Trade-off Studies Research Articles

A time trade-off study in the UK, Canada and the US to estimate utilities associated with the treatment of haemophilia.

Haemophilia is a rare bleeding disorder caused by a deficient or absent clotting factor, leading to frequent bleeding. Multiple intravenous (IV) infusions have been the standard prophylactic treatment; however, newer treatment options involve less frequent subcutaneous (SC) injections. To inform future health economic evaluations, this study applied the time trade-off (TTO) method for estimation of utilities associated with haemophilia treatment for both people with the disease and potential caregivers. Using the TTO method, utilities were estimated through two online surveys distributed in the UK, Canada and the US. In survey 1 (S1), adults from the general population aged 18years and above evaluated health states as if they were living with haemophilia themselves and were receiving treatment for the condition. In survey 2 (S2), adults from the general population with a child under the age of 15years evaluated health states as if they were treating their child for haemophilia. The surveys assessed the following treatment aspects: frequency of treatment, treatment device and injection site reactions. In total, 812, 739 and 703 respondents completed S1 and 712, 594 and 527 completed S2 in the UK, Canada and the US, respectively. In both surveys, the treatment device was associated with the largest impact on utilities for both people with haemophilia and caregivers. Monthly SC injections with a prefilled pen-device were associated with a significant utility gain compared with SC injections with a syringe and IV infusions. In S1, a lower treatment frequency was preferred in all three countries, while in S2, a lower treatment frequency was preferred only in the UK. Avoiding injection site reactions was associated with a significant utility gain in both surveys, but only in the UK and Canada. The study suggests that the administration of haemophilia treatment in particular has an impact on utilities for both people and caregivers living with the disease. Thus, less complex and time-consuming treatment devices are expected to improve health-related quality of life. This can be further modified additively by less frequent administration. These results can inform future health economic analyses of haemophilia and haemophilia treatment.

Fuel consumption and trailing-edge noise tradeoff studies via mission-based airfoil shape optimization

Aerodynamic drag is often used as a proxy for fuel consumption in aircraft design. However, the aeroacoustic byproduct of airfoil design, such as trailing-edge noise (TEN), is yet to be considered in aircraft applications, despite its inclusion in wind turbine designs. To explore the impact of TEN in airfoil design for aircraft, we establish a mission-based aerodynamic shape optimization framework. A surrogate-based detailed flight mission analysis (that can simulate a flight mission from takeoff to landing) is incorporated into the optimization framework to obtain realistic flight conditions during takeoff and landing—which are important to assess TEN metrics—and calculate accurate fuel consumption, where both are used to evaluate the objective function. To assess its effectiveness, we compare the results against those of the conventional single-point optimization. Not surprisingly, the mission-based optimization simultaneously reduces fuel consumption and TEN, while the single-point optima (performed at the low Mach region) reduce TEN at the expense of higher fuel consumption. This is due to the tradeoff between aerodynamic performance in the transonic region and aeroacoustic performance in the low Mach region, which cannot be properly analyzed without including flight mission analysis in the optimization loop.

Comprehensive correlation analysis of electromechanical behavior in high-stretchable carbon nanotube/polymer composites

In this study, a comprehensive correlation analysis of highly stretchable carbon nanotube (CNT)/polymer composites was conducted to predict the change in electrical conductivities in response to uniaxial deformation. To this end, the representative volume elements (RVEs) were generated by randomly distributing CNTs in a polymer matrix using a Monte Carlo simulation algorithm. The effective electrical conductivity was then calculated through a network model. Under uniaxial tensile strain, where the length of CNTs was maintained constant and their configuration kept straight, CNT translation and rotation were considered along with the effects of tensile strain and shrinkage, incorporating Poisson’s ratio. The RVE configuration was updated to account for changes in the network under these conditions. To achieve a strong correlation between the simulation and test results from the previously published works, numerous trade-off studies have been conducted on the RVE size, geometric periodicity, the length of CNT fibers, the mixing ratio of CNT fibers of CNT/polymer composites, and tensile strain. From the results it can be seen that excellent correlations can be only achieved with careful control of the aforementioned parameters.

