Category Archives: Week 8

Practice Makes Perfect

The pattern “practice practice practice” is what the title implies and focuses on one of the most important things in any kind of career. The idea that practice makes perfect has been apart of every job/hobby/club/etc. since the beginning of time. Since programming puts you in a situation where any mistake could ruin the entire project/work, you need to avoid mistakes at all costs. Practice allows for programmers to work on different things and see what works for both them and what ever they are working on. The pattern suggest that you solve an exercise multiple times over a few weeks from scratch and see how your solutions evolve and change overtime and use those in your future projects.
This pattern is something that I thought of when reading the breakable toys pattern since they have a similar aspect of taking things from work home and expanding your knowledge on things that could be used in projects. I felt like this would be something that I would need to do for most jobs in the field of computer science. I think one thing that I found interesting was how it suggests to use exercises in different books because it wasn’t something that I would have thought of to help practice on different aspects of coding. The pattern, similar to breakable toys, suggests to have fun with it and not worry about things like deadlines, production issues and so on cause it allows you to expand on what you learned and see what works and what doesn’t. I felt like this pattern had a lot that I wish I knew about when I began computer science classes because it would have made my learning experience easier and more enjoyable.
I will use this in my professional career since it seems to be something that would benefit me and help me to be a better developer and computer scientist. The idea of using different computer science books on different topics and using the exercise in the book were a good idea that I will use in my career as well. While old books may have the fundamentals of coding, it is important to get newer books focused more on the languages that are being used since they will have a good understanding of how to use the language to the best of its ability.

From the blog CS@Worcester – Tyler Quist’s CS Blog by Tyler Quist and used with permission of the author. All other rights reserved by the author.

Analysis and Comparison of Ascending and Descending Scales

With added pressure in realizing the semester is half over, as well as an upcoming interview for a position dealing with DSP and machine learning, I came into this week with newfound motivation. The focus that comes with a little bit of pressure is paradoxically quite freeing.

I had some issues when attempting to compare features between audio files. In hindsight, it was an obvious mistake that I had already learned in theory. But of course, applying theoretical knowledge always reveals the points of weak understanding.

As I’ve written in the past, MFCC (mel-frequency cepstrum coefficients) are most common with speech processing. There are time slices taken from the audio file and by default Librosa calculates 13 coefficients commonly used for speech processing. The MFCC is an array of time slices, each represented by 13 coefficients. These are plotted below, with color representing magnitude (from dark blue to dark red), time slices on the y-axis, and coefficients on the x-axis. The waveform, MFCC Delta, and Chromagram are also plotted.

The chromagram is of particular interest, as it extracts the frequencies in the time domain, revealing that the scale on the left is ascending and the scale on the right is descending. You can even see where my finger slipped playing the descending scale.

Analysis of an ascending and descending scale

This shows the importance of scale invariance when comparing features, which will also come to play in machine learning. This is why frames of equal time-slices, which usually overlap, are taken from an audio sample.

Originally, I was extracting features without cutting the audio files to the same size. This resulted in a larger MFCC. Attempting to plot the difference between the features caused an error. Files with the same length, however, naturally resulted in two arrays of the same size. Because they were only slightly off, I wanted to be sure that my understanding was correct, so I made the ascending scale exactly half the size and ran the program again.

Indeed, cutting the first sample in half reveals that the resulting matrix has half as many MFCC time slices. Librosa extracts the first 13 mel-frequency coefficients, so each array will be length of 13 and each time slice will have one of these arrays. Trying to find the difference by subtracting one matrix from another results in this error message:

ValueError: operands could not be broadcast together with shapes (44,13) (87,13)
Analysis after cutting the ascending scale in half

Also notice the chromagram only reveals 4 major frequencies. And because a chromagram is in the time domain, but the plot still has the same x-axis, the notes end at approximately the halfway point.

