Saturday, 17 August 2019

The MoMA comes to Melbourne




New York is probably one of the very few places that I really really want to go to in the United States (and I'd say that Vegas is the other, but come to think of it, Vegas would probably be one of those places that I'd drive down the strip once, have a beer at the casino, and then head off to go and see the Hoover Dam). However, due to complications having a slice of New York, in the form the the Museum of Modern Art (otherwise known as the MoMA) coming to Melbourne does temper that urge somewhat, even if it is the case that most of the works here are basically what one would consider Modern Art.

Yet, when it comes to art, it really feels as if New York is pretty much the centre of the American scene. Sure, Hollywood is where all of the movies are made, and some have even suggested that Los Angeles is probably America's cultural capital, but considering that the likes of the Broadway Musical, Andy Warhol, and many others, have come out of New York, I am almost inclined to feel that this city is not only America's cultural heart, but gives the nation more of a character beyond hamburgers, Chevy's and stock market crashes.

Arcadia and Metroplis

And so, our first encounter when we walked in through the entrance was a gallery in which we find, not American artists, but French, namely those of Gaugin, Van Gogh, and Seurat. What we encounter are the post-impressionists, as we start our trek at the beginning of the 20th Century. The world has changed, yet there is a struggle with the artists, between in idyllic landscapes of the past, and the massive metropolises of the future. At this time, though, the British Empire still rules the world as the sole superpower, yet little does anybody know, that by the end of the century, that position will move to the other side of the Atlantic.

Mind you, and this is something that I have mentioned previously, and that there was one particular technological invention that changed everything: the camera. In fact, the camera was one of those majorly disruptive developments of the time, literally putting portrait painters out of business. Mind you, the cameras of the time were pretty shocking, but what they did was that they forced artists to experiment and to look for different means challenging their audience. Notice, though, how with the impressionists, the focus was very much on colour, which ironically was something that the camera couldn't produce at the time.

This painting, called Evening at Honfluer, is by the artist Georges Seurat. He was the guy that invented the style known as pointilism, which is basically creating an image by using thousands upon thousands of little dots. It is quite interesting to look at, and is actually supposed to capture a scientific idea at the time, which believed that images were generated by thousands upon thousands of beams of life penetrating the eye. The other reason behind this painting is that Seurat had been cooped up in his apartment for quite a while, and was really looking for an opportunity to get outside.


It turns out that Van Gogh painted more than just one painting of the postie while he was in Arles unsuccessfully attempting to establish an artists' commune (of which only one artist, Paul Gaugin, even bothered to come and check out). Actually, the name of the postie is Joseph Roulin, and this particular painting was once owned by Norman Rockefeller, among many, many others, but was gifted to the MoMA in 1989. However, I have already written quite a few things on Van Gogh, so I guess I'll leave it at that and move on to somebody else.


These two posters are probably best done together, and not just because they were produced by the same artist (Jules Cheret, though that is probably quite obvious). These posters were produced using lithographic techniques, which basically means stone prints, as opposed to woodcuts, where the stamps are made of wood. The style was a new technique, particularly for posters, which has certainly been borrowed from the Impressionist movement, and here we are seeing them being used in the form of advertisements. The first, Fuller, is of the American cabaret dancer Loie Fuller, and the second being an advertisement for the Theatrophone, a form of telephone that would pipe music down to the listener - an early form of radio.

In a way, this is a theme that we begin to see through this exhibition, and that is that art does not necessarily exist on the walls of galleries and homes, but it exists everywhere, in the streets, on the bill posters, and even as the designs of your lounge suite, or the album cover. However, we are getting ahead of ourselves here, and instead we will slowly move ahead.


We now move from the Impressionists to the Expressionists, this one being painted by Ernst Ludwig Kirchner, who formed the collective known as Die Brücke (or the bridge). This painting is of the fashionable Königstrasse in Dresden. Notice the difference between the paintings of the impressionists and the expressionists - the painting is much harder, the colours much more solid, and also with a darker tone. This in a way emphasises the violence of the city scenes, as people push past each other for reasons only known to them. Yet also consider the faces, which are more like masks, also suggesting that this world is a nameless, faceless, and characterless work.


We can certainly see that the art of the modern era is starting to take on different tones. In this painting by Andre Derain, called Bathers, there has been some borrowing from non-European cultures, particularly with the mask like facial features. In one sense this painting is rather abstract, but not so abstract that we start to loose all features of the subjects, three women bathing in a river. Yet, the surroundings aren't distinct, instead focusing on the style, and the nature of the event.


This is another painting by Dauvin, this one called fishing boats. The style is known as Fauvism, which is nowhere near as well known as styles such as impressionism, or even cubism (thanks no doubt to Picasso). Notice how this painting seems to emphasise the bright colours, something that fishing boats in parts of Europe are well known for. Yet even with the colours, the shapes don't stand out as much - in fact they are quite vague and indistinct. This is a characteristic of such works at the time, which focus ever more on the colour, as the artists begin to move away from the realistic nature of the subjects of their works.

Machinery & the Modern World

The twentieth century could been seen as the century of the machine. Sure, machines have been with us for centuries, even if they were as simply as something like a wheel. However, in the twentieth century machines had not only taken a life of their own, but as begun the process of displacing us. The camera had displaced the painter, and film had displaced the theatre - it was a time where one had to adapt, or perish.