PCR89 Impact of Dosing and Administration on HRQoL Among People With Hemophilia: A Time Trade-Off Study Including 2.250 Respondents in the UK, Canada and the US

PCR89 Impact of Dosing and Administration on HRQoL Among People With Hemophilia: A Time Trade-Off Study Including 2.250 Respondents in the UK, Canada and the US

Multiobjective optimization of hydrostatic thrust bearing operating with electrorheological lubricant using Taguchi-fuzzy technique

An electrorheological (ER) fluid falls in the category of a smart lubricant. In an ER lubricant, the dielectric microparticles are suspended in an insulating lubricant like silicon oil. The properties of ER fluids change when they encounter an external electric field. In the present study, the ER lubricant is modeled using a continuous Bingham model. The finite element method is utilized to solve the Reynolds equation to compute fluid film pressure and associated performance indices like load-carrying capacity, stiffness, and damping parameters of hydrostatic thrust bearing. In the present study, the influencing variables, that is, recess shapes, compensating elements, and strength of an electric field have been optimized using the fuzzy-based Taguchi optimization technique. The optimal combination of recess shape, compensating element, and electric field is required to enhance the performance of the hydrostatic thrust bearing. The authors attempt to see the interaction of the input variable by the trade-off study graph. A Taguchi fuzzy-based multipurpose optimization was proposed to optimize the performance indices and an optimal combination of compensating elements, recess shape, and electric field has been presented.

Three-stage versus modified two-stage surgery for ulcerative colitis: a patient-centred treatment trade-off study.

There is ongoing debate about whether ileal pouch-anal anastomosis needs temporary diversion at the time of construction. Stomas may reduce risk for anastomotic leak (AL) but are also associated with complications, emergency department visits and readmissions. This treatment trade-off study aims to measure patients' preferences by assessing the absolute risk of AL and pouch failure (PF) they are willing to accept to avoid a diverting ileostomy. Fifty-two patients with ulcerative colitis, with or without previous pouch surgery, from Mount Sinai Hospital, Toronto, participated in this study. Standardized interviews were conducted using the treatment trade-off threshold technique. An online anonymous survey was used to collect patient demographics. We measured the absolute increased risk in AL and PF that patients would accept to undergo modified two-stage surgery as opposed to traditional three-stage surgery. Thirty-two patients (mean age 38.7 ± 15.3) with previous surgery and 20 patients (mean age 39.5 ± 11.9) with no previous surgery participated. Patients were willing to accept an absolute increased leak rate of 5% (interquartile range 4.5%-15%) to avoid a diverting ileostomy. Similarly, patients were willing to accept an absolute increased PF rate of 5% (interquartile range 2.5%-10%). Younger patients, aged 21-29, had lower tolerance for PF, accepting an absolute increase of only 2% versus 5% for patients older than 30 (P = 0.01). Patients were willing to accept a 5% increased AL rate or PF rate to avoid a temporary diverting ileostomy. This should be taken into consideration when deciding between modified two- and three-stage pouch procedures.

Trade-off study on environmental aspects of a reactivity controlled compression ignition engine using 1-hexanol and jatropha oil/diesel in dual fuel mode

The present research focuses on a modified engine characteristics that uses jatropha oil blended with diesel as the high reactivity fuel and 1-hexanaol as the low reactivity fuel. Experiments are carried out at peak load at constant injection pressure (600 bar) with different hexanol energy shares (5,10,15, 20, 25, and 30 %). Reactivity-controlled compression ignition (RCCI) engines reduced smoke emissions and oxides of nitrogen by 28 % and 39 % at full load compared to jatropha oil biodiesel. When the 1-hexanol share exceeded 20 %, the thermal efficiency is reduced slightly at full load and increased by 6 % at 20 % 1-hexanol share. The RCCI mode worked better with jatropha oil biodiesel/1-hexanol than the single-fuel mode and significantly increased heat release rate and peak pressure. While boosting engine performance slightly, RCCI mode operation in diesel engines has been observed to reduce 36 % of NOx emissions and 21.2 % of smoke opacity.

