• Title/Summary/Keyword: dropout

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Slew-Rate Enhanced Low-Dropout Regulator by Dynamic Current Biasing

  • Jeong, Nam Hwi;Cho, Choon Sik
    • Journal of electromagnetic engineering and science
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    • v.14 no.4
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    • pp.376-381
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    • 2014
  • We present a CMOS rail-to-rail class-AB amplifier using dynamic current biasing to improve the delay response of the error amplifier in a low-dropout (LDO) regulator, which is a building block for a wireless power transfer receiver. The response time of conventional error amplifiers deteriorates by slewing due to parasitic capacitance generated at the pass transistor of the LDO regulator. To enhance slewing, an error amplifier with dynamic current biasing was devised. The LDO regulator with the proposed error amplifier was fabricated in a $0.35-{\mu}m$ high-voltage BCDMOS process. We obtained an output voltage of 4 V with a range of input voltages between 4.7 V and 7 V and an output current of up to 212 mA. The settling time during line transient was measured as $9{\mu}s$ for an input variation of 4.7-6 V. In addition, an output capacitor of 100 pF was realized on chip integration.

Low-ripple coarse-fine digital low-dropout regulator without ringing in the transient state

  • Woo, Ki-Chan;Yang, Byung-Do
    • ETRI Journal
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    • v.42 no.5
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    • pp.790-798
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    • 2020
  • Herein, a low-ripple coarse-fine digital low-dropout regulator (D-LDO) without ringing in the transient state is proposed. Conventional D-LDO suffers from a ringing problem when settling the output voltage at a large load transition, which increases the settling time. The proposed D-LDO removes the ringing and reduces the settling time using an auxiliary power stage which adjusts its output current to a load current in the transient state. It also achieves a low output ripple voltage using a comparator with a complete comparison signal. The proposed D-LDO was fabricated using a 65-nm CMOS process with an area of 0.0056 μ㎡. The undershoot and overshoot were 47 mV and 23 mV, respectively, when the load current was changed from 10 mA to 100 mA within an edge time of 20 ns. The settling time decreased from 2.1 ㎲ to 130 ns and the ripple voltage was 3 mV with a quiescent current of 75 ㎂.

A 50-mA 1-nF Low-Voltage Low-Dropout Voltage Regulator for SoC Applications

  • Giustolisi, Gianluca;Palumbo, Gaetano;Spitale, Ester
    • ETRI Journal
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    • v.32 no.4
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    • pp.520-529
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    • 2010
  • In this paper, we present a low-voltage low-dropout voltage regulator (LDO) for a system-on-chip (SoC) application which, exploiting the multiplication of the Miller effect through the use of a current amplifier, is frequency compensated up to 1-nF capacitive load. The topology and the strategy adopted to design the LDO and the related compensation frequency network are described in detail. The LDO works with a supply voltage as low as 1.2 V and provides a maximum load current of 50 mA with a drop-out voltage of 200 mV: the total integrated compensation capacitance is about 40 pF. Measurement results as well as comparison with other SoC LDOs demonstrate the advantage of the proposed topology.

Tracing Students Performance by Intervention of the Academic Advisor

  • Mohamed, Abdelmoneim Ali;Nafie, Faisal Mohammed
    • International Journal of Computer Science & Network Security
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    • v.21 no.12spc
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    • pp.539-543
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    • 2021
  • Data mining technique was used to track student's performance during years studding in college and determine the impact of GPA_SEC on the GPA student rates according to the current academic advising method used on student's status. The study utilized a sample of 5436 individuals were drawn from two colleges in Majmaah University, KSA during 2013-2018 period. The results showed that the student's completion status in terms of graduation, dropout, Stumbling or dismissed was classified according to the average grades of admission from secondary school GPA_SEC. The results show the effect of the current academic advising that most of students gain less grades comparing with GPA_SEC in addition that the higher GPA_SEC was the higher graduation, dropout and dismissed decreased when GPA_SEC was high.. Therefore, the study recommends tracking students academically to evaluate their results of each semester to find out the causes of the deficiencies and addressing them within the departments.

