Online learning is one of the components of the broader category of distance learning. This mode of learning generally refers to any learning where the instructor is separated from the students by either, time or location. For a long time, this kind of learning has gone on in form of correspondence studies. There are two types of online learning that are common in today's online practice. They are asynchronous and synchronous forms of instruction (Kevin, 2009). Synchronous literally means at the same time. In this type of training, the learner interacts with the instructor through the web in real time. In asynchronous training, the student receives work from the instructor for completion at one's own time of convenience (Fisk et al, 2009).
The synchronous training is currently not very common due to the technicality involved in its implementation. This training requires students who are geographically dispersed to access the same website concurrently with the instructor. In this training, the instructor broadcasts audio materials to the learners through web based audio or teleconference phone call (Kevin, 2009). The instructor uses slide shows which the learners watch while they are connected to the conference website. The students have a chance to interact with the instructor via chat window or by asking audio questions via the phones. This type of training is most suited to academic programs such as college distance learning modules or continuing training programs. Asynchronous learning is more common since it creates an on-demand, just-in-time learning experience for the student (Fisk et al, 2009). In this case students are not required to schedule their times in line with that of the instructor. This training comes in even more flexible forms referred as facilitated and self-paced asynchronous training. In facilitated asynchronous training, the instructor interacts with students at different times (Fisk et al, 2009). The instructor posts materials such as assignments on a web page including all the required references to the students. Students are then able to discuss and interact with each other via threaded discussions and then submit their work via email to the relevant authorities. Students in this type of training enjoy a lot of interaction with other peers on web based discussion threads (Fisk et al, 2009). A limitation in this type of training is the lack of oral communication which implies that hard to learn concept are not properly explained to students. There is also the challenge of fixing schedules between the students who are geographically disconnected to the instructors. Self- paced instruction is more common in corporations as opposed to academic institutions. In this instruction, stand alone materials are posted on the web by the instructors where they are accessed and completed on the internet. Materials in this kind of instructions could include assessment exercises, discovery learning simulations and guided tutorials.
The evolution and expansion of computer technology has gone hand in hand with a revolution of online continuing education. In today's workforce, the requirement for professional development through training is essential for one to compete effectively. For working adults, acquiring such needed development requires the input of more time which is limited in light of their family and social responsibilities. The online learning tools were developed as a tool to curtail some of the dilemmas experienced by individuals limited by time and space. Online learning has been able to overcome the challenges of physical obstacles and time limitations. More and more institutions of higher learning have developed online training programs with accredited authority in a rapid increment as compared to the previous years. The revolution in on-line learning rose from the need for institutions to meet educational desires and pursuits of non-traditional students who are limited in time due to other full time commitments. The invention of the evening and weekend classes did not fully meet the needs for adult education that over the weekends finds themselves tied up to family obligations .Hence, online education has come up as the ultimate answer to such groups of students (Askov & Simpson, 2001). For online education to be successful, it has required that such students be exposed properly to computer literacy. This has been boosted by the skyrocketing of familiarity and public exposure to general use of computers in the last two decades. Internet users in North America have significantly shot up to an estimated figure of 251,735,000, an overall 73.9% increase in North America alone compared to the year 2000 when the estimated internet users were 108,096,800 (Miniwatts, 2009). This is an indication that more and more people are now using the internet. The statistics are an indicator of the potential number of people that institutions doing online training can access with little input of resources. As a result of this, the new millennium has seen large number of institutions actively involved in the development of online programs tailored to meet international standards and students.
Hybrid/ Blended Instruction
A significant number of universities have adopted hybrid learning. Hybrid learning is often used interchangeably to refer to blended learning. In this learning, which is now common in online instruction, the traditional face to face instruction is integrated with well organized web-based modules. In the learning process, a significant percentage of the conventional face to face is replaced by online instruction (Koohang & Durante, 2003). Hybrid learning finds a lot of application in courses which contain practical experiments where students are supposed to do physical assignments as requirements for course qualification. In radiology, this type of learning would be more appropriate since it would give students a chance to interact with biomedical equipments during physical interactions and meetings with the lecturers. The face to face experience also gives learners a chance to clarify questions and explanations that they find hard to grasp in the written materials sent via web. The advantages of this type of learning, as found in literature are flexibility, increased interaction, reduced seat time, convenience, decreased costs and probable increased learning. The challenges associated with hybrid instruction have been cited as the complexity of developing programs that would be convenient for instructors and learners. This is in consideration that online programs cater for students from far regions and countries (Koohang & Durante, 2003). There is also the challenge of allocating necessary time for redesigning courses and adapting students to learn in hybrid systems.
History of online learning
Contemporary information technologies have been used throughout time to create and support educational institutions. Change in technology over ages has continually forced changes in instructional techniques to conform to the most current and reliable techniques. During the medieval times, educational exchange was carried through oral transmission and students were forced to rely on memory and word of mouth. The invention of paper and the printing press revolutionized learning which was now done using books (Sumrall, 2002). The change to books was faced by challenges such as book cataloguing and this called for the development of systems that could support easy instruction using books. The need to integrate technology with education is a constant requirement as new technology is bound to occur continuously. In the 21st century, the challenge facing education is the need to incorporate the internet and related tools to actualize e-learning (Sumrall, 2002).
There have been external degree programs (via correspondence) for a long period of time. Distance education first appeared in a catalog of University of Wisconsin in 1892 (Wisconsin University, 2005). Australia which is considered a model in online learning had correspondence programs from as early as 1890's primarily because of sparse population and irregular settlement patterns. In the US, correspondence learning, the model for online learning, occurred as early as 1920's. Columbia University, for instance offered correspondence programs in 1920. The emergence of exclusive online educational centers has however been more efficiently incorporated with the revolution of computers. The pioneers of online studies in the US were Regents College which offered Regents External Degree programs. The institution is now an accredited school. In the State of California, California Western University was also among the pioneers and is now a state approved institution. The online programs have been stigmatized for a long time with some people seeing them as inferior programs.