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ÖgeConceptualisation and instrument development for mobile application usability based on android operating system(Lisansüstü Eğitim Enstitüsü, 2021) Kazdaloğlu, Abdullah Emin ; Gümüşsoy Altın, Çiğdem ; 682769 ; Endüstri MühendisliğiNotions such as mobile internet and mobile applications ceased to be a nascent concept when basic cell phones, which became prevalent in the society in the late 1990s, left their dominations to smartphones in the early 2010s. The technological infrastructure, which has made substantial progress in the framework of mobile concept, the organisational models of the companies and the penetration rate of the mobile internet among users exceeding the usage rate of desktop internet, has significantly speeded up the use of smartphones and mobile applications that may be used anywhere and anytime. Large-scale usage of mobile applications is based on companies developing mobile applications and directing their services to the context of mobile applications to remain firm in the competitive market. In this perspective, the Google Play Store and Apple App Store platforms, where mobile applications are delivered to users by Android and iOS operating systems respectively, stand out as an important figure with millions of different applications. The large number of mobile applications has given users the opportunity to turn to lots of different options. Hence, it has become requisite for companies to gain advantage in a strong competitive environment by better marketing their products and services in the digital environment in order to continue their viability. One of the essential points of ensuring adoption, preferability, and continuity in such a rapidly growing mobile application universe is that mobile applications can be used in a way that makes user experience better. Yet, when the literature was scrutinised well, it was noticed that mostly desktop computer or website usability models were adapted to the mobile device and application context or mobile application usability was tried to be evaluated with very usual criteria such as satisfaction, learnability, memorability, effectiveness, and effectiveness. It is crystal clear that the usability concept, which plays a more vital role in mobile technology, should not be addressed with the evaluation methods of desktop computers and these methods should not be directly adapted to the mobile device or mobile application concept. Therefore, mobile devices and particularly mobile applications with which users interact directly should have their own usability evaluation criteria. However, the lack of such a usability model for the Android operating system, which is one of the two largest operating systems and is currently preferred by roughly 4 out of every 5 smartphone user, is a major gap realised in the literature. Hereby, a comprehensive and conceptualised usability model for mobile applications running on the Android operating system should be established. In the literature part of this research, mobile technologies, mobile shopping applications that will be the subject of the analysis phase of the study, and the concept of usability are explained meticulously. A conceptual model for mobile application usability running on the Android operating system was established and verified with a survey instrument. Specifically, the guide for interface design of Android-based mobile applications, published by Google, was thoroughly analysed and adapted to the conceptual model. Then, in the light of this reviewed guide, 13 constructs illustrating the usability of mobile applications running on the Android operating system were originated. Open and axial coding was done following the methodology. The matrix was designed by listing these codes, and used in the next stage of this study. In the second phase of the methodology of this thesis, firstly items representing each construct within the context of the matrix were created and collected in the item pool. These items were first evaluated by experts and then by the end user, and items that were confusing, ambiguous and meaningless were removed from the pool or modified. In order to develop the scale, face validity check (pre-test), pilot test (n = 30) and content validity check (n = 41) were carried out, respectively. By virtue of these checks, a qualitative and quantitative (using PSA and CSV indices) evaluation of the scale was made. The study was strengthened by gathering feedback about the scale from those who voluntarily participated in these survey studies, and the corrections were made in the item pool thanks to the feedback received. The survey method was used in the analysis stage of this study. People using mobile shopping applications were selected as a target sample. In the analysis part, items in the item pool were adapted to the mobile shopping application concept. Several grounds for the analysis based on mobile shopping applications: increasing mobile shopping volume and popularity because of the Covid-19 pandemic, the reason some of the most downloaded applications in Google Play Store and Apple App Store in Turkey are shopping applications, large investments in the retail sector, policies of companies that direct their customers to mobile shopping and convenience and comfort factors with respect to customers. For exploratory and confirmatory factor analyses, two large samples (n1 = 293 and n2 = 340) were picked and factor, convergent and discriminant validation was fulfilled using IBM SPSS Statistics 26 and IBM SPSS AMOS 26 software. In addition, Cronbach's alpha values of the factors were calculated in both analysis stages and reliability was also measured. During the confirmatory factor analysis phase, nomological validation was made. For nomological validation, 13 constructs were taken into account as independent variables and examined how they affect the variables of brand