An Effective Onboard Cold-Sky Calibration Strategy for Spaceborne L-Band Synthetic Aperture Radiometers

The L band frequency shows high sensitivity to sea surface salinity. More stable brightness temperature (TB) measurements are required for L-band radiometers to reduce salinity retrieval errors than for high-frequency radiometers. Due to the complexity of L-band synthetic aperture radiometers, a carefully selected cold-sky target should be viewed using an L-band synthetic aperture radiometer for the purpose of absolute TB calibration since the celestial sky is relatively well characterized and stable in the L band. A novel, effective cold-sky calibration strategy is presented in this paper. The strategy of cold-sky calibration of the synthetic aperture radiometer is applied when and where the antenna main lobe points to the ‘flat’ celestial sky, and the impact of each type of foreign source, such as the sun or moon, on visibility values should be minimized in the meantime. Additionally, antenna thermal stability is also considered, which can cause antenna deformation, and the antenna patterns are affected. A high-precision and high-fidelity simulator is built for the cold-sky calibration optimized strategy. The orbital beta angle is introduced to characterize the variation in space environment temperatures. A planet that is considered spherical in shape requires significantly less computation than an ellipsoid one in the simulator. The trade-off study results for the planet shape assumption in the cold-sky calibration simulator are presented. Finally, the calibration uncertainty and performance are assessed.

A time trade-off study to determine health-state utilities of transplant recipients with refractory cytomegalovirus infection with or without resistance

BackgroundHealth-state utility values (HSUVs) for post-transplant refractory cytomegalovirus (CMV) infection (with or without resistance [R/R]) were determined using a time trade-off (TTO) survey completed by 1,020 members of the UK general public.MethodsExisting literature and qualitative interviews with clinicians experienced in treating R/R CMV were used to develop initial draft vignettes of health states. The vignettes were refined to describe three clinical states of R/R CMV: clinically significant and symptomatic (CS-symptomatic CMV); clinically significant and asymptomatic (CS-asymptomatic CMV); and non-clinically significant (non-CS CMV). Each clinical state was valued independently and combined with three events of interest: graft-versus-host disease; kidney graft loss; and lung graft loss to generate twelve vignettes. The final vignettes were evaluated by a sample of the UK general public using an online TTO survey. Exclusion criteria were applied to the final data to ensure that responses included in the analysis met pre-defined quality control criteria.ResultsOverall, 738 participants met the inclusion criteria and were included in the analysis. The sample was representative of the UK general population in terms of age and sex. Non-CS CMV had the highest mean HSUV (95% confidence interval) (0.815 [0.791, 0.839]), followed by CS-asymptomatic CMV (0.635 [0.602, 0.669]), and CS-symptomatic CMV (0.443 [0.404, 0.482]). CS-symptomatic CMV with lung graft loss had the lowest mean HSUV (0.289), with none of the health states considered on average worse than dead.ConclusionsPost transplant R/R CMV has substantial impact on the health-related quality of life of patients. The utility values obtained in this study may be used to support economic evaluations of therapies for R/R CMV infection.

Numerical modeling for mining dam cover infiltration design with geosynthetics: A trade off study

In the mining dam closure project, depending on the classification of the tailings, cover systems are used to reduce precipitation infiltration over time, avoiding future environmental impacts associated with metal leaching. Furthermore, reduced infiltration promotes reservoir drainage and therefore improved geotechnical stability. The covering system can be built from different materials, natural or synthetic, or even using waste itself. The main objective of this study is to present the results as a trade-off study of a one-dimensional modeling performed considering 3 configurations of geosynthetic covers, using the SOFTWARE SEEP/W emphasizing the importance and impact of the presence of geosynthetics. Since numerical models constitute an essential tool in the development of engineering projects, computational numerical modeling was carried out using Brazilian climatic parameters from the National Institute of Meteorology in conventional and automatic stations, and historical geotechnical parameters for a structure located in the state of Minas Gerais. Gerais (Brazil). For the comparison of the cover configurations, the thickness and type of the geosynthetic were varied. The results emphasize the importance of studying numerical modeling in the pre-closure design phase, to define a viable, economical and sustainable coverage, and contribute to the use of geosynthetics in this type of application.

