基于免疫遗传算法的支持向量机参数优化及其应用

支持向量机是在统计学习理论基础上发展起来的一种性能优良的新型机器学习方法,它具有坚实的理论基础,巧妙的算法实现。支持向量机的卓越性能依赖于它的参数的正确选择。本文采用改进的免疫遗传算法对支持向量机的参数进行优化。实验证明对于低维数据分类时,本文的优化算法比传统的网格法可以较大减少参数优化时间和提升分类的准确率。对高维的文本数据分类时,在保证分类准确率的前提下,仍然可以较大减少优化的时间。     

Designing an adaptive web-based learning system based on students’ cognitive styles identified online

This study developed an adaptive web-based learning system focusing on students’ cognitive styles. The system is composed of a student model and an adaptation model. It collected students’ browsing behaviors to update the student model for unobtrusively identifying student cognitive styles through a multi-layer feed-forward neural network (MLFF). The MLFF was adopted because of its ability on imprecise or incompletely understood data, ability to generalize and learn from specific examples, ability to be quickly updated with extra parameters, and speed in execution making them ideal for real time applications. The system then adaptively recommended learning content presented with a variety of content and interactive components through the adaptation model based on the student cognitive style identified in the student model. The adaptive web interfaces were designed by investigating the relationships between students’ cognitive styles and browsing patterns of content and interactive components. Training of the MLFF and an experiment were conducted to examine the accuracy of identifying students’ cognitive styles during browsing with the proposed MLFF and the impact of the proposed adaptive web-based system on students’ engagement in learning. The training results of the MLFF showed that the proposed system could identify students’ cognitive styles with high accuracy and the temporal effects should be considered while identifying students’ cognitive styles during browsing. Two factors, the acknowledgment of students’ cognitive styles while browsing and the existence of adaptive web interfaces, were used to assign three classes of college freshmen into three groups. The experimental results revealed that the proposed system could have significant impacts on temporal effects on students’ engagement in learning, not only for students with cognitive styles known before browsing, but also for students with cognitive styles identified during browsing. The results provide evidence of the effectiveness of the adaptive web-based learning system with students’ cognitive styles dynamically identified during browsing, thus validating the research purposes of this study.     

An improved method of early diagnosis of smoking-induced respiratory changes using machine learning algorithms

The purpose of this study was to develop an automatic classifier to increase the accuracy of the forced oscillation technique (FOT) for diagnosing early respiratory abnormalities in smoking patients. The data consisted of FOT parameters obtained from 56 volunteers, 28 healthy and 28 smokers with low tobacco consumption. Many supervised learning techniques were investigated, including logistic linear classifiers, k nearest neighbor (KNN), neural networks and support vector machines (SVM). To evaluate performance, the ROC curve of the most accurate parameter was established as baseline. To determine the best input features and classifier parameters, we used genetic algorithms and a 10-fold cross-validation using the average area under the ROC curve (AUC). In the first experiment, the original FOT parameters were used as input. We observed a significant improvement in accuracy (KNN = 0.89 and SVM = 0.87) compared with the baseline (0.77). The second experiment performed a feature selection on the original FOT parameters. This selection did not cause any significant improvement in accuracy, but it was useful in identifying more adequate FOT parameters. In the third experiment, we performed a feature selection on the cross products of the FOT parameters. This selection resulted in a further increase in AUC (KNN = SVM = 0.91), which allows for high diagnostic accuracy. In conclusion, machine learning classifiers can help identify early smoking-induced respiratory alterations. The use of FOT cross products and the search for the best features and classifier parameters can markedly improve the performance of machine learning classifiers.     

Personalized Learning Course Planner with E-learning DSS using user profile

Various methods of E-learning systems, based on information and communications, and geared towards improving learning effectiveness and students’ attention span, have been studied. However, most E-learning systems force students to follow the learning course or content established by a teacher. These methods are convenient, but they limit the effectiveness of E-learning.To overcome this limitation and increase effective learning, new techniques that reflect alternative learning styles, such as adaptive learning and personalized learning, have been studied. In this study, we proposed a Personalized Learning Course Planner (PLCP) that allows students to easily select the learning course they desire. User profile data was collected from the students’ initial priorities about learning contents as well as the test scores after their study. E-Learning Decision Support System (EL-DSS) in PLCP suggests an appropriate learning course organization, according to calculated results based on the user profile data.To verify the effectiveness of the proposed system, we implemented an English learning system consisting of PLCP. We conducted an experiment with 30 university students and evaluated students’ satisfaction by questionnaire analysis. The results indicate that the proposed system improved learning effectiveness and student satisfaction. Further investigation of the participants indicated that suggesting a learning course suitable for students’ previous test scores and priorities encouraged students to concentrate on the lesson.     