Thus, artists began to take up the challenge of competing with the machine, with artists such as Picasso, whose cubist paintings would take the three dimensional and compress it into the two. We also have artists who would take elements of the machine and create art around it, or even go as far as the legendary Marcel Duchamp, who would dare, and succeed, at taking an ordinary object and make the claim that this object was art. Of course. We even have architecture, even architecture of the modern home, which had transformed itself from a dirty hovel to a machine for living.


Guess what, this is Picasso, but if you are familiar with his work then you probably already know this. Yeah, this certainly doesn't look like what you would expect from him, but the thing is Picasso was an incredibly prolific artist, and while his most famous paintings are his cubist paintings, he did an awful lot more. In fact, even his doodles could garner quite a lot of money. Sticking with the theme though, this painting, which is cubist, exemplifies the disconnect that the new technological world was bringing about. The problem is that to be able to properly appreciate the painting, you need to look at it from the angle of the wall, because looking at it on a computer screen, well, it just looks like a muddy table.


This painting, by George Grosz, is called explosion, and it certainly looks like an explosion, and also goes to demonstrate the way art has changed at this time to capture raw emotion as opposed to just, well, capturing an image of a pretty landscape, or a person. Grosz fought for the Germans in World War I, but was discharged as being unfit to fight (which sort of says something because it wasn't easy to get out of the army back then). This painting brings about the destruction that was caused by the war, both physically and psychologically. In many ways the perspective of the painting changes based on how you look at it, but in all aspects it is about destruction, and a new type of destruction brought about by modern warfare.


This is an example of a style of painting known as futurism, and is painted by Giacomo Bella, and is called Paths of Movement. In this painting Bella is attempting to capture motion, and in particular the motion created by a bird known as a swift. Here it is hard to actually see the bird, as it flies across the canvas before our eyes. However, this painting was also inspired by photography of the movement of birds, which considering the time at which it was painted, was still in its infancy. Once again, we are seeing art move away from its traditional form, and in this instance, delving into the scientific world.



This piece, called Sun and Moon, is by the abstract artist Robert Delaney. In fact Delaney was an early adopter of the concept of abstract art, and the above is an example of this. The circle represents the universe, and the merging of the various colours represents the interplay not only between the sun and the moon, but also between the night and the day. Then again, the only reason I know this is because I read the plaque that happened to be placed under the painting. Basically, if it wasn't for that plaque I probably would have no idea what this actually meant, but then again that is probably because I'm a heathen

Okay, this may not be anywhere near as famous, or as gutsy, as Fountain, but this is another example of Duchamp's readymade, that is work of art that has been created out of prefabricated materials. Actually, this is slightly more because it is what he termed as an 'assisted readymade' namely because it is made out of a bicycle wheel and a kitchen stool. Basically it is a useless machine, which not only is it challenging the concept of art, something that he basically loved to do, but it is also challenging the concept of innovation, considering a lot of innovation is, well, useless. Then again, the thing with invention is that you do have to go through a lot of useless ideas before you stumble upon something that is truly transformative.



This painting, by Ferdinand Leger, is called Propellers. In a way it is basically Picasso meets the machine world were Leger takes Picasso's cubist techniques and applies it to a world of machines. Looking at this painting we can sort of make out the propellers, and the blades, and other items such as tubing and pistons. Leger appears to be trying to capture the dynamics of this new work, but he also senses a strange, outerworld beauty to it. Mind you, most people would probably just look at it, and not even read the little plaque down the side, but it is there that one can get the most information about a painting such as this one.

A New Unity

By now art is starting to become particularly strange with the development of, well, lots of different styles. Yet in these different styles one sort of sees a unity, and that unity in a way is a break with the past. Gone are pretty decorations to be replaced by geometric form and function that arose from the avant-garde movement. He we also meet constructivism for the first time, something that arose from the ruins of the Russian Revolution. It is here that we can certainly see a break with the past as the old world of Tsarist Russia has been left behind to be replaced with the dictatorship of the proletariat. In a way what we have is a nation that is now trying to find a new identity.

In a way this seems to the be the case across Western Europe as many people seek to try to understand a world that had gone, and a new one made in the trenches of the Great War. Gone was this ideal that humanity was on the cusp of something new, and instead we have a world seeking purpose and meaning. This, of course, were to come to a head ten years later with the onset of the Great Depression, however we are still in a world where people are attempting to drink the memories of the Great War away as we head into the roaring twenties, a time still dominated by outdated ideas of class and sex.


Well, now we are starting to get strange. This is by the Russian artist Lyubov Popova and is called Purely Architectonic. Well, I probably shouldn't call it strange since it is attempting to channel to works of the cubist, but what is it a painting of? Well, I guess that is the question, isn't it? Honestly, it simply looks like a collection of shapes, and really lacks any formal meaning as it is. Still, Popova did suggest that painting is like, well, engineering, and some engineers have described engineering as being an artform. Here, we are merging the two to a point where the artist isn't creating something, but rather building something out of basic blocks.


Here is another couple of works by another Russian artist, this one Kazimir Malevich, and the work is called Supremist Elements. Actually, they are titled square and circle as well, but the collection is Supremist Elements. So, what do we make of them because all they seem to be are a couple of shapes drawn on paper with a pencil, placed in a frame, at which point they ended up an in art gallery. Apparently he consider this form of art to be supreme, at least compared to the natural world. Well, in my mind it is just a couple of pencil sketches, and there is nothing all that supreme about it. Yet, it is what you could consider constructivist, that is that the artist has constructed it with their mind, as opposed to letting nature dictate the result. Still, I have my own opinion regarding the piece, but it does show us how humanity is ever attempting to claim supremacy over the natural world.


