Trade-off Method Research Articles

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

IntroductionHaemophilia 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.MethodsUsing 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 18 years 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 15 years 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.ResultsIn 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.ConclusionsThe 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.

Optimizing $c$-sum BKW and Faster Quantum Variant for LWE

The Learning with Errors (LWE) problem has become one of the most prominent candidates of post-quantum cryptography, offering promising potential to meet the challenge of quantum computing. From a theoretical perspective, optimizing algorithms to solve LWE is a vital task for the analysis of this cryptographic primitive. In this paper, we propose a fine-grained time/memory trade-off method to analyze c-sum BKW variants for LWE in both classical and quantum models, then offer new complexity bounds for multiple BKW variants determined by modulus q, dimension k, error rate alpha, and stripe size b. Through our analysis, optimal parameters can be efficiently found for different settings, and the minimized complexities are lower than existing results. Furthermore, we enhance the performance of c-sum BKW in the quantum computing model by adopting the quantum Meet-in-the-Middle technique as c-sum solver instead of the naive c-sum technique. Our complexity trade-off formula also applies to the quantum version of BKW, and optimizes the theoretical quantum time and memory costs, which are exponentially lower than existing quantum c-sum BKW variants.

Fumed silica additives enables tunable wettability of the resin for improved composite bipolar plate

Composite bipolar plates (CBP) composed of resin and conductive filler are critical components in proton exchange membrane fuel cell (PEMFC) for achieving mechanical strength and electrical conductivity. The conductive filler entirely enveloped by resin is of significance for the flexibility of the CBP; while connected resin blocks the continued conductive channels and thus weakens the electrical properties of CBP. Herein, we propose a trade-off method between flexibility and conductivity of the CBP by wettability regulations of the resin, in which fumed silica additives are introduced into epoxy as composite adhesives. The abundant hydrogen bonds are demonstrated to be well-formed between epoxy and fumed silica for decreasing surface free energy (SFE) between resin and graphite. As a result, the composite adhesive with 2 % fumed silica delivers moderate wettability enabling much improved CBP, which exhibits high electrical conductivity of 233.33 S cm−1 as well as flexural strength of 66.4 MPa. Moreover, the CBP also delivers improved areal specific resistance (5.34 mΩ cm2), thermal conductivity (10.58 W (m K)−1), and corrosion behaviors (0.0701 A cm−2) which guarantee the operation of the PEMFC. This work provides new insight from the wettability regulation of resins for improved CBP, which is an easy-operating method and has great potential for application in practical CBP fabrication.

Comparison of Caregiver and General Population Preferences for Dependency-Related Health States.

We assess whether the preferences regarding dependency-related health states as stated by informal caregivers are aligned with those expressed by the general population. The preferences of a sample of 139 Spanish informal caregivers of dependent patients are compared with those obtained via a sample of 312 persons, also from the Spanish general population. We assess 24 dependency states extracted from the DEP-6D using the time trade-off method. Descriptive statistics and regression methods are used to explore differences between the two samples. Mean difference tests establish that, for all but one of the 24 states, there are no significant differences between the samples. The estimated mean values ranged from - 0.64 to 0.60 for the caregiver sample and from - 0.60 to 0.65 for the general population sample, with a correlation of 0.96. On average, the classification of states as better or worse than dead matched in both samples (except for one state). Regression models also show that sample type does not have a significant average impact. After we introduce interaction effects, only the most severe level of two dimensions, cognitive problems and housework, result in significant differences-with the caregiver sample reporting higher values for the former, and lower values for the latter. Caregivers and the general population exhibit quite similar preferences concerning dependency-related health states. This suggests that the results of cost-utility analyses, and the resource allocation decisions based on them, would likewise not be significantly affected by the preferences used to generate the weighting algorithm.

