Edward Cm Lo

The available capacity computation model based on artificial neural network for lead-acid batteries in electric vehicles

Abstract The available capacity computation model based on the artificial neural network (ANN) for lead–acid batteries in an electric vehicle (EV) is presented. Comparing with the methods based on the Peukert equation, which is often used for the calculation of the available capacity for lead–acid batteries in EVs, this model is more accurate. The results of the experiment have proven the accuracy of the proposed model; the computation values are in good agreement with experimental data, the associated error has been considered acceptable from an engineering point of view.

A new battery available capacity indicator for electric vehicles using neural network

Abstract The ability to calculate the battery available capacity (BAC) for electric vehicles (EVs) is very important. Knowing the BAC and, thus, the driving range cannot only prevent EVs from being stranding on the road but also optimize the utilization of the battery energy storage in EVs. In order to determine the BAC, this paper presents a new neural network (NN) model of the lead–acid battery, based on the battery discharge current and temperature. Comparisons between the calculated BAC from the NN model and the measured BAC from experiments show good agreement. Furthermore, this new approach can readily be extended to the calculation of the BAC for other types of batteries.

Adaptive neuro-fuzzy modeling of battery residual capacity for electric vehicles

This paper proposes and implements a new method for the estimation of the battery residual capacity (BRC) for electric vehicles (EVs). The key of the proposed method is to model the EV battery by using the adaptive neuro-fuzzy inference system. Different operating profiles of the EV battery are investigated including the constant current discharge and the random current discharge as well as the standard EV driving cycles in Europe, the US, and Japan. The estimated BRCs are directly compared with the actual BRCs, verifying the accuracy and effectiveness of the proposed modeling method. Moreover, this method can be easily implemented by a low-cost microcontroller and can readily be extended to the estimation of the BRC for other types of EV batteries.

Neural network-based residual capacity indicator for nickel-metal hydride batteries in electric vehicles

This paper presents a new estimation approach for the battery residual capacity (BRC) indicator in electric vehicles (EVs). The key of this approach is to model the EV battery by using a neural network (NN) with a newly defined output and newly proposed inputs. The inputs are the discharged and regenerative capacity distribution and the temperature. The output is the state of available capacity (SOAC) which represents the BRC. Various SOACs of the nickel-metal hydride (Ni-MH) battery are experimentally investigated under different EV discharge current profiles and temperatures. The corresponding data are recorded to train and verify the proposed NN. The results indicate that the NN can provide an accurate and effective estimation of the BRC. Moreover, this NN can be easily implemented as the BRC indicator or estimator for EVs by using a low-cost microcontroller.

Estimation of battery available capacity under variable discharge currents

In this paper, a new mathematical model in semi-empirical form for lead-acid batteries is presented, which describes the relationship between the battery terminal voltage and the variable discharge current. Based on the proposed model, a new estimation method of the battery available capacity (BAC) in the presence of variable discharge currents is developed. The method involves the real-time identification of the model parameters which are then used to estimate the BAC according to the predefined cutoff voltage and the trend of battery terminal voltage during discharging. Thus, both temperature and aging influences on the BAC are considered inherently. Comparisons between the calculated results and the measured data confirm that the proposed method can provide an accurate real-time estimation of the BAC under variable discharge currents.

Oral health status and behaviours of preschool children in Hong Kong.

BackgroundDental caries is a major public health problem in many countries. Since the last territority-wide dental survey of Hong Kong preschool children was conducted in 2001, a survey to update the information is necessary. This study aimed to describe the dental caries experience of preschool children in Hong Kong and factors affecting their dental caries status.MethodsA stratified random sample of children from seven kindergartens in Hong Kong was surveyed in 2009. Ethical approval from IRB and parental consent was obtained. Clinical examinations of the children were performed by two calibrated examiners using disposable dental mirrors, an intra-oral LED light and ball-ended periodontal probes. A questionnaire to investigate possible explanatory factors for caries status was completed by the children’s parents. Caries experience was recorded using the dmft index. Multifactor-ANOVA was used to study the relationship between dental caries experience, and the background and oral health-related behaviours of the children.ResultsSeven hundred children (53% boys), mean age 5.3 ± 0.7 years were examined. The mean dmft score of the surveyed children was 2.2 and 51% of them had no caries experience (dmft = 0). Most (>95%) of the decayed teeth were untreated. Statistically significant correlations were found between dental caries experience of the children and their oral health-related habits, family income, parental education level and parental dental knowledge.ConclusionsEarly childhood dental caries was prevalent among the preschool children in Hong Kong. Their caries experience was associated with their oral health-related behaviours, socio-economic background, and parental education and dental knowledge.