支持向量机和遗传算法的人脸识别方法

支持向量机是一种基于小样本学习的有效工具,作为分类器被认为具有很高的推广性能,无需先验知识。但是参数的选取与支持向量机的识别性能是相关的,核函数参数σ²和惩罚因子C对支持向量机识别性能会产生很大的影响。针对支持向量机在人脸识别问题中的应用,提出了一种基于遗传算法（GA）的参数选择优化方法。利用笔者曾提出的基于小波分解和积分投影的人脸特征提取算法对人脸图像进行特征参数提取,然后利用优化的支持向量机进行识别。实验结果表明,该方法是有效的。     

A distributed system for learning programming on-line

Several Web-based on-line judges or on-line programming trainers have been developed in order to allow students to train their programming skills. However, their pedagogical functionalities in the learning of programming have not been clearly defined. EduJudge is a project which aims to integrate the “UVA On-line Judge”, an existing on-line programming trainer with an important number of problems and users, into an effective educational environment consisting of the e-learning platform Moodle and the competitive learning tool QUESTOURnament. The result is the EduJudge system which allows teachers to apply different pedagogical approaches using a proven e-learning platform, makes problems easy to search through an effective search engine, and provides an automated evaluation of the solutions submitted to these problems. The final objective is to provide new learning strategies to motivate students and present programming as an easy and attractive challenge. EduJudge has been tried and tested in three algorithms and programming courses in three different Engineering degrees. The students’ motivation and satisfaction levels were analysed alongside the effects of the EduJudge system on students’ academic outcomes. Results indicate that both students and teachers found that among other multiple benefits the EduJudge system facilitates the learning process. Furthermore, the experiment also showed an improvement in students’ academic outcomes. It must be noted that the students’ level of satisfaction did not depend on their computer skills or their gender.     

Development and evaluation of multimedia whiteboard system for improving mathematical problem solving

This study developed a web-based multimedia whiteboard system to help students learning with mathematical problem solving. The purpose is to promote a new online mathematical learning model that students not only use electronic whiteboard to write down their mathematical problem solving solutions but also use voice recording tool to give oral explanations about their thinking behind the solutions. To cultivate students’ critical thinking capability and encourage collaborative peer learning, the new learning model also requests students to criticize others’ solutions and reply to others’ arguments. With the multimedia supporting tools, students can communicate easily with each other about what they think and how they solve mathematical problems. We have conducted an experiment with sixth grade primary school students for evaluation. After the experiment, a questionnaire about students’ attitude toward the multimedia whiteboard system for math learning was then held. The results show that students were satisfied with the use of the multimedia whiteboard system for helping them with learning fractional division. Most students were interested in studying mathematics with the multimedia whiteboard system and thought this tool is particularly useful for doing collaborative learning. After analyzing the recorded solving processes and discussions content of students, we found that the performance of female students was superior to male students in communications and mathematical problem solving. Additionally, students with higher final exam grades had better mathematical abilities for doing critiques, arguments and communications.     

Recognizing and measuring self-regulated learning in a mobile learning environment

With the realization that more research is needed to explore external factors (e.g., pedagogy, parental involvement in the context of K-12 learning) and internal factors (e.g., prior knowledge, motivation) underlying student-centered mobile learning, the present study conceptually and empirically explores how the theories and methodologies of self-regulated learning (SRL) can help us analyze and understand the processes of mobile learning. The empirical data collected from two elementary science classes in Singapore indicates that the analytical SRL model of mobile learning proposed in this study can illuminate the relationships between three aspects of mobile learning: students’ self-reports of psychological processes, patterns of online learning behavior in the mobile learning environment (MLE), and learning achievement. Statistical analyses produce three main findings. First, student motivation in this case can account for whether and to what degree the students can actively engage in mobile learning activities metacognitively, motivationally, and behaviorally. Second, the effect of students’ self-reported motivation on their learning achievement is mediated by their behavioral engagement in a pre-designed activity in the MLE. Third, students’ perception of parental autonomy support is not only associated with their motivation in school learning, but also associated with their actual behaviors in self-regulating their learning.     

Examining students’ online interaction in a live video streaming environment using data mining and text mining

This study analyses the online questions and chat messages automatically recorded by a live video streaming (LVS) system using data mining and text mining techniques. We apply data mining and text mining techniques to analyze two different datasets and then conducted an in-depth correlation analysis for two educational courses with the most online questions and chat messages respectively. The study found the discrepancies as well as similarities in the students’ patterns and themes of participation between online questions (student–instructor interaction) and online chat messages (student–students interaction or peer interaction). The results also identify disciplinary differences in students’ online participation. A correlation is found between the number of online questions students asked and students’ final grades. The data suggests that a combination of using data mining and text mining techniques for a large amount of online learning data can yield considerable insights and reveal valuable patterns in students’ learning behaviors. Limitations with data and text mining were also revealed and discussed in the paper.     