Architecture Preliminary Design and Trade-Off Optimization of Stratospheric Airship Based on MBSE

System architecture design is crucial for forward design in aerostat system engineering, yet a comprehensive research framework has been lacking. This paper presents a new method for stratospheric airship architecture preliminary design and optimization trade-off, grounded in Model-Based Systems Engineering (MBSE) theory. Firstly, a requirement analysis for a stratospheric airship is conducted using SysML, leading to the analysis and acquisition of the airship’s mission architecture design. Additionally, a multidisciplinary coupling simulation platform is developed with MATLAB, and the architecture preliminary design’s Pareto front is derived using the NSGA-II algorithm. Finally, based on the Pareto optimization set, the TOPSIS algorithm is applied to derive the optimal architecture preliminary design scheme for the airship. The optimization results validate the accuracy of the architecture preliminary design obtained from the requirement analysis, the reliability of the multidisciplinary coupling simulation platform, and the feasibility of the optimization algorithms. This comprehensive study spans the requirement analysis to the optimal architecture scheme, providing theoretical reference and design guidance for the forward design of airship systems engineering.

Valuation of Multi-Dimensional Health States With a Bolt-On: Is There a Shortcut?

ObjectivesTo use the EQ-5D questionnaire with bolt-on dimensions in economic evaluation studies, new value sets are needed. In this study, we explored the feasibility of a new approach called the scaling factor model, which estimates bolt-on value sets using estimated EQ-5D dimensional weights. MethodsWe designed a 2-arm study, inviting university students to value health states with and without bolt-on items using the composite time trade-off method. We selected 25 health states from an orthogonal array and added the 5 mildest EQ-5D states in the design. In arm 1, EQ-5D without self-care and standard EQ-5D states were valued, and in arm 2, standard EQ-5D states and EQ-5D with vision were valued. By arm, we compared the mean observed values of health states with and without bolt-on item. Next, by arm, we estimated value sets for the EQ-5D with bolt-on states using both standard model and scaling factor model. Model performances were compared in terms of prediction accuracy and correlation with likelihood-based mean values. ResultsAdding a five-level bolt-on to EQ-5D resulted in statistically lower values. This effect was consistent across 2 arms and bolt-on items. The scaling factor models outperformed the standard models in all statistics. ConclusionsThe scaling factor model offers a methodologically viable and low-cost option for producing value sets for EQ-5D supplemented with bolt-on items. Future studies should further test this method using other bolt-on items and more relevant study populations.

Perfluoroalkyl compounds in groundwater alter the spatial pattern of health risk in an arsenic‑cadmium contaminated region

Integrated health risk assessment strategies for emerging organic pollutants and heavy metals that coexist in water/soil media are lacking. Contents of perfluoroalkyl compounds and potentially toxic elements in multiple media were determined by investigating a county where a landfill and a tungsten mine coexist. The spatial characteristics and sources of contaminants were predicted by Geostatistics-based and multivariate statistical analysis, and their comprehensive health risks were assessed. The average contents of perfluorooctane acid, perfluorooctanesulfonic acid, arsenic, and cadmium in groundwater were 3.21, 0.77, 1.69, and 0.14 μg L−1, respectively; the maximum content of cadmium in soils and rice highly reached 2.12 and 1.52 mg kg−1, respectively. In soils, the contribution of mine lag to cadmium was 99 %, and fertilizer and pesticide to arsenic was 59.4 %. While in groundwater, arsenic, cadmium and perfluoroalkyl compounds near the landfill mainly came from leachate leakage. Significant correlations were found between arsenic in groundwater and arsenic and cadmium in soils, as well as perfluoroalkyl compounds in groundwater and pH and sulfate. Based on these correlations, the geographically optimal similarity model predicted high-level arsenic in groundwater near the tungsten mine and cadmium/perfluoroalkyl compounds around the landfill. The combination of analytic network process, entropy weighting method and game theory-based trade-off method with risk assessment model can assess the comprehensive risks of multiple pollutants. Using this approach, a high health-risk zone located around the landfill, which was mainly attributed to the presence of arsenic, cadmium and perfluorooctanesulfonic acid, was found. Overall, perfluoroalkyl compounds in groundwater altered the spatial pattern of health risks in an arsenic‑cadmium contaminated area.

