Aggregate Utility Research Articles

Variation in the degree of concentration of prescription opioid utilization using different measures

BackgroundStudies of opioid prescribing patterns have shown that a small percentage of prescribers are responsible for a large portion of total prescriptions. There is some evidence that prescription opioid use may be similarly concentrated, but patterns may differ by population and choice of opioid utilization measure. The objective of this study is to determine what proportion of prescription opioid utilization was attributable to the top utilizers among Medicaid beneficiaries and how this proportion varies by the measure used. MethodsWe analyzed 2008–2009 Medicaid claims data from 14 states and created three claims-based measures of aggregate opioid utilization: total number of annual prescriptions, total annual milligrams morphine equivalent, and total days supply. We tested two versions of the total days supply measure: one assuming consecutive use and the other assuming concurrent use of prescriptions. ResultsThe top 20 % of prescription opioid users accounted for 66 % of prescriptions, 82–85 % of days supply depending on assumption, and 90 % of morphine milligram equivalents (MME). The degree to which prescription opioid utilization was concentrated among the top 20 % of users varied minimally across states. ConclusionsA small percentage of prescription opioid users account for a large share of prescription opioid use. Policy efforts should use metrics pertaining to days supply and total MME, not numbers of prescriptions, to more efficiently target heavy utilization. Policies targeting high-dose prescribing should consider the different ways that overlapping prescriptions may be taken.

Experimental investigation of eco-friendly concrete utilising waste glass

Concrete is one of the main structural materials used in the world; hence, improvement of the concrete mix design with respect to variable issues and requirements is of great importance. Moreover, environmental issues and waste materials have become major concerns these days. In this study, to move towards a more sustainable and eco-friendly construction industry, recycled waste glasses were used as partial replacement for sand and gravel aggregates in concrete. Simultaneously, the effects of silica fume as cement replacement and property enhancer in the eco-friendly concrete mix were investigated. The results of the conducted experiments indicated that utilisation of glass aggregates in general results in strength reduction. However, at proportions of 40% glass replacing aggregates and 5% microsilica replacing cement, no strength reduction was observed compared with normal concrete. An increase in the substitution of natural aggregates with glass reduced the total water absorption: at a proportion of 60% aggregate replaced by glass, the water absorption was reduced by 74%. On the other hand, with the replacement of 10% of cement with microsilica, water absorption decreased up to 17%. The results also indicated that an increase in the dosage of glass to 60% decreased the volume of permeable pore space by 70%.

Cost-benefit analysis of the production of ready-mixed high-performance concrete made with recycled concrete aggregate: A case study in Thailand

In the current green concrete structures, recycled concrete aggregate is used as recycled concrete waste. In this process, concrete waste is collected and crushed using a recycling procedure in order to produce crushed concrete which is then used in structural concrete where it replaces natural aggregate which is coarse. The recycled aggregate concrete is a sustainable concrete waste which in the long term can replace the demand for natural aggregate, a process which would, in turn, lead to its preservation. However, most concrete industries have been observed to be reluctant in the production of recycled aggregate concrete and utilization in its maximum potential. Industries are yet to embrace it not only due to its uncertain material performance but also due to its unexplored manufacturing plant operations which are yet to be established. This research aims to use of a cost-benefit analysis model of the production of ready-mixed high-performance concrete made with recycled concrete aggregate in Thailand. The model focuses on the evaluation of the financial effects which favor the recycled aggregate concrete manufacturing operations instead of the ordinary concrete. Research findings indicate that regardless of the manufacturing plant used, the price of recycled concrete aggregate cannot decrease below the price of natural aggregate concrete. The key result of this research is that recycled concrete aggregate manufacturing set-ups can be used in the industrial-scale manufacture of recycled concrete and at low prices. In addition, overhead bin type and front-end loader type of plants can be used to lower the incremental costs of recycled concrete aggregate. However, the demand and supply factors and the pricing effects of recycled concrete pose various difficulties which are hardly accounted for.

