Empirical Information Criteria for Time Series Forecasting Model Selection

In this paper, we propose a new Empirical Information Criterion (EIC) for model selection which penalizes the likelihood of the data by a function of the number of parameters in the model. It is designed to be used where there are a large number of time series to be forecast. However, a bootstrap version of the EIC can be used where there is a single time series to be forecast. The EIC provides a data-driven model selection tool that can be tuned to the particular forecasting task. We compare the EIC with other model selection criteria including Akaike's Information Criterion (AIC) and Schwarz's Bayesian Information Criterion (BIC). The comparisons show that for the M3 forecasting competition data, the EIC outperforms both the AIC and BIC, particularly for longer forecast horizons. We also compare the criteria on simulated data and find that the EIC does better than existing criteria in that case also.Exponential smoothing; forecasting; information criteria; M3 competition; model selection.

Prevalence, years lived with disability, and trends in anaemia burden by severity and cause, 1990-2021: findings from the Global Burden of Disease Study 2021

Background Anaemia is a major health problem worldwide. Global estimates of anaemia burden are crucial for developing appropriate interventions to meet current international targets for disease mitigation. We describe the prevalence, years lived with disability, and trends of anaemia and its underlying causes in 204 countries and territories. Methods We estimated population-level distributions of haemoglobin concentration by age and sex for each location from 1990 to 2021. We then calculated anaemia burden by severity and associated years lived with disability (YLDs). With data on prevalence of the causes of anaemia and associated cause-specific shifts in haemoglobin concentrations, we modelled the proportion of anaemia attributed to 37 underlying causes for all locations, years, and demographics in the Global Burden of Disease Study 2021. Findings In 2021, the global prevalence of anaemia across all ages was 24·3% (95% uncertainty interval [UI] 23·9–24·7), corresponding to 1·92 billion (1·89–1·95) prevalent cases, compared with a prevalence of 28·2% (27·8–28·5) and 1·50 billion (1·48–1·52) prevalent cases in 1990. Large variations were observed in anaemia burden by age, sex, and geography, with children younger than 5 years, women, and countries in sub-Saharan Africa and south Asia being particularly affected. Anaemia caused 52·0 million (35·1–75·1) YLDs in 2021, and the YLD rate due to anaemia declined with increasing Socio-demographic Index. The most common causes of anaemia YLDs in 2021 were dietary iron deficiency (cause-specific anaemia YLD rate per 100 000 population: 422·4 [95% UI 286·1–612·9]), haemoglobinopathies and haemolytic anaemias (89·0 [58·2–123·7]), and other neglected tropical diseases (36·3 [24·4–52·8]), collectively accounting for 84·7% (84·1–85·2) of anaemia YLDs. Interpretation Anaemia remains a substantial global health challenge, with persistent disparities according to age, sex, and geography. Estimates of cause-specific anaemia burden can be used to design locally relevant health interventions aimed at improving anaemia management and prevention. Funding Bill & Melinda Gates Foundation

Empirical information criteria for time series forecasting model selection

In this paper, we propose a new Empirical Information Criterion (EIC) for model selection which penalizes the likelihood of the data by a function of the number of parameters in the model. It is designed to be used where there are a large number of time series to be forecast. However, a bootstrap version of the EIC can be used where there is a single time series to be forecast. The EIC provides a data-driven model selection tool that can be tuned to the particular forecasting task. We compare the EIC with other model selection criteria including Akaike's Information Criterion (AIC) and Schwarz's Bayesian Information Criterion (BIC). The comparisons show that for the M3 forecasting competition data, the EIC outperforms both the AIC and BIC, particularly for longer forecast horizons. We also compare the criteria on simulated data and find that the EIC does better than existing criteria in that case also

Effect of Porosity on Electrical Insulation and Heat Dissipation of Fused Deposition Modeling Parts Containing Embedded Wires

While the effects of porosity on the mechanical strength of fused deposition modeling (FDM) parts have been thoroughly investigated, there exists a need for evaluating electrical and thermal properties. This work describes the method of determining the effect of porosity that resembles 3D printed electronics. In addition to mechanical strength, determination of desirable limit of electrical insulation and heat dissipation will allow the additive manufacturing community to fabricate power electronics components with reduced cost and improved performance. For experimentation, three different sets of coupons were fabricated using Polycarbonate (PC) thermoplastic with embedded bare copper wire. Characterization included high electrical stresses and thermal testing to determine the effect of porosity on insulation and heat dissipation, respectively. During electrical characterization, higher wire density resulted in reduced breakdown strength. In thermal test, the comparisons between as fabricated and heat-treated specimen showed that heat dissipation increased by an average of 30 % to 40 %.Mechanical Engineerin

