On-line Method Research Articles

An Online Condition Monitor Method for IGBT Independent of Collector Current

Junction temperature monitoring and fault diagnosis of power semiconductor devices can provide critical information to ensure the reliable operation of power electronic systems. In this article, an online condition monitoring method for insulated gate bipolar transistors (IGBTs), which is not affected by the collector current, is proposed based on the Miller voltage plateau of the conduction process. The relationship between the Miller voltage plateau and the junction temperature is analyzed, and an analytical model of the Miller voltage against junction temperature is established. By using this model and the conducting-state characteristics of the device, a reverse current phase measuring strategy is proposed to decouple the influence of the collector current on the junction temperature estimation, and an online measurement circuit of the Miller voltage is designed. In addition, the characteristics of the trigger voltage under different faults are analyzed to recognize fault types. The experimental results show that the proposed method has high sensitivity and good linearity. It is proven that the proposed measurement strategy is independent of the collector current, which can accurately distinguish the fault forms of IGBTs.

An Efficient Method for Antenna Design Based on a Self-Adaptive Bayesian Neural Network-Assisted Global Optimization Technique

Gaussian process (GP) is a very popular machine learning method for online surrogate-model-assisted antenna design optimization. Despite many successes, two improvements are important for the GP-based antenna global optimization methods, including: 1) the convergence speed (i.e., the number of necessary electromagnetic (EM) simulations to obtain a high-performance design) and 2) the GP model training cost when there are several tens of design variables and/or specifications. In both aspects, the state-of-the-art GP-based methods show practical but not desirable performance. Therefore, a new method, called the self-adaptive Bayesian neural network surrogate-model-assisted differential evolution (DE) for antenna optimization (SB-SADEA), is presented in this article. The key innovations include: 1) the introduction of the Bayesian neural network (BNN)-based antenna surrogate modeling method into this research area, replacing GP modeling, and 2) a bespoke self-adaptive lower confidence bound (LCB) method for antenna design landscape making use of the BNN-based antenna surrogate model. The performance of SB-SADEA is demonstrated by two challenging design cases, showing considerable improvement in terms of both convergence speed and machine learning cost compared with the state-of-the-art GP-based antenna global optimization methods.

Health state prediction of lithium-ion batteries based on XGBoost algorithm

The state of health of lithium-ion batteries is an extremely important indicator for the safe operation of electrical equipment. In order to solve the problem that the capacity of Li-ion batteries is difficult to measure online, this paper proposes an online method based on the XGBoost algorithm to estimate the state of health (SOH). First, health characteristics are extracted from the discharge voltage profile to characterise the capacity of the Li-ion battery. XGBoost is then used to predict SOH based on capacity drop. results show that the proposed method is able to estimate SOH with a root mean square error of less than 1.2% respectively. Furthermore, the proposed method was used for model training and prediction in less than 1 second.

The 9th International Conference on Sustainable Agriculture and Environment (ICSAE-9)

24-25 August, 2022 Surakarta, Indonesia This conference was held by Research and Development Centre for Biotechnology and Biodiversity (P3BB) Universitas Sebelas Maret in collaboration with:Indonesia Diaspora Network - UnitedFaculty of Agriculture, Universitas Sebelas Maret, IndonesiaFaculty of Art and Design, Universitas Sebelas Maret, IndonesiaFaculty of Economic and Business, Universitas Sebelas Maret, Indonesia Brief of the meeting International Conference on Sustainable Agriculture and Environment, abbreviated ICSAE, is a circuit meeting held since 2013. This conference is internationally recognized around the globe for its topic on sustainable agriculture and the environment. As we know, agriculture and the environment are essential for human beings, especially for food resources and other materials needed. It’s also not just about food, agriculture, and the environment are involved in economics, politics, design, and many related areas. This year, on August 24-25, 2022, this conference is held online in Surakarta, Indonesia, and is known as ICSAE-9. Sustainable is the keyword in agricultural and environmental management to assure global food security and maintain the high quality of human life. Accordingly, this conference is held to identify ideas, practices, and policies that constitute our concept of sustainable agriculture and the environment. We aim to provide a platform for researchers, academics, and practicing professionals worldwide to present their research and professional development activities in agriculture, environment, food, and other relevant subjects.Two years of the Covid-19 pandemic circumstances have taught us that the online method of delivering the conference effectively broadens the conference participant and disseminates the result. In ICSAE-9, we invite speakers to share their valuable information and knowledge. All the presentation mechanism was done by using the Zoom meeting online platform. There were 4 plenary sessions, 6 rooms for participants to present their specific topics, and a poster session. The ICSAE-9 received 162 papers presented virtually in oral and poster format. Per the presenter, the oral format was allocated for 10 minutes and 5 minutes Q n A, while the posters were presented digitally through the ICSAE website. To be more flexible, all the presentations from the presenter were recorded and uploaded to YouTube. Hence participants (commonly the non-registered ones) that can’t attend life can see the presentation in their flexible time. This is also the solution for the participants who don’t have a proper internet connection.At last, we would like to thank all the committee and all the participants for their contribution to the ICSAE-9. We do hope we can meet again in the future meeting.ICSAE-9 ChairList of committees are available in this pdf.