Optimized Performance of IEEE 802.15.4e DSME for Internet of Things

To enhance the reliability of the link and guarantee deterministic channel access, IEEE 802.15 TG4e has introduced DSME as an amendment to IEEE 802.15.4. In this article, we analyze the throughput and energy consumption of DSME mechanism. Further, we propose optimization framework to find contention window (CW) that can enhance the aggregate utility and minimize the energy consumption of a device. Results prove that the performance of DSME is improved by 80% using the optimal setting of CW. The results are finally validated using ns-3.

Effect of mix proportion on the structural and functional properties of pervious concrete paving mixtures

In recent years, pervious concrete pavement (PCP) is emerging as a novel pavement technology that is gaining a lot of attention amongst academicians due to its storm water runoff capabilities and mitigating urban heat island. This pavement technology consists of special types of concrete which has little amount of fines or no fines and interconnected voids. The different types of aggregate gradation, water-to-cement (w/c) and cement-to-aggregate, and compaction techniques with variations in efforts plays an important role in providing an optimum balance in the mixture designing of PCP mixtures. Therefore, the present study is an attempt to explore the possibility of variation of different aggregate gradation types with different proportion of w/c ratios for the production of PCP mixtures. Also, to study the effect of these mix properties on structural, functional as well as durable properties of PCP mixtures. Five aggregate gradation types and variability in w/c ratios were adopted in the present study viz. G1, G2, G3, G4 and G5, respectively. G1 and G2 consisted of larger-sized and well graded aggregates, while, G4 and G5 consisted of natural fines in proportion of 5% and 10%. Meanwhile, G3 consisted of binary blended single-sized aggregates: 30% of 10 mm and 70% of 4.75 mm. The above considered gradations were studied for porosity, density, permeability, compressive strength, flexural strength, and resistance to sulphate attack, at varied w/c ratios 0.30, 0.35, and 0.38, respectively. From an extensive laboratory investigation, it was observed that the G3 mix showed the best-balanced relation between all the afore-stated parameters, required for PCP mixtures. Hence, it can be recommended that the utilization of binary blended single-sized aggregates at a w/c ratio of 0.35 would provide an optimal solution keeping in mind the desired parameters of pervious concrete pavement mixtures are met.

Laboratory study on recycled concrete aggregate based asphalt mixtures for sustainable flexible pavement surfacing

Utilisation of recycled concrete aggregates (RCA) for highway pavement construction has been a sustainable attempt towards conservation of the natural resource base as well as mitigation against the environmental problems associated with harmful solid waste disposal. The performances of asphalt mixtures with 20%, 40%, 60%, 80% and 100% of coarse granite as well as 100% of coarse and fine granite replaced by RCA, for flexible pavement surfacing, have been evaluated in this paper. The mixture containing 100% granite was used as control. Marshal stability, flow, volumetric properties, resilient modulus, indirect tensile strength, moisture susceptibility, fatigue resistance, rutting resistance, impact strength, skid resistance, and abrasion resistance were tested for the mixes. With respect to resilient modulus and indirect tensile strength tests, the control mixture performed better than the RCA mixtures but the RCA mixtures generally performed better than the control in the other tests. The control recorded 9496 MPa and 1058 kPa for resilient modulus and indirect tensile strength respectively. These were comparable to the mix with 40% RCA with 9339 MPa and 1051.7 kPa resilient modulus and indirect tensile strength, respectively. It was concluded that RCA can be effectively utilised in asphalt mixtures but 40% RCA replacement is recommended for optimal pavement performance.

Primary care physician practice styles and patient care: Evidence from physician exits in Medicare

Primary care physicians (PCPs) provide frontline health care to patients in the U.S.; however, it is unclear how their practice styles affect patient care. In this paper, we estimate the long-lasting effects of PCP practice styles on patient health care utilization by focusing on Medicare patients affected by PCP relocations or retirements, which we refer to as “exits.” Observing where patients receive care after these exits, we estimate event studies to compare patients who switch to PCPs with different practice style intensities. We find that PCPs have large effects on a range of aggregate utilization measures, including physician and outpatient spending and the number of diagnosed conditions. Moreover, we find that PCPs have large effects on the quality of care that patients receive, and that all of these effects persist for several years. Our results suggest that switching to higher-quality PCPs could significantly affect patients’ longer-run health outcomes.

