Trade-off Approach Research Articles

Health State Utilities in Edentulous Patients: A Time Trade-off Approach.

Health is generally regarded as a very high good, and oral health may substantially affect the quality of life of patients. Oral health-related quality of life has usually been investigated by means of disease-specific descriptive instruments, such as the Oral Health Impact Profile and the General Oral Health Assessment Index. These instruments, however, do not enable a comparison of oral health-related quality of life with other medical diseases. Economic methods, such as the time trade-off technique, enable a comparison of the impact of oral health with other medical diseases and thus provide a means to build a bridge in quality-of-life assessments between medicine and dentistry. We included in our study a total of 58 patients who received a complete denture in our clinic in the last 10 y (between January 2001 and May 2012) and who were ≥65 y old. Patient preferences for the edentulous and poorest imaginable oral health state were assessed via the time trade-off method. Edentulous patients rated their current oral health state as 0.73 (SD, 0.25) and the poorest oral health state as 0.43 (SD, 0.33) on a scale between 0 (death) and 1 (best possible health state). These results are comparable to patient preferences for other serious diseases, such as breast cancer (0.75), asymptomatic HIV infection (0.69), depression (0.44), and osteoarthritis of the hip (0.44). In conclusion, our results suggest that oral health may substantially affect quality of life no less than other medical diseases. Health is generally considered the highest good of humankind. In the present article, we show that oral health substantially affects quality of life. In particular, we show that loss of teeth (i.e., being edentulous) reduces quality of life no less than other systemic diseases. Treatment modalities for the edentulous patient may therefore substantially improve the patient's well-being and should be a research priority.

A Genetic Algorithm-based approach for Project Management and developed design of construction

Construction Project Management processes aim at the optimization of three main KPIs: time, cost and quality. As the time / cost trade-off approach is well known, quality optimization is still pursued with a practical approach, often based upon Project Manager’s experience. A case study of construction of a new university building is presented, focusing on external walls detailed design. Wall performances concerning time, costs and quality depend on the performances of each of the product layer that composes the wall. For each layer three commercial options has been considered. Therefore, a time – cost – quality trade-off procedure has been implemented using Genetic Algorithms, with the aim of finding a set of optimal solutions for the construction of the building envelope.

Estimation of Total Transfer Capability in Intersystem Tie Lines of Electric Power Systems

Abstract The paper presents a method for real-time calculation of total transfer capability on the basis of a trade-off approach, witch gives optimal values of total transfer capability in all considered lines. To implement the trade-off approach we introduce a two-level structure to control the interconnected electric power systems, establish Control center receiving data from all power systems taking part in generation of a trade-off decision, perform state estimation and estimation of total transfer capability, and then work out a single rule for additional loading of controlled cutsets. An example of the calculation of total transfer capability in two cutsets under their simultaneous loading is presented.

Developing a time-cost trading-off model for construction projects in fuzzy environment (case study: weigh in motion system)

Completion time is an important issue on construction projects with limited practical duration usually studied comparing to construction or implementation cost. In this research work, the fuzzy behaviour of cost and time for project activities has been investigated based on predicted completion time followed by developing a mathematical model for making a trade-off approach for project planning. The objective function is to minimise project cost which is defined in discrete and continuous domains considering limited implementation time. According to the constraints, a nonlinear model was developed, so a linearisation technique has been utilised to convert that to linear. In addition, an acceptable range of changes (tolerance) is considered for the project completion time to achieve better solutions followed by making a sensitivity analysis process on results of time-cost trading-off approach. Installing a weigh in motion (WIM) system in the central Iranian road of Isfahan-Naein has been selected as case study and the proposed model has been validated using experimental data. Results revealed that the proposed model, which has been converted to linear, is capable to perform a time-cost trading-off approach for projects of those that do not have exact time and cost for project activities.