Plotting the absolute difference between MFCC features may not be visually illuminating, but potentially has uses for pattern identification. The real utility comes from comparing an audio sample to existing files. Take a look at the ascending versus ascending scales:

The absolute difference in MFCC features between ascending and descending scales

There is little difference in the higher coefficients, but some strong differences in the first coefficient. There are irregular differences through the rest of the plot, both in time and within coefficients. In isolation, this doesn’t reveal much. But when instead comparing two ascending scales offset by 0.1 seconds, the differences are very small. There are regular spikes in the first coefficient however, likely due to the earlier change of note in one sample.

The absolute difference in MFCC features between ascending scales, offset by 0.1 seconds

This lack of difference is one example of how a machine learning algorithm can detect whether a audio sample fits into a group. Actually training these models will be the topic for next week.

From the blog CS@Worcester – Inquiries and Queries by James Young and used with permission of the author. All other rights reserved by the author.

“Use the Source”

“Use the Source” is a pattern from Apprenticeship Patterns: Guidance for the Aspiring Software Craftsman by Dave Hoover and Adewale Oshineye. This pattern focuses on the need for reading code written by other developers. Some good sources of code to examine are open source projects. By examining source code, a programmer can see what their bad habits are and adopt new, better habits. Another benefit from code reading is learning new algorithms to solve different kinds of problems. Expanding one’s collection of code solutions allows a programmer to be flexible and able to solve more problems.

I found this pattern particularly interesting. Since programmers are constantly required to work with other’s code, it is imperative that they learn to read code efficiently with practice. I do not have much experience with this myself and this pattern has made clear how important reviewing other’s code is. Regardless of what career I pursue after graduation, it will be important to read code effectively. I will need to start looking into some open source projects so I can improve my skills. Now I just need to find some projects that I contribute to and am interested in.

“Use the Source” suggests contributing to open source projects for software you already use. This is very helpful advice to me; I use a lot open source software.

  • Atom: text editor
  • Eclipse: IDE
  • Insomnia: REST client
  • GIMP: image editor
  • Several different game system emulators

I briefly examined some of GIMP’s source code. GIMP has a label on issues for newcomers, allowing for quick access to simpler issues.  After reading through some of the code, I realized that it would take a great deal of time to get an idea of the project architecture.

I looked at this issue, (, and thought it seemed simple enough problem to start with. While the problem seemed simple, I could not navigate the repository and locate where the problem may be. GIMP is significantly more complex than any project I have worked on before. Ultimately, I was not able to make any headway on the issue. I was, however, able to read through portions of the code and begin to see some of the structure behind the it. Though I did not find what I was looking for, I did get a basic feel of the code’s flow.

As stated in Clean Code: A Handbook of Agile Software Craftsmanship by Robert C. Martin, developers read far more code than they write. With that being the case, “Use the Source” is an excellent way to grow your code reading skills.

From the blog CS@Worcester – D’s Comp Sci Blog by dlivengood and used with permission of the author. All other rights reserved by the author.

Digging In

The Dig Deeper pattern is all about knowledge and gaining more of it. More specifically, this pattern is about taking something new that you have learned or are currently learning and teaching yourself about that subject’s roots. It’s not enough to know how to use the subject matter to solve your specific issue, you need to know that subjects use as a whole to gain knowledge of its context. This pattern is about understanding how a system works as a whole and not just the part you are working on. This deeper knowledge allows you to understand your work more concisely based on the context of it as a whole, which will help you understand your specific issue even more.

When I first started reading on this pattern it felt like a very blunt lecture. It felt as though I was being told to learn everything to its fullest and if I do not then I will be a less desirable individual for hire. However, as I read on I realized it was not about having total knowledge of EVERYTHING, that would be overwhelming and nearly impossible. I began to understand that it was about delving your knowledge into specific things, subjects that you are currently working on. If you are working on a specific issue and find the solution, it’s not about knowing every way to solve the problem, but to know in detail the workings of your solution.