Fracture and Permeability Properties of Artificial Fly Ash and Slag aggregate Concretes at Different Water-to-Cement Ratios

This study presents an experimental investigation on the effect of artificial aggregate utilization fracture and permeability properties of concretes. For this, two types of artificial aggregates, namely, artificial fly ash aggregate (AFA) from cold bonding agglomeration process of fly ash and Portland cement and artificial slag aggregate (ASA) from cold bonding agglomeration process of ground granulated blast furnace slag and Portland cement, were replaced with natural aggregate to coarse aggregate. Moreover, to investigate the influence of water-to-cement ratio, three different water-tocement ratios of 0.35, 0.45, and 0.55 were considered in the concrete production. The concretes were tested for the mechanical property in terms of as compressive strength, modulus of elasticity, and splitting, net flexural strength, and fracture energy and also permeability property such as water sorptivity, water penetration, gas permeability, and resistance to chloride ion penetration. The test results were also analyzed by means of statistical technique, namely, GLM-ANOVA. It was found that the use of cold bonded fly ash and slag aggregates were very effective on the performance characteristics of concretes depending on w/c ratio.

Hybrid Methodology to Improve Health Status Utility Values Derivation Using EQ-5D-5L and Advanced Multi-Criteria Techniques.

This paper presented a new approach to the calculation of quality-adjusted life years (QALY) based on multi-criteria decision-making (MCDM) methods and using the EQ-5D-5L questionnaire. The health status utility values were calculated through a hybrid methodology. We combined the analytic hierarchy process (AHP), the AHP with a D-number extended fuzzy preference relation (D-AHP), the fuzzy analytic hierarchy process (F-AHP), and the technique for order preference by similarity to the ideal solution (TOPSIS) to obtain individual and aggregated utility values. The preference data were elicited using a sample of individuals from a Colombian university. In all tested methods, the ordinal preferences were consistent, and the weights were compared using the Euclidean distance criterion (EDC). We identified F-AHP-TOPSIS as the optimal method; its benefits were associated with modeling the response options of the EQ-5D in linguistic terms, it gave the best approximation to the initial preferences according to EDC, and it could be used as an alternative to the known prioritization method. This hybrid methodology was particularly useful in certain medical decisions concerned with understanding how a specific person values his or her current health or possible health outcomes from different interventions in small population samples and studies carried out in low- and middle-low-income countries.

КОНЦЕПТУАЛЬНІ ПІДХОДИ ДО ПОБУДОВИ МЕХАНІЗМІВ ВІДТВОРЕННЯ РЕСУРСНОГО ПОТЕНЦІАЛУ ПІДПРИЄМСТВ АГРАРНОГО СЕКТОРУ

One of the reasons for the increase in the competition level in the agrarian sphere between the participants of agro-industrial relations is the scarcity and limitation of resources. This made it necessary to determine the productivity of resource utilization. The purpose of the work is to summarize conceptual approaches to building mechanisms for reproducing the resource potential of agricultural sector enterprises. The relation between the concepts of managerial efficiency and economic efficiency is established on the basis of the scientific literature analysis. The origin and essence of these concepts are considered in terms of mercantilism, Keynesian theory. The theory of economic growth of R. Solow is characterized and its role in the question of resource potential formation is defined. The concept of competitiveness in the context of agrarian sector is defined. The main reasons that hinder the development of the domestic agro-industrial complex are outlined, as well as the necessity to create favorable conditions for the development of agribusiness is substantiated. Based on the analysis of statistical information, it is established that the low level of competitive development of agricultural enterprises of Ukraine is caused, first of all, by the lack of efficiency of the used information technologies and resource potential. The emergence of such a situation is explained by the difficulties in achieving and maintaining optimal proportions in macroeconomic regulation due to the influence of market and state mechanisms for the possibility of realizing the interests of the subjects of agro-industrial relations. The productivity of using the resource potential is a criterion for the efficiency of the agrarian economy, but its role in the development of domestic agro-industrial policy is still insufficiently understood. The imbalance of different groups of factors of social transformation has led to the accumulation of problematic issues in the agricultural sector, which significantly limit the development of the resource potential of agricultural enterprises. It is established that there is an inverse relationship between the productivity level of use of the resource potential and the employment level in the sphere of the agro-industrial complex. The international methodology for measuring the use of resource potential used in international practice cannot be fully implemented in domestic realities, since the indicators used in it do not sufficiently reflect the real state of affairs. In this regard, a model for measuring aggregate factor utilization of resource potential is proposed.

