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Saturday, 30 July 2016

ISO 9241-11 in a nushell

ISO 9241-11 is a set of INternational Standards started in 1998 by the INternational Standard Association. This international standard sets the rules for ergonomics for computer office work, aiming to establish guidelines for the users' health and safety and prescribes the untold benefits of gauging usability through performance and user satisfaction according to in-company context. This context comprises users, tasks, equipment and Physical/social environment.

Cognitive walkthrough - a more precise definition

The cognitive walkthrough is a usability evaluation method in which one or more evaluators work through a series of tasks and ask a set of questions from the perspective of the user.Its focus is on understanding the system's learnability for new or infrequent users. The objective of cognitive walktrhough is to identify usability problems in order to  evaluate ease of learning to use a system by exploring it. This method seeks to probe the following:

- relationship between how designers and users conceptualise a task;

- proper choice of vocabulary for on-screen terms;

- adequate feedback for an action;

In order to carry out this evaluation, it's required to set up a preparation stage to define:

-hypothise about user and the supposed knowledge they have about a task and its underlying interface;

- tasks scenario, thought through from a collection of important and recurrent tasks;

- correct sequence of actions to complete a given task;

- design blueprint illustrating each step and the ensuing interface changes.

The procedure to run this evaluation involves the following steps:

- projectist shows design proposal;

- evaluators think up situations about an interface/user interface based on the prior tasks scenario;

- evaluators simulate the execution of the task, asking questions as they go along;

- evaluators make note of key points that users need to know before getting started on the task and learn upon doing it.

The point of using a cognitive walkthrough as method for evaluating human-computer interaction is to make sure that users are capable of navigating a system interface by trial and error with no required training.

Thursday, 28 July 2016

Interface (computing)

Interface is the part of a system that supports communication with the user. The concept originally came from natural sciences to mean the threshold between states. It was used to describe the contents of a system as a black box, from which only the surface is known, therefore making communication possible only with said surface. Two neighbouring black boxes can only communicate with each other if their surfaces "match up". Nowadays an interface is a shared boundary across which software, computer hardware, peripheral devices, humans and combinations of these exhance information.

In addition for both interacting boxes it doesn't matter how their inner parts read the message and how the response is crafted based on the received input. The understanding is thta a border is a part of the self, and the black boxes need only to know the facing sides in order to insure communication. That matches the original Latin term inter "between" and facies "looks", later anglicized to face.

If one regards any system as a coherent whole, if it's worth-analysing, he will take it down into its individual parts. The position at which the starting and contact points function (upon which communication is established), represent the individual parts. To put them to use, these individual parts have to be put together again to become a greater whole than the sum of its individual parts.

Tuesday, 26 July 2016

cognitive walkthrough

Cognitive walkthrough is usability inspection method belonging to the family of analytical evaluation processes as opposed to empirical evaluation processes like usability test. In cognitive walkthrough a hypothetical user follows a course of action prescribed by a usability expert, who takes notes of the cognitive effort of the user to find his way in the interface. The goal of cognitive walkthrough is to determine the level of user learnability to use a service. This makes it clear for the software developers spot design flaws in the interface that affect user activity. Common issues brought to the fore by cognitive walkthrough include bad menu design and unsuitable mechanisms to undo an undesirable action. Action sequences

A typical cognitive walkthrough is split into 4 steps:

1- Define input - To first lay out the foundations for effective cognitive walkthrough, it's suggested to define the features of the target user. This involves establishing the user group most likely to be the end consumers of the product and what knowledge and experience they are most likely to have. Next some example tasks should be set up. These may range from one to numerous taks representative of the work environment of the end user. It's important that these tasks be chosen to match as close as possible the real tasks performed on the system. The next substep is the sequence of actions to perform the chosen tasks is determined, in an attempt to predict which path the user the user is most likely to choose.

2- check sequence of actions. The observer takes note of the solution path employed by the user to accomplish a given task, heeding the user's input and how he concluded that was the most efficient way to carry out the intended end. Some questions commonly asked at this stage are:
Will the user manage to produce the right effect?
Will the user be able to recognise the correct action to what he's trying to do?
Will the user establish a connection between the correct action and the desired effect?

 3- record critical information. At this point the observer will have two sorts of information obtained during the product analysis: 3-a) information about the user's experience and knowledge to successfully execute an action considering the various sequences necessary to do so; 3-b) information about actions that actually led to errors and thus to problems with teh user.

4- interface revision. The goal of cognitive walkthrough is to identify flaws in the interface, which in term leads to improvements in the interface design which should lead to overall better user satisfaction and more efficient system use.

As one can notice, a cognitive walkthrough starts with a task analysis suggesting the sequence of steps or actions required by a user to accomplish a task. The designers and developers of the software then walk through the steps as a group, asking themselves a set of questions at each step, gathering data during the walkthrough. Afterwards a report of potential issues is compiled. Finally the software is redesigned to address the issues identified.

The 8 Gestalt Laws

Gestalt Laws

Gestalt psychology is a branch of psychology that tries to explain how we apply pattern recognition of harmony of shapes in a frenetic world. The main principle of Gestalt is that the mind is capable of perceiving things as a global whole in order to make meaningful readings of common everyday objects. The main premise is that when the human mind exerts the principles of gestalt, the whole has a reality of its own regardless of its component parts. In a nutshell, the perception of an object or system only has meaning if it's complete. Were one to take it apart into its consituent parts, each bit would hold no relevance for the understanding of how it plays out its functions as opposed when it was part of the functioning whole. Another way of referring to Gestalt principles is that the whole is greater than the sum of its parts. Just assembling together a pile of components won't mean as much as having the same items working in unison to achieve a common goal. Another way of understanding this notion is that the whole is greater than the sum. According to gestaltists, the organisation of cognisition processes accounts for our faculty of recognising patterns and predicting behaviours. There are 8 laws to describe the underlying cognitive process that allows for our coherent organisation of information:

1 - Law of Proximity— The law of proximity states that when an individual perceives an assortment of objects they perceive objects that are close to each other as forming a group. For example, in the picture below, there are 72 circles, but we perceive the collection of circles in groups, associating the ones close to each other as a single group.

