Optimal Level Research Articles

Dynamic Asset Allocation and Retirement Decision with Consumption Ratcheting and Effort Choice

This study examines the problem of choosing optimal consumption, investment, early retirement, and effort levels for an economic agent who is unwilling to reduce their consumption over time. The agent’s income depends on a fixed wage rate, and varies proportionally with their level of effort, which incurs disutility due to labor. By applying the dual-martingale method, we reformulate the problem into its dual form, dividing it into two distinct sub-problems: one focuses on selecting a consumption path that does not decrease, while the other determines the optimal timing for early retirement. Using this method, we find optimal strategies in the form of explicit closed-form solutions.

Methylthio Substituent in SAM Constructing Regulatory Bridge with Photovoltaic Perovskites

Inverted (p‐i‐n) perovskite solar cells (PSCs) have experienced remarkable advancements in recent years, which is largely attributed to the development of novel hole‐transport layer (HTL) self‐assembled monolayer (SAM) materials. Methoxy (MeO‐) groups are typically introduced into SAM materials to enhance their wettability and effectively passivate the perovskite buried interface. However, MeO‐based SAM materials exhibit a mismatch in highest occupied molecular orbital (HOMO) levels with perovskite layer due to the strong electron‐donating capability of methoxy group. In this work, we introduced a methylthio (MeS‐) substituent that is superior to methoxy as a highly versatile self‐assembled molecular design strategy. As a soft base, sulfur atom forms a stronger Pb‐S bond than oxygen. Additionally, within the CbzPh series of SAM materials, MeS‐CbzPh demonstrates a more optimal HOMO level and enhanced hole transport properties. Consequently, the MeS‐CbzPh HTL based device achieved an impressive power conversion efficiency (PCE) of 26.01% and demonstrated high stability, retaining 93.3% efficiency after 1000 hours of maximum power point tracking (MPPT). Moreover, in comparison with the commonly used 4PACz‐based SAM molecular series, MeS‐4PACz also exhibited the best performance among its peers. Our work provides valuable insights for the molecular design of SAM materials, offering a highly versatile functional substituent group.

Past-performance-driven strategy updating promote cooperation in the spatial prisoner's dilemma game

Strategy update rules play an important role in repeated Prisoner's Dilemma games. This work proposes a modified strategy update rule based on the traditional Fermi function, in which individual past performance is taken into account in strategy update. Then, the consistency aspiration α serves as a benchmark to measure an individual's past performance, and the past performance score is dynamically adjusted during the evolution process according to the BM reinforcement learning rules. The computational results indicate that the proposed modified strategy update rules can significantly improve system cooperation t than the traditional version, and the network reciprocity effect is enhanced as the result of past performance is coupled into the strategy update rule. Moreover, different temptation to defection b exist a corresponding aspiration α result in maximizing system cooperation. Furthermore, an optimal sensitivity level β can also result in a maximizing system cooperation. As a whole, for α − β phase diagram, different a will correspond to an optimal value β that allows the system to achieve the maximum cooperation. Finally, the proposed mechanism is robust. Hopefully this can help to inspire further research on how to deal with social dilemmas.

Comparative Analysis of Silicone Mouth Swabs with Varying Hardness Levels for Optimal Plaque Removal in Elderly Oral Care.

Silicone mouth swabs have emerged as a promising alternative to gauze, sponge brushes, and soft-bristled toothbrushes, offering a balance between gentle cleaning and effectiveness. The flexibility and softness of silicone make it a suitable material for safely cleaning the sensitive oral tissues of elderly patients. This study aims to determine the optimal hardness level of silicone that maximises cleaning effectiveness while minimising the risk of trauma to oral tissues. A pseudo-plaque was created by mixing 6.0 g of Thicken Up Clear food additive with 12.0 ml of water and food colouring, which was then spread onto a NISSIN dentoform silicone rubber sheet (simulated soft tissue) with a thickness of 2.0 mm. Silicone heads with different hardness levels - 20, 30, 40, 50, and 60 Shore A - were attached to a V.P.2000 tooth brushing machine, operating at 75 rounds per minute with a force of 1.96 N. Each swab was used to brush the surface 25 times (n = 16 for each group). A one-way analysis of variance (ANOVA) revealed a statistically significant difference in pseudo-plaque removal among the five hardness levels, with an F-value of 106.161 (degrees of freedom = 4, 75, p 0.001). The Games-Howell pairwise comparison test showed that all five silicone hardness levels differed significantly from each other in their effectiveness in removing pseudo-plaque (p 0.05). No visible simulated soft tissue damage was observed before and after brushing, as inspected with a stereomicroscope in all experiments. The silicone oral swab with a hardness level of 60 Shore A was found to maximise pseudo-plaque removal in vitro. This finding is crucial for the development of specialised oral hygiene tools tailored to the needs of the elderly population, thereby enhancing oral health and overall well-being.