SDN-Based Centralized Downlink Scheduling with Multiple APs Cooperation in WLANs

Conventional DCF and RTS/CTS mechanisms perform the channel contention by a distributed and independent manner, which can lead to severe cochannel interference and low channel utilization in multiple APs dense deployment scenario. In this paper, we propose a channel scheduling cooperation algorithm called CCT-SDN (centralized concurrent transmission based on SDN) that enables multiple APs (Access Points) to perform cooperatively a centralized downlink transmission control, thus achieving higher system throughput and channel utilization by avoiding cochannel interference and implementing concurrent transmission. This design inherits the merit of the conventional distributed random channel access and adopts standardized OpenFlow protocol and Software Defined Network (SDN) architecture to make a centralized concurrent downlink traffic transmission decision among APs. Meanwhile, we also present a novel neighborhood relation storage scheme called SPRIM to enhance the retrieving efficiency of SDN controller, which enables CCT-SDN to perform a real-time control. Moreover, we also develop a theoretical model to prove the improvement of CCT-SDN. Furthermore, our solution does not require any modifications to existing ubiquitous 802.11 terminal devices and thus is likely to be widely deployed. Finally, extensive simulation results on Mininet-WiFi verify that CCT-SDN can achieve significant performance in terms of aggregate throughput, channel utilization, and packet loss rate in different deployment scenarios.

Influence of artificial aggregate on mechanical properties, fracture parameters and bond strength of concretes

The paper presented herein investigates the mechanical performance of concrete involving lightweight and normal weight aggregates with similar compressive strength. For this, two compressive strength values, 25 and 45 MPa, were considered for the concretes produced by normal and lightweight aggregates. Therefore, four concrete mixtures were designed at different water-to-cement ratios and cement contents. The lightweight aggregate utilized in this study was produced through cold bonding pelletization of fly ash and cement at ambient temperature in a specially designed tilted pan. The artificial lightweight aggregate used as a substitution of natural aggregate had similar particle size distribution to that of natural aggregate. The same mixing procedure was adopted to produce concrete and the testing specimens attained from each mixture were cured at the same circumstances. After the 28-day curing period, the specimens were tested for compressive strength and modulus of elasticity, splitting tensile and flexural strengths. Moreover, advanced mechanical properties such as fracture parameters, bond strength between embedded reinforcement and the concrete were also investigated. The test results indicated that it is possible to produce the lightweight aggregate concrete having similar compressive strength with the natural aggregate concrete, however, the utilization of artificial lightweight aggregates significantly influenced the investigated mechanical and fracture properties of the concretes despite having the similar compressive strengths. But, it was also observed that the utilization of lightweight aggregate made the concrete more ductile.

Prediction of Particle Packing Density of Alternative Fine Aggregates by Artificial Neural Network Applications

Particle packing density mainly influences the behavior of concrete. Experimental determination of particle packing density is arduous and time-consuming. Thus, artificial neural network (ANN) is a tool that helps in determining particle packing density faster and accurately. ANN is used to predict the properties of the concrete with natural aggregates only. However, utilization of alternative fine aggregates is a need of hour. The aim of this paper is to apply ANN to predict particle packing density of combined aggregates, viz. coarse, intermediate and fine aggregates. In addition, alternative fine aggregates, namely crushed rock sand (CRS), recycled fine aggregate (RFA) and coal bottom ash (CBA) are used. In this study, the main constraints used to design ANN are size distribution and packing density of individual aggregates. Feedforward network is used to determine particle packing density of combined aggregates. A total of 231 experimental datasets are used to train ANN for each alternative fine aggregate, and the results were compared. It was observed that the error percentages are well below 5% of experimental and ANN optimization analyses. The optimum packing proportions for river sand, CRS, RFA and CBA were 40:20:40, 30:30:40, 30:30:40 and 30:20:50, respectively.

