輔助高齡使用者評估的專家系統之開發： 以手機應用程式為例

The development of an expert system for elderly user evaluation: The smartphone application as an example

陳習之(HSI-CHIH CHEN)

指導教授 ： 盧俊銘

國立清華大學/工學院/工業工程與工程管理學系/碩士(2019年)

摘要

臺灣高齡人口的數量逐年增長，其購買潛力自然不容小覷，然而多數製造與開發者對於此類使用者的認識有限，導致市場上的消費性產品鮮少能完全滿足高齡族群的需求，也因此而錯失了良機。許多現有的人因工程的測試與評估技術能協助開發者了解使用者的需求並確認是否予以滿足，但通常需要有專業背景的人員始能順利執行，因此本研究期望發展一套專家系統，以輔助沒有評估經驗的開發者執行使用者評估，使其所開發的產品更加符合高齡使用者的需求。因高齡使用者接觸的產品類型眾多，本研究選定愈來愈多高齡者在日常生活皆會接觸、仰賴的手機應用程式做為研究標的物，在驗證此方法的可行性與有效性後，可再延伸至其他類型的產品或服務。
欲判斷一手機應用程式是否適合高齡使用者，大致上會經歷三個階段：（1）「有沒有使用此產品的動機、欲望？」，即高齡者接納一項新產品的心理需求；（2）「想要使用該產品後，實際操作時的基本互動—包含輸入以及輸出—是否符合使用者的能力限制？」；（3）「滿足操作的最低需求後，產品的操作過程是否有良好的易用性？」，例如是否直覺、順手…等。因此，本研究先將針對這三個面向搜尋相關文獻，以定義滿足各面向的評估指標、對應的測量工具與工具的使用方法、衍生的具體改善建議，進而整合為一套高齡使用者評估的知識資料庫，後續再開發容易理解、上手的使用者互動介面，即可以整併為一套專家系統。
當手機應用程式的開發者使用本研究開發的專家系統時，需依序完成三個步驟：（1）設定評估任務：選定欲評估應用程式中哪個流程，並輸入其任務名稱、任務敘述、預期應花費的時間等；（2）選擇手勢：選取該流程所涉及的操作手勢，如單擊、雙擊、拖曳…等；（3）設定易用性權重：成對比較效率、效用、可學習性、易接近性、通用性等五項易用性屬性，以決定相對重要性的排序。接著，系統將根據上述的設定提供高齡使用者評估的工具—包含評估指標、測量工具、評估流程—，待其邊參考邊自立完成、輸入評估結果後，系統會協助評斷當前的設計是否符合高齡使用者的需求，若有必要亦將提供具體的設計改善建議。
於系統開發完畢後，本研究招募兩位具備手機應用程式開發經驗且缺乏系統性使用者評估經驗的開發者、六位60歲以上的高齡使用者協助驗證此系統的可行性（無使用者評估經驗之手機應用程式開發者於開發過程中，能夠藉由此專家系統完成使用者評估的程度）；亦招募兩位手機應用程式開發者、七位60歲以上高齡使用者協助驗證此系統的有效性（開發者藉由專家系統的輔助完成使用者評估後，能夠依據評估結果改善應用程式的程度）與易用性（在使用專家系統取得使用者評估工具、執行使用者評估的過程中，手機應用程式開發者能夠達成效率、效能、滿意等目標的程度），其中協助驗證可行性的手機應用程式開發者與協助驗證有效性、易用性的開發者為相同兩人；協助驗證此系統的六位高齡者當中有四位協助驗證系統的有效性與易用性。
驗證結果顯示：缺乏系統性使用者評估經驗的手機應用程式開發者能夠有效率地藉由此專家系統的輔助於開發過程中完成使用者評估，且開發者自覺此專家系統提供的評估結果能夠有效地協助其改善手機應用程式；然而從高齡使用者的角度觀之，應用程式的改善未盡理想，並無法感受到明顯的差異，亦即有效性未盡理想。由於結果顯示此專家系統可行且易用，但有效性尚待改進，本研究進一步探討了影響有效性結果的潛在因素，包含開發者修改手機應用程式的動機與策略、高齡者填答評估量表的能力、開發者對高齡族群的熟悉程度、專家系統提供的評估協助之完整性、系統提供的改善建議之具體性等，並據此提出了專家系統的改善對策。
整體而言，本研究開發了一個專家系統，讓缺乏系統性使用者評估經驗的應用程式開發者能夠獨力執行高齡使用者評估，且系統可依評估結果提供改善建議以協助開發者修改手機應用程式，以符合使用者需求；基於系統驗證的結果，本系統應能輔助無使用者研究相關部門或專門人才的業者或個人評估開發的手機應用程式成品。此外，本研究蒐集並回顧了與高齡手機應用程式使用者的相關文獻，進而歸納整合為一涵蓋手機應用程式之易用性屬性、操作手勢、設計指引、高齡者心理需求的知識資料庫，未來亦可延伸應用於其他高齡使用者評估的相關研究。

