop an optimum strategy in case such risks arise to establish a successful CBDC system and benefit from its advantages. In this context, the aim of this study is to analyze all aspects (emergence process, positive/negative sides, projects, use cases, and technical infrastructure to be used) of this digital currency and to make a comprehensive evaluation of CBDC applications around the world. The evaluations show that many countries are not indifferent to this new digital currency, which has a very high development potential, and continue their research intensively in order not to fall behind the steps taken in CBDC.

From data to decision: integrated approach to pavement preservation in Iowa through treatment effectiveness analysis

ABSTRACT This investigation seeks to enhance ‘Iowa's Pavement Preservation Guide’ with a data-informed decision-making framework. Iowa DOT's databases were used as the data source for evaluating pavement performances under different preservation treatment regimens and determining the effectiveness of those strategies. Five preservation treatment methods for flexible and composite pavements, namely, crack sealing-and-filling, microsurfacing, slurry sealing, patching, and thin hot mix asphalt (HMA) overlays were evaluated using historic data from about 7000 road segments between 1998 and 2020. The data included various attributes describing pavement, road, and traffic characteristics required for analysing condition-based performance and treatment impacts. Two key indicators, service life extension (LE) and index benefit (IB), were defined and used to quantify treatment effectiveness in terms of pavement condition improvement and impact on deterioration rate. The treatment-effectiveness indicators were then factored into the cost analyses to assess the cost-effectiveness of preservation strategies. The results of the treatment effectiveness analysis were used to develop decision matrices that provide insights for selecting preservation treatments based on benefit–cost analysis considering both the overall condition and the dominant distress. This approach to treatment effectiveness highlighted the distinction between an optimum pavement preservation strategy and one that targets maximum service life extension.

Maternal mental health and breastfeeding duration: the role of optimism and coping strategies

Background/Aims Mental health can influence the likelihood that a woman will initiate and continue breastfeeding behaviour that is associated with improved infant and maternal health. Mental health outcomes are associated with variables such as optimism and coping. The aim of this study was to explore the relationship between coping, optimism and mental health, and their impact on breastfeeding duration. Methods A total of 612 women who had breastfed completed an online questionnaire comprising the hospital anxiety and depression scale, cognitive emotional regulation questionnaire, brief coping orientation to problems experienced inventory and life orientation test. Data were analysed using correlations, ordinal linear regression and mediation analysis. Results There was a direct relationship between breastfeeding duration and depression but no direct relationship between duration and anxiety. A mediation analysis showed no mediating between breastfeeding duration and depression. Optimism did mediate the relationship between anxiety and duration, with optimism being associated with reduced anxiety and increased duration. Conclusions The findings highlight the importance of support for mothers while breastfeeding to improve mental health outcomes and foster coping strategies, such as optimism.

Distributed Optimal Attitude Synchronization Control of Multiple QUAVs via Adaptive Dynamic Programming.

This article proposes a distributed optimal attitude synchronization control strategy for multiple quadrotor unmanned aerial vehicles (QUAVs) through the adaptive dynamic programming (ADP) algorithm. The attitude systems of QUAVs are modeled as affine nominal systems subject to parameter uncertainties and external disturbances. Considering attitude constraints in complex flying environments, a one-to-one mapping technique is utilized to transform the constrained systems into equivalent unconstrained systems. An improved nonquadratic cost function is constructed for each QUAV, which reflects the requirements of robustness and the constraints of control input simultaneously. To overcome the issue that the persistence of excitation (PE) condition is difficult to meet, a novel tuning rule of critic neural network (NN) weights is developed via the concurrent learning (CL) technique. In terms of the Lyapunov stability theorem, the stability of the closed-loop system and the convergence of critic NN weights are proved. Finally, simulation results on multiple QUAVs show the effectiveness of the proposed control strategy.

Optimal Maintenance Service Strategy of Service-Oriented Aviation Manufacturers for Two-Stage Leased System Under Capacity Limits

Optimal Maintenance Service Strategy of Service-Oriented Aviation Manufacturers for Two-Stage Leased System Under Capacity Limits

Clinical efficacy of clopidogrel and ticagrelor in patients undergoing off-pump coronary artery bypass grafting: a retrospective cohort study.