Morphological and agronomic features of potato cv. Gardena highly resistant to Phytophthora infestans (Mont.) de Bary depending on the nitrogen dose

In a 2-year field study, the impact of mineral nitrogen fertilization on the productivity of a new potato cultivar, promising due to the highest resistance to potato late blight among the registered ones, was compared to the proven, widely cultivated Denar cultivar. The study determined morphological features (size and weight of organs), physiological indicators (cover of soil by leaves – LAI. leaf greenness – SPAD) of potato plants during the growing season, yield and quality characteristics of tubers and optimal level of nitrogen fertilization. Tuber quality was assessed based on the share of tuber size and external defects in the yield structure. Optimal mineral nitrogen fertilization was determined based on the relationship between the increase in tuber yield and the increasing dose of this ingredient. The research took into account two factors: nitrogen dose (0, 50 kg‧ha–1, 100 kg‧ha–1, 150 kg‧ha–1) and cultivar (Gardena and Denar). The increase in the dose of mineral nitrogen fertilization to 150 kg‧ha–1 resulted in a significant increase in plant height, the weight of the root system, stems, leaves and the share of large tubers in the yield. It was shown that the Gardena cultivar was characterized by greater requirements for mineral nitrogen fertilization, low effectiveness of its use, a higher share of large tubers (diameter above 60 mm) and lower tuber yield than the Denar cultivar. In a year characterized by excess rainfall, plants produced a greater mass of the root system and the mass of the above-ground part, and in a year with an amount of rainfall close to optimal the final yield of tubers and the share of large tubers in the yield were higher.

Stable developmental patterns of gene expression without morphogen gradients

Gene expression patterns in developing organisms are established by groups of cross-regulating target genes that are driven by morphogen gradients. As development progresses, morphogen activity is reduced, leaving the emergent pattern without stabilizing positional cues and at risk of rapid deterioration due to the inherently noisy biochemical processes at the cellular level. But remarkably, gene expression patterns remain spatially stable and reproducible over long developmental time spans in many biological systems. Here we combine spatial-stochastic simulations with an enhanced sampling method (Non-Stationary Forward Flux Sampling) and a recently developed stability theory to address how spatiotemporal integrity of a gene expression pattern is maintained in developing tissue lacking morphogen gradients. Using a minimal embryo model consisting of spatially coupled biochemical reactor volumes, we study a prototypical stripe pattern in which weak cross-repression between nearest neighbor expression domains alternates with strong repression between next-nearest neighbor domains, inspired by the gap gene system in the Drosophila embryo. We find that tuning of the weak repressive interactions to an optimal level can prolong stability of the expression patterns by orders of magnitude, enabling stable patterns over developmentally relevant times in the absence of morphogen gradients. The optimal parameter regime found in simulations of the embryo model closely agrees with the predictions of our coarse-grained stability theory. To elucidate the origin of stability, we analyze a reduced phase space defined by two measures of pattern asymmetry. We find that in the optimal regime, intact patterns are protected via restoring forces that counteract random perturbations and give rise to a metastable basin. Together, our results demonstrate that metastable attractors can emerge as a property of stochastic gene expression patterns even without system-wide positional cues, provided that the gene regulatory interactions shaping the pattern are optimally tuned.

