qEUBO: A Decision-Theoretic Acquisition Function for Preferential Bayesian Optimization

Preferential Bayesian optimization (PBO) is a framework for optimizing a decision maker's latent utility function using preference feedback. This work introduces the expected utility of the best option (qEUBO) as a novel acquisition function for PBO. When the decision maker's responses are noise-free, we show that qEUBO is one-step Bayes optimal and thus equivalent to the popular knowledge gradient acquisition function. We also show that qEUBO enjoys an additive constant approximation guarantee to the one-step Bayes-optimal policy when the decision maker's responses are corrupted by noise. We provide an extensive evaluation of qEUBO and demonstrate that it outperforms the state-of-the-art acquisition functions for PBO across many settings. Finally, we show that, under sufficient regularity conditions, qEUBO's Bayesian simple regret converges to zero at a rate $o(1/n)$ as the number of queries, $n$, goes to infinity. In contrast, we show that simple regret under qEI, a popular acquisition function for standard BO often used for PBO, can fail to converge to zero. Enjoying superior performance, simple computation, and a grounded decision-theoretic justification, qEUBO is a promising acquisition function for PBO.Comment: In Proceedings of the 26th International Conference on Artificial Intelligence and Statistics (AISTATS) 202

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Exploiting Composite Functions in Bayesian Optimization

266 pagesBayesian optimization is a framework for global optimization of objective functions that are expensive or time-consuming to evaluate. It has succeeded in a broad range of application domains, from hyperparameter tuning to chemical design. However, many important problems are still out of its reach. This is partly due to the generality with which classical Bayesian optimization methods treat the objective function, often ignoring available structures that can be extremely useful for optimization. Thus, there is an incentive to identify structural properties arising commonly in practice and develop methods able to leverage them to improve sampling efficiency. This dissertation focuses on objective functions with a composite structure, i.e., objective functions evaluated via two or more functions, some of which take as input the output of others. Composite objective functions are pervasive in real-world applications. They arise, for example, in calibration of expensive simulators, optimization of manufacturing processes, and multi-attribute optimization with preference information. This work develops a general framework to exploit composite functions within Bayesian optimization and demonstrates how it can dramatically improve sampling efficiency and even unlock new applications

Accordo di Cooperazione tra L'Universita Degli Studi di Verona, L´Universitá Degli Studi di Cuenca E L´Instituto del Cáncer, Solca Núcleo di Cuenca

Italian

Acuerdo de Cooperación entre la Universidad de Estudios de Verona, Italia la Universidad de Cuenca, Ecuador El Instituto del Cáncer de Solca, Núcleo de Cuenca, Ecuador

Españo

Performance of ferrierite promoted with tungsten or boron species during the linear butene skeletal isomerization

Ammonium and potassium ferrierites were modified with tungsten or boron species using incipient wetness and wet impregnation or ion exchange. Catalytic behavior during the linear butene skeletal isomerization was measured at 300 and 450ºC, at atmospheric pressure and 0.15 atm 1-butene partial pressure. At 3000C and a short time, catalysts having strong acid sites practically reach the same high butene conversion with a low isobutene selectivity. Those acid sites favor undesirable side reactions. At a long time, conversion decreases. At a short time, tungsten exchanged on potassium-ferrierite produces two times the ferrierite’s isobutene yield. At a long time, boron impregnated on ferrierite reaches the largest isobutene production. At 450ºC, the high conversion is maintained even at a long time. At this temperature, tungsten impregnated on potassium-ferrierite, sample without strong acid sites, practically produces the same isobutene yield of ferrierite, even though its conversion is only a half of the ferrierite one. By considering by-product distributions, it can be inferred that dimerization and oligomerization reactions take place. Carbonaceous deposits were characterized by temperature-programmed oxidation and FTIR. The acid strength of active sites influences the coke amount. Independent of temperature, carbonaceous deposit formed on samples with strong acid sites is between 6.0 and 7.4%. The smallest amount (1.0%) is formed on tungsten impregnated potassium-ferrierite, which only displays the low-temperature combustion peak after reaction at 300ºC. Reaction temperature and type of acid sites affect the nature of carbonaceous deposit. Both olefinic species and aromatic rings appear in the deposit formed at 300ºC; aromatic coke increases when reaction takes place at 450ºC. Isobutene dimeric species play a role in coke formation.Fil: Astudillo, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Fauda, Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Querini, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Comelli, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

Multi‐information source Bayesian optimization of culture media for cellular agriculture

Culture media used in industrial bioprocessing and the emerging field of cellular agriculture is difficult to optimize due to the lack of rigorous mathematical models of cell growth and culture conditions, as well as the complexity of the design space. Rapid growth assays are inaccurate yet convenient, while robust measures of cell number can be time-consuming to the point of limiting experimentation. In this study, we optimized a cell culture media with 14 components using a multi-information source Bayesian optimization algorithm that locates optimal media conditions based on an iterative refinement of an uncertainty-weighted desirability function. As a model system, we utilized murine C2C12 cells, using AlamarBlue, LIVE stain, and trypan blue exclusion cell counting assays to determine cell number. Using this experimental optimization algorithm, we were able to design media with 181% more cells than a common commercial variant with a similar economic cost, while doing so in 38% fewer experiments than an efficient design-of-experiments method. The optimal medium generalized well to long-term growth up to four passages of C2C12 cells, indicating the multi-information source assay improved measurement robustness relative to rapid growth assays alone

Home automation architecture: design and implementation using ESP8266

This paper presents a methodology of design and implementation details of a solution based on Internet of things (IoT) applied to home automation. The solution is implemented using the system on a chip ESP8266. The proposed architecture allows the interaction between sensors and actuators (client nodes) linked through a home wireless network. The protocol was implemented in the application layer of the TCP/IP model, while subtle changes on the remaining layers of the TCP/IP stack are applied, as follows: 1) The IEEE 802.11 standard is used in the physical layer to define basic aspects such as transmitter power and receiver sensitivity; 2) CSMA/CA was used as a media access method, allowing multiple stations to use the same transmission medium; 3) in the network layer, the interaction between the nodes is configured in mesh mode, where each node uses a 32-bit identifier based on its MAC address; 4) the transport layer is configured using TCP, to guarantee reliability in data delivery; and, 5) the MQTT protocol is used in the application layer. To evaluate the performance of the proposed protocol, there were manufactured prototypes of the client nodes. An application for Android-based mobile devices was also developed, so that the user can control and manage the network from their own device.Prag