Surrogate worth trade-off method for multi-objective thermal power load dispatch

The multi-objective thermal power dispatch (MTPLD) problem allocates power demand among the committed generating units while minimizing the operating cost and pollutant's emission objectives simultaneously, subject to physical and technological constraints. The success to find MTPLD solution relies on the decision-maker's ability to select compromised solution under uncertain/diverse conditions and the search algorithm's potential to generate non-dominated solutions. Owing to ambiguous choice of objectives, this paper presents a fuzzy surrogate worth trade-off approach to decide the preferred solution among the non-dominated solution set. The uniformity of non-dominated solution set is maintained exploiting a quality measure approach. This paper presents a novel foraging activity paradigm to generate non-dominated solutions. The presented approach comprises of fly and walk behavior of preys. The direction of turn heuristic of prey handles system's equality constraint. The search algorithm balances exploration and exploitation and handles system constraints autonomously. The performance of proposed algorithm is investigated using generalized benchmark functions and multi-fuel, medium and large power system MTPLD problems. The experimental results shows that the proposed approach is robust, depends on least parameters and retains Pareto quality in independent trials while generating non-dominated solutions in a trial run.

Multi-objective thermal power load dispatch using chaotic differential evolutionary algorithm and Powell’s method

In this work, a chaotic differential evolutionary and Powell’s pattern search (CDEPS) algorithm is proposed to solve multi-objective thermal power load dispatch (MTPLD) problem. The chaotic differential evolutionary method is responsible for the diversification, and Powell’s pattern search is dedicated to exploitation. Further, the performance of two CDEPS variants based on Gauss map and Tent map is investigated. The proposed MTPLD solution procedure either identifies a solution close to Pareto front or diversifies the existing Pareto frontier and finally selects a suitable compromising solution among the available options. In order to select the best compromising solution, a combination of surrogate worth trade-off approach and fuzzy theory is proposed as choice of objectives is ambiguous. The uniformity of Pareto front is evaluated by exploiting a quality measure approach. The performance analysis is done using generalized benchmark test functions and complex MTPLD problems. The ability of CDEPS to diversify Pareto front is verified by uniformity analysis of Pareto front. The one-sample Wilcoxon’s test and two-sample Mann Whitney’s test are used to analyze the experimental results. The exhaustive analysis shows that the Tent map-based CDEPS has better ability to generate quality generation schedule with uniform Pareto front quality and faster convergence rate.

Fuzzy trade-offs in data envelopment analysis

Production trade-offs represent simultaneous and possible changes to the inputs and outputs in the technology under consideration. However, since trade-offs are illative and subjective, in many real applications, the data of production trade-offs cannot be precisely measured. Occasionally, a crisp trade-off cannot reflect desirable judgment of expert. This paper develops the trade-off approach in data envelopment analysis (DEA) using imprecise trade-offs represented by fuzzy sets. We develop some fuzzy versions of trade-off DEA models by using some ranking methods based on the comparison of α-cuts. We show in numerical examples how our models become useful for detecting sensitive trade-offs. In other words, our approach can be seen as extension of the trade-off approach that provides users with models, which represent real evaluation of decision making units (DMU) with good judgments as possible trade-offs.

Fuzzy trade-offs in data envelopment analysis

Production trade-offs represent simultaneous and possible changes to the inputs and outputs in the technology under consideration. However, since trade-offs are illative and subjective, in many real applications, the data of production trade-offs cannot be precisely measured. Occasionally, a crisp trade-off cannot reflect desirable judgment of expert. This paper develops the trade-off approach in data envelopment analysis (DEA) using imprecise trade-offs represented by fuzzy sets. We develop some fuzzy versions of trade-off DEA models by using some ranking methods based on the comparison of α-cuts. We show in numerical examples how our models become useful for detecting sensitive trade-offs. In other words, our approach can be seen as extension of the trade-off approach that provides users with models, which represent real evaluation of decision making units (DMU) with good judgments as possible trade-offs.

The Taxation of Environmental Pollution: A Model for Tax Revenue-Environmental Quality Tradeoffs

The paper analyzes the Willamette River in Oregon. Here a model (combining the least-cost model and the constraint method of multi-objective programming) is used to determine the appropriate tax rate on environmental externalities, incorporating both revenue and environmental quality objectives. The study finds the following. (1) By using the optimal tax rate, the appropriate tax revenue is determined. (2) The efficient solution set (including tax revenue and water quality considerations) is found by using differing optimal tax rates. (3) The optimal point (solution) in the efficient solution set is chosen by the geometrical argument approach and trade-off analysis approach.