A Direct Comparison Between Discrete Choice With Duration and Composite Time Trade-Off Methods: Do They Produce Similar Results?

ObjectivesDiscrete choice experiments including a duration attribute (DCEd) represent a promising candidate method for valuing health-related quality-of-life instruments. However, it has not been established that DCEd can produce similar results as composite time trade-off (cTTO) or EuroQol Valuation Technology (EQ-VT) valuations of the EQ-5D-5L instrument. This study provides a direct comparison between cTTO and EQ-VT, and DCEd valuation methods. MethodsAn EQ-VT study was conducted in Trinidad and Tobago to value the EQ-5D-5L. 1079 respondents each completed 10 cTTO tasks and 12 discrete choice experiments tasks without a duration attribute. A separate sample of 970 respondents each completed 18 split-triplet DCEd tasks. Several regression models were applied to the EQ-VT data, and the DCEd data were analyzed using mixed logit models with an exponential discount rate. The estimated values were compared using scatterplots and Bland-Altman plots. ResultsThe ordering of dimensions was identical in level 5 for cTTO/EQ-VT and DCEd models, with pain/discomfort being the most important dimension and usual activities being least important. cTTO/EQ-VT models produced a value for state 55555 ranging between −0.52 and −0.69, whereas this was −0.543 for the nonlinear mixed logit model for the DCEd data. Scatterplots and Bland-Altman plots suggested excellent agreement between cTTO/EQ-VT and DCEd-based estimates. ConclusionsCTTO/EQ-VT and DCEd valuations produce similar results when correcting DCEd for nonlinear time preferences. The ordering of importance of the dimensions and scale are identical, suggesting that the 2 methods measure the same construct and produce similar results.

Privacy protection and utility trade-off for social graph embedding

In graph embedding protection, deleting the embedding vector of a node does not completely disrupt its structural relationships. The embedding model must be retrained over the network without sensitive nodes, which incurs a waste of computation and offers no protection for ordinary users. Meanwhile, the edge perturbations do not guarantee good utility. This work proposed a new privacy protection and utility trade-off method without retraining. Firstly, since embedding distance reflects the closeness of nodes, we label and group user nodes into sensitive, near-sensitive, and ordinary regions to perform different strengths of privacy protection. The near-sensitive region can reduce the leaking risk of neighboring nodes connecting to sensitive nodes without sacrificing all of their utility. Secondly, we use mutual information to measure privacy and utility while adapting a single model-based mutual information neural estimator to vector pairs to reduce modeling and computational complexity. Thirdly, by keeping adding different noise to the divided regions and reestimating the mutual information between the original and noise-perturbed embeddings, our framework achieves a good trade-off between privacy and utility. Simulation results show that the proposed framework is superior to state-of-the-art baselines like LPPGE and DPNE.

The minimal important difference in orthodontic treatment duration: a survey across adult patients.

The minimal important difference (MID) is defined as the smallest difference that the patient perceives as important. Furthermore, the smallest worthwhile effect (SWE) is the important change measured with the benefit-harm trade-off method. The aim of this study was to evaluate the MID in orthodontic treatment duration to inform the decision regarding seeking procedures to accelerate orthodontic tooth movement and reduce treatment duration. We constructed a survey eliciting views of the MID from adult participants from four countries undergoing orthodontic treatment. Ten questions addressed reduction in the treatment duration for both durations 12 and 24 months, and four questions were related to the reduction in treatment duration that the patients would require to undergo surgical or non-surgical adjunctive procedures. We applied a univariable random effects logistic regression model to examine the association between the participants' characteristics and the MID. Then, we fitted a multivariable logistic random effects regression including significant predictors. Four hundred and fifty adults, with a median age of 21 (interquartile range: 19-24), undergoing orthodontic treatment participated in the survey. Of the respondents, 60% considered 15 days as a trivial reduction from 12 months duration of therapy and 70% considered15 daysa trivial reduction from 24 months. Of the respondents, 48% considered the period of 2 months a moderate reduction from 12 months, and 60% considered 2 months a moderate reduction from 24 months. From these results, we inferred that patients considered reductions of approximately 1 month as the MID in the treatment duration for both 12 and 24 months. However, SWE was considerably more than the MID for most of the participants to decide undergoing surgical adjunctive procedures to reduce the time of therapy. The participants required smaller SWE to undergo non-surgical procedurescompared to surgical procedures. The MID in the treatment duration is one month for both treatment durations 12 and 24 months. Patients require a greater SWE than the MID to undergo adjunctive procedures to shorten the duration, particularly for surgical procedures.