This is a movie poster by Validmir and Georgii Stenberg and is advertising a 1926 movie called The Three Million Case. Mind you, I use the word advertising in as loose a way as possible considering that, as you can tell, this is in Russian, and in 1926 Russia was actually called The Soviet Union. Well, no doubt this is a Russian film, and no doubt the rich people are the bad guys. However, the main reason that I have posted it here is because I thought it looked cool. However, as we continue on our trek through the MoMA you will discover that a lot of the art actually involves movie posters and album covers.


Thus here we have another example, this one from a 1921 film called Pounded Cutlet. Actually, the original title is 'At the Ringside'. If this one looks strikingly similar to the one above, that is because it is also by the Stenberg brothers. You can probably figure out that I do actually appreciate their work, with the rather modernist styles. Honestly, it is a shame that they don't make posters like this anymore.



These nine drawings are by the Russian constructivist Alexandra Exter, and are from her portfolio of works called Stage Sets (or Decors de Theatre). These weren't commissioned works, but rather works that she designed that could be used for operatic, ballet, or other theatrical performances. These designs, along with numerous others, were included in her portfolio. I'm not entirely sure whether they ended up being built, however they have certainly landed up on the walls of the MoMA.


This final piece that we will look at for the time being is called Colour Structure by Joaquin Torres Garcia. He came to Paris and not really satisfied with the direction of the surrealists decided to establish his own group known as Cercle et Carre (otherwise translated to Circle and Square). As you can probably deduce from the name, this group was more interested in geometric abstraction. An example is above, where the entire painting has been divided into rectangular shapes of various sizes, each of them having a vibrant colour. While it was was suggested that they were 'primary' colours, one can tell that this is not actually the case. Mind you, it does sort of feel as if the curator really had no idea if the painting carried any meaning, and just talked about its composition (which, in some cases, is all that really can be said).


Creative Commons License

The MoMA comes to Melbourne by David Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Saturday, 10 August 2019

More On Error Detection

Well, we have already looked at some basic forms of error detection in a previous post (though annoyingly much of this subject covered areas that we have already covered), so instead of going over old ground I will instead refer you back to the post that covered Hamming Code and SECDED error detection techniques. However, just to be painful, these aren't actually the only forms of error detection out there, particularly since there is more to errors than just single bit errors.

Sure, computers these days may be efficient enough that double bit errors are an extreme rarity, and errors of more than two bits pretty much never happen, however we are talking about what goes on inside the computer. Things are very different when we are talking about transferring data between computers, particularly over wireless frequencies. You see, while we might get single and double bit errors, there is also another type of error that might occur - the burst error. This is where multiple bits are effected, and could occur in multiple ways, such as, say, a sun spot causing interference with our wireless transmission. In fact, interference is a very big problem when it comes to such transmissions, so we need a way to be able to detect them.

That is just a simple diagram to show how or why a burst error can occur. Here is a diagram showing what a burst error could look like:

As mentioned previously, error detection works on the process of redundancy, that is by adding extra bits to make sure that the data that is received is the correct data. These bits are known as parity bits. However, the problem with the error detection systems that we explored in the previous post is that while it is all well and good for single, and even double, bit errors, they are completely useless when it comes to burst errors, and this is the type of error detection that we want to be able to detect.

So, there are a couple of methods available to us.

Two Dimensional Parity Check 

In this method we basically place the bits into a series of rows. Once again, like the other parity bits we chose whether we want it to be even or odd. Say we want it to be even, so at the end of the row we will have a parity bit that will make all the ones in the row even, so if there is an odd number of 1s then the parity bit will be 1 otherwise it will be zero.

However, there is a second dimension to this method. Note how we mentioned that we would place the streams into rows. Well, you then go down the columns, and have a parity column. Once again, if the number of 1s in the column is odd then the bit in the parity row is 1, and vice verse.

You might have realise that we will then have a cell, the one that is at the intersection of the parity column and parity row. So, what goes in there. Well, once again a parity bit for the row and the column.

Let us do this with the following bit streams: 1100111, 1011101, 0111001, 0101001.

11001111
10111011
01110010
01010011
01010101

That might look a little confusing, but eventually it will make sense. So, if one, or more, of the bits come through in error, they can be detected. In fact, with the parity-parity bit in the corner, can detect them, as well as the ones in the column.

11111111
10111011
01110010
01010011
01010101

So, you can see how were have changed two of the bits on the first row. Sure, the parity bit on row 1 won't register an error, but the parity bits on column 3 and 4 will register an error. Yet there is still a problem. Consider this.

11111111
10001011
01110010
01010011
01010101

These four bits have come across in error, and rows 1 and 2 won't register the error, neither will columns 3 and 4. Unfortunately there are flaws. As such, we need something just that little bit more complicated.

Cyclic Redundancy Check (CRC)

Are you familiar with polynomial long division. In fact, are you familiar with polynomials. Well, this video might not explain polynomials (you will need to go elsewhere for that, maybe Kahn Academy).


CRC is actually one of the more powerful, and most common forms of error detection, probably because it is accurate, and it works. Okay, it might not be able to correct errors, but it certainly can detect them.