TRusT: A Two-stage Robustness Trade-off approach for the design of decentralized energy supply systems

The design of decentralized energy supply systems is a complex task and thus best addressed by mathematical optimization. However, design problems typically rely on uncertain input data, such as future energy demands or prices. Still, conventional optimization models are usually deterministic and thus neglect uncertainties. For this reason, the deterministic optimal solution is in general suboptimal or even infeasible. Robust design methods are available to guarantee security of energy supply, however, they usually lead to significant additional costs. In this work, we show that energy supply systems with guaranteed secure energy supply are not expensive per se. For this purpose, we propose the Two-stage Robustness Trade-off (TRusT) approach. The TRusT approach considers the trade-off between expected costs in the nominal scenario and costs in the worst case while guaranteeing security of energy supply. Thereby, the TRusT approach identifies balanced robust energy supply systems which are cost-efficient in both the daily business and the worst case. The TRusT approach can be applied and solved efficiently. In a case study, we identify robust design options which ensure security of energy supply at low additional costs. Hence, the TRusT approach is a suitable tool to design cost-efficient and secure energy systems.

Multi-criteria framework as an innovative tradeoff approach to determine the shelf-life of high pressure-treated poultry

A multi-criteria framework combining safety, hygiene and sensorial quality was developed to investigate the possibility of extending the shelf-life and/or removing lactate by applying High Hydrostatic Pressure (HHP) in a ready-to-cook (RTC) poultry product. For this purpose, Salmonella and Listeria monocytogenes were considered as safety indicators and Escherichia coli as hygienic indicator. Predictive modeling was used to determine the influence of HHP and lactate concentration on microbial growth and survival of these indicators. To that end, probabilistic assessment exposure models developed in a previous study (Lerasle, M., Guillou, S., Simonin, H., Anthoine, V., Chéret, R., Federighi, M., Membré, J.M. 2014. Assessment of Salmonella and L. monocytogenes level in ready-to-cook poultry meat: Effect of various high pressure treatments and potassium lactate concentrations. International Journal of Food Microbiology 186, 74–83) were used for L. monocytogenes and Salmonella. Besides, for E. coli, an exposure assessment model was built by modeling data from challenge-test experiments. Finally, sensory tests and color measurements were performed to evaluate the effect of HHP on the organoleptic quality of an RTC product. Quantitative rules of decision based on safety, hygienic and organoleptic criteria were set. Hygienic and safety criteria were associated with probability to exceed maximum contamination levels of L. monocytogenes, Salmonella and E. coli at the end of the shelf-life whereas organoleptic criteria corresponded to absence of statistical difference between pressurized and unpressurized products. A tradeoff between safety and hygienic risk, color and taste, was then applied to define process and formulation enabling shelf-life extension. In the resulting operating window, one condition was experimentally assayed on naturally contaminated RTC products to validate the multi-criteria approach. As a conclusion, the framework was validated; it was possible to extend the shelf-life of an RTC poultry product containing 1.8% (w/w) lactate by one week, despite slight color alteration. This approach could be profitably implemented by food processors as a decision support tool for shelf-life determination.

Paradoxes or trade-offs of entrepreneurship: Exploratory insights from the Cambridge eco-system

The literature in business and management studies presents trade-offs (either/or) and paradoxes (both/and) as two different approaches of making choices. However, research in entrepreneurship has not analyzed entrepreneurial decisions through a paradox and a trade-off approach. Using insights from unstructured interviews with founders of start-ups in health care and medical devices industry in Cambridge (MA, USA), this study explores two approaches entrepreneurs follow while making decisions, a trade-off versus a paradox approach. Four dimensions emerge from the analysis: technology, market, customer, and team. Results show that within each dimension, in some cases successful entrepreneurs consider a trade-off approach (e.g. technology push over market pull, simplicity over complexity, or breakthrough over incremental). In other cases, they take a paradoxical approach (e.g. passion versus preparedness, improvisation versus planning, exploitative versus explorative innovations, a reactive versus a pro-active approach). Occasionally founders consider a trade-off approach in an early stage and move to paradox later (e.g. when deciding about listening to early versus late adopters or when selecting a single versus multiple market applications). Because of high certainty, a paradoxical approach occurs more often at a later stage of venture creation.