Evaluation of Hybrid Learning in the University: A Case Study Approach

Hybrid learning is a type of educational system in which some students attend class in person while others engage virtually from home. Hybrid learning has been applied in all educational institutions since the pandemic. BINUS University used a Learning Management System called Binusmaya to support teaching and learning activities for both hybrid and fully online learning. The objective of this study is to assess the effectiveness of hybrid learning at BINUS University based on student performance academically and non-academically. It focuses on students from the 2019–2020 academic year. The survey obtained 200 replies using a quantitative technique and a Google form as the media questionnaire. Previous research has shown that hybrid learning provides effective results in terms of academic achievement. Compared to this study, few criteria are used to measure the effectiveness of hybrid learning, such as environment, knowledge, and skills. In addition, we have added the comparison between hybrid learning and the full online method at BINUS University. The results indicate that hybrid learning is ineffective compared to fully online learning. Furthermore, hybrid students were dissatisfied with their overall results, and students pursuing full-time online courses outperformed hybrid students. This study also provides some approaches to increasing the effectiveness of hybrid learning at BINUS University. Doi: 10.28991/HIJ-2022-03-04-03 Full Text: PDF

Implementation of Information Technology (IT) at The Impact of The Covid-19 Pandemi in The Islamic Boarding School (Survey)

Islamic boarding schools are the original Indonesian Islamic education institution with traditional culture. The existence of a Covid-19 pandemic resulted in school learning policies and boarding schools using the online method. It is conducted to break the chain of spread of the Covid-19 virus. It has an impact on various activities in Islamic boarding schools and on the need to use information technology (IT). Research was used for an initial mapping of the implementation of IT in Islamic boarding schools. The study aimed to determine to what extent IT adoption was in the Islamic boarding school in the Special Region of Yogyakarta. The method used is a survey with descriptive analysis. The survey was carried out on the board of Islamic boarding schools. The questionnaire contained the identification of the types of Islamic boarding schools and four variables related to IT implementation in Islamic boarding schools. The four variables are application information/ information systems used by Islamic boarding schools, from where Islamic boarding schools obtain information systems, existing system integration, and Android-based applications. The results obtained were that 88.9% of the 58 Islamic boarding schools already had an information system. Islamic boarding schools have a diverse information system, such as the new student admission, boarding school information systems, school information systems, monitoring systems, financial systems, and administrative systems. There are 44.2% of the system which has integrated data and functionality and 59.5% systems based on Android. The average Islamic boarding school that applies to IT is a boarding school with some students (santri) of more than 400, and the category is a modern salafiah Islamic boarding school. The challenges facing Islamic boarding schools in IT implementation are the lack of human resources, infrastructure limitations, and the lack of socialization of information systems in the guardian of students.

Application of the Online Method with the Whatsapp Application to Increase Student Learning Motivation through Providing Classical Guidance Information Services in Class VII-1 Even Semester UPT SPF SMP Negeri 2 Sunggal Academic Year 2021/2022)

This study aims to find out how to increase student motivation in Class VII-1 at UPT SPF SMP Negeri 2 Sunggal. This study uses a quantitative approach using the online method with the Whatsapp application. The subjects in this study were students of class VII-1 at UPT SPF SMP Negeri 2 Sunggal for the 2021/2022 academic year, with a total of 32 students consisting of 14 boys and 18 girls. The data collection technique was carried out using individual absorption percentage techniques and classical completeness, as well as by observing teachers about the implementation of service purchases through the use of online methods with the Whatsapp application. The results of this study are that the application of the online method with the Whatsapp application in class VII-1 can increase learning motivation in providing Guidance and Counseling material services. This can be seen from the results of student learning outcomes obtained from cycle I and cycle II, namely: 04% and 23%.