A novel energy-aware utility maximization for efficient device-to-device communication in LTE-WiFi networks under mixed traffic scenarios

To meet the ever increasing data traffic demand from Device-to-Device (D2D) users, more mobile broadband bandwidth will be needed. Given the large amount of spectrum available in the unlicensed band, it is now being considered by the cellular operators as a complementary tool to augment their service offering. However, due to the uncontrollable interference from collocated WiFi networks, the available bandwidth for the D2D users cannot be guaranteed. In this paper, we introduce an approach for resource allocation to D2D users by aggregating spectrum resources from both licensed and unlicensed bands. An optimization framework that maximizes the utility functions of all the D2D pairs while minimizing the overall energy consumption when transmitting on licensed and unlicensed bands is proposed. Since the aforementioned spectrum and power allocation problem is NP-hard in nature, we therefore, propose a two-step framework for resource allocation to D2D pairs. In the first step, an efficient resource (LTE Resource Blocks (RBs) and unlicensed subchannels) assignment scheme is obtained by formulating a convex optimization problem, which maximizes the aggregate utility of D2D pairs while maintaining fixed transmission power on all the RBs/unlicensed subchannels. In the next step, a non-linear programming problem that maximizes the aggregate utility over sum energy consumption is formulated based on the spectrum resource allocation results obtained from the previous step. The optimization problem determines the transmission power on all the allocated RBs/subchannels by using primal-dual decomposition theory and the gradient update method. As a result of this, we observe that a user and the resource preferences can be considered while performing resource allocation. We further observe that in a network comprising of two category of users (viz., one who have subscribed to real time Quality of Service (QoS) services and second who have subscribed to Best Effort (BE) services), the proposed resource allocation scheme gives priority to QoS services when allocating resources. Extensive simulations and comparison with various benchmark schemes show that aggregating both licensed and unlicensed resources indeed improves the utility of the D2D pairs.

On the Futility of Dynamics in Robust Mechanism Design

We consider a principal who repeatedly interacts with a strategic agent holding private information. In each round, the agent observes an idiosyncratic shock drawn independently and identically from a distribution known to the agent but not to the principal. The utilities of the principal and the agent are determined by the values of the shock and outcomes that are chosen by the principal based on reports made by the agent. When the principal commits to a dynamic mechanism, the agent best-responds to maximize his aggregate utility over the whole time horizon. The principal's goal is to design a dynamic mechanism to minimize his worst-case regret, that is, the largest difference possible between the aggregate utility he could obtain if he knew the agent's distribution and the actual aggregate utility he obtains. We identify a broad class of games in which the principal's optimal mechanism is static without any meaningful dynamics. The optimal dynamic mechanism, if it exists, simply repeats an optimal mechanism for a single-round problem in each round. The minimax regret is the number of rounds times the minimax regret in the single-round problem. The class of games includes repeated selling of identical copies of a single good or multiple goods, repeated principal-agent relationships with hidden information, and repeated allocation of a resource without money. Outside this class of games, we construct examples in which a dynamic mechanism provably outperforms any static mechanism.

Effect of clay in alternative fine aggregates on performance of concrete

The worldwide utilization of alternative fine aggregates (AFA) in the construction sector is increasing exponentially these days due to extensive exploitation of natural sand. However, presence of excessive clay in AFA is considered harmful for fabrication of concrete and mortar. The existence of fine sediments like clay at the interstices of AFA highly influence the performances of concrete. Three types of AFA such as crushed rock sand (CRS), coal bottom ash (CBA) and recycle fine aggregates (RFA) are used in present study. Keeping in view, assessment of clay content in AFA is carried out by methylene blue test and their effects on performance of concrete. In this study, the volume fraction of AFA is varied by 30%, 50%, 75% and 100% respectively. Efforts were also made to develop standard correlation curve of methylene blue value of fine aggregates to corresponding clay content. The methylene blue value for all fine aggregates were well within 6 mg/g and correspondingly less than 5% clay content. Results indicated that MBV greater than or equal to 1.50 is not suitable for preparing concrete. It is also observed that properties and durability of these AFA concrete depend on the amounts of clay.