The Law of Proximity implies that we consider the circles belonging to groups according to how close they are to each other.

2 - Law of Similarity— This law states that assorted ietms are perceptually grouped together if they bear a striking similarity to each other, like shape, colour, shading or other visible qualities. For example, the figure illustrating the law of similarity portrays 36 circles all equal distance apart from one another forming a square. In this depiction, 18 of the circles are shaded dark and 18 of the circles are shaded light. We perceive the dark circles as grouped together, and the light circles as grouped together forming six horizontal lines within the square of circles. This perception of lines is due to the law of similarity.

Law of Similarity or how like belongs to like.

3 - Law of Closure—The law of closure states that people perceive objects such as shapes, letters, pictures etc., as a whole unit when they are not complete even if parts of it are missing. For instance, when reading text from another interlocutor and you realise a mispelled or incomplete word you use your perception to fill in the gaps,like in incomplete words like hippopotamu, distinctiv, semiti, hobbl and indstry. The persumption of what the word is supposed to be happens on the subconscious level. The Law of Closure is widely applied when taking notes and writing on-field reports which need to be quickly done without much worry to form when we use abbreviations and shot forms for words. A good strategy of the law of closure in this context is using only consonants when writing down words, except for the first word e.g.: adrs for address. cty for city. redsgn for redesign etc.

4- Law of Symmetry— the mind perceives objects as being symmetrical and forming around a center point. IN this process the mind seeks to form a coherent shape in order to better information about said object.

5 - Law of Common Fate— this law states that objects are perceived as lines that move along the smoothest path. Experiments using the visual sensory modality found that we perceive elements of objects to have trends of motion, which indicate the path that the object is on.

6 - Law of Continuity— the elements of an object are integrated into perceptual wholes if they are aligned within an object. In cases where there is an overlap of the lines and shapes between objects, the two objects are perceived as two single uninterrupted entities.

7 - Law of Good Gestalt— elements are perceived as belonging to the same group if they have a pattern that is regular, simple and orderly. Regular and simple shapes are favoured over irregular and complex-looking shapes for good design and easily memorable signs.

8 - Law of Past Experience—The law of past experience implies that under some circumstances visual stimuli are categorized according to past experience. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together. For example, the English language contains 26 letters that are grouped to form words using a set of rules. If an individual reads an English word they have never seen, they use the law of past experience to interpret the letters "L" and "I" as two letters beside each other, rather than using the law of closure to combine the letters and interpret the object as an uppercase U.

Sunday, 24 July 2016

Usability - all you will ever need to know

Usability, communicability, applicability. These are, simply put, the main pillars that support the whole concept of human-computer interaction. Usability is concerned with user satisfaction of the system of which he is a user and how efficient said system is. Communicability is the way the system interface manages to get information across to the user. In other words, a system with good communicability is a system whose icons, menus, dialogue boxes and any form of communicative means are arranged in such a way that it doesn't take much time for the user to understand the intended purpose the system wants to convey. Any message on screen should be clear, concise and right to the point, with no useless jibba jabba involved. Applicability deals with the usefulness of the system. A system with a high level of applicability is multipurpose and capable of being used in contexts other than the intended one it was orginally designed for. Ideally, an interface is said to have high applicability value if it can potentially increase the user's skill to perform a certain task he's been assigned to.

Usability may seem by far the most important of the three core concepts. Actually, usability is the most transparent requirement for good human-computer interaction from the user's point of view. Moreover,
a system that has an expected degree of usability also more often than not addresses the other two requests for optimal HCI interaction in equally desired levels.

Usability can also be understood as the effectiveness, efficiency and satisfaction with which specified users achieve specified goals in particular environments, where effectiveness is the accuracy to completely achieve a desired goal in a given context, while efficiency is the resources to goal achieved ratio. Satisfaction addresses the question of comfort and acceptability of a work system by the users and people affected by its use.

Friday, 22 July 2016

Cognitive-Experiential Self-Theory (CEST)

Cognitive-Experiential Self-Theory (CEST) is a dual-process model of perception devised by Seymour Epstein, based around the idea that people use two separate systems for information processing: analytical-rational and intuitive-experiential. The former is deliberate, slow and logical, while the latter is fast, automatic, and emotionally driven. They operate independently of each other, but the result of their interaction produces behaviour and conscious thought, giving rise to a person's observable personality.On an individual level, there might be a marked difference in preference for one processing means over another.This difference can be measured using the Rational Experiential Inventory (REI) which takes into account two criteria for cognitive activity: Need for Cognition (conscious effort to process information) and Faith in Intituition (experiential measure).

Although it might seem superficially more appealing to exercise the rational system at the expense of the experiential system, it doesn't work this way. Suppressing the experiential system and contriving for the rational system to be overrepresented on a daily basis will eventually cause knowledge and skills that are regarded as part of the analytical-rational domain to shift to the intuitive-experiential sphere, although it's entirely possible for our analytical-rational to mend the performance of the experiential system. Given enough cognitive resources, it's possible for the rational system to even hold sway over the amount of influence that the experiential system exerts on our decision-making processes.