A Clickstream Analytical Tool for Video LecturesYao-Yu Yang
The paper presents an ongoing development of an analytical tool for the clickstreams of video lectures. This work was motivated by the increasing number of video tutorials in graphical software applications. Although the clickstreams have been used to examine students’ detailed behaviors, few analytical tools have been designed from the instructors’ viewpoint. The tool we have developed includes four major interfaces: (1) accumulated behavior, (2) individual time history, (3) video control, and (4) a note-taking area. We also designed a global time controller, which users may move in all of the interfaces except the note-taking area, thus synchronizing the time stamps among the other interfaces. An actual CAD video lecture clickstream of 53 students and 103,679 clicks was used to validate the tool. We found that the analytical tool can help identify students' behaviors.
2013APRU_NO40-abstract-mobilePIV_YangYaoYuYao-Yu Yang
Limited particle image velocimetry (PIV) methods were used in field due to three main difficulties: 1. On-site computing device is needed; 2. An observing station is required for cameras; 3. The locating and camera calibration are complex. To overcome these problems, we used four parallel laser pointers as ground reference points and a smartphone as a computing core for calculating and demonstrating the flow field of the river. The research verified and showed the feasibility of the device. In conclusion, we developed a portable, affordable and easy-operation flow field measuring device.
1) A student named Kevin was in a serious car accident and had to use a wheelchair. He felt depressed being unable to navigate obstacles.
2) Engineers from NTU developed BotBeep Clip, a device that detects obstacles using laser light and camera and warns users with beeping sounds.
3) The simple, low-cost device helps wheelchair users gain independence by alerting them to obstacles and can also call for help in emergencies by connecting to social networks.
A Clickstream Analytical Tool for Video LecturesYao-Yu Yang
The paper presents an ongoing development of an analytical tool for the clickstreams of video lectures. This work was motivated by the increasing number of video tutorials in graphical software applications. Although the clickstreams have been used to examine students’ detailed behaviors, few analytical tools have been designed from the instructors’ viewpoint. The tool we have developed includes four major interfaces: (1) accumulated behavior, (2) individual time history, (3) video control, and (4) a note-taking area. We also designed a global time controller, which users may move in all of the interfaces except the note-taking area, thus synchronizing the time stamps among the other interfaces. An actual CAD video lecture clickstream of 53 students and 103,679 clicks was used to validate the tool. We found that the analytical tool can help identify students' behaviors.
2013APRU_NO40-abstract-mobilePIV_YangYaoYuYao-Yu Yang
Limited particle image velocimetry (PIV) methods were used in field due to three main difficulties: 1. On-site computing device is needed; 2. An observing station is required for cameras; 3. The locating and camera calibration are complex. To overcome these problems, we used four parallel laser pointers as ground reference points and a smartphone as a computing core for calculating and demonstrating the flow field of the river. The research verified and showed the feasibility of the device. In conclusion, we developed a portable, affordable and easy-operation flow field measuring device.
1) A student named Kevin was in a serious car accident and had to use a wheelchair. He felt depressed being unable to navigate obstacles.
2) Engineers from NTU developed BotBeep Clip, a device that detects obstacles using laser light and camera and warns users with beeping sounds.
3) The simple, low-cost device helps wheelchair users gain independence by alerting them to obstacles and can also call for help in emergencies by connecting to social networks.
2. 用傳統定位參考點,經過水槽與模擬影像的驗證。最後,在行動手機照相計算與通訊
技術方面,由於開發手機的攝影與計算功能時需要考慮維持手機的功能性,我們透過 Java
Native Interface(JNI),將在 C++開發環境開發的程式植入手機程式中,利用此種隔離式開
發方式,有助於確認演算法正確性與手機功能性。本裝置經過雷射平行測試、雷射點定位
測試和流場方向偵測測試,證實此方法具可行性。
關鍵字:影像辨識、表面流速、行動裝置、雷射參考點、裝置整合、非接觸式
Development of a Mobile Surface Flow Measuring Device
Using Image Analysis
Yao-Yu, Yang6
、Franco, Lin7
、Min-Cheng, Wen8
、Wen-Yi, Chang9
、Shih-Chung, Kang10
Abstract
During flooding events, the traditional velocity measurement in the river may put the surveyors in
danger, hence the development of non-contact measurements is necessary. The particle image velocimetry
(PIV) has been recognized as one of the potential and precise methods in the recent studies. However, an
on-site PIV has two main difficulties: 1. the difficulty for camera and computer installation in the field;
and 2. the high labor needed for conducting the field survey and system calibration. In this study, we
developed a mobile PIV device, which includes techniques of the laser projection as ground reference
points, the flow image recognition method and the integration of communication, computation and
display on the mobile phone. Now, the mobile PIV device has been validated in the laboratory
experiments. In the future, we would like to extend this study to practical applications.
Keywords: image recognition、surface flow velocity、mobile device、laser reference point、device
integration、non-contact
6
Computer-Aided Engineering Group, Department of Civil Engineering, National Taiwan University,
student
7
National Center for High-performance Computing, National Applied Research Laboratories,Assistant
research fellow
8
Computer-Aided Engineering Group, Department of Civil Engineering, National Taiwan University,
student
9
National Center for High-performance Computing, National Applied Research Laboratories,Associate
research fellow
10
Computer-Aided Engineering Group, Department of Civil Engineering, National Taiwan University,
Associate professor
9. 正方式改為萬向輪軸校正,使雷射平行精度提
升,並以延時計算的方式解決手機影像取樣頻
率低的問題,再以計算實驗水流與實際河流流
速做測試,以完整研究與開發此裝置。
五、誌謝
本研究承蒙行政院國家科學委員會計
畫補助(NSC 101-2625-M-492 -006)及財團法
人國家實驗研究院國家高速網路與計算中心
提供計算資源,謹此致謝。
六、參考文獻
李戎威,「淡水河即時洪水預測模式之建立及實
務應用」,Taiwan Association of Hydraulic
Engineer,第 9 期,第 1-37 頁 (2006)。
「中水局轄區測站流量測定成果報告」,經濟部
水利署中區水資源局 (2007)。
Chih-Weiempty, C.,” The study of velocity
distribution measurement by using ADCP for
natural river - a case study on Zengwun discharge
gauging station,” Master Dissertation, Department
of Hydraulics and Ocean Engineering, National
Cheng Kung University (2012).
Ying-Chih Lin, Mu-Shou Chu, Hsun-Chuan Chan,
Shen-Ching Kao, Jan-Mou Leu , "Estimation of
High Discharge Using Measured Surface
Velocity," Journal of Chinese Soil and Water
Conservation, 42(1), 23-36 (2011).
Fujita, I. and T. Hino, "Unseeded and seeded PIV
measurements of river flows videotaped from a
helicopter," Journal of Visualization, 6(3),
245-252 (2003).
「即時三維立體影像技術量測河川高流量研究
計畫」,第十河川局,台灣水利署 (2008)。
Zhang, Y. and Z. Wang. “A Flexible Camera
Calibration Method for Computer Visual 3D
Reconstruction System,”, 8th International
Conference on Signal Processing (2006).
Ming-Ching Lee, ” Development of Non-contact
Methods for Water Surface Velocity and River
Discharge Measurements,” Ph.D. Dissertation,
Department of Hydraulic and Ocean Engineering,
National Cheng Kung University (2003).