Ticagrelor is reportedly more effective than clopidogrel in preventing atherothrombotic events in patients with percutaneous coronary intervention. However, the optimal antiplatelet therapy strategy after off-pump coronary artery bypass grafting (OPCABG) is yet to be established. This study was performed using the prospectively-maintained database at our institution. Patients who underwent OPCABG were divided into the clopidogrel and the ticagrelor groups. Propensity score matching analysis was performed between the two groups. The clinical outcome was the occurrence of major adverse cardiovascular event (MACE), defined as a composite of vascular death, myocardial infarction, or stroke 1 year after surgery. In total, 545 patients completed the entire follow-up assessment. After propensity score matching, 232 patients each were included in the clopidogrel and ticagrelor groups. The primary outcome occurred in 7.8% and 4.3% of patients in the clopidogrel and ticagrelor groups, respectively (P=0.113). CYP2C19 variants (*2, *3, and *17) did not impact the clinical outcomes, regardless of the use of clopidogrel or ticagrelor. The rates of MACE were significantly lower in patients carrying the ABCB1 C3435T CT/TT genotypes in the ticagrelor group than in those carrying the ABCB1 C3435T CC genotype in the clopidogrel group (1.4% vs. 9.1%, adjusted P=0.030), as well as those carrying the ABCB1 C3435T CC genotype in the ticagrelor group (1.4% vs. 8.9%, adjusted P=0.036). The ABCB1 C3435T CC genotype was significantly associated with the incidence of 1-year MACE (HR=1.558, 95% CI 1.109-2.188, P=0.011). Patients who experienced severe perioperative bleeding exhibited a significantly higher incidence of MACE than those who did not experience severe perioperative bleeding (14.0% vs. 4.9%, adjusted P=0.007). There was no significant difference in the 1-year MACE between patients receiving clopidogrel and those receiving ticagrelor after OPCABG. Notably, The ABCB1 C3435T CC genotype was related to a higher risk of MACE.

Re-watering solution facilitates seed germination and seedling growth of Carex schmidtii: Implication for species re-introduction in degraded semi-arid wetlands

Water deficiency threatens the health and function of wetlands in semi-arid areas. Optimum re-watering is an effective method for close-to-natural restoration to mitigate wetland degradation. Although the ecological importance of optimal re-watering as a nature-based solution for promoting wetland plant growth has been widely recognized, the response mechanisms of seed germination and seedling growth to re-watering are still poorly understood despite their decisive impact on plant life history. To fill this gap, this study compared the characteristics of seed germination and seedling growth in Carex schmidtii under initial water content with three levels (30%, 50%, and 70%) and five re-watering treatments (maintained at constant water content and re-watering to 100% on 7th, 14th, 21st, and 28th day). Moreover, the degree of reserve mobilization during four germination stages (seed suckering, sprouting, 20% germination, and seedling growth) was investigated. The results showed that water deficiency and re-watering treatments significantly affected C. schmidtii seed germination, seedling growth, and reserve mobilization. Compared with the other treatments, 50% moisture content and re-watering to 100% on the 14th day (50%-RT3) treatment significantly improved germination traits (germination rate, daily germination rate, germination index, and vigor index) and seedling growth characteristics (shoot length, root length, shoot biomass, root biomass, and total biomass). Furthermore, the degree of mobilization of starch, soluble protein, fat, and soluble sugar accumulation in C. schmidtii seeds under 50%-RT3 was higher than that in the other treatments. The structural equation model showed that the characteristics of seed germination and seedling growth of C. schmidtii were directly related to water deficiency and re-watering treatments, whereas reserve mobilization indirectly affected seed germination and seedling growth. These findings demonstrated that water deficiency and re-watering treatments have a crucial regulatory effect on seed germination and seedling growth of wetland plant species through a dual mechanism. This study provides information for the formulation of an optimum re-watering strategy for wetland vegetation restoration in semi-arid areas of the world.

Toward Rapid and Optimal Strategy for Swarm Conflict: A Computational Game Approach

Toward Rapid and Optimal Strategy for Swarm Conflict: A Computational Game Approach

Comparison of multi-criteria decision-making methods for selection of optimum passive design strategy

In the pursuit of achieving high-performance building design, the selection of the most suitable passive design strategies often involves the use of multi-criteria decision-making (MCDM) methods to address multiple conflicting criteria simultaneously. However, identifying the appropriate MCDM method for a specific building design context poses a challenge, as methods commonly effective in other contexts may not yield equivalent results. This study evaluates five MCDM methods (AHP, COPRAS, TOPSIS, VIKOR, and WSM) to understand their sensitivity in recommending the best solution. The considered criteria are energy demand, thermal comfort and daylight availability. The sensitivity analysis involves the impact of the variability of assigned weights on the rank shifting given by the considered MCDM method and the sensitivity of each criterion to weights variability. The findings reveal that implementing a fair-weight allocation leads to similar top 5 solutions among all MCDM methods. However, when a negative shift is applied to each criterion weight, AHP demonstrates greater robustness to weight variability compared to the other methods evaluated, while VIKOR is the most sensitive to weight variation.