중국관련학과의 경쟁력확보에 관한 연구 - 대학정보공시를 활용한 전국대학의 양적 분석을 중심으로 -

  • Kim, Si-Yong;Chae, Dong-U
    • 중국학논총
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    • no.67
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    • pp.157-177
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    • 2020
  • The rapid change in the university environment due to the decrease in the school-age population calls for enhancing the competitiveness of China-related departments. In this paper, the university's competitiveness and dropout rate were studied in combination with various factors such as geographical location of Chinese-related departments set up at national universities, convergence with other departments, competition rate for entrance exams, scholarships, and employment rate that have a comprehensive impact on student satisfaction. In particular, the dropout rate presented research results that could help universities strengthen their competitiveness in China-related departments, such as by differentiating customized academic strategies according to the atmosphere of elimination through multiple regression analysis and quantile analysis. We hope this thesis will be the basis for policymaking and judgment in China-related departments.

A Study on the Academic Dropout of College Students (대학생의 중도탈락에 관한 연구(D대학 중심))

  • Lee, Jae-Do
    • Journal of the Korea society of information convergence
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    • v.1 no.1
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    • pp.47-54
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    • 2008
  • This study analyzed the status and causes for the dropouts of college based on the survey conducted among 14,210 freshmen attending D College, other than the supernumerary special selection, from 2001 through 2005. A significant difference was shown in all items of general characteristics. The dropout rate of women, generally selected and general highschool graduated were higher than for men, specially selected and special high school graduated, respectively. The most dropouts were due to Not Return(40.16%), followed by Unenrolled(32.98%), Voluntary Leave(26.05%) and Expelled(0.81%) in order. In the distribution of the central tendency values measured from the entire subjects, the high school records and the days of absence showed a positive skewness, while the college records showed a negative skewness with the data mostly around a higher grade. The standard deviation indicating that the dropouts got the scores higher than those of the continuing students demonstrated that there was relatively insignificant difference in scores between two groups. It was demonstrated that both the high school records and the days of absence affected the dropout. The lower the high school records were, and the more the days of absence were, the more influence both items had on the dropout. The influence degree of each item was similar. Lower the scores were in terms other than the first term in the freshmen year, the more influence it had on the dropout. The most dropouts were influenced by the scores of the freshmen year, followed by the credits of the second term, the scores of the first term, the scores of the second term, and the credits of the first term in the freshmen year. Among the general characteristic items, the most dropouts were influenced by the course of study, followed by the gender. The effect of other items was insignificant.

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A Study on the Social Support, Ego-resiliency and Stress Coping Strategies of School-Dropout Adolescents (학업중단 청소년의 사회적지지, 자아탄력성과 스트레스 대처방식 연구)

  • Kim, Hyun-ji;Yang, Myong-Suk
    • Journal of Digital Convergence
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    • v.15 no.1
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    • pp.23-34
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    • 2017
  • This study investigated relative explanation of social support, ego-resiliency and stress coping strategies to help adaptive coping style of school-dropout adolescents under stress situation. To this end, 101 school-dropout adolescents were surveyed by visiting and requesting the outofschool youth supporting project, youth detention center, and adolescent protective and treatment facilities in Daejeon, Cheongnam, and Chungbuk. As analysis methods, descriptive statistical analysis, pearson's correlation, and hierarchical analysis were conducted and the research results are as follows. First, stress coping strategies showed positive relationship with social support and ego-resiliency. Second, a variable that showed greater explanation power for stress coping strategies was the environmental variable, the social support. Third, it was identified that there was greater explanation power when the environmental variable, the social support, and the personal variable, the ego-resiliency, were put in at the same time for stress coping strategies. According to the result, this study implies that schools, community, national policy effort and systemetic approach are required as well as improvement of personal coping capabilities in order to overcome difficulties school-dropout adolescents face.

Feasibility of Deep Learning Algorithms for Binary Classification Problems (이진 분류문제에서의 딥러닝 알고리즘의 활용 가능성 평가)