Tracing elementary school students’ study tactic use in gStudy by examining a strategic and self-regulated learning

This study investigated, with the help of log file traces (f = 172), how 20 elementary school students used study tactics when studying science within the gStudy learning environment and examined how tactic use contributed to the students’ achievement. The analysis of this study is divided into two parts. First, at the situational level, the focus is on capturing the tactics that were used in different gStudy sessions, classifying the gStudy sessions based on the tactic use, and illustrating the patterned use of tactics during these sessions. Second, at the individual level, the focus is on examining individual students’ typical methods of using tactics, which helps to illustrate how tactic use contributes to the students’ achievement. The gStudy sessions were classified into three categories on the basis of tactic use: rare, moderate, and frequent. Findings indicate that frequent tactic use did not contribute to deep learning. Moderate tactic use was fairly effective for learning, but rare tactic use contributed to deep learning. The results did not show that the use of many study tactics improves learning; rather, they suggest that the distinguishing feature in strategic learning is not the tactic use itself but the way the tactic is performed.     

Active learning SVM with regularization path for image classification

In classification problems, many different active learning techniques are often adopted to find the most informative samples for labeling in order to save human labors. Among them, active learning support vector machine (SVM) is one of the most representative approaches, in which model parameter is usually set as a fixed default value during the whole learning process. Note that model parameter is closely related to the training set. Hence dynamic parameter is desirable to make a satisfactory learning performance. To target this issue, we proposed a novel algorithm, called active learning SVM with regularization path, which can fit the entire solution path of SVM for every value of model parameters. In this algorithm, we first traced the entire solution path of the current classifier to find a series of candidate model parameters, and then used unlabeled samples to select the best model parameter. Besides, in the initial phase of training, we constructed a training sample sets by using an improved K-medoids cluster algorithm. Experimental results conducted from real-world data sets showed the effectiveness of the proposed algorithm for image classification problems.     

Get out of MySpace!

To understand the student experience on social software, the research aims to explore the disruptive nature and opportunity of social networking for higher education. Taking four universities, the research: (1) identifies the distinction between the students’ current usage of social software; (2) reports on the students’ experience on opportunities and challenges of learning with social software; and (3) introduces principles as a guideline in using social software for learning. Quantitative research methods (web-based questionnaires) were incorporated to investigate the pattern of learners’ usage. Qualitative methods (student interviews) were adopted to clarify and further inform this relationship and their attitudes towards social software for learning. The results demonstrate a massive use of educational technology with distinct divide between the learning space and personal space. Student voices reveal that the central problem of such divide is due to the contrast perception and experience of ‘learning/studying and social life’. We argue that online learning and social personas may overlap but that learning needs to be designed so that it addresses the individual preferences to combine or separate the two domains. The paper concludes with a few principles of learning with social software grounded in students’ experience and Vygotsky’s paradigm.     

一种新的软间隔支持向量机分类算法

软间隔支持向量机（SVM）分类算法是目前最具有代表性的模式分类算法之一,它在应用中的一个主要困难是确定控制参数C.提出一种新的软间隔SVM分类算法,通过松弛变量改变约束条件,允许数据点进入分离区域但不越过分类超平面,从而避免了参数C的确定问题.计算机实验和故障诊断实例表明,基于新算法的SVM分类器有较高的分类准确性和较好的泛化性能,能够实际应用于模式分类.     

融合渐近性的灰狼优化支持向量机模型

大数据的发展对数据分类领域的分类准确性有了更高的要求;支持向量机(Support Vector Machine,SVM)的广泛应用需要一种高效的方法来构造一个分类能力强的SVM分类器;SVM的核函数参数与惩罚因子以及特征子集对预测模型的复杂度和预测精度有着重要影响。为提高SVM的分类性能,文中将SVM的渐近性融合到灰狼优化(Grey Wolf Optimization,GWO)算法中,提出了新的SVM分类器模型,该模型对SVM的参数与数据的特征子集同时进行优化,融合SVM渐近性的新灰狼个体将灰狼优化算法的搜索空间导向超参数空间中的最佳区域,能够更快地获得最优解;此外,将获得的分类准确率、所选特征个数和支持向量个数相结合,提出了一种新的适应度函数,新的适应度函数与融合渐近性的灰狼优化算法将搜索引向最优解。采用UCI中的多个经典数据集对所提模型进行验证,将其与网格搜素算法、未融合渐近性的灰狼优化算法以及其他文献中的方法进行对比,其分类准确率在不同数据集上均有不同程度的提升。实验结果表明,所提算法能找到SVM的最优参数与最小特征子集,具有更高的分类准确率和更短的平均处理时间。     