A review of the current treatment methods for retroperitoneal fibrosis with obstructive uropathy

AbstractIntroduction and aimsRetroperitoneal fibrosis (RPF) is a fibroinflammatory disease in which patients may suffer obstructive uropathy (OU). The optimum treatment strategy for RPF with secondary OU is currently unclear, and the aim of this literature review is to assess the methods used to treat this patient cohort.MethodsMedline, Embase, Cinahl, the Cochrane Library and PubMed were systematically searched to find studies assessing treatment outcomes in this patient cohort. After reviewing the studies' titles, abstracts and full texts, 12 were found that matched our search aims. Data from these publications were analysed and reported.ResultsThe demographic and symptomatic features of patients across the 12 studies were representative of the general RPF population. No randomised control trials (RCTs) were found, and just one study formally compared outcomes between patients who underwent different treatment strategies. Many of the studies concluded that using medical and surgical methods in combination led to positive outcomes; whereas, others found positive outcomes following a variety of regimens. Many studies also highlighted, however, that significant minorities required further treatment after initial therapy. Conclusions regarding optimum treatment methods were limited as most publications did not formally compare outcomes following different strategies and had an observational study design.ConclusionAlthough positive outcomes were commonly seen following medical, surgical and a combination of treatments, the literature currently lacks research formally comparing outcomes after assigning specific treatment protocols to groups of RPF patients. More research is therefore required to determine how to best manage RPF leading to secondary OU.

Determining the Economically Optimum Metaphylactic Strategy for Cattle Cohorts of Varied Demographic Characteristics.

Metaphylactic antibiotic use in feeder cattle is a common practice to control respiratory disease. Antimicrobial stewardship is important to ensure continued efficacy and to protect animal welfare. The objective of this study is to identify characteristics of cohorts of cattle that had not received metaphylaxis that would have benefited economically from the use of metaphylaxis. Cohorts (n = 12,785; 2,206,338 head) from 13 feedlots that did not receive metaphylaxis were modeled using an economic model to estimate net returns for three metaphylactic options. Logistic regression models with covariates for entry weight, sex, average daily weight gain, number of animals per cohort, and days on feed, with feedlot as a random effect, were used to determine the model-adjusted probability of cohorts benefiting economically from metaphylaxis. Most (72%) cohorts in this data set that had not received metaphylaxis at arrival would not economically benefit from metaphylaxis. Sex, entry weight category, number of cattle in the cohort, and average daily weight gain were associated with the likelihood of benefitting economically from metaphylaxis. The results illustrated that cattle cohort demographics influenced the probability that cohorts would benefit economically from metaphylaxis and the type of metaphylaxis utilized, and integrating this information has the potential to influence the metaphylaxis decision.

Substratifying the risk of covert malignancy in significant rectal polyps: Outcomes from a specialist multidisciplinary team (MDT).

A treatment strategy for patients with a significant polyp or early colon cancer (SPECC) of the rectum presents a challenge due to the significant rate of covert malignancy and lack of standardized assessment. For this reason, NICE recommends multidisciplinary meetings to improve outcomes. The primary aim of the present study was to report the performance of our specialist early rectal cancer (SERC) multidisciplinary team (MDT) in correctly substratifying the risk of cancer and to discuss the limitations of staging investigations in those patients with "poor outcomes". This was a retrospective review of patients referred to our SERC MDT from 2014 to 2019. Lesions were assigned by the MDT to three pre-resection categories (low, intermediate, high) according to the risk of covert malignancy. Resection method and final histology were compared to the pre-resection categories. Of 350 SPECC lesions, 174 were assessed as low-risk, 108 intermediate-risk and 68 high-risk. The cancer incidence was 4.8%, 8.3% and 53%, respectively (15.5% overall). Eight lesions were categorized as low-risk but following piecemeal resection were found to be malignant. Five lesions, three of which were categorized as high-risk, were ultimately benign following conventional surgery. One pT1sm1 cancer, removed by anterior resection, may have been treated by local excision. A total of 83% of malignant polyps were triaged to an en bloc resection technique and surgical resection avoided for nearly all benign lesions. However, 12 patients from this cohort were deemed to have a poor outcome because of miscategorization. Further comparative research is needed to establish the optimum strategy for rectal SPECC lesion assessment. There is currently no consensus for staging significant polyps of the rectum. This paper reports the effectiveness of a specialist early rectal cancer MDT to correctly risk-stratify significant rectal polyps. It underscores the importance of accurate categorization for treatment decision-making, while acknowledging the limitations of current staging modalities.

