視障者網頁瀏覽可及性之設計改善

The Design for Improvement of Accessibility in the Internet Browse for the Blind and Visually Impaired

林芝嬅(Jhih-Hua Lin)

指導教授 ： 黃雪玲

國立清華大學/工學院/工業工程與工程管理學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00050

摘要

近年來，網際網路的使用已經成為現代人生活很重要的一部分；不受時間地點的限制便可自由取得資訊的特性，使其也成為視障者的一個新興資訊管道。
　　視障者藉由螢幕報讀軟體將螢幕上的平面視覺資訊轉換為線性的聽覺或觸覺資訊。然而許多網頁中複雜的結構、以及沒有替代文字的圖形資訊等，經常導致資訊無法被適當地轉換，使視障使用者容易迷失於網路之中，並影響其使用意願。雖然已有許多無障礙規範提出使網頁更容易閱讀的設計方法，然而目前仍有許多大型網站難以被視障者所閱讀。
因此本研究乃致力於提升視障者瀏覽網路的品質。首先使用GOMS分析台灣地區目前常用的兩種螢幕報讀軟體後，本研究發現在使用網路搜尋時，螢幕報讀軟體NVDA較台灣視障中小學普遍使用的導盲鼠有較佳的表現。爾後本研究藉由第一次可用性評估，探討網路搜尋以及NVDA對於國中視障生接收資訊所產生的影響；此外亦導入科技接受模型，探討影響視障者決定瀏覽網路的因素。
根據第一次的可用性評估結果，本研究發現視障者在使用網路搜尋前後，其接受資訊的績效仍須透過長期觀察乃能了解其真正變化。而科技接受模型的分析結果則顯示網路可及性是影響視障者決定是否使用網路的重要因素。
有鑑於此，本研究試圖協助視障者在網站中建立良好的心智地圖以進行定位，因而根據視障者瀏覽網路的心智模型提出兩套網站定位方案：瀏覽紀錄數列法、層級大小法，並設計第二次可用性評估進行衡量。統計分析後，結果顯示視障者在使用這兩種方法的情境下，比起沒有使用任何方法、自行瀏覽網站時的情境下，於效率、效益、滿意度皆有顯著的提升；即視障者在使用本研究所提出的兩種方法後，能有效建構網站的心理地圖。

關鍵字

視障者 ； 網際網路 ； 無障礙 ； 可用性評估 ； 科技接受模型

並列摘要

In recent years, the Internet has become an important part for people’s living activities. Due to the characteristic that is not restricted by time and place, the Internet also becomes a new information channel for blind and visually impaired.
Blind and visually impaired use screen readers so that the information on the screen can be transformed into the auditory or tactile messages. However, lots of information could not be transformed, and as the complex structure of web pages and the image without alternative text. Therefore, blind and visually impaired might lose themselves in the Internet and decrease their willingness to use the web. Though there are many accessibility guidelines for improving the design of web pages, a lot of web pages still do not comply with and are hardly read by the blind and visually impaired.
After using GOMS to analyze the screen readers that were widely used in Taiwan, it is found in this study that NVDA is better in the Internet surfing than G-mouse is. The latter is the most commonly-used screen reader for students in primary and secondary schools in Taiwan. Then a usability test is used to investigate if Internet searching using NVDA could improve the knowledge for the blind and visually impaired. In addition, Technology Acceptance model was used to find out the factors that could impact the blind and visually impaired using the Internet.
The result of the usability test did not reveal significant effect of using NVDA and the Internet search for the blind and visually impaired. The reason might be that the experiment time was limited in this study. Technology Acceptance model showed that the availability was one of the important factors that could influence the blind and visually impaired on using the Internet.
Therefore, the follow up study aimed to assist the blind and visually impaired to set up appropriate mental map of web site and provide the location information in a large web site. According to the mental model of the blind and visually impaired, two methods were designed: Hierarchy-size-method and Record-series-method. Then, the second usability test was conducted to evaluate the effect of the designed methods. The result showed that the blind and visually impaired could perform better as they used either method in terms of measurements of effectiveness, efficiency, and satisfaction. Less effort was needed by the users to establish the mental map of web site comparing to no method.

並列關鍵字

the blind and visually impaired ； the Internet ； accessibility ； usability test ； technology Acceptance model

參考文獻

35. Research, Development, and Evaluation Commission, Executive Yuan (2010). 電子治理成效指標與評估：G2A 與G2D。

3. Bernhard Beck-Winchatz, Mark A. Riccobono(2007). Advancing participation of blind students in Science, Technology, Engineering, and Math. Advances in Space Research, Volume 42, Issue 11, 1 December 2008, 1855-1858.

5. Bernhard Beck-Winchatz, Steven J. Ostro(2003). Using asteroid scale models in space science education for blind and visually impaired students. Astronomy Education Review 2 (2).

6. Bustamante, E. A., & Spain, R. D. (2008). Measurement Invariance of the NASA TLX. Human Factors and Ergonomics Society Annual Meeting Proceedings, 52, 1522-1526.

7. Christopher Newell(1994). People with disabilities and the information society. Issues and Opportunities for Health Promotion, Health Issues, (44), 29-30.