  • Kim, Kitae;Lee, Bomi;Kim, Jong Woo
    • Journal of Intelligence and Information Systems
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    • v.23 no.1
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    • pp.95-108
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    • 2017
  • Recently, AlphaGo which is Bakuk (Go) artificial intelligence program by Google DeepMind, had a huge victory against Lee Sedol. Many people thought that machines would not be able to win a man in Go games because the number of paths to make a one move is more than the number of atoms in the universe unlike chess, but the result was the opposite to what people predicted. After the match, artificial intelligence technology was focused as a core technology of the fourth industrial revolution and attracted attentions from various application domains. Especially, deep learning technique have been attracted as a core artificial intelligence technology used in the AlphaGo algorithm. The deep learning technique is already being applied to many problems. Especially, it shows good performance in image recognition field. In addition, it shows good performance in high dimensional data area such as voice, image and natural language, which was difficult to get good performance using existing machine learning techniques. However, in contrast, it is difficult to find deep leaning researches on traditional business data and structured data analysis. In this study, we tried to find out whether the deep learning techniques have been studied so far can be used not only for the recognition of high dimensional data but also for the binary classification problem of traditional business data analysis such as customer churn analysis, marketing response prediction, and default prediction. And we compare the performance of the deep learning techniques with that of traditional artificial neural network models. The experimental data in the paper is the telemarketing response data of a bank in Portugal. It has input variables such as age, occupation, loan status, and the number of previous telemarketing and has a binary target variable that records whether the customer intends to open an account or not. In this study, to evaluate the possibility of utilization of deep learning algorithms and techniques in binary classification problem, we compared the performance of various models using CNN, LSTM algorithm and dropout, which are widely used algorithms and techniques in deep learning, with that of MLP models which is a traditional artificial neural network model. However, since all the network design alternatives can not be tested due to the nature of the artificial neural network, the experiment was conducted based on restricted settings on the number of hidden layers, the number of neurons in the hidden layer, the number of output data (filters), and the application conditions of the dropout technique. The F1 Score was used to evaluate the performance of models to show how well the models work to classify the interesting class instead of the overall accuracy. The detail methods for applying each deep learning technique in the experiment is as follows. The CNN algorithm is a method that reads adjacent values from a specific value and recognizes the features, but it does not matter how close the distance of each business data field is because each field is usually independent. In this experiment, we set the filter size of the CNN algorithm as the number of fields to learn the whole characteristics of the data at once, and added a hidden layer to make decision based on the additional features. For the model having two LSTM layers, the input direction of the second layer is put in reversed position with first layer in order to reduce the influence from the position of each field. In the case of the dropout technique, we set the neurons to disappear with a probability of 0.5 for each hidden layer. The experimental results show that the predicted model with the highest F1 score was the CNN model using the dropout technique, and the next best model was the MLP model with two hidden layers using the dropout technique. In this study, we were able to get some findings as the experiment had proceeded. First, models using dropout techniques have a slightly more conservative prediction than those without dropout techniques, and it generally shows better performance in classification. Second, CNN models show better classification performance than MLP models. This is interesting because it has shown good performance in binary classification problems which it rarely have been applied to, as well as in the fields where it's effectiveness has been proven. Third, the LSTM algorithm seems to be unsuitable for binary classification problems because the training time is too long compared to the performance improvement. From these results, we can confirm that some of the deep learning algorithms can be applied to solve business binary classification problems.

System Development and Management for Underachieved Students (자존감 향상 프로그램 개발 및 운영사례)

  • Kim, Young-Jun;Kim, Hee-Kyo;Oh, Kyeong-seok
    • Journal of the Korea Convergence Society
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    • v.9 no.6
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    • pp.183-190
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    • 2018
  • With decreasing the number of high school graduates, it is vital for each college to maintain its enrollment number as well as to preserve its dropout rate in a lower level. It is true that all universities and colleges have experienced inevitable dropouts that were in fact more serious in 2 to 3-year colleges. There have been prior studies to examine what factors affected to students' dropout in various ways. However, no specific programs were employed to mitigate the rates of dropout. In this study, new encouraging program is introduced for the students who were not ready to study and isolated from classroom. The result showed that the program led to the GPA enhancement in larger number of participants. Nevertheless, the sustainablity of the program would be unclear unless it combines with other existing programs.

Dropout Prediction Modeling and Investigating the Feasibility of Early Detection in e-Learning Courses (일반대학에서 교양 e-러닝 강좌의 중도탈락 예측모형 개발과 조기 판별 가능성 탐색)

  • You, Ji Won
    • The Journal of Korean Association of Computer Education
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    • v.17 no.1
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    • pp.1-12
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    • 2014
  • Since students' behaviors during e-learning are automatically stored in LMS(Learning Management System), the LMS log data convey the valuable information of students' engagement. The purpose of this study is to develop a prediction model of e-learning course dropout by utilizing LMS log data. Log data of 578 college students who registered e-learning courses in a traditional university were used for the logistic regression analysis. The results showed that attendance and study time were significant to predict dropout, and the model classified between dropouts and completers of e-learning courses with 96% accuracy. Furthermore, the feasibility of early detection of dropouts by utilizing the model were discussed.

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