An examination of the relationship between burnout and grit in college athletes

Burnout symptoms are a detrimental concern many athletes have at some point throughout their athletic careers. In order to assist athletes with performing at their optimal level, there is a need to better understand the burnout phenomena and the ways it can interact with other performance variables, such as grit. Given that grit is a predictor of success in a variety of domains (e.g., Duckworth & Yeager, 2015; Eskreis-Winkler et al., 2014; Fernández-Martin et al., 2020), the purpose of the study was to examine the relationship between grit and burnout. It was hypothesized that there would be an inverse correlation between grit and burnout. Grit and burnout data was collected from Division I student-athletes (n = 241) towards the end of their competitive seasons. Further, the student-athletes year in college was considered as a potential moderator between grit and burnout. The results indicated that student-athletes who scored higher in grit, also scored higher in burnout, hence the hypothesis was not supported. Additionally, there was a stronger positive relationship between grit and burnout for first-year students and sophomores, when compared with juniors and seniors. It is plausible athletes who are grittier are more likely to persevere through stress and challenges, including burnout symptoms, especially during their first two years of college. Athletes higher in grit may also be investing more effort into their sport, which could be increasing symptoms of burnout, as well. The results of this study warrant further investigation to clarify the interaction between grit and athlete burnout.

Experimental investigation and optimization of one-part alkali-activated self-compacting concrete mixes

Emphasizing the growing importance of sustainability, alkali-activated materials (AAMs) have emerged as a revolutionary alternative for cement in the construction sector. This study delves into the fresh, mechanical, and microstructural properties of One-Part Alkali-activated Self-compacting Concrete (OPASC) mixes. While mixtures of Ground Granulated Blast Furnace Slag (GGBFS) and Fly Ash (FA) were utilized as the precursors, powdered sodium metasilicate was employed to function as the activator. To streamline experimental design and reduce the economic demands of extensive testing, the Taguchi-Grey Relational Analysis (GRA) was utilized to identify optimal multi-response parameter levels. This method considered binder content (B) within a range of 700–800kg/m³, water-to-binder (W/B) ratios between 0.38 and 0.42, and Na2O percentages from 5% to 7% as key input variables. Results indicated that the designed mixes recorded workability values satisfying the EFNARC guidelines, compressive strengths greater than 60MPa, split-tensile strengths in the range of 3.5-4.6MPa, and flexural strengths varying between 5.5-7.2MPa. The mix parameters for the optimal mix, with the highest mean grey relational grade, were identified from the Taguchi-GRPA approach as B = 750kg/m3, W/B = 0.4, and N = 6%. Microstructural analysis revealed the formation of C/N-A-S-H type gels, which are instrumental in developing a compact matrix enhancing the mechanical properties. A good agreement between actual experimental results obtained for a different set of verification mixes with those predicted by regression-equations confirmed the potency of the Taguchi-GRA approach in optimizing the OPASC mix parameters.

A data-driven optimization model for the scattered storage assignment with replenishment

Modern warehouses are transitioning from pure storage facilities to order fulfillment centers. To improve order-picking efficiency, picking areas are restricted to small zones to save picker travel distance and thus can only store a limited quantity of SKUs. As a result, replenishment must be frequently carried out which not only causes intensive working efforts but also impacts the order-picking efficiency. Despite of the important role of replenishment, it has been seldom considered in storage assignment planning. This paper proposes a novel optimization model for the storage assignment problem considering both the order-picking and replenishment operations. Instead of the traditional first-extract-then-optimize paradigm, we develop an effective solution method for the problem by integrating the extraction and optimization steps together to avoid the loss of information. Intensive experiments and a case study are presented, the results of which indicate significant advantages of our model against the state-of-the-art counterpart. Several managerial implications are derived: (1) Order data implies substantial useful information for storage assignment planning, including but not limited to the demand correlation of products; (2) The replenishment efforts are intensive and negatively correlated to the order-picking efforts, which therefore should not be neglected in storage assignment planning; (3) To minimize the total working efforts, the optimal replenishment level r of the (r,S) replenishment policy should be more than 0.4S but less than 0.6S with respect to each SKU.