So, we have a block of k bits, and the transmitter generates a series of n bits known a the Frame Check Sequence (FCS). The FCS is then added to the block, and the block that happens to be k+n is exactly divisible by a predetermined number. So, if when the frame is received, the remainder is 0, then there is no error. Otherwise the frame is discarded and a resend request is then made.

So, to do this we need some definitions:
  • M(x) is the message that has a k-bit sequence;
  • P(x) is the generator polynomial represented in an n-bit sequence;
    • P(x) is fixed for a given scheme;
    • P(x) is known by both the sender and the receiver;
  •  Create a block polynomial F(x) based on M(x) and P(x);
    • F(x) is divisible by P(x);
Let us see how we can turn a binary number into a polynomial. We will start with the binary number 110010101.

It is then turned into a polynomial as follows:

1* x8 + 1* x7+0*x6 + 0* x5+1*x4 + 0* x3+1*x2 + 0* x1+1*x0

Well, x0 is 1 so we can get rid of that. Also, anything multiplied by 0 is going to be 0, so we can get rid of them. We will also drop the 1s, because they are redundant. So, we are left with the following:

x8 + x7+1*x4 +1*x2 +1

Now that we have worked that out, let us get onto some polynomial division.

At one end we have the following:

M(x) = 100100
P(x) = 1101
n = 3.

We get n by looking at P(x) and noting that the highest bit is three, so that will be n.

Once we have that, we multiply M(x) by n. So, in this instance we have x3(x5 + x2)

To multiply we basically multiply each one inside the brackets by the one outside. Also, to multiply polynomials, you actually add the indices, as such (x5+3 + x2+3). So, we end up with: x8 + x5.

Clear as mud? I thought so.

Now comes the fun part - we divide xnM(x) by P(x). I'll go through it step by step below:

So, that first x under the divisor sign, well you deduct 3 from the 8 (the 3 coming from the first x) and then write the result above the line.


Next, we multiply x5 with each of the x's that we are dividing by, and write them beneath, as such:


Next, we 'divide' the x that is above, by the x that is below, or you could say that you deduct the indice of the x below from the x above, and if it is, well you don't write it down.



Well, is x7 greater than x3 so we repeat the process all over again:


So, do you see what has happened here? Well, once again x6 is greater than x3 so we continue. In fact, here is the rest:

So, the only thing we are interested in here is the 1 right at the bottom, which is the remainder. In fact the remainder is in reality 001, namely because we take into account all the values lower than x6. We then append the 001 to the end of M(x) and send it, so the message being sent will actually be: 100100001. Once the message is received at the other end, we go through the entire process again, and if the remainder is 0, then there are no errors, but if the remainder is 1, well, there is an error and the frame is discarded.

Creative Commons License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Sunday, 4 August 2019

Prototypes - Beginning the Design

Well, we have already explored the context scenario in the previous post on personas, though in part they probably form more the part of the prototypes. In a way what we were doing there was sketching out the functionalities of our application with how each of the personas would use it. In a way it allows our apps to start taking shape. It also helps us keep focused on what we really need to do as opposed to what we would think would be really cool to do. It sort of comes down to that 100 in 1 type of idea in that what one person may really, really want, pretty much everybody else is either not interested in it, or rabidly hates it.

Here we can begin to sketch out the design, or the functionality, of the app. Now, we aren't going for anything too fancy here - that comes later, what we are doing now is just getting an idea of how the app is going to fit together, and how people are going navigate around it. Sort of like a flow diagram.

As we could see from the personas, everybody is going to be using the app in their own special ways, which is why the context scenarios are important. Once we have our ideas on the utilisation of the app, we can then start bringing everything together to see how our app is going to work, and how each to the functionalities are going to relate to the various parts of the app.

Now this is how the process begins to flow. By looking at the context scenarios, we can determine what the user's needs happen to be, whether it be data or functional. In the scenario we had with our stock market app, the data needs might not just be the share price, but also any news that is related to that share, and the various metrics, such as PE/Ratio and Buy/Sell spread that are also attached to it. As for functional needs, well, we might need a way to keep track of our portfolio, and to buy and sell shares when necessary. However, these data and functional needs are going to differ across our persona.

However, before we continue, consider this flow chart below, and it gives a good idea of the development phase.

Scenario-based approach to design Two 
However, one of the important factors here is the user experience, so while we are determining functional and data needs, we should also be focusing on the user experience. Remember, this is one of the key points here - a user that doesn't have a great experience is going to be a user that will end up looking for something else. Sure, if you hold a monopoly on functionality then, well, your users are going to be struggling to find a competitor, but get that idea out of your head - it is unlikely you are going to be in that situation, unless you score a job with Facebook or Youtube.

Now, once we have the context scenario, we can then create a table that gives us an idea of what functionalities are required. Now, I have previously created a key path scenario, which is also quite similar, but the key path scenario tends to flow on from this table.


I'll be honest, and was basically using the Commsec app as a basis for this, since I'm not really all that interested in creating my own app (unless it involves computers using machine learning to understand stock price movements, and buying and selling on my behalf, but unfortunately you can really only buy and sell through a brokerage). 

Now there is what is called the posture. This is basically the feel of the app, and we need to consider the users in this regard. Is it a professional app, a transient app, or a fun app. It's not all that good having a stock trading app that looks as if it belongs in a cartoon, people simply wouldn't take it all that seriously. We also need to consider input methods, particularly when we are dealing with mobile devices. Traditional computers handle inputs through keyboards and mice, however mobile devices have resulted in so many other means of input that we really need to take it into consideration. For instance, facial gestures may actually be a valid form of input.