Analytical aspects of combining holistic evaluation and decomposition elicitation for preference modeling in the FITradeoff method

AbstractCombining the traditional elicitation by decomposition with holistic evaluations within a decision process with multiple criteria is a peculiar aspect of the Flexible and Interactive Tradeoff (FITradeoff) method since two paradigms in preference modeling are integrated. Even though this integration leads to significant benefits to the decision process, it brings several implications that deserve a deep and detailed analysis with regard to some analytical aspects of the mathematical modeling of the method. Integrating the information obtained by these two different protocols causes significant modifications in the space of weights that may have noteworthy impacts on the results. Hence, this paper focuses its efforts on tackling and investigating such aspects of the FITradeoff method. We analyze properties and analytical aspects of FITradeoff in depth, in order to investigate how the information of holistic judgments can be inserted into the mathematical model of FITradeoff and to determine the potential implications of such integration, such as defining preference relationships and identifying potentially optimal alternatives. In addition, a new heuristic to reduce the number of questions in the elicitation by decomposition of FITradeoff is proposed. We also address situations of inconsistencies that may arise due to the conflicting information provided by decomposition and holistic judgments, as well as ways to solve such inconsistencies.

Using the benefit-harm trade-off method to determine the smallest worthwhile effect of intensive motor training on strength for people with spinal cord injury

Study designInterviews using the benefit-harm trade-off method and an online survey.ObjectivesTo determine the smallest worthwhile effect (SWE) of motor training on strength for people with spinal cord injury (SCI).SettingSCI units, Australia.MethodsForty people with recent SCI who had participated in motor training as part of their rehabilitation program (patient participants) and 37 physiotherapists (physiotherapist participants) working in SCI were recruited. The patient participants underwent an iterative process using the benefit-harm trade-off method to determine the SWE of motor training on strength. The physiotherapist participants were given an online survey to determine the SWE for five different scenarios. Both groups considered the SWE of a physiotherapy intervention involving an additional 12 h of motor training for 10 weeks on top of usual care. They were required to estimate the smallest improvement in strength (points on the Total Motor Score of the International Standards for Neurological Classification of SCI) to justify the effort and associated costs, risks or inconveniences of the motor training.ResultsThe median (interquartile range) smallest improvement in strength that patient and physiotherapist participants deemed worth the effort and associated costs, risks or inconveniences of the motor training was 3 (1–5) points, and 9 (7–13) points, respectively.ConclusionsPeople with recent SCI are willing to devote 12 h a week for 10 weeks to motor training in addition to their usual care to gain small changes in strength. Physiotherapists wanted to see greater improvements to justify the intervention.

Is Blepharoplasty Cost-effective? Utility Analysis of Dermatochalasis and Cost-effectiveness Analysis of Upper Eyelid Blepharoplasty.

