Transcript

Basic Introduction

Welcome to the next lecture on Usability Testing. So till now we were looking into, how do we make prototypes and what are the different types of prototypes. Now we will get into the testing phase. Testing is very very important. You making a product without validating it with a customer. You might not be able to get or develop a better product. Even in academics if there is a set of teaching going on. End of the teaching there will be a small test to validate your knowledge or your understanding of the course.

So testing is very important. So from the testing, we might get more insight about the product. So now we will try to see the usability testing and primarily it will be focused towards efficiency of the product whatever you have developed.

Efficiency

• What is usability testing? Usability testing is a technique used in user-centered interaction design to evaluate a product by testing it on users. So here you will try to get all the experience. Aesthetics, form, color, texture. Then you will talk about functionality. Then you will talk about, when he tries to wear; response, the feeling, the effect, the betterment of the product, all these things.

So usability testing is a technique used in user-centric interaction design to evaluate a product by testing it on users. Till now maybe you yourself would have declared as a user and you would have tested it. Saying that it is vow! It’s like you standing in front of mirror and saying I look beautiful. It’s now what happens is, you try to show your product to others and try to get their feedback.

• This can be seen as an irreplaceable usability practice, since it gives direct input on how really user uses the system. For example when you try to develop a toy for a kid, and you keep the toy in front of the kid. The first thing what the kid will do is, it will try to put it into its mouth. So when you try to develop a toy, you would have not even thought about it. So that is what it is. Since it gives direct input. How real user uses the system. And when you try to develop a toy, it is also expected when a kid gets overenthusiastic or when it is bored, it throws the toy. So there will be an impact which comes on the toy, the toy still has to withstand.

Okay. So same way when you are trying to develop agricultural implements, the skill level of the people who are using the instruments or the product is not so great. And in the user field, you cannot ask them to do a feather touch. So it has to be as rugged as possible. And there is a huge impact load. The people who are involved there have lot of muscular power. So they would try to use it in a very vigorous manner. So if you try to make it completely with plastic or with anything else. It might fail in the first go itself. So that is what is how really user uses the system.

• Important testing parameters will be three, in that
  1. Efficiency
  2. Capacity
  3. And throughput

Are the three important testing parameters, which generally people use for testing it.

Efficiency

• The concept of efficiency is used to evaluate, how well a machine performs its designed task in terms of quantity and quality. For example I try to take 1 liter of fuel, fill it in my product and if the product gets drained. Or if the energy for running the product uses 1 liter of petrol in 5 minutes, then the product efficiency is extremely poor, however good might be your product, but it is no way energy efficient. So when we try to talk about that we try to talk in terms of efficiency. Second thing is what amount of mechanical load the farmer has to apply in driving the system. When I talk of agricultural implements, please don’t think only farm, it is also used for cattle rearing, and then it is also used for hair trimming which is used in sheep or extracting milk from cow. So all these things are part of agricultural implements. So here what is the efficiency it works.
• Owner and the manager of farm enterprise are deeply concerned with the efficient operation of the equipment and other resources, because inefficient operation leads to greater operating expenses and reduce the profitability. For example you try to develop a plowing machine, a mechanical plowing machine which costs around a lakh or which costs about x price. And with this x price, if he has to use it in his farm. And he will take the break even after 10 years. Then naturally people will not try to buy such capital intensive equipments, why because in agriculture industry it is always a seasonal based industry. So here it is not going to be used all through the year. So only in particular seasons it will be used in an efficient manner, and rest of the time maybe it will be idle. So we should keep that also in mind. So that is what they are trying to talk about here.
• Efficiency is usually expressed as a percentage. Because efficiency is a ratio of two quantities having the same unit. The unit gets cancelled. So you try to get a percentage of it. Percentage is calculated by comparing two quantities and multiplying it by 100.

Then efficiency maximize and minimize. So here it can be like a speedometer. It can be like a level indicator. It can be, nowadays people try to walk so many steps. It also tries to say efficiency in terms of exhausting energy. You can also talk in terms of finance. So there is an indicator which is used. So efficiency will always be shown in a pictorial manner. So you can see green means good. Red means poor or bad.