Functional elements

Now, let us go back to our stock market app and consider what functional elements are required:

Functional Element: View Stock
Include: Name of Stock, Stock Price, News, and Charts

Functional Element: Buy Stock
Include: Purchase price, number of stocks, value to purchase, timed purchase, purchase based on price or volume.

Now, we also need to take into account things like real-estate - that is how much of the screen we have available. You will have a lot more real estate on a desktop than you will have on a handheld device. However, being able to buy and sell stocks on a hand held device may be a lot more convenient that having to wait until you are in front of a computer. We also need to take into account proximity - you know, like buttons next to each other, and also other factors such as what displays are available.

Then there are also the various views, or you could say the screens on which various functions play out. For instance you will have the front page from which you can access other parts of the app. Then you have the stock view, and a part of that might be the chart view. Finally there is the view which enables you to buy, or sell, a stock.

Pen to Paper

Well, now we get to work and start designing our app. Ironically, even some of the most advanced companies still use pen and paper. Honestly, I don't blame them, particularly since it is much quicker to sketch a basic design than it is to muck around on a drawing program in these early stages. Okay, there are some other disadvantages, but it is a start. An example for my app is below:


But I think this one is a much better example:

Source: Martha Eierdanz
These are basically known as 'paper prototypes' and it is here we begin to work out the user experience. As you can see, the example above is much more detailed than my example, but it is here that the creators have gone into more detail. However, my mockup was a basic start that was scribbled in thirty seconds, unlike the example above, which probably took a lot more time.

The thing with paper prototypes is that you can start to see how the app will take place, and if you start to see problems with the usability, you can then start to remodel it here before getting into the really time consuming and tedious parts - the ones you draft on the computer. What it also allows us to do is to experiment with alternate scenarios before we settle on the final design.

Mockups and Fidelity

There are two types of prototypes here - the high fidelity and the low fidelity. The low fidelity is still the basic design where we are looking to filling in some of the gaps in the original paper designs. The high fidelity prototype is much closer to the finished product, however ideally, when you get there you pretty much want to be in the position where you only need to make minor changes as opposed to scrapping the whole project and starting from scratch. High fidelity prototypes are incredibly time consuming to produce, and you really want to move from there to the beta release.

So, there are some pros and cons for both models. The low fidelity tends to be cheaper to develop, enables you to explore multiple avenues, is a useful tool through which to communicate, good for identifying market requirements, and a great way to explore the proof of concept. However, on the flip side, it is difficult for the back end coders to be able to develop the code (this is usually happening concurrently), there is a limited scope for checking errors, the process tends to be driven by the facilitator, there is a limited scope for usability testing, and finally there are navigational and flow limitations (the flow of the app is a very important aspect of the user experience).

With high fidelity prototypes, there is the problem of cost - it is very expensive to develop. However, you have complete functionality, it is predominantly driven by the user, there is a fully implemented navigational system, there is a look and feel of the final production, and can help quite a lot with marketing and sales. Other then cost, there is also the problem of time, and it also doesn't work all that well when you are still at the proof of concept stage.

Now we have the horizontal and vertical prototypes - the horizontal one is where you have a look at the breadth of the functionalities, but don't go too deeply, which the vertical prototype is where you select a single function and explore it in detail. Now, at this stage the aesthetics are of little concern, but we should still have an idea of the look and feel of the app - the look being how it is perceived, and the feel being how it is experienced.

We have already discussed paper prototyping, but as mentioned it is a handy tool. In fact one method is to have a hole cut in a sheet of paper that simulates the screen. One person plays the computer and another plays the user. By pressing parts of the screen, which simulates clicking, the computer moves the screen as necessary. You can also simulate text entry simply by writing something down. However, instead of my explaining it, consider this video exploring how pintrest used paper prototyping:


Doing it on paper isn't the only option, as you now have a number of applications, such as Balsamiq and Azure, which allows you to prototype digitally. Honestly, I still prefer using paper, probably because that no matter how bad my drawing skills are, drawing on a computer is even worse.

And Finally

Look, I did want to mention wire frames, but that is basically what is covered above with the paper prototypes - wire frames are basically very rough sketches of the app. However, there is another process called Storyboarding. Now, this is used in film production, where the film is created on paper using rough sketches based on how it is going to look. It also appears in UX design, namely to visualise the keypath scenarios.

Anyway, I'll leave it at that, and next time we will be usability testing.
Creative Commons License

Prototypes - Beginning the Design by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Monday, 29 July 2019

Chaos in the Forest - A Midsummers Night Dream

Well, in the space of a couple of days I have gone from one of Shakespeare's earlier plays to one of his more complex, and detailed plays. I guess that is what happens when you have a company that will perform multiple plays over a short space of time. Then again, this is how I believe the Globe in London sets its program, namely with there being three or four plays being staged at once. Mind you, whenever I've been in London I've only had the chance to see one of those plays, particularly since the plays at The Globe get booked up pretty quickly. In a way, I was actually quite fortunate to even get to see The Tragical History of Dr Faust at a moment's notice, even if I ended up getting the times confused and turning up late. Actually, come to think of it, the only plays that I have seen at the Globe (the other being Macbeth) were tragedies, so I am not all that sure of how their comedies turn out. Then again, I do have a collection of plays on DVD that I bought when I was in London, so I can always watch one of them, hoping that one of them does happen to be a comedy.

