Nowadays, the Human Machine System (HMS) is considered to be a proven technology, and now plays an important role in various human activities. However, this system requires that only a human has an in-depth understanding of the machine operation, and is thus a one-way relationship. Therefore, researchers have recently developed Human Adaptive Mechatronics (HAM) to overcome this problem and balance the roles of the human and machine in any HMS. HAM is different compared to ordinary HMS in terms of its ability to adapt to changes in its surroundings and the changing skill level of humans. Nonetheless, the main problem with HAM is in quantifying the human skill level in machine manipulation as part of human recognition. Therefore, this thesis deals with a proposed formula to quantify and classify the skill of the human operator in driving a car as an example application between humans and machines. The formula is evaluated using the logical conditions and the definition of skill in HAM in terms of time and error. The skill indices are classified into five levels: Very Highly Skilled, Highly Skilled, Medium Skilled, Low Skilled and Very Low Skilled. Driving was selected because it is considered to be a complex mechanical task that involves skill, a human and a machine. However, as the safety of the human subjects when performing the required tasks in various situations must be considered, a driving simulator was used. The simulator was designed using Microsoft Visual Studio, controlled using a USB steering wheel and pedals, as was able to record the human ii path and include the desired effects on the road. Thus, two experiments involving the driving simulator were performed; 20 human subjects with a varying numbers of years experience in driving and gaming were used in the experiments. In the first experiment, the subjects were asked to drive in Expected and Guided Conditions (EGC). Five guided tracks were used to show the variety of driving skill: straight, circular, elliptical, square and triangular. The results of this experiment indicate that the tracking error is inversely proportional to the elapsed time. In second experiment, the subjects experienced Sudden Transitory Conditions (STC). Two types of unexpected situations in driving were used: tyre puncture and slippery surface. This experiment demonstrated that the tracking error is not directly proportional to the elapsed time. Both experiments also included the correlation between experience and skill. For the first time, a new skill index formula is proposed based on the logical conditions and the definition of skill in HAM.

Context: The problem this thesis address is concerned with experimental software engineering and is associated with validity of the studies with students as subjects. Often in software engineering experiments students are used because students are easily available and are willing to participate in experiment studies, professionals are rarely available to participate in research study and there are several benefits of using students as research subject.The validity of experiments studied with students are questioned because students are less experienced and skilled compared to professionals. Objectives: The goal of this research is to find evidence whether or not the research studies with students as subjects can be trusted to get valid results. Identify factors that influence the results of experiment studies with students. Identify the ways to improve the validity of experiment studies with students. Methods: In this systematic literature review a number of article sources are used, including Compendex, Inspec, IEEE Xplore, ACM Digital Library, and Springer Link. Experiment studies in software engineering are selected after reading titles and abstracts to decide whether the articles are relevant to the subject. Snowball sampling is done to identify several experiment studies that address same research problems. Results: It is found that graduate students serve as good proxies to study professional practices compared to undergraduate students, because there are significant differences between result/findings of studies with undergraduate students as subjects and studies with professionals as subjects. The following factors influencing the results of experiment studies are identified: Number of subjects, Task related knowledge, Motivation levels of subjects, Training provided, Task related experience and Incentives or grades given for participation in the experiment. This study also identifies some problems with the way of conducting and reporting experiments in software engineering. Addressing these problems could improve the validity of experiment studies with students. Conclusion: The results indicate that students can be used to study professional practices but they cannot be said true for all areas and problems of software engineering because the results of experiment studies with different type of subjects in different area and problems are varying. Which means that whether or not students could be used to study a professional practice depends upon the research problems being studied, type of students subjects chosen for the study, difference between students chosen and professionals to whom the results/findings will be generalized. We conclude that graduate students serve as good proxies to study professional practices compared to undergraduate students. The cumulative experience or overall industry or academic experience of subjects does not seem to be affecting the result/findings of experiment studies unless the overall experience includes task related experience. Even though the study identified above mentioned factors that influences the results/findings of experiment studies there still might be few factors which the study might have failed to identify due lack of data. We suggested improvements for reporting that could improve the comparability of studies. / Often in software engineering experiments students are used because students are easily available and are willing to participate in experiment studies, where as professionals are rarely available to participate in research study. This thesis investigates whether it is ok to use students as experiments subjects while studying professional practices. Thesis also investigates the factors which influences the results of experiment studies with students. The derived knowledge from the thesis can assists researchers improve the way of conducting and reporting software engineering experiments, It also aids in improving the comparability of experiment studies.