Usability Issues

‘Usability requirements specify the acceptable level of user performance and satisfaction with the system.’

Usability plays a very vital role in making an application user friendly and easy to use or vice versa. Due to the small size of mobile devices there are several changes that need to be accommodated according the need of applications used on it, for example a keyboard might become a touch screen or voice authentication, screen resolution and size will be smaller than a normal laptop screen. For some users it might be difficult to accept as there is a lot of deskilling in IT industry. But usability is one aspect which can make use of new devices very easy by considering its users and the targeted audiences. Usability can overcome several issues which might stop a potential user to get benefits from mobile computing or any new technology. Below are the important aspects needs considerations while designing a mobile computing device.

Form Factor of End User Device

Form factor deals with the size of hand held or mobile device, it is a very important design issue needs very much consideration before designing a new device or even providing an application on an existing device. Size makes a huge difference when it comes to usability as several applications only fail because of their bad design, for instance if the screen is too small to provide the full functionality of an application then alternate can be seek to provide same functionality but with less or simple usability.

Similar issues can thought when it comes to input method, before going into any kind of production or development of such applications it is always a good idea to consider the targeted users either they will accept it or not. People with partial or less vision mite need an alternative to hand help devices as they might not enjoy typing on a tiny keypad and get annoyed, alternatives can always be considered to overcome these issues. At this early stage where mobile computing is buzzing and several famous services like MSN Messenger, eBay, Yahoo and many other known services are showing a huge interest in mobile computing, this is the time to consider this critical issue of either user will be satisfied with the limited functionality or will accept full functionality on limited form factor.

Battery Life

The concept of being mobile means that anyplace anytime, but time can be an issue in this case. As the technology is advancing it also has some implications on the new technologies and battery life is one of them. Now days a simple phone with a built-in camera in it provide maximum of 6-8 hours of talk time or we can also say usage time. If same implies on the mobile or hand held devices how acceptable it will be for the user to rely on it. Below is list of talk time or use time of some famous mobile computing devices.


Talk / Usage Time (Hours)

RIM BlackBerry Curve


RIM BlackBerry 8800


Samsung UpStage


Motorola RAZR V3i


HTC Mogul


Nokia N95


Helio Ocean


RIM BlackBerry Pearl


Sony Ericsson W300i


Samsung SGH-i607


Table 1: Battery Life Chart

Looking at the figures in table 1 it can be seen that the maximum usage time for a device is 10 hours, will it be good enough for a regular user who is using computing in their business almost 24 hours a day, and once ran out of battery what will be the substitute for it, will user be carrying a spare battery every time, but this is not the solution if for some reason two batteries aren’t enough then what will be the possibility. Without the battery any electrical devices nothing more than a piece of stone, and the high tech application we are seeing in this modern era of computing for how long they can be lithium ion battery.

It needs consideration at design stage because at this applications can be designed to be able to run using minimum amount of battery.

Input Methods

After form factor it is one of the most important aspects needs considering at design stage, as we are aware that every computing device from a notebook to a PDA needs to be provided with some input in order to perform a task. Inputting information or data into a computing device can be done in several ways like touch screen, small keypad, voice recognition etc. if a suitable input method is not considered at design time it can lead the service to a failure, depending on the type of application it should be decided what type of input method will be used. It is quite obvious that different applications has different input needs for instance an accounting software mostly need a numeric pad where as an email device like blackberry might need both, do there will be enough flexibility when deciding the input method. To overcome this issue flexible input types should be provided or a combination of most needed depending on the application and the user as well. (Kent Lyons, 2004)

According to a research done at College of Computing and GVU Center Georgia Institute of Technology Atlanta, mobile input capabilities can be increased via two complementary methods:

- By increasing a user’s data entry capability with the Twiddler chording keyboard which can be attached with the mobile device and work as a keyboard. This will provide the same feeling and comfort of using a keyboard.

- Through reusing conversational information with a dual purpose speech.


Just looking back a year when iPod nano first came out users ended up cracking them in their pockets because of its delicate design and volatile body people were so use to the typical iPod that they problems with the durability of iPod nano. Similarly when a mobile device is design the element of toughness will never be ignored for instance if a mobile device is so delicate that it cannot be used on the go then it lost its purpose. At design time it is very important to consider the environment where the device will be used and must comply with it. If device is very delicate and needs more than extra care then user will be more worried about the care and always have a fear of damage.

These devices must be design to tolerate minor drops and falls and must not be very sensitive to the weather.

Health & Safety Issues

Several health and safety issues are related with the use of mobile phones which need consideration at design time. First of all is the risk of using battery assisted power supply which can in very few cases has caused fire, the famous example is of Dell laptops where a whole batch of production had a manufacturing fault in batteries causing a serious explosion. The use of battery material in this case need a lot of consideration as it is usually a pocket device and can cause serious injuries to the user in case of explosion or short circuit. (Paul Hales, 2006)

Due to the small size of hand held mobile devices screen might give eye sight issues in long run plus some other factors like constant use of touch screen or keypad might have some side effects. All these exceptions need consideration at design level because there are many implications which can be imposed in case it does not meet the health and safety standards.

Portable or Fixed

The aspect of being fixed here means that services should only be limited by only allowing them at certain places or where there is big user demand, but as soon as we hear the word mobile, the concept of being fix at a place doesn’t fancy it much. The reason for enabling mobile services is to provide freedom of place and access to information from anywhere and anytime.

The charm of mobile will be lost if it is fixed by providing services only at certain places not flexibly everywhere. A good example is the GPRS services which provide hot spots where users can access there data, but as soon as they are away from the hot spot they are unable to connect.

Both device and network should be portable so that they can be taken anywhere without the fear of having any geographical restrictions at least in one or more neighbouring countries. Imagine if we can only use our mobile phones at certain places instead of every where, we definitely don’t want to limit the benefits we are receiving from it.

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