So, here we have what is basically one of my favourite plays, though one interesting thing about this play is that I remember seeing a Royal Shakespeare Company production of it when they made an appearance in Adelaide. Actually, I believe that is the only time they have actually toured Australia, which is a shame, since if I want to see one of their performances, at least a live performance, I would have to travel to London, or even to Stratford Upon Avon, where they happen to be based. Then again, if I do make the trek one day, maybe I'll be lucky and actually get to see a performance with Patrick Stewart and David Tennant (both of whom I believe are based with the company). However, this post isn't about a play that I saw many years ago, but rather one that I have seen more recently, in fact the previous night, if going by when I am actually writing this post (5 December 2018), as opposed to when I get around to publishing the post.


I could start by giving a rundown of the play, but the problem is that, like many of Shakespeare's other advanced plays, this one is actually pretty complex. In fact we have three sets of characters who I'll refer to as the nobles, the mechanicals, and the fairies. Now, of the nobles we have Theseus (of the minotaur fame) and Hypolita, a former amazon and Theseus' new wife. The mechanicals are basically a group of peasants who have decided to put on a play to celebrate the wedding. I won't go too much into the plot with regards to the faeries, namely because of some peculiarities with this particular production.

However, going back to the nobles, we have Demetrius and Lysander, and Helena and Hermia. Now, Helena loves Demetrius, but Demetrius, who used to love Helena, is now in love with Hermia. However the problem is that Hermia and Lysander love each other, so for a part of the play we have Helena chasing Demetrius who is not returning her affections. To make matters even more complicated, Hermia's father doesn't want her to marry Lysander, but to marry Demetrius, and if she refuses then she has either the choice of execution, or becoming a nun. Since she will have none of this, they run off into the forest. They are then followed by Demetrius and Helena, while the mechanicals decide that they need to practice their play, and also head off into the forest.

City and the Country

One of the interesting things I have seen in these performances is that the roles of Theseus and Hyppolita, and Oberon and Titania are generally played by the same person. This, in a way, creates a reflection on how in Athens it is Theseus and Hypolita who are the rulers, however disappearing into the forest does not mean that they are able to escape authority, since in the forest they are now under the authority of the faeries. One interesting thing is that the play is bookended by scenes set in the city, so the main characters flee the city for the forest, and then return at the end for the plays completion.

 

The forest seems to always be this wild and chaotic place in the plays of Shakespeare. Well, considering As You Like It, the forest there is nowhere near as dangerous as the forest in this particular play. I have already written extensively on the concept of the forest in As You Like It, so I'll refer you to those posts for reference. However, in A Midsummer Night's Dream, the forest is a wild, dangerous, and chaotic place. The characters flee Athens believing that the forest will offer them safety, however that cannot be further from the truth. Instead they suddenly all find themselves enchanted, and thus under the control of the faeries.

One of the interesting aspects of this performance was that the faeries were styled as Maori's, which shouldn't be all that surprising considering that this is a New Zealand production. However, it seemed as if they went as far as to translate the play into one of the Maori langauges, or at least the parts where the faeries were communicating with each other. This did create a bit of a problem, namely because we completely missed the plot regarding Titania and the changeling. Could the play survive without that plot? Well, it seems as if it was able to, though in one sense it was an incredibly risky move to make.

However, we were still able to watch how the faeries were able to manipulate and control the characters. For instance, we have the scene where Bottom's head is transformed into that of a donkey, and then we have Titania falling madly in love with the donkey. Then we have Oberon attempting to rectify the discord between the lovers, namely because it hurts to see Helena repeatedly being rebuffed. Well, that didn't turn out all that well considering that both Demetrius and Lysander end up falling in love with Helena.


The catch is that since Helena had been rebuffed by both for so long, when they suddenly fall madly in love with her, she finds it to be quite suspicious - as if they are having her on. In a way it sort of reminded me of games that would be played when I was in primary school. However the term madly is probably appropriate here because this isn't a play about romantic (of chivalric) love, but rather a play where the characters are enchanted. As such the whole scene should be completely ramped up with its insanity.

Dreaming of Love

Well, that is another rather interesting concept because not only is the play bookended by the city, but the suggestion is that all of the events that occurred in the forest occurred as if it were in a dream. Characters fall asleep quite regularly in this play, and when they fall asleep things inevitably change. For instance, Lysander falls asleep being in love with Hermia, and wakes up in love with Helena. In the same way Puck falls asleep with the head of an ass, and awakes with the head of a human.

I'm not inclined to suggest that the city represents civilisation, and the forest represents the wilds of nature, but in a sense they do. Theseus rules the city while the faeries rule nature. However, the city is also representative of the waking world while the forest is representative of the dreams. This is an interesting way to look at things, particularly since dreams tend to be quite chaotic and wild, and at times can trick us into believing that what we are experiencing is real. Yet it seems that in the world of dreams we get dragged along, as if we are passengers in a movie.


However, is it not also the case that in the waking world the same things are true. In many situations we are simply being dragged through life. Sure we have choice, or the illusion of choice, but many aspects of the world are completely out of our control. Yet in another sense, the waking world in many cases is very dull and drab, with us going to work and going home, on packed trains or jammed roads. In a sense the waking world is very dull and dreary, where as the world of the dreams can have an almost magical quality.

