Greg C. Lee

Enhancing the teaching experience of pre‐service teachers through the use of videos in web‐based computer‐mediated communication (CMC)

The provision of feedback to students is an important aspect of teaching and learning processes. It is often a necessary requirement for the stimulation of self‐reflection. This paper describes the use of video‐enabled, web‐based computer‐mediated communication (CMC) for the provision of feedback to pre‐service, trainee teachers who were involved in a Teaching Practicum course within a teacher‐education programme. Pre‐service teachers’ micro‐teaching and field‐teaching performances were videotaped and made available for viewing within the CMC system. Experienced high‐school teachers were asked to critique the pre‐service teachers’ performances and to lead the discussions using the CMC system. The results of questionnaires that were administered to all participants of the study indicated that the system effectively enhanced pre‐service teachers’ teaching experience. Five reasons cited for the success were: easy access to taped teaching sessions; better assessment of personal teaching style; more sharing of one’s teaching and more learning from peer teaching; more concrete feedback; and more effective involvement of experienced teachers.

A team-teaching model for practicing project-based learning in high school: Collaboration between computer and subject teachers

Project-based learning (PBL) is a highly effective means of motivating students to learn independently. However, training or encouraging teachers to practice PBL in their classrooms is challenging, especially if the educational system does not accommodate creative teaching practices. In particular, in a test-driven educational system, time constraints and an excess of teaching content makes it difficult to practice PBL at the high school level. This work presents a novel team-teaching model that is based on collaboration between subject teachers and the computer teacher to facilitate PBL in the classroom. A two-year experiment was conducted to study the feasibility of the proposed model, in which the school computer teacher conducts PBL with the 10th grade students in the first year, and subject teachers conduct PBL with the 11th grade students in the second year. Experimental results indicate that the proposed model is feasible in the given educational setting. No class time was lost, and the subject teacher successfully conducted PBL activities. Furthermore, a follow-up survey indicated that the students enjoyed the PBL activities in both classes.

Use of BBS to facilitate a teaching practicum course

Abstract In this paper, a study on using the electronic bulletin board system (BBS) in promoting reflective thinking among student teachers in a teaching practicum course is presented. With the aid of BBS, student teachers have opportunities to exchange teaching experiences, which indirectly develops reflective thinking.

Region-based image retrieval using color-size features of watershed regions

This paper presents a region-based image retrieval system that provides a user interface for helping to specify the watershed regions of interest within a query image. We first propose a new type of visual features, called color-size feature, which includes color-size histogram and moments, to integrate color and region-size information of watershed regions. Next, we design a scheme of region filtering that is based on color-size histogram to fast screen out some of most irrelevant regions and images for the preprocessing of the image retrieval. Our region-based image retrieval system applies the Earth Movers Distance in the design of the similarity measure for image ranking and matching. Finally, we present some experiments for the color-size feature, region filtering, and retrieval results that demonstrate the efficiency of our proposed system.

Assembler for de novo assembly of large genomes

Significance Assembling a large genome faces three challenges: assembly quality, computer memory requirement, and execution time. Our developed assembler, JR-Assembler, uses (a) a strategy that selects good seeds for contig construction, (b) an extension strategy that uses whole sequencing reads to increase the chance to jump over repeats and to expedite extension, and (c) detecting misassemblies by remapping reads to assembled sequences. Compared with current assemblers, JR-Assembler achieves a better overall assembly quality, requires less execution time and requires, with one exception, less memory. The advantages of JR-Assembler in memory usage and execution time will increase slowly as the read length increases. Thus, contrary to the prevailing view, the extension approach seems superior to the de Bruijn graph approach. Assembling a large genome using next generation sequencing reads requires large computer memory and a long execution time. To reduce these requirements, we propose an extension-based assembler, called JR-Assembler, where J and R stand for “jumping” extension and read “remapping.” First, it uses the read count to select good quality reads as seeds. Second, it extends each seed by a whole-read extension process, which expedites the extension process and can jump over short repeats. Third, it uses a dynamic back trimming process to avoid extension termination due to sequencing errors. Fourth, it remaps reads to each assembled sequence, and if an assembly error occurs by the presence of a repeat, it breaks the contig at the repeat boundaries. Fifth, it applies a less stringent extension criterion to connect low-coverage regions. Finally, it merges contigs by unused reads. An extensive comparison of JR-Assembler with current assemblers using datasets from small, medium, and large genomes shows that JR-Assembler achieves a better or comparable overall assembly quality and requires lower memory use and less central processing unit time, especially for large genomes. Finally, a simulation study shows that JR-Assembler achieves a superior performance on memory use and central processing unit time than most current assemblers when the read length is 150 bp or longer, indicating that the advantages of JR-Assembler over current assemblers will increase as the read length increases with advances in next generation sequencing technology.