Low‐noise readout circuit for thermo‐electrical cooler‐less uncooled microbolometer infrared imager

A low-noise analogue frontend readout circuit is presented for VOx microbolometer infrared imager without thermo-electrical cooler. A modified differential mirror structure with substrate temperature and self-heating effect compensation ability is used, targeting below 40 mK noise equivalent temperature difference (NETD) with 17 μm pixel pitch. Noise characteristics are investigated to give an optimal trade-off approach to reach lower NETD at same power consumption compared with traditional readout structures.

Response of semi-arid savanna vegetation composition towards grazing along a precipitation gradient—The effect of including plant heterogeneity into an ecohydrological savanna model

(1)Ecohydrological models of savanna rangeland systems typically aggregate plant species to very broad plant functional types (PFTs), which are characterized by their trait combinations. However, neglecting trait variability within modelled PFTs may hamper our ability to understand the effects of climate or land use change on vegetation composition and thus on ecosystem processes.(2)In this study we extended and parameterized the ecohydrological savanna model EcoHyD, which originally considered only three broad PFTs (perennial grasses, annuals and shrubs). We defined several sub-types of perennial grasses (sub-PFTs) to assess the effect of environmental conditions on vegetation composition and ecosystem functioning. These perennial sub-PFTs are defined by altering distinct trait values based on a trade-off approach for (i) the longevity of plants and (ii) grazing-resistance.(3)We find that increasing grazing intensity leads to a dominance of the fast-growing and short-lived perennial grass type as well as a dominance of the poorly palatable grass type. Increasing precipitation dampens the magnitude of grazing-induced shifts between perennial grass types. The diversification of perennial grass PFTs generally increases the total perennial grass cover and ecosystem water use efficiency, but does not protect the community from shrub encroachment.(4)We thus demonstrate that including trait heterogeneity into ecosystem models will allow for an improved representation of ecosystem responses to environmental change in savannas. This will help to better assess how ecosystem functions might be impacted under future conditions.

Linearly polarized small patch array fed by corporate SIW network

ABSTRACTIn this article, a linearly polarized 2 × 2 patch array uniformly fed by a corporate substrate integrated waveguide network for Ku band is presented. Undesired main beam steering is avoided by means of a fully corporate feeding network, although grating lobes may appear due to greater separation between radiating elements. Moreover, a reduced patch separation to avoid grating lobe appearance leads to an antenna matching coefficient degradation due to the proximity of antenna discontinuities. In consequence, a tradeoff approach has been developed, achieving a measured 4.1% matching bandwidth and a measured gain of 13.27 dBi, which corresponds to an 86% radiation efficiency. Good agreement between simulated and measured results is observed in all cases. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:587–593, 2016

A randomised trial of the effect of different fluid consistencies used in the management of dysphagia on quality of life: a time trade-off study: Table 1.

thickened fluids are commonly advised to minimise the risk of aspiration in people with dysphagia, although many do not comply with this treatment. In health economics, utilities are values that reflect an individual's preferences for different health states. We examined the healthcare utilities, elicited using a time trade-off approach (TTO), from healthcare professionals and non-dysphagic patients, associated with long-term use of thickened fluids. the risk of aspiration with thin fluids was explained to consecutive hospital patients without dysphagia (n = 76) and to a convenience sample of healthcare professionals (n = 75) who were then randomly allocated to drink as much as possible of 200 ml of pre-prepared water of Grade 1 (very mildly thick) or Grade 2 (mildly thick) consistency. A standardised script with a ping-pong approach was then used to elicit TTO utilities for use of thickened fluids using a 10-year horizon. median (inter-quartile range) utilities were 0.7 (0.5-0.9) for those receiving Grade 1 and 0.5 (0.3-0.7) for those receiving Grade 2 consistency fluid (Mann-Whitney test, P = 0.001). Thus, for example, on average those allocated to Grade 2 fluid would be willing to sacrifice 5 years of a 10-year lifespan not to be restricted to fluid of that consistency. There were no significant differences between patient and professional values. patients and professionals judge that long-term use of thickened fluids would significantly impair quality of life. Utilities associated with more viscous fluids are particularly low.