Formation of the human potential of students through educational technologies

It is seen that the study is designed with the aim of creating the human potential of students through educational technologies. The research was carried out with the participation of 128 primary school students continuing their education in primary schools in the Kazakhstan region and the study was carried out in the fall term of 2022–2023 in the quantitative research model. A 3-week training was given to the participants included in the study. The subjects of educational technologies and human potential were conveyed on the participant groups in the research and participation was expected. The data collection tool used in the research was delivered to the participant groups by online method and collected. The analysis of the data was made by using the Statistical Package for the Social Sciences programme, frequency analysis, t-test and the results were added to the research in the presence of tables. In the case of the results obtained from the research, it is seen that the use of educational technologies benefits the participant groups in the research and that human potential is formed, thanks to this activity.
 Keywords: Educational technologies, human potential, primary school students, distance education;

Technology of formation of students' skills of educational and cognitive activity through mathematical modelling

The study was examined, the technology for creating students' educational and cognitive activity skills through mathematical modelling was aimed and designed. As a model, this study was helped by the quantitative research model, and the research was carried out in the fall term of 2022–2023. 172 volunteer students who continue their education in high schools participated in the research. In the study, 3 weeks of online training was given to the students. The data collection tool was delivered to high school students by online method and collected. The analysis of the data was added to the research by tabulating the findings from the participants. When the results dimension of the study was examined comprehensively, it was concluded that the cognitive activity levels of the students were high through mathematical modelling. While this situation was determined as good for education, it was concluded that it was used by reflecting the mathematics and technology systems in the course.
 Keywords: High school students, mathematical modelling, cognitive activity, mathematics, independent work, cognitive impairment, mathematical modelling, problem, verbal calculation;

Capacitive Interdigitated Electrodes Sensor for the Field Device to Measure Moisture Content in the Nitrile Gloves Manufacturing Industry

This paper investigates the impedance spectroscopy technique in determining moisture content in Nitrile gloves. Interdigitated electrode was designed and fabricated, then evaluated on LCR Impedance meter subjected to frequency range of 100Hz, 120Hz, 1kHz, 10kHz, 20kHz and 100kHz. Samples of Nitrile gloves were compounded and prepared for different moisture content level and regression analysis was performed to evaluate the relationships between capacitance and moisture content of the glove samples. Experimental results indicated that the capacitance value is a strong function of moisture content in gloves and also that the capacitance of moisture content in Nitrile gloves decreased with increasing drying time over the measured frequency range whilst statistical analysis results have confirmed that the 1kHz, 10kHz and 20kHz signal frequencies have highest reliable prediction of the nitrile gloves’ moisture content with high R2 value of 0.96, 0.97 and 0.97, respectively. The ability to determine average moisture content of Nitrile gloves via a non-destructive and online method, utilizing a low-cost instrument, will be of considerable use in the glove industry. This method could also be extended to other types of gloves and rubber products.

Research on Identification Algorithm of Cascade Control System

Aiming at the problem of object model identification of modern industrial process control systems, a new closed-loop moment parameter identification online method based on the data of normal operation of the running system is proposed. In this method, only one step response data of the system is required, and appropriate convergence factors are introduced into the Laplace formula, the trapezoidal integral method is used to calculate the values of two derivatives of the transfer function, then the four unknown parameters of the second-order model can be solved by fitting the data with the least square method, and the target model can be identified. Finally, the simulation results of building different objects through Matlab show that the identification method has general applicability and good robustness with high recognition, and it is not sensitive to noise signals.