This cross-sectional prospective study measured utility values of upper eyelid dermatochalasis to quantify its impact on quality of life and assess cost-effectiveness of upper blepharoplasty. Utility of dermatochalasis was assessed using the standard reference gamble and time trade-off methods, with dual anchor points of perfect eye function and perfect health. The utility value obtained was used to create a Markov model and run a cost-effectiveness analysis of blepharoplasty as a treatment for dermatochalasis while utilizing the societal perspective. One hundred three patients with dermatochalasis recruited from an urban outpatient ophthalmology clinic completed the utility survey. The authors determined utility values for dermatochalasis ranging from 0.74 to 0.92 depending on the measurement method (standard reference gamble/time trade-off) and anchor points. The cost-effectiveness analysis yielded an incremental cost-effectiveness ratio of $3,146 per quality-adjusted life year, well under the conventional willingness-to-pay threshold of $50,000 per quality-adjusted life year. Probabilistic sensitivity analysis with Monte Carlo simulation demonstrated that blepharoplasty would be cost-effective in 88.1% of cases at this willingness-to-pay threshold. Dermatochalasis has an impact on quality of life that is significantly associated with level of perceived functional impairment. Rising health care costs have underscored the importance of providing value-based treatment to patients, and the results of this study suggest that blepharoplasty is a cost-effective treatment option for symptomatic bilateral upper eyelid dermatochalasis.

Nash equilibrium selection using a hybrid two-player static game with trade-off ranking method

The paper aims to suggest the ranking of an optimal solution when there exists more than one Nash equilibrium in the game theory solution concept. Many studies tend to merge the game theory with the multi criteria decision-making (MCDM) method to cater the real-situation problems. In the paper, a novel hybrid non-cooperative static game in game theory is combines with the trade-off ranking (TOR) method in MCDM. The proposed hybrid method is used to rank multiple Nash equilibria concerning some criteria. The methodology for both static game and TOR method are explained in the paper. The game theory model used is a two-player non-constant-sum static game. The proposed methodology is tested using international cooperation in Iran. The result suggests the ranking of the combined strategies using the proposed method.

Prediagnostic evaluation of multicancer detection tests: Design and analysis considerations.

There is growing interest in multicancer detection (MCD) tests, which identify molecular signals in the blood indicating a potential preclinical cancer. A key stage in evaluating MCD tests is a prediagnostic performance study, in which investigators store specimens from asymptomatic persons and later test stored specimens from cancer cases and a random sample of controls to determine predictive performance. Performance metrics include cancer-specific true and false positive rates and a cancer-specific positive predictive value, with the latter compared to a decision-analytic threshold. The sample size tradeoff method, which trades imprecise targeting of the true positive rate for precise targeting of a zero false positive rate can substantially reduce sample size while increasing the lower bound of positive predictive value. For a 1-year follow-up, with ovarian cancer as the rarest cancer considered, the sample size tradeoff method yields a sample size of 163,000 compared with a sample size of 720,000 based on standard calculations. These design and analysis recommendations should be considered in planning a specimen repository and in the prediagnostic evaluation of MCD tests.

A review of time-memory trade-off techniques

This paper delves into the discussion of time-memory trade-off techniques in the field of cryptanalysis. The method was initially introduced by Hellman in 1980, subsequently, DP trade-off, rainbow trade-off, and checkpoint trade-off have been proposed to enhance the efficiency of cryptographic attacks. This paper elaborates on the concept of rainbow trade-off and their variants and presents optimizations in terms of storage and runtime speed for time-memory trade--off methods. Ingenious storage optimization significantly reduces the storage overhead of pre-computed tables, and the rapid advancement of implementation platforms achieves speed optimization for the online phase. Through these optimization measures, time-memory trade-off methods exhibit even more remarkable performance in practical applications. For researchers and practitioners in the field of cryptography, the content of this paper provides valuable references and insights for their work.

A study of oil and gas producers subsector portfolio using the trade-off ranking method

In the topic of stock selection, numerous multi-criteria decision-making (MCDM) techniques have been applied to handle selection difficulties. This paper proposes a compromise approach for the subsector stocks of oil and gas companies, motivated by the pandemic crisis and the political issue in Malaysia. The paper presents a novel analysis of the existing trade-off ranking (TOR) method for ranking the stocks of oil and gas producers in conflicting multi-criteria problems. As a result, the TOR technique ranks the subsector stocks effectively for two criteria weights. Comparison with TOPSIS shows that both methods exhibit similar performance.