Estimating Soil Moisture with Landsat Data and Its Application in Extracting the Spatial Distribution of Winter Flooded Paddies

Dynamic monitoring of the spatial pattern of winter continuously flooded paddies (WFP) at regional scales is a challenging but highly necessary process in analyzing trace greenhouse gas emissions, water resource management, and food security. The present study was carried out to demonstrate the feasibility of extracting the spatial distribution of WFP through time series imagery of volumetric surface soil moisture content (θv) at the field scale (30 m). A trade-off approach based on the synergistic use of tasseled cap transformation wetness and temperature vegetation dryness index was utilized to obtain paddy θv. The results showed that the modeled θv was in good agreement with in situ measurements. The overall correlation coefficient (R) was 0.78, with root-mean-square ranging from 1.96% to 9.96% in terms of different vegetation cover and surface water status. The lowest error of θv estimates was found to be restricted at the flooded paddy surface with moderate or high fractional vegetation cover. The flooded paddy was then successfully identified using the θv image with saturated moisture content thresholding, with an overall accuracy of 83.33%. This indicated that the derived geospatial dataset of WFP could be reliably applied to fill gaps in census statistics.

Eco-efficiency measurement and material balance principle: an application in power plants Malmquist Luenberger Index

Incorporating Material Balance Principle (MBP) in industrial and agricultural performance measurement systems with pollutant factors has been on the rise in recent years. Many conventional methods of performance measurement have proven incompatible with the material flow conditions. This study will address the issue of eco-efficiency measurement adjusted for pollution, taking into account materials flow conditions and the MBP requirements, in order to provide ‘real’ measures of performance that can serve as guides when making policies. We develop a new approach by integrating slacks-based measure to enhance the Malmquist Luenberger Index by a material balance condition that reflects the conservation of matter. This model is compared with a similar model, which incorporates MBP using the trade-off approach to measure productivity and eco-efficiency trends of power plants. Results reveal similar findings for both models substantiating robustness and applicability of the proposed model in this paper.

Responding to Different Groups within a Social Movement: A Tradeoff Approach

Using social movements theory we examine why firms respond differently to different actors of the same social movement, and focus specifically on environmental social movements that pressure firms ...

Using the Analytic Hierarchy Process to Derive Health State Utilities from Ordinal Preference Data

BackgroundThe EuroQol five-dimensional questionnaire is a standardized instrument used in the economic evaluation of health care to measure health state preferences across disease groups. A time trade-off (TTO) approach is commonly used to elicit preferences from the public. However, there are issues regarding how best to measure worse-than-dead states; at present, extreme valuations are rounded up to more acceptable values. TTO elicitation is also cognitively demanding for respondents and is therefore expensive to investigate. ObjectivesTo describe how the analytic hierarchy process approach could be used to generate utilities from the ordinal relationships between the health states instead of the ordinal relationships between health states, allowing potentially useful preference data to be incorporated rather than excluded as they are at present. It was applied to the Measurement and Valuation of Health study data set, measuring health state preferences for the United Kingdom. MethodsThe analytic hierarchy process approach was explained. Five approaches to structure pairwise comparisons of health state preference were described (two concave, two convex, and one linear). ResultsAll approaches described predicted the rankings of health states well. However, utilities derived followed an unconventional, bunched shape compared with the original Measurement and Valuation of Health TTO study. An approach was identified by optimizing the parameters, minimizing the sum of squared errors between the ordinal “health state ranking” approach and the original TTO-derived utilities. ConclusionsThis approach outlined offers the potential to convert ordinal preference data into cardinal utilities. It is simpler than TTO studies to carry out and removes the need to directly alter results of the preference ranking exercise.