Carbon Neutrality Computational Cost Optimization for Economic Dispatch With Carbon Capture Power Plants in Smart Grid

To achieve carbon neutrality, reducing carbon emissions is crucial in dispatching problems in smart grid. Though renewable energy such as wind power has low carbon emissions, it suffers from random generation, which makes the thermal power necessary for a stable supply power system. To reduce carbon emissions, the thermal power plants are transformed into carbon capture power plants, which brings new challenges to economic dispatch algorithms. Besides, there are usually many constraints to keep the security operation of power systems, which incurs a large problem scale and high computational cost. Most existing methods either do not consider reducing carbon emissions, or suffer from high computational costs. In this paper, a framework for the carbon capture plants with wind power to reduce both running costs and carbon emissions is designed to support carbon neutrality. To reduce computational cost, initial-training and fine-tuning are used. A deep neural network is employed to describe the relationship between users' load and the constraints, which provides guides for finding the active constraints. Therefore, the problem scale can be significantly decreased, making the optimal dispatching strategy obtained quickly. The experimental results on real-world data show that the proposed framework can obtain the optimal strategy efficiently.

Distributed Optimal Solutions for Multiagent Pursuit-Evasion Games for Capture and Formation Control

In this paper, distributed optimal solutions are designed for networked multiagent pursuit-evasion (MPE) games for capture and formation control. In the games, the pursuers aim to minimize the distance from their target evaders while the evaders attempt to maximize it, and at the same time, all players desire to maintain cohesion with their teammates. The goals of agents are obviously reflected in the obtained optimal control strategies which consist of an attracting term and/or a repelling term. Nash equilibrium is obtained by means of optimal strategies using the solutions of the HJI equations. Furthermore, three scenarios are considered in the MPE game: one-pursuer-one-evader, multiple-pursuer-one-evader, and multiple-pursuer-multiple-evader, where sufficient conditions are given for pursuers in achieving exponential capture or formation control with ultimate zero or bounded errors. It is shown that the conditions depend on the structure of the communication graph, the parameters in the controllers, and the expected formation configurations. Finally, both simulations and real flight experiments successfully demonstrate the effectiveness of the proposed strategies.

A Condition Knowledge Representation and Feedback Learning Framework for Dynamic Optimization of Integrated Energy Systems.

An optimal energy scheduling strategy for integrated energy systems (IESs) can effectively improve the energy utilization efficiency and reduce carbon emissions. Due to the large-scale state space of IES caused by uncertain factors, it would be beneficial for the model training process to formulate a reasonable state-space representation. Thus, a condition knowledge representation and feedback learning framework based on contrastive reinforcement learning is designed in this study. Considering that different state conditions would bring inconsistent daily economic costs, a dynamic optimization model based on deterministic deep policy gradient is established, so that the condition samples can be partitioned according to the preoptimized daily costs. In order to represent the overall conditions on a daily basis and constrain the uncertain states in the IES environment, the state-space representation is constructed by a contrastive network considering the time dependence of variables. A Monte-Carlo policy gradient-based learning architecture is further proposed to optimize the condition partition and improve the policy learning performance. To verify the effectiveness of the proposed method, typical load operation scenarios of an IES are used in our simulations. The human experience strategies and state-of-the-art approaches are selected for comparisons. The results validate the advantages of the proposed approach in terms of cost effectiveness and ability to adapt in uncertain environments.

Optimal Traffic Control for a Tandem Intersection With Improved Lane Assignments at Presignals

This article focuses on the optimal traffic control strategy for a tandem intersection with pre­signals. First, the impact of a lane assignment scheme at presignals on the operational performance of the tandem intersection is analyzed. An improved lane assignment method is thus proposed to avoid setting the lanes with the same traffic flow direction adjacent to each other as far as possible. Second, vehicle delay models behind the presignals and in the sorting area are established, respectively. Third, considering green times of presignal phases and sorting area lengths on all approaches as variables, an optimization model is proposed to minimize the average vehicle delay. Finally, a case study is conducted on a congested intersection in Changchun, China, to validate the proposed method. The effects of the proposed improved lane assignment scheme on the tandem intersection are analyzed compared with the traditional lane assignment scheme. The results show that the former can decrease average vehicle delay by 22.9% and increase intersection capacity by 18.6%.