基于免疫优势克隆文化算法的故障诊断方法及其在TE过程中的应用

免疫优势克隆选择算法是一种新型的免疫算法,具有较强的局部和全局搜索能力.将其与文化算法结合,提出一种新型的免疫优势克隆文化算法,它可以更好地利用先验知识指导种群进化;并设计了新的动态接受函数来促进文化算法内部知识更新,提高算法的搜索能力.将该算法用于支持向量分类器的核参数优化中,构造性能良好的分类器,并将其用于Wine dataset的数据分类和化工TE过程的故障诊断中,实验结果表明,该算法能够准确地对SVM的核函数参数进行寻优,提高了故障诊断的准确性,具有应用推广价值.     

A non-biased form of least squares support vector classifier and its fast online learning

As an effective learning technique based on structural risk minimization, SVM has been confirmed an useful tool in many machine learning fields. With the increase in application requirement for some real-time cases, such as fast prediction and pattern recognition, the online learning based on SVM gradually becomes a focus. But the common SVM has disadvantages in classifier’s bias and the computational complexity of online modeling, resulting in the reduction in classifier’s generality and the low learning speed. Therefore, an non-biased least square support vector classifier(LSSVC) model is proposed in this paper by improving the form of structure risk. Also, a fast online learning algorithm using Cholesky factorization is designed based on this model according to the characteristic of the non-biased kernel extended matrix in the model’s dynamic change process. In this way, the calculation of Lagrange multipliers is simplified, and the time of online learning is greatly reduced. Simulation results testify that the non-biased LSSVC has good universal applicability and better generalization capability, at the same time, the algorithm has a great improvement on learning speed.     

The impact of Social Multimedia Systems on cyberlearners

The phenomenon of social learning analytics presents a synergy between variety of disciplines, such as business intelligence, educational data mining, cyberlearning, and cyber infrastructure. The main contribution of this research is to combine two types of social learning analytics, social learning network analysis and social learning content analysis in studying the impact of the Social Multimedia Systems (SMSs) on cyberlearners. The research study provided in this paper is based on the survey data collected in spring 2011 at Western Kentucky University. The evidence obtained from the analysis shows that SMS impacts (a) the digital communication between faculty and students; (b) students’ success and grades; (c) the amount of materials covered and learned; (d) the effectiveness of studying; (e) the depth of learning; (f) the ability to focus on the most important learning objectives; (g) the degree of collaboration among students; and (h) the students’ motivation of studying.     

Chaotic antlion algorithm for parameter optimization of support vector machine

Support Vector Machine (SVM) is one of the well-known classifiers. SVM parameters such as kernel parameters and penalty parameter (C) significantly influence the classification accuracy. In this paper, a novel Chaotic Antlion Optimization (CALO) algorithm has been proposed to optimize the parameters of SVM classifier, so that the classification error can be reduced. To evaluate the proposed algorithm (CALO-SVM), the experiment adopted six standard datasets which are obtained from UCI machine learning data repository. For verification, the results of the CALO-SVM algorithm are compared with grid search, which is a conventional method of searching parameter values, standard Ant Lion Optimization (ALO) SVM, and three well-known optimization algorithms: Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Social Emotional Optimization Algorithm (SEOA). The experimental results proved that the proposed algorithm is capable of finding the optimal values of the SVM parameters and avoids the local optima problem. The results also demonstrated lower classification error rates compared with GA, PSO, and SEOA algorithms.     

Optimization techniques for improving power quality data mining using wavelet packet based support vector machine

This paper aims at automatic classification of power quality events using Wavelet Packet Transform (WPT) and Support Vector Machines (SVM). The features of the disturbance signals are extracted using WPT and given to the SVM for effective classification. Recent literature dealing with power quality establishes that support vector machine methods generally outperform traditional statistical and neural methods in classification problems involving power disturbance signals. However, the two vital issues namely the determination of the most appropriate feature subset and the model selection, if suitably addressed, could pave way for further improvement of their performances in terms of classification accuracy and computation time. This paper addresses these issues through a classification system using two optimization techniques, the genetic algorithms and simulated annealing. This system detects the best discriminative features and estimates the best SVM kernel parameters in a fully automatic way. Effectiveness of the proposed detection method is shown in comparison with the conventional parameter optimization methods discussed in literature like grid search method, neural classifiers like Probabilistic Neural Network (PNN), fuzzy k-nearest neighbor classifier (FkNN) and hence proved that the proposed method is reliable as it produces consistently better results.