The Cryogenic Anticoincidence Detector for the NewAthena X-IFU Instrument: A Program Overview

Athena (advanced telescope for high-energy astrophysics) is an ESA large-class mission, at present under a re-definition “design-to-cost” phase, planned for a prospective launch at L1 orbit in the second half of the 2030s. It will be an observatory alternatively focusing on two complementary instruments: the X-IFU (X-ray Integral Field Unit), a TES (TransitionEdge Sensor)-based kilo-pixel array which is able to perform simultaneous high-grade energy spectroscopy (~3 eV@7 keV) and imaging over 4′ FoV (field of view), and the WFI (Wide Field Imager), which has good energy spectral resolution (~170 eV@7 keV) and imaging on wide 40′ × 40′ FoV. Athena will be a truly transformational observatory, operating in conjunction with other large observatories across the electromagnetic spectrum available in the 2030s like ALMA, ELT, JWST, SKA, CTA, etc., and in multi-messenger synergies with facilities like LIGO A+, Advanced Virgo+, LISA, IceCube and KM3NeT. The Italian team is involved in both instruments. It has the co-PIship of the cryogenic instrument for which it has to deliver the TES-based Cryogenic AntiCoincidence detector (CryoAC) necessary to guarantee the X-IFU sensitivity, degraded by a primary particle background of both solar and galactic cosmic ray (GCR) origins, and by secondary electrons produced by primaries interacting with the materials surrounding the main detector. The outcome of Geant4 studies shows the necessity for adopting both active and passive techniques to guarantee the residual particle background at 5 × 10−3 cts cm−2 s−1 keV−1 level in 2–10 keV scientific bandwidth. The CryoAC is a four-pixel detector made of Si-suspended absorbers sensed by Ir/Au TESes placed at <1 mm below the main detector. After a brief overview of the Athena mission, we will report on the particle background reduction techniques highlighting the impact of the Geant4 simulation on the X-IFU focal plane assembly design, then hold a broader discussion on the CryoAC program in terms of detection chain system requirements, test, design concept against trade-off studies and programmatic.

Investigation of Interior Permanent Magnet Synchronous (IPMS) Machine Applications in Electrical Vehicle Engine Industry

This paper discusses the selection of an interior permanent magnet synchronous machine and converter for a 100V-200V DC, 100-400 Hz, 150-175 Nm, 30kW-100kW, 1550-4100 rpm electrical vehicle engine alternator. The electrical vehicle engine application requirements are outlined including the engine coupling configuration. Then the characteristics of different machines and their converters are compared through a competitive trade-off study framed by the alternator requirements; direct-drive induction, variable-reluctance, surface permanent magnet synchronous machine, and interior permanent magnet synchronous machine are all considered. The results of the study indicate that the interior permanent magnet synchronous machine is a potentially superior candidate, and so this machine is selected for further investigation. The preliminary findings are described, and the paper concludes with a discussion of current work addressing analytic design.

Design and Testing of Disconnection Actuators for Enhancing Safety and Preventing Failure Escalation

The growing demand for reliability has led to an increased interest in developing effective disconnection systems for enhancing the safety of and preventing failure escalation in engineering systems. Considering this prospect, the design optimization of two disconnection actuators composed of a coaxial magnetic coupling linked to an electromagnetic device is presented and discussed. The disconnection actuator delivers a contactless torque transmission through the coaxial magnetic coupling, whereas the torque transfer is interrupted by the electromagnetic device in case a failure is detected via a dedicated algorithm. The performed design procedure relies on 2D finite element analysis, and trade-off studies are carried out to achieve an optimized geometry of an electromagnetic device. Finally, two disconnection actuators, for high-speed and high-torque applications, are prototyped and tested, with the aim of evaluating their disconnection capability. For both disconnection actuators, the developed force and voltage–current characteristics are measured along with the disconnection time.