Real-time eye-gaze estimation using a low-resolution webcam

Eye detection and gaze estimation play an important role in many applications, e.g., the eye-controlled mouse in the assisting system for disabled or elderly persons, eye fixation and saccade in psychological analysis, or iris recognition in the security system. Traditional research usually achieves eye tracking by employing intrusive infrared-based techniques or expensive eye trackers. Nowadays, there are more and more needs to analyze user behaviors from tracking eye attention in general applications, in which users usually use a consumer-grade computer or even laptop with an inexpensive webcam. To satisfy the requirements of rapid developments of such applications and reduce the cost, it is no more practical to apply intrusive techniques or use expensive/specific equipment. In this paper, we propose a real-time eye-gaze estimation system by using a general low-resolution webcam, which can estimate eye-gaze accurately without expensive or specific equipment, and also without an intrusive detection process. An illuminance filtering approach is designed to remove the influence from light changes so that the eyes can be detected correctly from the low-resolution webcam video frames. A hybrid model combining the position criterion and an angle-based eye detection strategy are also derived to locate the eyes accurately and efficiently. In the eye-gaze estimation stage, we employ the Fourier Descriptor to describe the appearance-based features of eyes compactly. The determination of eye-gaze position is then carried out by the Support Vector Machine. The proposed algorithms have high performances with low computational complexity. The experiment results also show the feasibility of the proposed methodology.

Content-based watermarking in image authentication allowing remedying of tampered images

Fragile watermarking techniques are developed to ensure the credibility and integrity of images in open communication channels. Many related studies have proposed methods for accurately localizing tampered areas, but the ability to recover such areas has received less attention. Therefore, we propose a content-based fragile watermarking technique that can both accurately localize tampered areas and correct them in details, using embedded content-based watermarks. Our scheme provides a novel watermark structure. It adopts JPEG-compressed watermark prototypes and categorizes them into smooth, mid-textured, and textured areas. To resist forged-watermark attacks and promote self-recovery ability, the relationships among blocks are created by a toral automorphism with an asymmetric key structure. Furthermore, the watermark prototypes are disordered by a one-way hashing function and encrypted by a public-key encryption function to increase the security of watermarks. Finally, the watermarks are embedded to protect the integrity of images. Experiments show that the proposed scheme can correctly localize tampered areas and remedy them to the extent of JPEG-compression quality even when 50% of the image is cropped, and resist forged-watermark attacks.

Indexing and Teaching Focus Mining of Lecture Videos

This paper proposes an indexing and teaching focus mining system for lecture videos recorded in an unconstraint environment. The slide structure can be reconstructed by an edge-based shot change detection algorithm. Besides, the teaching focus can be extracted according to instructor’s behavior, including the gesture, the lecture time for each slide, and the speech speed. Experiment results show the feasibility of the proposed method, that is, the slide shots can be correctly detected even if the illumination conditions is variant or the slides are obstructed by the instructor or students, and the teaching focus can be well extracted to provide learners an efficient way to study.

Using Concept Maps to Aid Analysis of Concept Presentation in High School Computer Textbooks

In this study we use concept maps as the tool for examining concepts presented in three high school computer textbooks. All three textbooks were endorsed by Taiwans Ministry of Education (MOE). The concepts relating to CPU was selected as a sample for analysis. Two high school computer teachers first worked independently and then together to draw concept maps for each of the textbooks. Our analysis revealed that the textbooks did not cover the important concepts appropriately and failed to address the connections between the concepts. While all three textbooks elaborated on some concepts using examples, only a few analogies were used. The study also showed that concept maps can be an effective tool for analyzing the conceptual framework of important concepts within a textbook.

Visualizing programming in recursion and linked lists

Taipei, Taiwan 106 Ieeg, mjlin]@ice.ntnu. edu.tw