Efficacy of surgical intervention over conservative management in intertrochanteric fractures among nonagenarians and centenarians: a prospective cohort study.

Optimal treatment strategy for nonagenarians and centenarians with hip fractures (NCHF) remained unknown. The authors aimed to compare the outcomes of surgical and conservative management in NCHF. A prospective cohort study was conducted based on CPMHF database with NCHF patients hospitalized during 2014-2020. Comorbidities were evaluated by mECM score and restricted cubic spline was utilized to visually assess the dose-effect relationship between the mECM and outcomes. Propensity score matching was performed to balance baseline characteristics between nonsurgical and surgical groups. Multivariate logistic regression, Cox proportional hazard analysis, and survival analysis were employed for unfavorable outcomes (UFO) evaluation. Competing risk of death were analyzed based on Fine and Gray's hazard model and then constructed nomogram models for predicting survival rates. Subgroup analyses were used to determine potential population heterogeneity and sensitivity analyses were performed to test robustness of the results. The authors found increasing trends for UFO with the increase in the mECM score, and that high mECM score (HMS, ≥3) was independently associated with a 2.42-fold (95% CI: 2.07-3.54; P =0.024) increased risk of UFO, which remained significant after considering the competing role of death and were more pronounced in nonsurgical treatment, women, no insurance, and patients with spouse (all P for interaction <0.05). Surgical intervention was identified to be significant protective factors for UFO (RR, 0.59; 95% CI: 0.46-0.75; P <0.001) and severe complications (RR, 0.63; 95% CI: 0.41-0.96; P =0.033) after propensity score matching, as well as survival (HR, 0.40, 95% CI: 0.28-0.58; P <0.001), which remained significant after considering the competing role of death and in all sensitivity analyses and were more pronounced in HMS participants ( P for interaction=0.006). Subgroup analyses revealed surgical patients with HMS had a significantly higher UFO rate (excluding death, P <0.001) while nonsurgical patients with HMS had higher mortality rate as compared to the others ( P =0.005). Surgical treatment for NCHF yields better outcomes compared to conservative treatment.

Long-term clinical outcomes of hypofractionated stereotactic radiotherapy using the CyberKnife robotic radiosurgery system for jugular foramen schwannomas.

Jugular foramen schwannomas (JFSs) are rarely seen, benign tumors with slow growth. Today, management options for JFSs include observation, surgery, and radiation. However, the optimal treatment strategy remains controversial. Stereotactic radiosurgery serves as a minimally invasive alternative or adjuvant therapeutic regimen of microsurgery. Gamma Knife radiosurgery is suitable for patients with JFS who have small- and medium-sized tumors and normal cranial nerve (CN) function. Hypofractionated stereotactic radiotherapy (HSRT) offers a potential radiobiological advantage and may result in better preservation of normal structures compared to single-fraction stereotactic radiosurgery. The aim of the article was to review the clinical and radiographic outcomes of patients with JFS who were treated using HSRT. The authors retrospectively analyzed 74 patients with JFS who received HSRT between January 2009 and January 2020 in the authors' center. Among them, 53 patients were newly diagnosed with JFS, 19 patients had a previous history of microsurgical resection, and the other 2 patients underwent CyberKnife because of tumor recurrence after Gamma Knife radiosurgery. A total of 73 patients had preexisting CN symptoms and signs. The median tumor volume was 14.8 cm3 (range 0.5-41.2 cm3), and most of them (70.3%) were ≥ 10 cm3. The radiation dose regimen was prescribed depending on the tumor size, and more fractions were used in larger tumors. The median margin doses prescribed were 18.2 Gy/2 fractions, 21.0 Gy/3 fractions, and 21.6 Gy/4 fractions. The median follow-up was 103 months (range 18-158 months). After treatment, 42 (56.8%) patients had tumor regression, 27 (36.5%) patients had stable tumors, and 5 (6.8%) experienced tumor progression. Among them, MRI revealed that 1 patient had a complete response. Three patients received surgery at a median of 25 months because of tumor progression. One patient underwent ventriculoperitoneal shunt insertion for hydrocephalus that developed after HSRT independent of tumor progression. The 5-year progression-free survival rate was 93.2%. Preexisting cranial neuropathies improved in 46 patients, remained stable in 14, and worsened in 14. HSRT proved to be a safe and effective primary or adjuvant treatment strategy for JFSs, although 14 patients (18.9%) experienced some degree of delayed symptomatic deterioration posttreatment. This therapeutic option was demonstrated to provide both excellent tumor control and improvement in CN function.