Data-driven reduced-order modeling for nonautonomous dynamical systems in multiscale media

In this article, we present data-driven reduced-order modeling for nonautonomous dynamical systems in multiscale media. The Koopman operator has received extensive attention as an effective data-driven technique, which can transform the nonlinear dynamical systems into linear systems through acting on observation function spaces. Different from the case of autonomous dynamical systems, the Koopman operator family of nonautonomous dynamical systems significantly depend on a time pair. In order to effectively estimate the time-dependent Koopman operators, a moving time window is used to decompose the snapshot data, and the extended dynamic mode decomposition method is applied to computing the Koopman operators in each local temporal domain. Many physical properties in multiscale media often vary in very different scales. In order to capture multiscale information well, the dimension of collected data may be high. To accurately construct the models of dynamical systems in multiscale media, we use high spatial dimension of observation data. It is challenging to compute the Koopman operators using the very high dimensional data. Thus, the strategy of reduced-order modeling is proposed to treat the difficulty. The proposed reduced-order modeling includes two stages: offline stage and online stage. In offline stage, a block-wise low rank decomposition is used to reduce the spatial dimension of initial snapshot data. For the nonautonomous dynamical systems, real-time observation data may be required to update the Koopman operators. The online reduced-order modeling is proposed to correct the offline reduced-order modeling. Three methods are developed for the online reduced-order modeling: fully online, semi-online and adaptive online. The adaptive online method automatically selects the fully online or semi-online and can achieve a good trade-off between modeling accuracy and efficiency. A few numerical examples are presented to illustrate the performance of the different reduced-order modeling methods.

Rl4dtn: Q-Learning for Opportunistic Networks

Opportunistic networks are highly stochastic networks supported by sporadic encounters between mobile devices. To route data efficiently, opportunistic-routing algorithms must capitalize on devices’ movement and data transmission patterns. This work proposes a routing method based on reinforcement learning, specifically Q-learning. As usual in routing algorithms, the objective is to select the best candidate devices to put forward once an encounter occurs. However, there is also the possibility of not forwarding if we know that a better candidate might be encountered in the future. This decision is not usually considered in learning schemes because there is no obvious way to represent the temporal evolution of the network. We propose a novel, distributed, and online method that allows learning both the network’s connectivity and its temporal evolution with the help of a temporal graph. This algorithm allows learning to skip forwarding opportunities to capitalize on future encounters. We show that explicitly representing the action for deferring forwarding increases the algorithm’s performance. The algorithm’s scalability is discussed and shown to perform well in a network of considerable size.

Online detection of measurement error in three-phase CVT based on equivariant adaptive source separation

As a key device for signal acquisition in power systems, the capacitor voltage transformer (CVT) has been widely used in high-voltage power grids with a capacity of 110 kV and above. However, the long-term stability of error in its measurements is poor and requires effective detection work. The conventional method of regular offline detection has the problems of power failure and operation difficulty. An online method for identifying errors in measurements of the CVT based on equivariant adaptive source separation is proposed in this paper. Under normal operation, the secondary output information of three-phase CVT is linearly correlated, and equivariant adaptive separation via independence (EASI) is used to analyze the correlation of data matrix. By constructing the main space and residual space, the primary voltage fluctuation is separated from the metering error. According to the separated signal characterizing the measurement error information, the standard quantity is established to realize the online detection of measurement error of three-phase CVT. In view of the non-stationary time-varying characteristics of power system operation, the data model is continuously updated according to successively acquired, which effectively improves the accuracy of the state assessment of the three-phase CVT. The simulation and experimental results show that the proposed method outperforms the independent component analysis (ICA), which can well meet the requirements of 0.2-level accuracy and have an evaluable change in amplitude that is better than 0.05%.

Movable Surface Rotation Angle Measurement System Using IMU.

In this paper, we describe a rotation angle measurement system (RAMS) based on an inertial measurement unit (IMU) developed to measure the rotation angle of a movable surface. The existing IMU-based attitude (tilt) sensor can only accurately measure the rotation angle when the rotation axis of the movable surface is perfectly aligned with the X axis or Y axis of the sensor, which is always not possible in real-world engineering. To overcome the difficulty of sensor installation and ensure measurement accuracy, first, we build a model to describe the relationship between the rotation axis and the IMU. Then, based on the built model, we propose a simple online method to estimate the direction of the rotation axis without using a complicated apparatus and a method to estimate the rotation angle using the known rotation axis based on the extended Kalman filter (EKF). Using the estimated rotation axis direction, we can effectively eliminate the influence of the mounting position on the measurement results. In addition, the zero-velocity detection (ZVD) technique is used to ensure the reliability of the rotation axis direction estimation and is used in combination with the EKF as the switching signal to adaptively adjust the noise covariance matrix. Finally, the experimental results show that the developed RAMS has a static measurement error of less than 0.05° and a dynamic measurement error of less than 1° in the range of ±180°.

