scholarly journals Emulator-based Bayesian optimization for efficient multi-objective calibration of an individual-based model of malaria

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Theresa Reiker ◽  
Monica Golumbeanu ◽  
Andrew Shattock ◽  
Lydia Burgert ◽  
Thomas A. Smith ◽  
...  

AbstractIndividual-based models have become important tools in the global battle against infectious diseases, yet model complexity can make calibration to biological and epidemiological data challenging. We propose using a Bayesian optimization framework employing Gaussian process or machine learning emulator functions to calibrate a complex malaria transmission simulator. We demonstrate our approach by optimizing over a high-dimensional parameter space with respect to a portfolio of multiple fitting objectives built from datasets capturing the natural history of malaria transmission and disease progression. Our approach quickly outperforms previous calibrations, yielding an improved final goodness of fit. Per-objective parameter importance and sensitivity diagnostics provided by our approach offer epidemiological insights and enhance trust in predictions through greater interpretability.

2021 ◽  
Author(s):  
Theresa Reiker ◽  
Monica Golumbeanu ◽  
Andrew Shattock ◽  
Lydia Burgert ◽  
Thomas A. Smith ◽  
...  

AbstractIndividual-based models have become important tools in the global battle against infectious diseases, yet model complexity can make calibration to biological and epidemiological data challenging. We propose a novel approach to calibrate disease transmission models via a Bayesian optimization framework employing machine learning emulator functions to guide a global search over a multi-objective landscape. We demonstrate our approach by application to an established individual-based model of malaria, optimizing over a high-dimensional parameter space with respect to a portfolio of multiple fitting objectives built from datasets capturing the natural history of malaria transmission and disease progression. Outperforming other calibration methodologies, the new approach quickly reaches an improved final goodness of fit. Per-objective parameter importance and sensitivity diagnostics provided by our approach offer epidemiological insights and enhance trust in predictions through greater interpretability.One Sentence SummaryWe propose a novel, fast, machine learning-based approach to calibrate disease transmission models that outperforms other methodologies


2021 ◽  
pp. 027836492110333
Author(s):  
Gilhyun Ryou ◽  
Ezra Tal ◽  
Sertac Karaman

We consider the problem of generating a time-optimal quadrotor trajectory for highly maneuverable vehicles, such as quadrotor aircraft. The problem is challenging because the optimal trajectory is located on the boundary of the set of dynamically feasible trajectories. This boundary is hard to model as it involves limitations of the entire system, including complex aerodynamic and electromechanical phenomena, in agile high-speed flight. In this work, we propose a multi-fidelity Bayesian optimization framework that models the feasibility constraints based on analytical approximation, numerical simulation, and real-world flight experiments. By combining evaluations at different fidelities, trajectory time is optimized while the number of costly flight experiments is kept to a minimum. The algorithm is thoroughly evaluated for the trajectory generation problem in two different scenarios: (1) connecting predetermined waypoints; (2) planning in obstacle-rich environments. For each scenario, we conduct both simulation and real-world flight experiments at speeds up to 11 m/s. Resulting trajectories were found to be significantly faster than those obtained through minimum-snap trajectory planning.


2020 ◽  
Vol 12 (8) ◽  
pp. 1319
Author(s):  
Xiaofan Sun ◽  
Bingnan Wang ◽  
Maosheng Xiang ◽  
Liangjiang Zhou ◽  
Shuai Jiang

The Gaussian vertical backscatter (GVB) model has a pivotal role in describing the forest vertical structure more accurately, which is reflected by P-band polarimetric interferometric synthetic aperture radar (Pol-InSAR) with strong penetrability. The model uses a three-dimensional parameter space (forest height, Gaussian mean representing the strongest backscattered power elevation, and the corresponding standard deviation) to interpret the forest vertical structure. This paper establishes a two-dimensional GVB model by simplifying the three-dimensional one. Specifically, the two-dimensional GVB model includes the following three cases: the Gaussian mean is located at the bottom of the canopy, the Gaussian mean is located at the top of the canopy, as well as a constant volume profile. In the first two cases, only the forest height and the Gaussian standard deviation are variable. The above approximation operation generates a two-dimensional volume only coherence solution space on the complex plane. Based on the established two-dimensional GVB model, the three-baseline inversion is achieved without the null ground-to-volume ratio assumption. The proposed method improves the performance by 18.62% compared to the three-baseline Random Volume over Ground (RVoG) model inversion. In particular, in the area where the radar incidence angle is less than 0.6 rad, the proposed method improves the inversion accuracy by 34.71%. It suggests that the two-dimensional GVB model reduces the GVB model complexity while maintaining a strong description ability.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Seok-Jin Hong ◽  
Byoung-Eun Yang ◽  
Dae-Myoung Yoo ◽  
Sung-Jae Kim ◽  
Hyo-Geun Choi ◽  
...  