This pattern further enforced my idea that you can do anything, learn anything if you put your mind to it. If there’s something I really want to excel at, deepening my knowledge can only help me achieve my goal. Being able to fully express my knowledge on the specific things I have worked on, though maybe few, is far greater than a larger quantity of surface knowledge. It reminds me of using MongoDb for the first time in our libre food pantry project. It’s all good and well to set up a database and query and get the results you want. However, it’s much more important to understand how the database functions beyond my own entries and data types I’m working with. In furthering my knowledge I was able to communicate my understanding into the other areas of the project including tying the database to a Java REST API. I fully agree with the ideologies of this apprenticeship pattern, dig deeper into your knowledge and it can only benefit you.

From the blog cs@worcester – Zac's Blog by zloureiro and used with permission of the author. All other rights reserved by the author.

Use Your Title

I’m promoting you from Senior Engineer to Lead Engineer. The pay is the same but people will disrespect you less.

—Dilbert’s Pointy-Haired Boss

“Use your Title” is a very effective pattern for those who feel like the title they have is everything in life. We all have our own goals in life, and we approach differently to achieve them. For some, a software engineer position is all they have wanted to achieve in life, and there are others who would not feel accomplished until they become seniors or leaders in the industry. On the other hand, it happens to have an unimpressive title, even though you have given more authority in your position than your title or job description says. In this case, people get discouraged and lose hopes that one day they would get what they deserve.

In my opinion, we should “Use our Title” in a way that benefits us professionally. Titles are only made to feed our egos. What is more important is that we should never stop learning or stop searching for better opportunities that would complete us professionally. Let’s think of it as climbing mountains. The second highest mountain in the world is K2. If a person’s goal a year ago was to climb that mountain, he/she would feel accomplished when he/she gets there, but then he/she would feel the need of having another goal to achieve and would end up climbing Mount Everest. This tells us that even when we get to have the title we always dreamed of in the industry, there’s more we can achieve.

In this pattern, I found interesting the part that suggests writing down a long and descriptive version of our job title. I think this would help us reflect on what we do at our workplace, if the title matches with the authority we have given, and maybe find the need to update the title with superiors’ permission. I, myself am going to try and see what I find out when it comes time to update it.
As a conclusion, make sure your skill level matches your job description and title, and no matter how far you go with titles, remind yourself that your apprenticeship is not over.

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

Dig Deeper: Finding the Marianas Trench of knowledge

This particular pattern is quite resonant with me, or at least the context section of it, considering it describes my entire academic experience in computer science fairly well. An excellent analogy would be a lake a mile wide but a foot deep; or at least it would be but a foot is very generous to the depth of my knowledge and a mile is delusional considering the limited scope of languages and tools I am familiar with. However, the sentiment expressed in this section still holds: “You learn only enough about any tool to get today’s job done”. I’m ‘you’. It is not for a lack of interest, at least not in all the subjects we have covered, that I do not go very deep into them – it’s exclusively a matter of time and mental resources. I have found that I have only had the time and energy to cover a subject as much as it takes to complete the require work or project associated it.

An example that comes to mind was last semester when working on both a REST API and Angular web front end – and by working on, I mean learning frustratedly as quickly as possible while working with both for the first time independently. There felt like so little time that I had to at one point neglect the JDBC features built into the Spring Initializer because I simply did not have the time to dig through the documentation. I had to instead use a less efficient and redundant method I knew well. Additionally, on the front-end side, I was able to brute force a lot of scalability because it was easier to use the limited knowledge I had to write ngOnInit and onResize methods to handle window sizing; as opposed to learning built in scalability tools or utilizing CSS more effectively.

To learn these methods would have taken a considerable amount of time that I simply did not have. Luckily this semester the pace at which the site is being built is much more manageable, as is the distribution of work amongst four people. So, with this time I hope to gain a better understanding of the tools and techniques I wish to utilize, before I do so. The pattern suggests writing a blog post, unfortunately this one does not fit that prompt. Speaking of which, I find the idea of going back to read a technological paper from 1976 to be a massive waste of time – but that’s just me. Regardless, and as always, I will seek a more reasonable middle ground between the pattern and what I find effective.