A trade-off between farm production and flood alleviation using land use tillage preferences as a natural flood management (NFM) strategy

Trade-off studies effectively compare rational decisions when choosing alternatives. This study utilizes a Bayesian belief network (BBN) model to analyse land use tillage practices for flood management, considering climate, soilscape, slope, and farming systems. The BBN comprises three sub-models using soil samples, farm surveys, synthetic datasets, and literature review data. In one scenario, conventional tillage on a 3° slope increased the net value of crop yield (50.85 %) and positive farm effects (49.64 %) but increased surface runoff (66.24 %) and reduced flood alleviation benefits (58.56 %). On the other hand, conservational tillage on a 3 ° slope yielded lower crop yield increase (14.11 %) and farm production effects (13.80 %) but reduced surface runoff (51.05 %) and increased flood alleviation benefits (45.06 %). Similarly, conventional tillage on a 12 ° slope showed similar crop yield and farm production effects, with slightly higher surface runoff (66.88 %) and reduced flood alleviation benefits (59.13 %). Conversely, adopting conservational tillage on a 12 slope resulted same extent of reduction in crop yield increase band (14.11 %) and farm production effects (13.80 %) but effectively reduced surface runoff (50.42 %) and improved flood alleviation benefits (44.49 %). Therefore, a trade-off between farm production and flood alleviation was identified when tillage preference was applied as a natural flood management strategy. Results showed this trend was particularly pronounced amongst soils on slopes. The model can help users in informed decisions on tillage for sustainable farming, with the potential for improvement through additional variables and farm-specific data.

From a Grassland to a Bush Capital: A Historic Review of Canberra’s Green Infrastructure Development

Canberra was built in harmony with its landscape setting, creating a legacy of urban form well-connected to the natural environment. Its urban design and planning not only amplified the surrounding natural landscape such as forested hills and mountains but also created a human-made green urban character. However, plans for future development as a compact city pose a challenge to conserving the city’s green spaces. A green infrastructure plan is necessary to consider the city’s green space design heritage and the linked socio-ecological values while minimising the urban footprint. The paper employs a historical literature review to understand the factors and characteristics that shaped Canberra’s green character and the socio-ecological values of its green spaces. The research found the influence of historical and modern design and planning concepts in consolidating green infrastructure and creating ecological corridors and social infrastructure. One of the essential conditions for maintaining the unique character of Canberra is the preservation of the socio-ecological values of its existing green spaces. A trade-off study must be conducted to balance green infrastructure planning while considering these values, in light of development changes.

Design and Testing of an Adaptive In-phase Magnetometer (AIMAG), the Equatorial-Electrojet-Detecting Fluxgate Magnetometer, for the CAS500-3 Satellite

Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is a suite of scientific instruments used in the Compact Advanced Satellite 500-3 (CAS 500-3), which is planned to be launched by the KSLV (Korean Space Launch Vehicle) in 2025. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electrojet (EEJ) and the equatorial ionization anomaly (EIA), both of which play important roles in the dynamics of ionospheric plasma in the dayside equator region. The magnetic field generated by the EEJ is tiny (~several nT) compared to the background geomagnetic field (~30,000 nT); thus, a high-resolution magnetometer with a wide dynamic range is required to investigate its correlation with the EIA. To achieve this required resolution, IAMMAP includes a set of improved fluxgate magnetometers named the AIMAG (Adaptive In-phase MAGnetometer), which was developed by adopting new technologies. Here, we report the analysis results of the manufactured AIMAG performance based on trade-off studies for optimizing the circuit and sensor configurations. The results support that the AIMAG sensor and electronic circuits with new concepts and technologies will lead to successful observations of EEJ signatures in the ionosphere.

Liquid hydrogen storage design trades for a short-range aircraft concept

Preliminary design trades for the liquid hydrogen storage system of a short-range aircraft are presented. Two promising insulation methods, namely rigid foam and multilayer insulation, are identified as main design drivers. In addition, the maximal pressure and the shape of the hydrogen storage tank influence the aircraft performance and the insulation efficiency. In this study, the hydrogen storage tanks are integrated in wing pods. The main effects driven by the design parameters are addressed using conceptual and preliminary methods: models are carried out for the storage mass, additional drag, propeller efficiency loss and the dynamical thermodynamic behavior of the liquid hydrogen storage. These effects are coupled making an integrated design method necessary. For the sizing of the liquid hydrogen storage, a multidisciplinary workflow is set up including the aircraft sensitivities on the design mission block fuel. The trade-off study reveals the opposing trend between insulation efficiency and aircraft performance. For the insulation architecture based on rigid foam, the penalties implied by the storage tank on aircraft level and the penalties due to vented hydrogen can be balanced and result in minimal block fuel for the design mission. The application of multilayer insulation avoids venting during the design mission, but has an increased penalty on the aircraft performance compared to rigid foam insulation. Besides the criterion of minimal block fuel, the dormancy time is compared, indicating the thermal efficiency. Applying multilayer insulation, the dormancy time can be increased significantly calling for a discussion of operational requirements for hydrogen-powered aircraft.