Exploring Pharmacists’ Experiences with Annual Renewal of License of Practice in Nigeria

Consistent with the global best practices, pharmacists practicing in Nigeria are mandated by law to renew their professional licenses annually. However, there is limited data regarding pharmacists’ experience with the renewal of practice licenses in Nigeria. Therefore, we aimed to provide this data. A cross-sectional study was conducted in an online survey (using Google FormTM). Eligible respondents were registered pharmacists in Nigeria. A questionnaire (link) that examines experiences towards renewing their license was developed and validated. The survey link was shared with the respondents via social media platforms, namely, Facebook, WhatsApp and Twitter. A total of 349 pharmacists responded to the survey, of which 313 (89.7%) completed the questionnaire. Of these respondents, 276 (88.2%) reported renewing their licenses annually. Among those, 18 (48.6%) do not renew their licenses due to the high cost of license renewal, 9 (24.3%) due to cumbersome process and 8 (21.6%) reported licenses not required in their place of work, were the common reasons for not renewing their licenses. A total of 277 (88.5%) respondents indicated a preference in the online method of license renewal. Of the respondents, 43.5% and 64.2% disagreed with linking Mandatory Continuing and Professional Development (MCPD) and payment of professional associations’ dues with re-licensure, respectively. Twenty (6.4%) rated the performance of the Pharmacists Council of Nigeria (PCN) as excellent and 143 (45.7%) as good. A high proportion of pharmacists (276 out of 313) renew their practice licenses in Nigeria. However, a reasonable number of pharmacists 82 (29.7%) in this study reported inconsistent attitudes towards license renewal. Therefore, there is a need for interventions to encourage pharmacists to renew their licenses annually.

Remote online monitoring system for transformer winding deformation based on current–voltage characterized graph

Transformer winding deformation threatens the power system’s safe and stable operation, and early detection of transformer winding deformation can reduce economic losses. This work analyzed the basic principle of the transformer winding deformation online method based on the current–voltage characterized graph. The simulation model was established and the frequency of the identification signal was changed to study the influence of the signal frequency on the change rate of the parameters of the characteristic graph. Combined with cloud technology, a remote online monitoring system for transformer winding deformation based on a current–voltage characterized graph was developed and experiments were carried out. The results showed that the deformation of the transformer winding affected the change of its impedance, thus causing the change of the parameters of characterized graph. The impedance of the transformer was mainly composed of its reactance, and the signal frequency has no significant effect on the rate of change of the parameters of characterized graph. The developed system can monitor the health status of transformer winding. This work can provide a scientific basis and experimental basis for early detection and early warning of transformer winding deformation.

Checklist-based active learning in anatomy demonstration sessions during the COVID-19 pandemic: Perception of medical students

Human anatomy is an essential component of the medical curricula. Anatomy education has been significantly affected during the COVID-19 pandemic. The aim of this study was to explore student's perceptions on a blended learning approach using Checklist-based Active Learning in Anatomy Demonstration Sessions (CALADS) as a method in comparison to the two previously used methods; namely face-to-face Structured Problem-Related Anatomy Demonstrations (SPRAD) and online anatomy learning. A comparative, cross-sectional, survey-based study was conducted. The survey was composed of 13 questions that explored preference of learning anatomy in demonstration sessions of 4th year pre-clerkship students who have had their anatomy learning through face-to-face SPRAD in year 2 (before the COVID-19 pandemic), online in year 3 (during the COVID-19 pandemic), and CALADS method in year 4. Descriptive statistics were used, and the level of significance was set at P<0.05. The survey exhibited high internal consistency (Cronbach's α=0.953). Validity of the survey was established through exploratory factor analysis. The preferred method for more than half of the students was the CALADS method. Face-to-face SPRAD came next and lastly came the online method. However, more students preferred the online method in comparison to face-to-face method for "learning radiological anatomy". There were no statistically significant differences between male and female students regarding any of the survey questions. CALADS method, as a hybrid, student-centered, interactive learning method of learning practical anatomy, was preferred by pre-clerkship students as a more effective method in understanding anatomy than face-to-face and online learning methods.