From the blog CS@Worcester – Press Here for Worms by wurmpress and used with permission of the author. All other rights reserved by the author.

Reflect As You Work

This apprenticeship pattern caught my eye for discussing the Peter Principle, which states that an individual will only be promoted if they do well in a position. The result of this is an organization full of people who have been promoted to positions in which they no longer perform well, creating an incompetent organization.

Reflecting as you work is meant to prevent this. The idea is simple enough: constantly probe your work process and ask yourself whether it is ideal. Take note of the positive aspects, but also the negative aspects so that they can be fixed.

The pattern suggests focusing on increasing skill rather than experience. This is a subtle but important distinction, because spending a lot of time doing a single thing wrong is still a lot of experience, but it’s not necessarily useful as a professional.

In certain parts of our industry,
it is quite easy to repeat the same year of experience 10 times without making significant progress in your abilities.

Apprenticeship Patterns

I certainly reflect on my work when it’s done, but I tend to focus on the work itself rather than the process. I’ve spent countless hours before a project commit making sure every line of code is perfect and the necessary documentation is in place. This led to nice code and happy professors or managers, but it didn’t help my work process. It was doing more of the same; obtaining a good result, but without improvement in workflow.

Figuring out how work processes connect is a helpful practice to identify counterproductive habits. We tend to take the path of least resistance and easily fall into a workflow that we assume works best for us, but this may be an illusion due to our limited scope of experience. We know redundancy can be reduced within a project’s architecture. We strive for this. Why then, would we not give our work process the same courtesy?

This pattern is a great example of software development’s being more than simply writing code. And by writing code, I mean using tests, DevOps, OOP, and anything else that can be considered a software engineering practice. As the entire book aims to prove, software development is an organic, human process. Moving from a software apprentice, to journeyman, to master requires understanding your own flaws, not just the flaws in your product.

From the blog CS@Worcester – Inquiries and Queries by James Young and used with permission of the author. All other rights reserved by the author.

Apprenticeship Pattern Review 7: Sustainable Motivations

I feel like most people have been in this situation: you have passion for a hobby and decide that you want to take your craft to the next level. In doing so, a mountain of unforeseen stress and complications arise and at some point along the way you might even forget what motivated you to get to where you are in the first place. Sustainable motivations are important no matter what you are applying this pattern to. This pattern is especially important in the life of a software craftsman.

In an industry where it is all too easy to retreat into competence because the pay is “good enough”, it is easy to lose sight of the motivation that made you decide to devote your life to becoming a software developer. I can’t even describe the joy I felt as a sophomore in high school when I set out to make an, albeit shoddy, clicker game in JavaScript, and after slaving over the code for days I finally understood exactly how a game loop had to function in order to make the game playable. I proceeded to spend that weekend glued to my screen implementing all of the features I had only dreamed of days before, barely remembering to relieve myself periodically. It is that entering into a state of flow and  working through complex problems with the end result being something I created that made me fall in love with the craft. Sometimes I fall victim to forgetting what it is about programming that I love since it feels like I have been in school for a long time and the future in regards to employment and making ends meet is up in the air. To quote David Wood, “do what you love and the money will follow”. Making sure to never let your motivations become misguided is important into keeping energy and creativity levels as high as they can be.

An important distinction between motivations can be made. That is intrinsic versus extrinsic. The more intrinsic your motivations, meaning doing so because you find it personally rewarding, versus extrinsic motivations, doing so because you seek a reward, the more sustainable your motivations will be. I know I am extrinsically motivated by money and the desire to succeed for my family and teachers, and I am intrinsically motivated by the desire to create, the desire to increase the complexity of life, and the desire to solve problems. I find this pattern important because motivations truly change your outlook and mood when facing life. This pattern applies to everything in life and I think writing down motivations is a good exercise for my software development career and in life.


From the blog CS@Worcester – Creative Coding by John Pacheco and used with permission of the author. All other rights reserved by the author.