Dental caries and erosion status of 12-year-old Hong Kong children

BackgroundThis study aimed to assess the dental caries and erosion status of 12-year-old Hong Kong children and study the determinants of dental caries and dental erosion of these children.MethodsThe survey was performed from 2011 to 2012 with ethics approval. Stratified random sampling was adopted to select 12-year-old children in 7 primary schools in Hong Kong. The participating parents were asked to complete a self-administered questionnaire concerning their children’s diet and oral health habits. The children were examined for caries status with WHO criteria by 3 calibrated examiners. Detection of dental erosion followed Basic Erosive Wear Examination (BEWE) criteria.ResultsA total of 704 children were recruited and 600 (316 boys, 53%) participated in the survey. There were 124 children (21%) with caries experience (DMFT > 0) and their DMFT was 0.34 ± 0.76. About half of their decay was unfilled (DT = 0.16 ± 0.52) The DMFT of girls and boys were 0.45 ± 0.89 and 0.23 ± 0.61, respectively (p = 0.001). Girls also had a higher DT (0.21 ± 0.62 compared with 0.11 ± 0.41, p = 0.013) and FT than boys (0.23 ± 0.63 compared with 0.12 ± 0.44, p = 0.016). Most children (75%) had at least some sign of erosion (BEWE > 0), but no severe erosion (BEWE = 3). Logistic regression showed girls who consumed soft drinks and took vitamin C supplements had higher caries risk. Dental erosion was more severe among the children who had caries experience and consumed fruit juice.ConclusionsThe 12-year-old Hong Kong children had low caries experience, and almost half of the decay was left untreated. Although severe erosion was not found, many children had early signs of erosion.

Dietary behavior and knowledge of dental erosion among Chinese adults

ObjectivesTo study the dietary behavior and knowledge about dental erosion and self-reported symptoms that can be related to dental erosion among Chinese adults in Hong Kong.MethodsChinese adults aged 25-45 years were randomly selected from a list of registered telephone numbers generated by computer. A telephone survey was administered to obtain information on demographic characteristics, dietary habits, dental visits, and knowledge of and presence of self-reported symptoms that can be related to dental erosion.ResultsA total of 520 participants were interviewed (response rate, 75%; sampling error, ± 4.4%) and their mean age was 37. Most respondents (79%) had ever had caries, and about two thirds (64%) attended dental check-ups at least once a year. Respondents had a mean of 5.4 meals per day and 36% had at least 6 meals per day. Fruit (89%) and lemon tea/water (41%) were the most commonly consumed acidic food and beverage. When asked if they ever noticed changes in their teeth, most respondents (92%) said they had experienced change that can be related to erosion. However, many (71%) had never heard about dental erosion and 53% mixed up dental erosion with dental caries.ConclusionHong Kong Chinese adults have frequent intake of food and many have experienced symptoms that can be related to dental erosion. Their level of awareness of and knowledge about dental erosion is generally low, despite most of them have regular dental check-ups. Dental health education is essential to help the public understand dental erosion and its damaging effects.

A novel induction machine design suitable for inverter-driven variable speed systems

Induction machines designed for inverter-driven variable speed systems are different from those fed directly from a utility power line. In this paper, a novel design approach for inverter driven induction machines is presented and implemented. This is followed by an investigation on sizing equations and rotor slot shape specifically for this purpose. The proposed approach permits the integration of the design of machines with inverters, comprehensive performance analysis, and system optimization, resulting in 20-30% higher power density for the induction machine than those designed for direct utility power supplies by conventional methods. Simulation analysis and experimental results are presented to substantiate the conclusions.

Relationship between children’s oral health-related behaviors and their caregiver’s sense of coherence

BackgroundSense of coherence (SOC) is hypothesized to be an important psychological factor that enables people to cope with stressors and successfully maintain and improve health. Mother’s SOC has been shown to be an important psychological factor associated with oral health and oral health-related behaviors of adolescents and 11- to 12-year-old children. However, little is known about the relationship between the caregiver’s SOC and oral health-related behaviors of the preschool children. The objective of this study was to investigate the relationship between oral health-related behaviors of 5-year-old children in Southern China and SOC of their caregiver.MethodsA cross-sectional study was conducted in a randomized sample of 1332 children aged 5 years and their caregivers in Guangzhou, Southern China. Data were collected through questionnaires completed by the caregivers. The Chinese short version of Antonovsky’s SOC scale (13 items) was employed to assess the caregiver’s SOC. The outcome variables were the child’s oral health-related behaviors, including frequency of sugary snack intake, toothbrushing frequency, utilization of dental service, and pattern of dental visits. Multiple logistic regression was used to analyze the relationship between the variables.ResultsNo association was found between the children’s sugary snack intake and the mother’s or the father’s SOC. After adjustment for other significant factors related to the child’s oral health-related behaviors, 8.9% of the children whose grandparents (as caregivers) had higher SOC scores had a lower frequency of sugary snack intake, compared with the children whose grandparents had lower SOC scores (OR = 0.61, 95% CI = 0.50–0.73, p = 0.008). The other measures of oral health-related behaviors of the child were not significantly associated with the caregiver’s SOC.ConclusionSugary snack intake behavior of the 5-year-old children was not associated with the mother’s or the father’s SOC. It was associated with the SOC of their grandparents, who are a small group of the caregivers in China.