Abstract Background Chronic periodontitis is a multifactorial inflammatory disease resulting in patients exhibiting high levels of inflammatory factors causing systemic inflammatory bone destruction that may lead to osteoporosis development. The association between periodontitis and osteoporosis has been documented; however, the findings remain unclear. This study aimed to identify the association between periodontitis and osteoporosis using a cross-sectional study design and Korean Genome and Epidemiology Study (KoGES) health examinee data. Methods This cross-sectional study used epidemiological data from the KoGES during 2004–2016. Of 125,324 participants (age, 40–79 years), 9969 with periodontitis and 115,332 controls (without periodontitis) were selected. We analyzed the history of osteoporosis and fractures of all participants. All participants were examined according to age, sex, income group, obesity, smoking habits, alcohol consumption, and food intake. To analyze the odds ratio (OR) of periodontitis for those with osteoporosis and fractures, a logistic regression model was used. Results The adjusted odds ratio (aOR) of periodontitis for osteoporosis was 2.16 (95% confidence interval [CI], 2.01–2.31; P < 0.001). The aOR of periodontitis for any fracture was 1.54 (95% CI 1.46–1.62; P < 0.001). Conclusion Osteoporosis and fractures are associated with periodontitis. Performing regular oral hygiene and examinations of bone mineral density are recommended to prevent aggravation of osteoporosis and periodontitis.


2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S105-S105
Author(s):  
Blanca Soto ◽  
Miriam Canet ◽  
Diego Erdmenger

Abstract Background Sexual violence is a global health problem, in terms of age and sex, showing a significant negative impact on health. Incidence in Guatemala is among the highest of the region reaching an average of 23 cases reported daily nationally per statistics from the Ministry of Health in 2015. Methods Retrospective analysis of the database of all sexual violence cases reported from a secondary -level national hospital in Guatemala from January 2005 to September 2015 (period A) and in-depth analysis on demographic and epidemiological data along with information of the follow-up of cases between January 2012 and September 2015 (period B) was performed. Results Period A: 500 cases; female (96%; 481/500). Assault occurred between 16–20 years (34%; 163/481) 11–15 years (22.25%; 107/481), and 21–30 years (22.04%; 106/481). From all reported male cases, 73.68% (14/19) occurred under 15 years. Period B: 154/217 (70.96%) cases included; female (95.45%; 147/154), mean age: 17.87 years. Assault occurred in public spaces (57.14%; 88/154) and victim’s home (29.87%; 46/154). Almost 13% of victims reported history of previous assault, 5.84% by the same aggressor. More than one aggressor participated in 36.37% of assaults. Physical violence was associated in 57.79% of cases. Most victims (92.76%; 141/152) consulted within 72 hours of the assault. HIV, VDRL, and Hepatitis B testing performed in 100, 52, and 33.77%, respectively, were negative. Follow-up visits at 3, 6, and 12 months after the aggression were attended by 20.78% (30/154), 1.95% (3/154), and 1.95% (3/154) of victims, respectively. Psychology support was completed only in 18.18% (28/154). Emergency contraception was provided when indicated; pregnancy as result of the aggression was reported in nine cases (5.84%). Conclusion The study shows that young women were the most vulnerable group for sexual violence. There is a lack of multidisciplinary approach and follow-up. Interventions on infectious diseases screening have to be optimized to reduce the risk of ETS transmission. This evidence supports the need for a specialized clinic to ensure access to comprehensive health services for victims. Disclosures All authors: No reported disclosures.


2013 ◽  
Vol 10 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
M. S. Rahman ◽  
S. Mithu ◽  
M. T. Islam ◽  
M. J. Uddin ◽  
R. R. Sarker ◽  
...  

Brucellosis is an important bacterial zoonotic disease causing significant economic loss in dairy industries worldwide including Bangladesh. But limited studies are devoted to determine the prevalence of brucellosis in goat in all districts of Bangladesh. Therefore, a cross-sectional study was undertaken to determine the seroprevalence of brucellosis in Black Bengal goats in Nilphamari Sadar and Kishoreganj upazillas of Nilphamari district of Bangladesh using Rose Bengal Test (RBT) as screening test and I-ELISA as confirmatory test. A total of 154 sera samples from Black Bengal goats were collected from Nilphamari district. Epidemiological data on the selected Black Bengal goats were collected using a structured questionnaire. The overall seroprevalence of brucellosis was found to be 2.59% in Black Bengal goats. A significantly (p<0.01) higher prevalence of brucellosis was found in Black Bengal goats with the history of previous abortion (33.33%). An insignificant (p>0.05) but higher prevalence of brucellosis was found in adult Black Bengal goats (>24 months) than young. The prevalence was relatively higher in cross-bred than pure Black Bengal goats, in female than male and in pregnant than non-pregnant Black Bengal goats. The result of the study will provide baseline data for control of brucellosis in goat in Bangladesh.DOI: http://dx.doi.org/10.3329/bjvm.v10i1-2.15646