TypeScript, a better version of JavaScript

TypeScript, is it really a better
version of JavaScript? If you are like me and you never used JavaScript before
and then were told that TypeScript is better you will probably have the same
reaction, “OK, so what?”. Well it turns out it is a very useful thing, it is a wrapped
version of JavaScript that will pay attention to the types of variables used
and so on, hence the name. In my search for some answers I have stumbled upon THIS blog by Valentino
Gagliardi named TypeScript Tutorial For Beginners: The Missing Guide (2019).
Like it says it is a whole tutorial, but it also explains in some simpler words
what TypeScript is and why it is useful with a lot of examples. I will go through
it and then look for some more. What helped me right away was Valentino’s explanation
of what is TypeScript: “The definition from the official website says: “a typed
superset of JavaScript” but it assumes you know what a “superset” is and what
“typed” means. Instead to keep things simple you can think of TypeScript as of
“a layer on top” of JavaScript.”

Most of the blog is what it is
supposed to be, a Tutorial, and in my opinion it does it in a very good way, he
starts in an easy way to show certain things, even when somethings is not right
away understandable Valentino comes back to it later and explains in more
detail, what is a plus for me as well is that he does in somewhat humorous way
and that makes the whole learning a more easy going process. Having those kinds
of Tutorials is very helpful for me because knowledge can be learned but what
needs to happen is also the understanding of when and where to apply said knowledge
and with this blog post I’m starting to understand that about TypeScript.

Learning in school about best tools to perform today’s jobs and being able to see it in action before I am thrown into the deep end is a huge plus for me and it should be for everybody else as well. I am always very grateful for the opportunities like this one. I have found out that the TypeScript is used at my work in other departments which tells me it is a good thing to learn and maybe use to further my career. I cannot wait to start writing some more advanced programs in this format, but everything needs to be done slowly, you must learn to walk before you can run and I do intend to be able to run eventually.

From the blog #CS@Worcester – Pawel’s CS Experience by Pawel Stypulkowski and used with permission of the author. All other rights reserved by the author.

Time for some more REST

This week I have chosen to deepen my understanding of REST API. The article, “RESTful API Design Tips from Experience” by Peter Boyer, goes over good RESTful design practices. The article covers many topics, including some I do not have experience with but are still useful for a greater understanding overall.

The article proposes that the API should state its version
in the URLs. The author suggests adding a prefix to all URLs to specify API
version. This makes the eventuality of version updates easier to handle.

A simple tip mentioned in the article is the use of plurals.
When designing endpoints, plurals should be used instead of the singular form.
This is to avoid possible misunderstandings of what the endpoint is used for.

Example:             /orders/customers          VS           /order/customer

Another tip in the article is to use nesting for
relationship filtering. From what I understand, it is better to have multiple
path variables for filtering than the use of query strings. The example in the
article is very clear on the tip. Following this advice will make your
endpoints easier to read.

The author advises to keep your API as flat as possible. He
suggests that creating and fetching data should have a longer resource path
than updating and deleting data. I do not really understand why this is the
case. My best guess is the shorter path reduces unnecessary processes.

The next tip I found interesting was the important, if not
obvious, idea for pagination of results. When working with larger databases, requests
can have thousands of results. Since it would be impossible to display all the
data, it makes sense to partition the results into pages and return one page at
a time. Pagination can also significantly reduce the expense of a request.

The last tip I will mention from the article is the usage of
status codes.  HTTP status codes should
be used consistently and properly. This means the status should use the proper
code and provide additional details when necessary: an error code with a
message of why the error occurred.

Overall, I found Boyer’s article to be very informative. I
only mentioned a few of the topics raised in his article but all the topics are
interesting and useful. Reading through this article gave me a better
understanding of the nuances of RESTful API design and has helped me comprehend
my current coursework (CS343) better. I suggest to anybody that is new to REST
to read this article.

Article Referenced:

From the blog CS@Worcester – D’s Comp Sci Blog by dlivengood and used with permission of the author. All other rights reserved by the author.