關鍵字

易用性 ； 操作手勢 ； 心理需求 ； 設計指引

並列摘要

Despite the increasing growth of the elderly population in Taiwan, there are limited consumer products suitable for elderly users available in the market. Although there are many testing and evaluation methods to help confirm whether a product fits the user’s needs or not, most of them require an expert to get involved. Thus, this study aims to develop an expert system to help product developers who are without prior experience to easily conduct evaluation with elderly users, so as to better meet the elderly users’ needs. Among the many consumer products, mobile phone applications that have become more and more frequently used in daily lives were defined as the target product.
Before using a mobile phone application, the elderly may ask three questions: (1) “Does it satisfy my needs?” i.e. psychological needs that motivate the elderly to accept it. (2) “After being willing to use it, does the basic interaction fit my capability?” (3) “If the product fits the lowest requirement of use, is it easy to use?” To solve these problems, three aspects of knowledge were taken into consideration, including psychological needs, basic interaction, and general usability. Following this, literature review was conducted to define the three aspects of knowledge, that are subsequently integrated into a database. Integrated with an understandable and easy-to-use interface, an expert system was hence developed.
While using this system, the application developer has to first identify the tasks to be evaluated, including the name, description, and completion time of the task. After specifying gestures required for operation (such as tap, long tap, drag), the application developer has to set priorities of usability properties by making pair-wise comparisions among effectiveness, efficiency, learnability, accessibility, and generability. Subsequenity, evaluation tools will be automatically presented with instructions for the application developer to follow. Once the evaluation is completed, the system will help judge whether the design is suitable for elderly users. If needed, suggestions for improving the application will be provided as well.
After building the system, two mobile developers without any experience of systematic user evaluation and six elderly users over 60 years old were recruited to help validate the usability of the expert system. Besides, two developers and seven elderly users over 60 years old were recruited to help validate the effectiveness and feasibility of this system. The two developers are the same in all of the validation, whereas four elderly users help evaluate both usability and effectiveness of the expert system.
The results showed that mobile application developers without prior experience of systematic user evaluation can complete user evaluation with this system’s assistance, and they considered the evaluation results as helpful for improving the design of mobile applications. However, the elderly users didn’t recognize the difference between the original and revised versions of the mobile application, showing that the effectiveness of the system isn’t good enough. Interviews were further performed to help explore the possible factors that led to this result, including motivation and strategy for developers to modify mobile apps, the elderly user’s ability to well understand the evaluation scales, the developers' familiarity with the elderly users, the comprehensiveness of the assistance provided by the expert system, and the clarity of the suggestions for design improvement provided by the system. Following them, strategies for improving the expert system were proposed.
In summary, this study proposes a system to help mobile application developers conduct user evaluation with elderly users. Besides, suggestions for design improvement can be provided based on the evaluation results. According to the validation results, this system should be able to help companies or individuals evaluate the final product of mobile applications with elderly users. Besides, this study reviewed literature related to elderly users of mobile applications, and then integrated usability attributions, gestures, design guidelines and psychological needs of elderly users in a knowledge database. This database can be further extended for related studies in the future.

並列關鍵字

usability ； gesture ； psychological needs ； design guideline

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