Human Computer Interaction

By: Ajmal Khan

When looking at HCI, research will be done to help give a better understanding as to what aspects need to be taken into consideration when designing eCan ecommerce. It is essential for . This is what will be researched and taken into consideration:

Disabilities

Visual

Errors

Administration

Usability

Disabilities are spilt into "Cognitive, perceptual and physical impairments (PIs)". These disabilities "can all hinder the use of computing technologies".

"Aging can have substantial effects on cognitive ability". This can be influenced by perceptual and physical impairments. Human beings can suffer mild impairment which will not affect their ability to use programs. Some suffer from a combination of impairments, though mild, can cause problems. The problem this causes is that not all problems can be catered for. Cognitive decline can be aided by designing systems to "allow every step to be carried out at the user's own pace", primarily defines the old from the young as additional time to complete tasks is required by older people as their cognitive functions have declined over time.

Attention is another cognitive impairment can be caused by aging, immaturity, emotional problems and genetics. To minimise attention problems here is "to grab the users' attention" by highlighting critical information appropriately, to keep the interest of the user. Memory loss and Dementia is another to be taken into consideration. "Limitation in memory affects people with age and non-age related cognitive impairment" wherever feasible, designs need to be carefully planned and implemented to minimise "the burden of memory off the user" by the use of "prompts and reminders" and navigation. One of the largest causes of dementia is Alzheimer's Disease and strokes.

Visuospatial, Iconic and Verbal Abilities are another three cognitive types that needs to be considered. Other than memory there is marked "decline in visuospatial and verbal abilities in older people" causing difficulty with layout, organisation, iconic memory and limitations in verbal ability, these symptoms are apparent in Autism affecting people of all ages. So we will take in to consideration by the layout and text. Designs could well be put in place with thorough research aid people with strokes, but with Alzheimer's it would be very difficult in the long term as the condition gets progressively worse over time.

Perceptual impairment is split in to "hearing impairments, mental impairments, speech impairments and visual impairments".

Hearing is "constantly fluctuating air pressure" and is converted in the form of "pitch, timbre and loudness" this is done through the three parts of the ear, outer, middle and inner. Pitch is measured against the "frequency of a pure tone" or the "frequency of a complex tone". Human beings are more sensitive to frequencies, ranging from 1000 Hz to 5000 Hz, the ability to hear any frequencies higher or lower than this deteriorate with age.

Timbre "is the sensation closely related to the quality of sound". As everyday sounds are very complex, the quality of the sound becomes very important. This allows can allow someone to judge the same note played by a different instrument, or even if the volume of a sound system has been slightly. Loudness is the "intensity of the sound" measured in decibels (dB). The loudest sound level that can be heard without any long term damage being caused to the ear is 120 dB, but what is being heard is related to the frequency of the sound. Hearing is the combination of pitch, timbre and hearing, any problems with any of the elements of hearing can cause confusion or an incorrect conclusion on what is being heard. Any sounds that may be used will be simple and very different to each other.

Mental impairments such dyslexia and autism can cause difficulty. Dyslexics can have difficulties with information relayed textually. But speech can "alleviate the need to read and write and allow more accurate input and output" in very severe cases, but with less severe cases "spelling correction programs" can help, the spell check facilities similar to those used in Ms Word would not be considered to be of any use as it does not "recognise their idiosyncratic word construction methods" or even minor displacement of characters in words. Which also affects the way dyslexics read as they will perceived some words to be incorrectly spelt as confusion can occur with similar words.

Sufferers of autism have their "ability to communicate and interact with people around them and to make sense of their environment" affected, manifesting itself primarily in three ways social interaction, communication and imagination. To aid in the use of the e-shop in a can text will be kept simple and easy to read, and if possible speech output will be also be integrated, but any sever cases will be very difficult to cater for.

Speech is "the oral expression of language", this impairment is something that will not be catered by a design independently, and the speech system provided in Windows if feasible will be used for speech. Visual impairment has attracted a lot of attention in research as it is seen as potentially "one of the most debilitating" impairments. Due to the rise in GUI systems there has been a reduction in "possibilities for visually impaired users", to aid users with "text-based interaction, screen readers using synthesized speech or Braille output devices" have been used, though such devices are very restricted in trying to interpret the graphical interface. Colour also needs to be considered, colours used have to be as distinct as possible, and it should not be affected by contrast.

Physical impairments require adaptive interfaces to allow users to actually use a computer system correctly, as this is not something that will be considered in the design as it cannot be catered for by software, as this is more a hardware related issue.

Cultural impact on colours also needs to be considered "blue should not be used to display critical information", also as approximately 10% of the population is colour blind "being unable to discriminate between red and green" it is very important that use of these colours is kept to a minimum unless absolutely necessary. Screen resolutions will also need to be taken into consideration as the visually impaired may have low resolution set on the VDU so there is not point in creating a layout which will need a high resolution setting.

Errors are a very important part of the final design, the final product itself will need to work without errors but it must be capable of alerting the user of any errors they have made, this will need to be covered by validation within the design of the e-shop in a can. There could be actual prompts to alert the user, or sounds such as beeps or an alarm. Or even a traffic light system red, yellow and green, red for danger, yellow for caution and green to continue. But before anything like this can be implemented impairments will have to be taken into consideration. We must also plan and design for errors so that even if the user makes a mistake, validations and function have to be put into place so that the user will do the right thing.

Administration cannot be too complicated with the e-shop in a can, as the added complication will mean it will take longer to get full working knowledge and understanding of how the whole system has to work. There will have to be full security access in the initial layout setup of the e-shop in a can, easy access and manipulation of the data in the database that will be used.

Usability is "how easy it is to learn and use a system". This is something that should be central to the design and development of any product. In usability every aspect of product needs to be taken into consideration. From the way it looks to the naked eye, to the way it works. For the e-shop in a can colours and layout will have to be considered, then there is also navigation. Things that need to be taken into consideration consist of the time taken or needed to complete tasks, how often the user will have to repeat the same procedure, the time user may spend dealing with errors. These are important for the end consumer and the administration. Any final visual effects that might be implemented, will have to be within any safety and legal regulations.

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