Yet is it not also the case that many of us, on the weekend, seek to escape to the wilderness, or at least those of us who aren't forced to work on the weekends. In a way it feels as if the weekend is like that dream world, that world where we aren't under the chains of our employers, aren't forced to work to make sure that there is food on our table or a roof over our head. Yet every Monday we find ourselves back at our desk, once again wandering why the weekend went so fast, and looking at another five days of doing the same thing over and over again. In a way, like the city and the forest, the weekend is the dream, the time we spend out in the forest, while the week is the reality that we must slog through.

Yet one of the darker aspects of the play, and there are certainly some rather dark aspects, is that the faeries not only inhabit the realm of the dreams, but are also masters over it. Sure, they make mistakes, such as enchanting the wrong person, so that we suddenly have the woman who has recently been scorned now being chased all over the forest by two men who are madly in love with her. Yet, the woman who was being pursued now finds herself being left behind.

Let us quickly make mention of this idea of love. These are nobles that we are talking about here, so marriage didn't occur because they were in love, marriages occurred due to agreements made by their parents. We can actually see the conflict here because Hermia and Lysander are in love, but the wish of Hermia's father is that she marry Demetrius. At first, Demetrius was in love with Helena, but changed his mind and decided that he would be happy to marry Hermia. As we know, they decide to run away, namely because they didn't want to follow the rules of the society in which they lived, but to follow their heart's desire. As we have already discussed, their desire to flee from one authority has them find themselves subject to another.


Notice also the setting of the play - Athens. Theseus was a mythical king of Athens, though Plutarch was rather convinced that he actually existed (as did numerous other ancients). In a sense, this story has been set not just in the distant past, but in the mythical past. This goes beyond the plays set in Italy, or even in Rome, but rather in a time that is shrouded in mystery. In a way this dream world is being thrust further back to an ancient time, further distancing the events from the every day life of the audience.

The Ridiculous Play

One thing that I noticed was that sometimes we don't need to worry about the language to be able to enjoy the play. In a sense, much of the play was visual, something that is generally not conveyed through the written word. This is probably why no two Shakespearian plays are necessarily the same. This is somewhat different from the plays of the likes of Oscar Wilde and Bernard Shaw. Here the details such as costumes and stage directions are very specific. However, take the language out of the play and sometimes it can be very, very confusing. This was not so much the case with this play, particularly since the players went out of their way to make it appear quite farcical.

Basically we were watching slapstick humour, and as long as we know what is going on, who is who, and who loves who, then the language doesn't matter, This is probably one of the beauties of Shakespeare, and that is that you can enjoy the play even if you struggle with the language. Mind you, it is English, and as I have said in the past, and will say again, plays are meant to be performed, not read, though I notice that getting into a group that will read Shakespeare is still a very popular past time.


Interestingly, there is always that story about how students struggle with the language of Shakespeare, yet even today he is not only still being performed, but the audiences are still flocking to see his plays performed. Of course, we have groups experimenting with the plays, and changing them, but they are still very popular, even in their purest form. In a way, costumes may be adjusted, if only to help us understand what is going on. For instance, in this play Lysander and Hermia were dressed in green, and Demitrius and Helana were dressed in red. As for the mechanicals, they wore hi-vis vests, simply to demonstrate that they are members of the working class.

So, let us finish off with the mechanicals' play - Pirimus and Thisbee. The performance is supposed to be bad, really really bad. Then again, these guys are working class, and in a sense Shakespeare didn't seem to think much of them, particularly since they are the butt of many of his jokes. They are rude, crude, and completely incompetent. In many cases they are only in the plays to provide some comic relief. In fact it is interesting that the fools, or the jesters, are never the ones who are considered to be the comic relief, but the ones who will confront the main character and challenge him. This is not the case with the lower classes.


One thing you will notice though is that during the performance the audience are jeering and making jokes. Remember, this is a private performance for Theseus, his wife, and the guests at the wedding. It actually makes me wander whether this is what Shakespeare would have experienced when he performed for the monarch (particularly King James). Then again, half of the reason is that this play is bad, and the performance is bad, however a part of me feels that this may not have been the case with the Kings Men, since you only landed up there if you were particularly good.

Creative Commons License

Chaos in the Forest - A Midsummers Night Dream by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Saturday, 20 July 2019

Encoding Signals

Well, now that we have looked at how we turn sound into numbers, or computer data, lets see the methods that we can use to actually transfer this data from one point to another. Well, when it comes to sound you can shout, but the thing is that there is only a certain distance that the sound can reach before it becomes almost impossible to hear.

Let us use the example of a message. Say we write a message down on a sheet of paper. Now, there are a number of ways we can send that message. Obviously you could hold it up, but that wouldn't be all that good since you will need to be pretty close to be able to read it. Secondly you could throw it, but if you have ever attempted to throw a piece of paper, you probably know how futile a task that is. Well, you could screw it up and throw it, but that would increase the distance only slightly. The next option is to turn it into a paper aeroplane. Well, that might actually increase the distance, depending on a lot of factors such as wind, and whether it is raining. The final method would be folding it up, placing it in a envelope, and putting it in a letter box. From there it gets placed on a motorcycle, and depending on the destination, even on a plane. Well, it looks as if we can now send our message a considerable distance.

You might be wandering why I went through that example, and honestly, I am sort of wandering about it myself, though I do tend to have this ability of rabbiting on about nothing in particular, except that there is a method to my madness. As you can see, a message in its basic form can't really travel all that far, however if we attach it to something else, such as a motor bike, or a plane, then suddenly this message can travel, comprehensively, a lot faster. This is the same when it comes to data. One of the terms used when it comes to attaching data to a signal is modulation, another term is encoding. Actually, encoding is a term used more for digital data, since it is a way of mapping the digital data, that is made up of 0s and 1s, onto a signal, and there are a number of ways to do this.