Quantitative acquisition of differential absorption cross sections of chlorobenzenes at different temperatures

Chlorobenzene is considered an essential organic synthesis intermediate and a precursor for the generation of persistent organic compounds in the waste disposal process, for which accurate detection of gaseous chlorobenzene can further help understand and control various chemical processes and effectively reduce pollution. Differential optical absorption spectroscopy is a reliable online method for detecting gaseous chlorobenzenes. It is crucial to investigate the effect of temperature on the optical absorption of the chlorobenzenes to quantify chlorobenzenes more precisely at various temperatures. A method to fix the effect of temperature variation on absorption spectra of chlorobenzene is initially proposed in this study, and it gave accurate concentrations. The proposed method can effectively improve the accuracy of chlorobenzene concentration measurements with an inverse concentration deviation of 3.2 % or less. The differential absorption cross sections at various temperatures are studied to understand how chlorobenzene absorption cross sections vary with temperature. Such a study is also helpful in reducing the concentration inversion errors induced by the variation of absorption cross sections of chlorobenzene with temperature. A novel method of introducing the binary function of the differential absorption cross sections with respect to wavelength and temperature is also proposed. The fitting of the binary function is done by downscaling functions at fixed wavelength and fixed temperature,respectively. Both fitting approaches obtained continuous differential absorption cross sections in the 201–220 nm wavelength band and 288–473 K temperature range, along with less than 2.74 % deviation in the concentration inversion measurements. Finally,based on the temperature specificity of the shape of the differential absorption cross sections,we developed another method using differential absorption spectroscopy for the simultaneous measurement of temperature and concentration, with a temperature prediction error of less than 1.89 %. This method is favorable to the applications of differential absorption spectroscopy in simultaneous measurement of temperature and concentration.

Knowledge and Practice Regarding Contact Lens Wear and Care Among Undergraduate Students in Universiti Sains Malaysia

Contact lenses are thin optical correction lenses worn on the eye and rest on the cornea’s surface. The number of individuals who wear contact lenses is growing every day, but many people are unaware of the benefits and drawbacks of wearing them. Contact lens wear and care that is not adhered to can lead to severe ocular complications and permanent vision loss [1]. Overall rates of non-compliance with good contact lens wear have been cited in the literature as ranging from 40-91% in the past [2]. Knowledge and practice regarding contact lens wear and care is very important to control its progression and its complication effectively.&#x0D; &#x0D; The objective of this cross-sectional study is to determine the knowledge and practice regarding contact lens wear and care and factor associated with the practice among undergraduate students in Universiti Sains Malaysia who have experienced wear contact lens. The questionnaire adopted from Abd Aziz et al [3] was distributed using the online method of Google form between January to May 2022. Data were analyzed using SPSS 26. Descriptive statistics were performed to determine the knowledge and practice. General linear regression modelling was used to analyze factors associated with practice.&#x0D; &#x0D; A total of 170 undergraduate students from various faculties on 3 campuses of USM aged 20-27 years old were involved in this study. Regularity of contact lens use showed most respondents used contact lens as occasionally (38.8%) and for 4-6 days per weeks (25.3%). Half of respondent mentioned their purpose of contact lens use as a refractive error (51.2%) and there is similar percentage in term of duration of contact lens use for less than 1 year and 5 years (30% and 30.6% respectively). Mean score of knowledge was 21.71 ± 2.46 with 51.8% of the respondents in this study have poor knowledge of contact lens wear and care. Mean score of practice was 22.49 ± 2.76 with majority of the respondent (74.1%) have poor practice regarding contact lens wear and care. In the final model of general linear regression, factors associated with the practice of contact lens wear and care were gender, course of study, purpose of using contact lens, duration of contact lens use and knowledge of contact lens wear and care (p &lt; 0.05).This study indicate there is a need for health education and awareness program to contact lens wearers especially among young people regarding contact lens usage, care, and its related complications