2020 ◽  
Vol 13 (4) ◽  
pp. 325-328
Author(s):  
Satya Wydya Yenny

Although acne is usually recognized as an adolescent skin disorder, the prevalence of adults with acne is increasing. The clinical and epidemiological data of acne were evaluated with a view to establishing possible contributing etiological factors and observing whether clinical features differ from adolescent acne. Division of Dermatology and Venereology Outpatient Clinic Dr. M. Djamil hospital padang during January 2016 until December 2018.Retrospective study performed in Medical Cosmetic Division of Dermatology and Venereology Outpatient Clinic Dr. M. Djamil hospital padang during January 2016 until December 2018. Data was taken from medical records. Out of 224 patients included in the study 54.01% were women and 45.98 % were men. Majority of the patients had comedonal acne (45.53 %), whereas nodulocystic was the least common (13.39%). Most common predominant site of involvement was cheek (44.20 %), followed by chin (25.45 %), and mandibular area (14.58 %). Family history of acne was present in 57.70 %. Scarring was observed in a 39.2 %. Acne is predominant in women, with the most commonly involved of the cheeks, with the most common type was comedones type.


Author(s):  
Pallavi Singh ◽  
Milind A. Patvekar ◽  
Bhavika Shah ◽  
Alisha Mittal ◽  
Asmita Kapoor

<p class="abstract"><strong>Background:</strong> Alopecia areata is one of the commonest types of non-scarring alopecia involving the scalp and/or body. As there is paucity of recent epidemiological data from our country, this study was conducted to determine the latest clinical and epidemiological trends of scalp alopecia areata.</p><p class="abstract"><strong>Methods:</strong> A hospital-based observational study consisting of 100 cases of clinically diagnosed scalp alopecia areata who reported to the Dermatology OPD, Dr. D.Y. Patil Medical College, Pune, was conducted for a period of six months. Socio-demographic and clinical information was collected and clinical examination was performed on all patients. The data was evaluated using appropriate statistical methods.<strong></strong></p><p class="abstract"><strong>Results:</strong> Out of the 100 cases enrolled, males (64%) outnumbered females (36%). The commonest presenting age group was 21-30 years (44%). Disease onset was sudden in 80% patients and 59% cases had a progressive disease course. Majority (75%) had a disease duration of less than 3 months. Majority cases were asymptomatic (80%) with no precipitating factors (90%). Past history and family history of alopecia areata were present in 13% and 9% cases, respectively. Personal and family history of associated diseases were present in 27% and 22% patients, respectively. Most patients had single (61%), patchy (83%) lesions with occiput (45%) being the commonest initial site. Nail changes were present in 22% cases, of which pitting (13%) was the commonest nail finding.</p><p class="abstract"><strong>Conclusions:</strong> This study reflects the clinical profile of scalp alopecia areata in a tertiary care hospital.</p>


1999 ◽  
Vol 5 (1_suppl) ◽  
pp. 93-96 ◽  
Author(s):  
C.F. Dowd ◽  
C.C. Phatouros ◽  
A.M. Malek ◽  
T.E. Lempert ◽  
P.M. Meyers ◽  
...  

Options for treatment of intracranial aneurysms have expanded with the advent of the Guglielmi Detachable Cod (GDC) eight years ago. We have reviewed 435 cases of intracranial aneurysms treated at UCSF by endovascular means using the GDC system. Of these, 55% represent anterior circulation aneurysms, and 45% are located in the posterior circulation. Additionally, 55% of the aneurysms presented with subarachnoid hemorrhage (SAH) and 45% were unruptured. Factors which hindered optimal coiling include the following: wide aneurysm neck in relation to the overall aneurysm size, mural thrombus, giant aneurysm, arteries originating from the aneurysm sac, and middle cerebral location. After initial experience was gained, we tended to avoid these aneurysms especially in the non-ruptured group. This may be especially important in light of new epidemiological data suggesting that the natural history of unruptured aneurysms is significantly lower than previously thought. New technical developments which may reduce the risk of treating unruptured aneurysms include the two-dimensional coil, the three-dimensional coil, the balloon-assist technique for wide-necked aneurysms, and combined stent-coil procedures.


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