Analysis of the Consumer Perceptions of Online Shopping: Case of Bangladesh

Though online shopping has become a new type of retail shopping, it has been adopted worldwide, including in Bangladesh, influencing ordinary citizens\u27 lives. In Bangladesh, consumers have not been habituated to online shopping frequently. This study aims to identify consumer perceptions of online shopping in Bangladesh. The study has 140 sample sizes from the Chuadanga district by forming a self-structured closed-ended Questionnaire. The SPSS version 16.0 statistical tool is used in this study. Several statistical tools, like frequency tests and percentages, were used to measure the objective. We found that consumers are primarily young, below 30 ages, who shop online to save time, and for available varieties of products and services and prefer to pay through cash on delivery method. Most consumers feel risk in online shopping and are also concerned about the security of the payment system. Overall, Consumers are satisfied with online shopping. Also, this study has a few limitations. Future research with a larger sample size and additional variables is recommended

Ultrasonic Embedding of Continuous Carbon Fiber into 3D printed Thermoplastic Parts

A novel multimaterial fabrication process was developed to embed continuous bundles of carbon fiber (CF) into polycarbonate (PC) substrates using ultrasonic energy. Continuous CF possesses superior reinforcement properties compared to that of chopped or short fibers. In this research, dry continuous CF bundles were impregnated with a PC solution prior to embedding. Three printing raster orientations were studied (0°, 45°, and 90°), where three layers of CCF were embedded within each test specimen. Characterizations including tensile, flexural, and dynamic mechanical analysis were carried out to investigate reinforcement related properties. Results showed an increase in ultimate tensile strength between neat PC (37 MPa) and CF reinforced specimens (141 MPa). An automated ultrasonic embedding process allowed for the selective deposition of CF, regardless of the raster orientation. Future development of continuous CF reinforced parts could enable smart part fabrication, with applications in structural health monitoring, microwave shielding, and thermal management.Mechanical Engineerin

Fast-food and obesity: Status among the younger population in Bangladesh

Increasing rate of fast-food consumption has been associated with different health related concerns (e.g., obesity, heart disease). This study aimed to determine the prevalence of fast-food consumption among young adult students in Chittagong, Bangladesh, and to assess the correlation of fast-food consumption with obesity. A total of 440 youth was included using a systemic random sampling from universities and colleges in Chittagong in order to perform a cross-sectional analysis. The students who reported frequent fast-food consumption (1–3 times per week) accounted for 30.5% (n=134) of the sample, while 32.5% (n=143) of participants reported consuming fast-food 8–15 times per month. There was a significant (p=0.030) difference between students who consumed and did not consume fast-food. Youth who reported consuming fast-food and soft drinks more than 4 times per week constituted 35.0% (n=154), followed by approximately 27.7% (n=122) who consumed these items 1–3 times per week. In addition, an obesity epidemic was observed among those who reported low levels of physical exercise or lack of sleep. The study illustrates that Bangladeshi youth face an increasing risk of becoming overweight and obese. Prevention is regarded as the most effective way to reduce the prevalence of obesity

Fast-food and obesity: Status among the younger population in Bangladesh

Increasing rate of fast-food consumption has been associated with different health related concerns (e.g., obesity, heart disease). This study aimed to determine the prevalence of fast-food consumption among young adult students in Chittagong, Bangladesh, and to assess the correlation of fast-food consumption with obesity. A total of 440 youth was included using a systemic random sampling from universities and colleges in Chittagong in order to perform a cross-sectional analysis. The students who reported frequent fast-food consumption (1–3 times per week) accounted for 30.5% (n=134) of the sample, while 32.5% (n=143) of participants reported consuming fast-food 8–15 times per month. There was a significant (p=0.030) difference between students who consumed and did not consume fast-food. Youth who reported consuming fast-food and soft drinks more than 4 times per week constituted 35.0% (n=154), followed by approximately 27.7% (n=122) who consumed these items 1–3 times per week. In addition, an obesity epidemic was observed among those who reported low levels of physical exercise or lack of sleep. The study illustrates that Bangladeshi youth face an increasing risk of becoming overweight and obese. Prevention is regarded as the most effective way to reduce the prevalence of obesity