The smallest worthwhile effect on pain intensity of nonsteroidal anti-inflammatory drugs and exercise therapy for acute and chronic low back pain: a benefit-harm trade-off study.

What are the smallest worthwhile effects of nonsteroidal anti-inflammatory drugs (NSAIDs) for people with acute and chronic low back pain (LBP)? What is the smallest worthwhile effect of individualised exercise for people with chronic LBP compared with no intervention? Benefit-harm trade-off study. Participants were recruited by advertisement on social media and included if they were English-speaking adults in Australia who had non-specific LBP. Pain intensity. A total of 116 people with acute LBP and 230 people with chronic LBP were recruited. For acute LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 30% (IQR 10 to 40%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 27.5% (IQR 10 to 50%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of exercise additional to no intervention was a 20% (IQR 10 to 40%) reduction in pain intensity. There were small associations between baseline pain, duration of pain and level of exercise and the smallest worthwhile effect of NSAIDs for acute LBP. There were no other clear associations. For people with LBP, the smallest worthwhile effect of exercise and NSAIDs additional to no intervention is approximately a 20 to 30% reduction in pain. These results can inform the interpretation of the effects of NSAIDs and exercise in randomised trials and meta-analyses, incorporating consumers' perspectives. Further research on comparisons between different interventions and on other core LBP outcomes may inform decision-making. OSF osf.io/3erjx/.

Energy Harvesting for Wireless IoT Use Cases: A Generic Feasibility Model and Tradeoff Study

A battery-less IoT offers a sustainable alternative to battery-powered IoT devices, which produce billions of dead batteries every year. Devices are instead powered by a small supercapacitor, which is recharged by a renewable energy source. However, since IoT devices are often characterized by intermittent periods of high energy consumption followed by periods of reduced activity, conventional average energy consumption models can not be used to assess if an IoT devices can be powered by energy harvesters. Therefore, this paper presents an alternative feasibility evaluation approach that focuses on modeling the worst-case periods with peak energy consumption and short idle times, which pose the highest constraints on the capacitor’s behavior. This approach simplifies the characterization of the wireless technology energy consumption as these worst-case periods can be determined by a few parameters. The methodology is then applied to combinations of popular IoT technologies (LoRaWAN, BLE Mesh, and 6TiSCH) and energy sources (solar, kinetic, and radio frequency energy) for two common IoT use cases. We show that the proposed parameters can be successfully extracted with power measurements for different network configurations and that the Power Management Unit configuration has a non-negligible impact on the communication requirements. Finally, we discuss how to apply the model to other technologies and other use cases.

On Power-Efficient Low-Complexity Adaptation for D2D Resource Allocation with Interference Cancelation.

This paper presents a detailed framework for adaptive low-complexity and power-efficient resource allocation in decentralized device-to-device (D2D) networks. The adopted system model considers that active devices can directly communicate via specified signaling channels. Each D2D receiver attempts to allocate its D2D resources by selecting a D2D transmitter and one of its spectral channels that can meet its performance target. The process is performed adaptively over successive packet durations with the objective of limiting the transmit power on D2D links while reducing the processing complexity. The proposed D2D link adaptation scheme is modeled and analyzed under generalized channel conditions. It considers the random impact of potential D2D transmitters as well as the random number of co-channel interference sources on each D2D link. Interference cancelation schemes are also addressed to alleviate co-channel interference, which can ease the D2D resource allocation process. Generalized formulations for the statistics of the resulting signal-to-interference plus noise ratio (SINR) of the proposed adaptation scheme are presented. Moreover, generic analytical results were developed for some important performance measures as well as processing load measures. They facilitate tradeoff studies between the achieved performance and the processing complexity of the proposed scheme. Insightful results for the distributions of SINRs on individual D2D links under specific fading models are shown in this paper. The results herein add enhancements to some previous contributions and can handle various practical constraints.