Utilization of recycled concrete aggregates for light-stabilization of clay soils

Due to the abundance of urban building constructions and renewals in developing and developed countries, there is a continuous increase in the amount of construction and demolition (C&D) wastes that is landfilled. Recycling and reuse of construction and demolition materials, in applications such as in pavement constructions and non-structural building elements, results in preserving natural resources and reducing environmental pollution. This experimental study evaluates the viability of using recycled concrete aggregates (RCA) for improving the shear/compressive strengths and deformation properties of clay soils. A comprehensive series of compaction, uniaxial compression and direct shear tests were performed on carefully proportioned mixtures of RCA and a clay soil. Test results and observations indicate that the introduction of RCA to clay soils results in lower dry density and higher unconfined compressive strength (UCS) which increases with moist curing. Clay soils mixed with RCA have higher tendencies for dilative behavior (during shear) and enhanced shear strengths compared to the parent clay soil. Mixing RCA with clay soils results in stronger, stiffer and less compressible blends that are particularly suitable for construction purposes such as sub-base/subgrade of road pavements.

Life-Cycle Greenhouse Gas Emission Analyses for Green Star's Concrete Credits in Australia

To fulfil the needs of the future, the Australian building sector seems to contemplate toward sustainable design. A Green Star Environmental Rating System is one of many green-building rating systems that has been employed throughout the world. For this rating system, the “Material” category occupies 14% of credit points, which could be achieved from eight major categories. To help engineers and designers have simple tools to process sustainable projects, this paper develops a computer-aided model to calculate life-cycle greenhouse gas (GHG) emissions for conventional and high-strength concrete to maximize Credit 19B.1: Life-cycle impacts—Concrete in the Green Star Design and As Built in Australia. The model has been built under Microsoft Excel and Visual Basic platforms; thus, it is flexible and appears to be one of the effective ways to provide concrete mixture design using its life-cycle GHG emissions. Options to maximize Credit 19B.1 have also been discussed for normal and high-strength concrete. The model demonstrates the relationship between the utilization of supplementary cementitious material, coarse and fine aggregates used in concrete, a water-to-cement ratio with concrete strength, as well as sustainable points to be achieved.

Effective utilization and recycling of mixed recycled aggregates for a greener environment

Abstract Both global warming issue and ozone layer depletion have triggered the awareness of the utilization of recycled materials in construction industry for a greener environment. The utilization and recycling of mixed recycled aggregates (MRA) comprising recycled fine aggregates (RFA) and recycled coarse aggregates (RCA) were explored for construction applications using the coupled Taguchi-RSM optimization approach. Under stringent durability requirements, 35% RCA combined with 6% RFA can be utilized while 70% RCA combined with 30% RFA under non-stringent conditions for non-structural applications. Our study also revealed large potential applications of pretreated mixed recycled aggregates in above-ground structural construction applications. Furthermore, review of literatures revealed presence of behavioral, technical, legal and market barriers which can be overcome through proposed measures. Our study also revealed a payback period of 3 years for recycling investments and revenue generation of HK$ 12 billion within the first ten years of operation and prevention of 20.9–50.1 × 106 KgCO2 equivalent emission annually. In order to achieve these benefits, a pragmatic, recycling-based closed-loop construction and demolition management approach is recommended to achieve a greener environment. Government should take active leading role towards CDW recycling through high-impact policy making and implementation.

Diverging identities: a model of class formation

Abstract This paper is an application of Identity Economics. Since the literature in this field is recent, the paper begins with an extensive review of the key contributions. The current paper analyses the process and psychological costs of social polarization arising from economic inequalities. It may have some application to the current social divisions evident in the votes for Brexit and Donald Trump, and protest movements such as the gilets jaunes. In a simple model, people rationally maximize their utility from esteem, by selecting a subjective salient identity from two objective identities: nationality and job. The model shows how an increase in wages for the upper half of the population can lead those with high incomes to drop nationality as their salient identity, forming a new ‘elite’ class. This rational switch in the identity of high-income workers has efficiency and redistributive effects, reducing aggregate utility and generating regressive transfers.