• So efficiency can be expressed mathematically in several forms. In the most general terms efficiency = output/input. Output is, what is the yield you are getting divided by what is the investment you have invested into the product to get the output.
• Efficiency is a ratio of what we got out of something relative to what we put inside. For example 1 kilowatt of power is given to a motor and the motor efficiency is only 20%, while putting it into good use. Then it is no way energy efficient
• If the output of 9 units is 9 units and the input is 10 units, the efficiency is 90%.
• If the output is 5 units and the input is 10 units, the efficiency is declared as 50%
• Efficiency can also be expressed by comparing the actual performance to the theoretical performance. So it can be expressed as actual/theory. For example you might say, I can run at 100 kms per hour, but actually you may run only 30 kms per hour. So this talks about human efficiency as 30%.
• It is important to remember that an efficiency calculation provides a mathematical answer.
• The answer is only a tool or an information, that can be used to make decisions.
• For example if you determine that the fuel efficiency of an automobile is 20 miles per gallon. That is not sufficient information to determine if the automobile is performing satisfactorily.
• This number must be compared to the historical performance, manufacturer’s guidelines, or the other data to take a decision whether it is efficient. Suppose you try to work. You are able to climb 10 stairs, first day, the next day you go to 11 steps. There is definitely a 10% improvement in your efficiency. But that does not mean that the system has become efficient. If a normal man is supposed to walk 30 steps per day and you have walked only 11 steps, when you compare it as against the standard, you are able to realize what is your efficiency. When it moves from 10 to 11; 10% improvement is a relative improvement. But it is always better to check with a standard data, or a manufacturer’s guidelines data

Performance Efficiency

• Performance efficiency refers to a quality of work done by a machine. The performance I write, the performance of plowing, the performance of a sickle. How frequently you have to sharpen? The material gets corroded. The swath which is used for cutting the grass in the farm. The wire which is attached to a grass cutter, the life of it. So all these things are performance.
• The importance of performance evaluation is not the same for all machines. Inside a machine there can be several sub-systems. Each of the sub-systems have different efficiency. And when you sum it up, some might be positive, some might be negative. When you sum it up, you get a different efficiency. So performance efficiency for a sub-system is different, for a full system is different. But unfortunately we will always talk in terms of a full system.
• For example the quality of a job for primary tillage like plowing is not as critical to the profitability of the farming enterprise, as the quality of the job for a combine.
• In addition it would be very difficult to mathematically evaluate the quality of plowing.
• For harvesting machines, performance efficiency is a measure of an actual performance of the machine compared to that of a desired performance.
  o For example if the machine is a combination, the bushels of grain harvested would be measured and compared to the total bushels of standing grains in the field.
• Combines could also be evaluated, according to the amount of damaged grain.
• Other harvesting machine would be evaluated on the basis of the amount of bruising of fruits or a number of cracked shells. So this is all talking about the performance efficiency.
• A combine can lose grains in three different ways: the gathering units can shatter grain from the head or drop heads. The threshing unit can fail to remove grain from the head as it passes through the machine, and the separation and cleaning unit can fail to separate the grain from the material other than grain.
• The losses are usually expressed as a percentage of the yield of the farm.
• Evaluating combine losses is a multiple-step problem.
• What we want to know is the amount of grain that the combine failure to put into the grain bin.

Field Efficiency

There is something also called as the field efficiency,

• Field efficiency is usually used to evaluate the performance of tillage or harvesting machines.
• It is a comparison of the actual amount of work done by a machine compared to what it would do with no lost time or capacity.
• The maximum rate that a machine can perform is determined by the width of the machine and the speed at which it travels. So field efficiency and performance efficiency are different.
• When a machine operates with a constant width, and travels at a constant speed. It would perform at 100% field efficiency.
• The machine is capable of 100% field efficient for a shorter period of time. But as soon as the speed changes or the width changes; the efficiency drops below 100%.
• The primary cause of loose efficiency is lost time, and a working width of the machine less than the maximum.

So a long narrow field can enhance the efficiency of the field operation. You can see how the plowing happens or how the harvesting happens in a narrow field. Long narrow field, how is it done.

In this lecture we talked about efficiency. Efficiency we talked about performance efficiency, we talked about field efficiency. I am sure you will be able to appreciate how are the usability tests made and one such technique is efficiency measuring technique.

Thank You.