An Analysis of the Determinants of the Health-Related Quality of Life in Asian Patients With Cluster Headaches During Cluster Periods Using the Time Trade-Off Method.

Patients with cluster headache (CH) exhibit impaired health-related quality of life (HRQoL). However, there have been few studies related to the HRQoL of patients with CH from Asian backgrounds. This study aimed to determine the impact of CH on HRQoL and to identify the factors affecting HRQoL in patients with CH during cluster periods. This prospective study enrolled patients with CH from 17 headache clinics in South Korea between September 2016 and February 2021. The study aimed to determine HRQoL in patients with CH using the EuroQol 5 Dimensions (EQ-5D) index and the time trade-off (TTO) method. Age- and sex-matched headache-free participants were recruited as a control group. The study included 423 patients with CH who experienced a cluster period at the time. EQ-5D scores were lower in patients with CH (0.88±0.43, mean±standard deviation) than in the controls (0.99±0.33, p<0.001). The TTO method indicated that 58 (13.6%) patients with CH exhibited moderate-to-severe HRQoL deterioration. The HRQoL states in patients with CH were associated with current smoking patterns, headache severity, frequency, and duration, and scores on the Generalized Anxiety Disorder 7-item scale (GAD-7), Patient Health Questionnaire 9-item scale (PHQ-9), 6-item Headache Impact Test, and 12-item Allodynia Symptom Checklist. Multivariable logistic regression analyses demonstrated that the HRQoL states in patients with CH were negatively correlated with the daily frequency of headaches, cluster period duration, and GAD-7 and PHQ-9 scores. Patients with CH experienced a worse quality of life during cluster periods compared with the headache-free controls, but the degree of HRQoL deterioration varied among them. The daily frequency of headaches, cluster period duration, anxiety, and depression were factors associated with HRQoL deterioration severity in patients with CH.

Building a 5D Database of Heliostats Flux Distributions: Toward High Flexibility High Accuracy Flux Control for Odeillo's Big Solar Furnace

In order to increase the flexibility and the control of the concentrated solar flux provided to test processes and materials at the big solar furnace in Odeillo (up to 1000 kW and 10000 KW/m2), extensive and accurate knowledge of the individual contribution of each of the heliostats is required, for all their aiming points. For a solar furnace, with double mirror reflection and heavily changing shadow of the solar beams, this would require too much experimental time to record this behaviour systematically, either directly (flux measurements of all the configurations) or indirectly (simulation by ray tracing based on the real optical configuration measured, both at macroscopic and microscopic scale). This work here presents a trade-off method based on real flux measurement, but at sampled configurations, then interpolated to fill in missing data. 5 dimensions have been sampled: heliostats (1D) + aiming directions (2D) + flux distributions (2D). An evaluation of the method is presented based on actual experimental data, with a discussion of the experience.

Computation Offloading for Energy and Delay Trade-Offs With Traffic Flow Prediction in Edge Computing-Enabled IoV

An unprecedented prosperity in artificial intelligence promotes the development of Internet of Vehicles (IoV). Assisted by edge computing, vehicles enable to offload data to edge servers in close proximity to users for processing, thus making up for the shortage of local computing resources. However, due to the uneven space-time distribution of traffic flow, edge servers of a certain road segment may be overwhelmed by the surge of service requests. Furthermore, IoV system will incur significant additional energy consumption and time delay because of the absence of a proper computation offloading scheme between edge servers. To cope with above challenges, a computing offloading method for energy and delay trade-offs with traffic flow prediction in edge computing-enabled IoV is proposed. We first design the graph weighted convolution network (GWCN) that can fully excavate the connectivity and distance relation information between road segments to conduct traffic flow prediction. The short-term prediction results are utilized as the basis for adjusting the resource allocation of edge resources in different regions. Then, a computation offloading method driven by deep deterministic policy gradient (DDPG) is leveraged to obtain an optimal computation offloading scheme for edge servers. Finally, extensive comparative experiments demonstrate the low prediction error of GWCN and superior performance of DDPG-driven method in reducing total time delay and energy consumption.