loyalty, continued intention to use and satisfaction, which are frequently associated with usability in the literature. According to the analysis results, it was proved that the usability model created for Android-based applications has a significant effect on satisfaction, continued intention to use and brand loyalty and predicts these variables decently. Moreover, in the evaluation phase of both factor analysis, the fact that the loadings of the items included in the factors were above the required threshold approved this thesis. As a result, this study is very significant for practitioners working in the field of mobile applications. It will be a guide for mobile application developers and companies working in this sector. The created mobile application usability conceptualisation will allow the use of the practitioners to develop new mobile applications or to enhance an existing application. Therefore, in the last part of the study, the implications of the study and its theoretical contributions for practitioners are mentioned, besides.
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ÖgeInstrument development to evaluate the usability of OTT platforms(Graduate School, 2023-06-23) Coşkun, Muhammed Çağrı ; Gümüşsoy Altın, Çiğdem ; Pekpazar, Aycan ; 507181115 ; Industrial EngineeringHuman beings have begun to experience serious technological developments that started in the twentieth century and have been developing more rapidly since the beginning of the twenty-first century. In the twentieth century, various technologies were only accessible to the elite, but today all kinds of technologies have entered the lives of people of all ages. So much so that almost every action performed by human beings now has a dimension that touches technology. In particular, the introduction of many smart devices, such as smart phones and smart televisions, into people's lives and the fact that people benefit from these technologies have accelerated the transition to digital. Changes in people's needs have been very effective in this digital transformation. In recent years, there have been many technological developments to meet these needs. Thus, the transition to digital has changed the way many different jobs are done, and moreover, it has opened new opportunities for companies. One of the areas of change in this context is watching television, or in today's terms, content consumption, which has become a routine in people's daily lives. In the past, people used to watch black-and-white television channels, but with the development of digital technologies, a new generation of content broadcasting platforms has emerged that can be used on many different devices, such as phones, computers, and televisions. One of the biggest disadvantages of traditional television is that it broadcasts linearly, and another is that it broadcasts only on television, which means that people had to be tied to a place. Therefore, this change in people's needs has found new solutions thanks to technological developments. In this context, the concept of over-the-top (OTT), which is the subject of this study, has started to enter people's lives in the last two decades. OTT differs from traditional television in that it broadcasts over the internet and delivers content to users over the internet. When the OTT concept is examined, it is seen that there is not a single type but many different types. These differences arise from the adoption of different business models. A literature review reveals that there are five different business models: subscription-based, advertising-based, transaction-based, hybrid, and free. Companies that adopt the subscription-based business model offer subscriptions to their users with different payment options, such as monthly or yearly, for a certain fee and offer all content to their users during this period. Companies using the ad-based business model offer all their content free of charge to users, but in order to generate revenue, they show ads to users while they consume content. In the transaction-based business model, companies rent or sell their series or movie contents to users for a certain period of time. Companies that basically operate around these three business models can sometimes adopt more than one business model. The business model adopted by such companies is called hybrid. Apart from the four models, companies that offer their content to their users without any expectation of income have adopted the free business model. When the literature is examined, it is seen that there are some driving forces for users to switch from traditional broadcasting to OTT platforms. In this study, the driving forces are explained in six categories. The first driving force is the COVID-19 pandemic, which has caused a change in the lifestyles of all people. The COVID-19 pandemic started in 2020, and its impact lasted for a long time. During this time, people had to stay in quarantine and carry out their work at home. However, the long duration of this situation and the fact that people had to spend time at home made many people look for different activities. One of the most important of these activities is consuming content through various OTT platforms. Studies show that this trend has continued after the pandemic. The second driving force is people's desire to increase their comfort level. Traditional televisions, which cannot provide the desire to consume content anywhere and anytime without being tied to time and space, have accelerated people's turn to OTT platforms. The third driving force, technological developments, is one of the most important factors increasing the usage rate of OTT platforms. In fact, the widespread use of 5G technology following 2G and 3G, the cheapening of technological devices such as smartphones, and the launch of campaigns by telecom operators for OTT platforms have enabled OTT platforms to become widespread. The fourth driving force is