Performance improvement by an optimum companding-based Non-Uniform quantization scheme in low-bit resolution IMDD-UFMC system

In this paper, an optimum non-uniform quantization method is presented in the intensity-modulated direct detection universal filter multicarrier (IMDD-UFMC) system to achieve the system performance improvement with low-bit resolution digital-to-analog converter (DAC). By this specifically-designed companding quantizer without the probability density function (PDF) estimation, the number and interval size of the quantization interval allocated in the low probability region and the high probability region can be balanced with a modified optimal mapping relationship to obtain the optimal quantized level and then the low quantization noise is realized to greatly reduce the bit resolution of DAC in IMDD-UFMC system. Owing to this scheme is essentially a peak-to-average power ratio (PAPR) suppression technology of signal distortion, PAPR performance can be improved at the same time. Compared to the clustering and nonlinear programming schemes, the system performance in term of bit error rate (BER) can be improved and the difficulty of implementation can be reduced in the 25-Gb/s transmission system through 20-km fiber transmission. Moreover, a simplified method is presented by fitting the corresponding companding curve with error function and logistic function, which further decreases the complexity of the optimal non-uniform quantization. In this way, our scheme can offer a significant advancement in the design of IMDD-UFMC systems and has the potential to enhance the performance of future multi-carrier optical communication systems.

Does corporate board gender diversity influence shareholder value?

This study investigates the influence of board gender diversity on the shareholder value of South African-listed non-financial companies on the JSE from 2013 to 2022. The study used a quantitative quasi-experimental method to examine the influence of board gender diversity on shareholder value creation measures from a multi-theoretical perspective. The board gender diversity measures include the proportion of women directors on the board, the Blau index for board gender diversity, and dummy variables indicating the presence of one, two, three, or more women directors on the board, as well as skewed board, tilted board, and balanced board. Shareholder value creation is proxied using standardised market value added, market-to-book ratio, and Tobin’s Q. The study utilises fixed effects models based on linear and curvilinear models to test the hypotheses. According to linear models, all board gender diversity measures demonstrate a significant positive, negative, or no effect on shareholder value creation measures, aligning with the multi-theoretical perspective of corporate governance research. However, curvilinear quadratic models suggest that the Blau index for board gender diversity and the proportion of women directors on board positively and negatively affect shareholder value creation, highlighting an inverted U-shaped effect. The results recognise the "too much- of- a -good- thing” effect and a possible optimal(or worse) level of board gender diversity as crucial. In conclusion, this study demonstrates that the claim of the ‘‘one size fits all’’ board gender diversity mechanism in creating and maximising shareholder value, often implicitly stated by regulators and advisors, may be misleading.

Optimizing Palm Oil Production Scheduling In Nigeria Using Balanced Transportation Problem

This paper deal with optimizing palm oil production of a production firm in Nigeria using balanced Transportation problem in other to reduce or increase/ minimize the production cost and increase or maximize production, profit and efficiency. Here the scheduling challemnge is developed and modeled as a balanced of transportation problem as requires in creation of an optimum production schedule. This resulted in allocating optimal and maximum production level such that the given demand were meet at a minimum cost .

A novel linear programming-based predictive control method for building battery operations with reduced cost and enhanced computational efficiency

Battery energy storage systems can be readily integrated with buildings to enhance renewable energy self-consumptions while leveraging time-variant electricity tariffs for possible operation cost reductions. The extensive variability in building operating conditions presents significant challenges in developing universally applicable methods for optimal controls. To ensure reliable and robust controls, this study integrates predictive control with efficient linear programming to effectively fine-tune battery controls for real-time operations. An adaptive time aggregation scheme has been proposed to streamline the optimization process by accounting for unique changes in energy balances and tariffs. Comprehensive data experiments, based on measurements from 95 unique building operation scenarios, have been conducted to quantify the control performance given different optimization formulations, varying types and levels of prediction uncertainties in building energy demands and PV generations. The results validate the value of the method proposed, leading to 11.75% to 34.63% operation cost reductions on average, while reducing computation steps by 87.75% to 92.60% compared with conventional linear programming approaches. The insights obtained are useful for developing flexible building control strategies with improved computation efficiency and robustness, while providing extensible optimization frameworks for buildings with various energy patterns and storage systems.