Actually, encoding will output a digital signal, while modulation will output an analog signal. This usually occurs where the medium that is transporting the signal can only handle analog signals - wires are an example of this. We also have a couple of other things I should mention:

Unipolar: This is where the signal exists in a single state, either positive or negative.

Polar: This is somewhat different, in that the signal changes state based upon the logic value of the data. So, a 1 might be positive, and a 0 might be negative.

Differential Encoding: This occurs where the data bits are represented by changes between the elements as opposed to elements themselves. An example would be where a 1 represents a -ve to a +ve change, which a 0 represents a +ve to a -ve change.

Ratio: This refers to the number of data elements that are carried by a single signal element. The table below should be helpful in this regard.


Digital Data, Digital Signals

Now, this is where the fun begins. There are a number of ways to transmit digital data, and we will be looking at a few of them, as well as including a number of diagrams. I think that a list might be better here:

  • Return to Zero: There are three voltage levels, +ve, -ve, and zero. The signal returns to zero in the middle of the pulse, and is either high to zero, or low to zero.
  • Non-return to Zero: The signal doesn't return to zero in the middle of the pulse, though there are a few ways that it can be done:
  • Non-return to Zero Level (NRZ-L): here we have 0 as the high level, a 1 as the low level.
  • Non-Return to Zero - Invert on Ones (NRZ-I): Here if the signal is a 0, there will be no change, but if the signal is a 1, then it will invert. This occurs at the beginning of the signal.

With the Non-Return to Zero, both are easy to implement, but the problem is that there is no synchronisation, and there is no error correction. Further, there is a lot of needless changing.

Biphase Encoding
The difference here is that each of the segments has a transition in the middle, which is a means of self clocking and synchronising. The transitions at the period boundary do not mean anything, there are only there to place the signal into the correct state.
  •  Manchester: This is a mix of return to zero and NRZ-L. For a zero it transitions from high to low in the middle of the segment, and the opposite for a one.
  • Differential-Manchester: This combines the RZ and the NRZ-I. Basically at the beginning of the segment there is no transition for a 0, and a transition for a 1.
The benefits is that they have only two voltages, +ve and -ve, they allow for self clocking. The problems is that once again there is no error checking, there is no functionality for DC (direct current), and the multiple changes require a wider bandwidth.

Bipolar Encoding
Here we have three voltage levels, +ve, -ve, and 0 to represent our bits. There are two forms: Bipolar Alternate Mark Inversion and and Psuedoterenary.
  • Bipolar AMI: 0 represents no line, or a zero voltage, while 1 is either a +ve or a -ve. The voltage alternates for successive ones.
  • Pseudoterenary: Well, this is basically the opposite to the above.

Analog Data, Digital Signals

This is the process of turning analog data into a digital signal, otherwise known as digitisation. The benefits for this are numerous, including that there being no need for an amplifier, but rather a repeater. Amplifiers are problematic since while they can amplify the signal, they also have this habit of amplifying any noise that is with the signal. In fact it allows more efficient use of digital switching techniques, as well as being able to use Time Division Multiplexing as opposed to frequency division (more on that later).

Analog signals are digitised using a system called pulse amplitude modulation, and pulse code modulation is the most common. Samples are taken at around 8000 samples per second, and are usually recorded with an 8 bit depth. This will result in a digital rate of 64000 bps (namely 8 * 8000). For standard voice grade circuits, this is usually done at 3300 samples per second.

Instead of going through all the details, this image probably says it all:


Digital Data, Analog Signal

Well, even in our digital age, it is still necessary for us to be able to transmit digital data along analog lines - such as the telephone lines. In fact the NBN requires a digital to analog conversion, since fibre optic only allows analog signals. So, to do this you need to modulate the digital data onto the analog signal, normally by combining the signal m(t) onto the carrier frequency fc, to produce the signal s(t). The bandwidth is usually centered on the carriers frequency.

So, how is this done? Well, there are a couple of ways:

Amplitude Shift Keying
Here, the binary values are represented by two different amplitudes of the carrier frequency. A 0 will be, well, 0, but a 1 might be the actually sine wave - s(t) = Asin(2πft).
It might be better to have a look at it as a diagram:

Frequency Shift Keying
This is another way of doing it, so that while the amplitude stays the same, the frequency changes:
0 = Asin(2πf1t)
1= Asin(2πf2t)




Phase Shift Keying

This is where the phase of the signal is shifted to represent 0s and 1s. Differential phase shift keying shifts the phase relative to the previous transmission as opposed to some reference signal.

0 = Asin(2πft).
1 = Asin(2πft+θ).


Analog Data, Analog Signal

Okay, this is the final one, and it is probably still around, if Alan Jones' antics are anything to go by (he is a radio announcer in Sydney, well known for his rather controversial statements that tend to get blown all out of proportion by the media).

There are two types: Amplitude Modulation and Frequency modulation. Basically the data is mapped onto the carrier signal in a way that either leaves the frequency the same and changes the amplitude (AM) or leaves the amplitude alone and changes the frequency.

Once again, pictures probably say a lot more than words.

So, this is amplitude modulation:


And finally, frequency modulation:



Creative Commons License

Encoding Signals by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me