the rich content that OTT platforms offer to their users. OTT platforms can measure whether content is liked or disliked through various methods, and moreover, they can determine what kind of content is more in demand. Therefore, OTT platforms have an advantage over traditional television in producing content that appeals to users. The fifth driving force is competition among OTT platforms. The high level of competition causes companies to work on different strategies and compete on price and content quality, and therefore these developments favor the user. The final driving force is the concept of binge-watching. This concept, which has emerged in recent years, means watching several episodes of a series at once. In particular, companies such as Netflix, which releases all episodes of a season on the same day, have led to the development of this concept. This behavior, which is also quite common among young people, is associated with OTT platforms and affects the increase in their usage rate of OTT platforms. In this context, the fact that people of almost all ages have started to use OTT platforms has led to the emergence of many usability problems. In research on usability, researchers have interpreted usability in different ways. In some studies, usability has been referred to as efficiency and satisfaction, but it has also been referred to as learnability. The concept of usability, which is also examined in standards such as ISO 9241 and ISO 9126, has been the focus of companies such as Google, Microsoft, and Apple, and they have published guidelines for developing user-friendly interfaces. However, with the emergence of various design approaches, usability evaluation has become essential. As a result of the literature review, usability evaluation methods have been divided into three main categories: inspections, testing, and inquiry techniques. The methods related to inspection, where the focus is on expert evaluation, consist of heuristic evaluation and cognitive walking methods. There are many methods within testing methods. In usability evaluation, methods such as field work, laboratory work, and remote testing can be used, while testing methods can also include think-aloud and focus group studies. In the last class on inquiry techniques, different scales could be used. Examples of these methods are the system usability scale and the questionnaire for user interaction satisfaction. As a result, researchers have many options for evaluating usability. Within the scope of this study, a survey was developed to evaluate the usability of OTT platforms that provide web-based services. In this study, which started with literature research, Google, Microsof, IBM, Apple TV guidelines, WCAG 2.1, WCAG 3.0, ISO 9126, and ISO 9241 standards were examined in detail to determine the factors affecting usability, and categorical structures were tried to be created. In this study, in which a method consisting of six stages was followed, the Apple TV manual played the main role. First, the Apple TV manual was analyzed line by line to create a conceptual structure, and all sentences that could be related to usability were collected. Using open and axial coding technique, the collected statements were grouped together according to their similarities and divided into categories that were thought to represent them. These categories were accessibility and customization, account management and user features, brand perception and identity, data entry and search, design and layout, help and support, navigation, privacy and data protection, and streaming and content delivery. Then, in the second stage of the study, a face validity check was conducted. The aim of this stage, in which all criteria were evaluated by expert, was to eliminate the ambiguity and semantic problems of the collected criteria. Three accredited employees participated in the face validity check. Following this stage, a pilot test was carried out with 26 real users, again to eliminate the ambiguity and semantic problems of the criteria. In the final stage of this phase, a content validity check was conducted with the participation of 30 users. In this stage, PSA and CSV indices were calculated to measure the extent to which each criterion corresponds to the categorical structure. As a result of this part, final changes were made to the criteria pool, and the third stage of the method was started. In the third stage, explanatory and confirmatory factor analyses were conducted to evaluate the measurement properties of the prepared scale. In the exploratory factor analysis stage, 650 users evaluated the Netflix website. Then, using the IBM SPSS 25 program, factor loadings and Cronbach's alpha values were calculated. In the next stage of confirmatory factor analysis, a new survey was conducted with 600 participants. The convergent and discriminant validity was tested by using IBM SPSS 25 and IBM SPSS Amos 25 programs. The Cronbach's alpha values, average variance extracted (AVE), composite reliability (CR) values and goodness of fit and badness of fit indices were calculated. Nomological evaluation was also made at this stage. The extent to which the nine factors are explained by the independent variables (brand loyalty, intention to continue use, and satisfaction output) frequently used in the literature was calculated. When the results were analyzed, it was seen that the nine factors explained the variables of brand loyalty, intention to continue using, and satisfaction to a great extent. As a result, this study will be a very good guide for designers who will design interfaces for web-based OTT platforms. In this study, which can be used to evaluate the usability of any designed OTT web interface, the criteria of the questionnaire can be used as a checklist, or design improvements can be made by considering categorical structures. In addition, the methodology followed in this study can be used by researchers to develop scales for the evaluation of different platforms for usability evaluation.