Identification of the enzyme activity of human Demodex aspartic protease and its function to hydrolyse host macromolecules and skin cell proteins

Aspartic protease (ASP), a common proteolytic enzyme, plays an important role in the pathogenesis of numerous parasites. However, its role in Demodex remains unclear. Herein, we studied the expression, purification, enzymatic activity detection, and hydrolysis function of human Demodex ASP. The findings showed that recombinant ASP (rASP) possessed aspartic protease activity, which reached optimum levels at pH 2.5–3.0 and 35 °C. Furthermore, the activity of Demodex folliculorum rASP (Df. ASP) was considerably higher than that of Demodex brevis rASP (Db.rASP). Df.rASP also exhibited a more potent hydrolytic ability than Db.rASP. Df.rASP hydrolysed IgG, IgM, and fibronectin, whereas Db.rASP only slightly hydrolysed IgG. Mass spectrometry analysis revealed that Df.rASP exerted hydrolytic effects on 38 HaCaT proteins, more than the 23 proteins hydrolysed by Db.rASP. Sequence alignment and structure modelling of the substrate binding cleft identified three distinct amino acids between Df. ASP and Db. ASP, which should be the molecular basis for their difference in enzymatic activity and hydrolytic function. These results imply that Df.rASP may play a more critical role in the pathogenesis of human Demodex, and molecular data will provide a scientific basis for future analyses of their molecular pathogenesis.

Optimisation Studies on Performance Enhancement of Spray Cooling - Machine Learning Approach

The performance optimisation of spray cooling heat transfer systems has been identified as a significant step in improving process efficiency, and the application of machine learning tools is a recent development that has enhanced this. This study aims to maximise the heat transfer coefficient for spray cooling at low heat flux levels. The effects of nozzle inclination angle, water pressure, and spray height on heat transfer coefficient were studied. Taguchi L27 orthogonal array technique was used to perform the experiments. A maximum heat transfer coefficient of 181.4 kW/m2K was obtained at a nozzle inclination angle of 60o, spray height of 4 cm, and water pressure of 15 psi. Analysis of variance was performed to find the significance of each variable and its interactions. The results show that for the maximum heat transfer coefficient (181.4 kW/m2K), the optimum levels of the independent variables were A3H1P3, i.e., the highest level of nozzle inclination angle (60o), the lowest level of spray height (4 cm), and the highest level of water pressure (15 psi). The support vector machine outperformed the Random Forest algorithm and Multiple Regression analysis regarding prediction accuracy with a maximum error of 0.15% and root mean squared error of 0.01.

Influence of the use of ground enhancement materials on the reduction of electrical resistivity in grounding systems: a review

A grounding system (GS) is an indispensable component in an electrical system network, as it is responsible for conducting electrical discharges to the ground due to faults caused by lightning strikes or transient system failures. Globally, it is estimated that 40 lightning strikes occur per second on the planet, amounting to around 1.2 billion per year, resulting in daily losses of various electrical equipment and human fatalities ranging from 6,000 to 24,000. Additionally, soil resistivity, which impedes the flow of electricity from electrical discharges into the ground, leads to inadequate mitigation of electrical overload effects, resulting in poor GS performance. Consequently, the implementation of ground enhancement materials (GEMs) to reduce impedance to optimal levels becomes necessary. The objective of this review is to broadly examine the current status of GEMs reported in the literature for use in GS, focusing on their composition and their effectiveness in improving soil conductivity and dissipating electrical currents as well as to identify emerging trends and current challenges in the development and application of these materials, in order to provide information to guide future research in the design and implementation of efficient and safe GS.

Research of the operating modes of a combined drip irrigation system with aerosol irrigation for cultivating a cherry orchard