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ÖgeUsability of mobile applications: A conceptualization and instrument development study based on Apple human interface guidelines(Graduate School, 2023-04-07) Yıldız Çetin, Kübra ; Gümüşsoy Altın, Çiğdem ; 507191117 ; Industrial EngineeringSmartphones and their services make people's lives much more accessible and enable them to use their limited resources more effectively. With the advancement in technology, the capabilities of smartphones have also increased, and several mobile applications have been developed. Through these mobile applications, people can perform and manage many activities, from making hospital appointments to financial transactions, communication, and educational activities. For instance, mobile e-government applications enable various public services to be performed with a single click with less physical effort. Being available at any time and from any location is one of the most important advantages of mobile applications. The portability of mobile devices and their suitability for a variety of user settings are important features for users. Users always expect to be able to seamlessly enjoy the service a mobile application promises to deliver. However, the use of mobile applications in a wide range of usage environments and some physical constraints, such as small screen sizes, are the factors that complicate usability studies for mobile applications. The ever-evolving nature of smartphones, in parallel with developed technology, also complicates the design of mobile application interfaces. All these difficulties and the continued widespread use of mobile applications have accelerated the studies related to mobile application usability. Initial studies on mobile application usability were derived from previous studies on website usability. However, the characteristics of websites differ from mobile applications in terms of the devices they are used and the usage environment. Therefore, the usability of mobile applications should be handled individually. In the literature, an essential part of the studies on mobile application usability focus on only one type of mobile application, such as mobile health, mobile commerce, and mobile learning. These studies are helpful in evaluating usability for a particular type of mobile application. On the other hand, this study provides a comprehensive usability model that may be used in the design and evaluation phases of any kind of mobile application by software developers. Furthermore, the developed survey instrument based on the mobile application usability concepts evolved may be used to understand the significant factors in the usability assessment of mobile applications from the users' perspective. In this study, a three-step formal methodology was used to conceptualize and develop a survey instrument: conceptualizing the constructs, developing the scale, and evaluating the measurement properties. In the first stage, the first matrix of open codes was created by examining Apple's human interface guidelines line by line, which was taken as the main source of the open and axial coding procedure for the conceptualization of constructs. This open code matrix, consisting entirely of qualitative data, was then examined eight more times and open and axial coding procedures were applied. The finalized matrix consists of 16 axial codes, 29 subcategories, and 92 open codes. Sixteen constructs are conceptualized, namely instant start, branding, orientation, collaboration, content, search, privacy, graphics & animations, realism, control obviousness & reliability, effort minimization, consistency & standardization, concise & user-driven language, feedback, navigation, and transition. In the second stage, an initial item pool consisting of 113 items measuring 16 constructs was created by making use of the open codes created in the previous section and the relevant literature. The initial version of the items was screened with a procedure. First, a face validity check was performed to eliminate vague items. Then the survey items were applied to real users with a pilot study, and a content validity check was performed to validate the items. As a result of analyses, 69 items representing 16 constructs were revealed to evaluate the measurement properties of the scale. At the final stage, the measurement properties of the developed survey instrument were evaluated with exploratory and confirmatory analyses. The factor structure was discovered with the first collected data (n1=476), and the discovered factor structure was confirmed with the second data collected with different participants(n2=583). The target audience of these survey studies is social media mobile application users, which is one of the most widely used mobile application types and appeals to a large part of society. In the exploratory analysis, two items with factor loadings lower than the threshold value were excluded from the item pool. Confirmatory analysis was performed with 67 items representing 16 constructs to validate the constructs and their corresponding items revealed with explanatory analysis. The internal reliability, convergent validity, discriminant validity and fit indices of the measurement model were examined, respectively. Finally, for the nomological validity of the developed scale, the fit indices of the structural model and the effects of constructs on satisfaction and continued intention to use were examined. The results show that the scale developed for mobile application usability explains a significant part of the variability in satisfaction and continued intention to use. In addition, the significant relationships between mobile application usability constructs and satisfaction and continued intention to use provide evidence for the applicability of the developed survey instrument.