Relevance. Irrigation of agricultural crops plays a key role not only in increasing the yield of these crops, but also in preserving it, especially under stressful temperature conditions. One of the effective methods of water conservation during irrigation is drip irrigation. Drip irrigation technology allows you to accurately dose water, taking into account the needs of specific crops and maintaining an optimal level of soil moisture. It is important to note that this technology helps save water and reduce the risk of soil overmoistening. In addition to drip irrigation, there is also aerosol irrigation. This irrigation technology allows more efficient use of water resources and provides optimal conditions for the ground air layer for the growth and development of plants under stressful temperature conditions.Methods. The objectives of the study are to study the technologies and technical means of irrigation of a young cherry orchard to maintain optimal modes through the use of drip irrigation with aerosol irrigation in the Central part of the Non-Chernozem zone of Russia. During the research, two factors were analyzed: studying the impact of various irrigation methods and moistening volumes on the formation of trees of the Gostinets and Zhukovskaya varieties of sweet cherry.Results. The field experiment is conducted on the territory of «Kolomenskaya Yagoda» LLC in the Moscow Region. The conducted studies have shown that the selected irrigation method using a combined irrigation system on sod-podzolic soils in the central part of the Non-Chernozem zone of Russia for growing a young cherry orchard of the Gostinets and Zhukovskaya cherry varieties meets the criteria of environmental safety and economic efficiency.Conclusion. From the point of view of profitability, it is most effective to grow a young cherry orchard by maintaining humidity in the root zone of the soil within 80-100% of the lowest moisture capacity and relative humidity of the ground air layer in the range of 55-70%.

Funding deposit insurance

We present a quantitative model of deposit insurance to characterize the optimal levels of coverage for depositors and premiums raised from banks. Premiums contribute to a deposit insurance fund that lowers taxpayers’ resolution cost of bank failures. The key model tension is the policymaker’s dynamic tradeoff between building a fund to discourage moral hazard and insulate taxpayers from large fiscal shortfalls, and allowing banks to productively invest their deposits. We find that risk-adjusted premiums reduce moral hazard, enabling the policymaker to increase the share of covered deposits to total deposits by 12.5 percentage points and decrease the share of expected annual bank failures from 0.74% to 0.60%. The model predicts a fund-to-covered-deposits ratio that matches the data and declines in taxpayers’ income due to taxpayers’ risk aversion.

THE ROLE OF A CLIENT-ORIENTED APPROACH IN MANAGING WEB DESIGN PROJECTS

The article is devoted to the study of the place of the client-oriented approach in the management mechanism of web design projects. In the context of the dynamic development of the digital economy, as well as increased competition in the market of services in this area, the task of adapting development processes to individual customer needs becomes urgent. The purpose of the study is to identify the most effective methods of implementing a client—oriented approach to web design project management and characterize their impact on the final result. There are contradictions in understanding the optimal level of client participation in the project: on the one hand, high customer engagement helps to ensure that their needs are met, on the other hand, it sometimes significantly slows down the development process and significantly increases costs. It was concluded that the use of a client-oriented approach, provided that there is a well-organized process of interaction with the customer, can improve the quality of services and customer satisfaction, which, in turn, contributes to the successful implementation of projects. The novelty lies in the fact that an innovative methodology "Integrative client-centered design" is proposed. It is based on the synthesis of best practices of project management, design thinking, Agile approaches adapted to the specifics of web design projects. The article will be useful for web design project managers, developers, as well as management and marketing specialists who seek to implement effective strategies for interacting with customers.

A full factorial design for the decolorization of real textile wastewater using iron-rich montmorillonite by sonocatalytic process

In this study, the sonocatalytic process was used to remove colour from the effluent of a textile factory located in Turkey. Clay from a brick-tile factory located in the city of Eskisehir was used to enhance the effect of ultrasound (US) at 20 kHz frequency and 750 W power. The structure, morphology and composition of the clay were identified by characterization studies including FT-IR, XRD, XRF, SEM and TGA. The clay consists mainly of montmorillonite and iron-rich montmorillonite as smectite minerals, nontronite, quartz minerals, calcite and dolomite as minor clay minerals. In the scope of the study, Design of Experiment (DoE) and a Full Factorial Design (FFD) was used to determine the operating conditions that affect the color removal efficiency of textile industry wastewater. pH, clay amount, time, and H2O2 concentration were determined as critical factors using Analysis of Variance (ANOVA). It has been confirmed that when the critical factors for color removal efficiency—specifically, a pH of 2. 2 grams of clay, a duration of 120 minutes, and 35 ppm of H2O2—are kept constant, the resulting removal percentage was predicted as 94% approximately by using regression model. The optimal levels of factors have been verified by the validation experiments.