Category Archives: Week 9

A Machine Learning Model That Recognizes Spoken Digits (Introduction)

This week, I managed to prove (to myself, at least) the power of MFCCs in speech recognition. I was quite skeptical that I could get anything to actually recognize speech, despite many sources saying how vital they are to DSP and speech recognition.

A tutorial on Tensorflow I found a couple of months ago sparked the idea: if 2-dimensional images can be represented as a 1-dimensional array and used to train the model, perhaps the same could be done with features extracted from an audio file. After all, the extracted features are nothing but an array of coefficients. So this week, armed with weeks of knowledge of basic Tensorflow and signal processing, I finally tried to get it to work. And of course, many problems arose.

After hours of struggling with mismatches in the shape of the data, waiting for the huge dataset to reload when I made a mistake, and getting no results, I finally put together the last piece of code that made it run correctly, and immediately second-guessed the accuracy of the model (“0.99 out of 100, right???”).

Of course, when training a model, a result this good could be a case of overfitting. And indeed it is, because it is only 95% accurate when using separate test data. And even this percentage isn’t the whole story. The test data comes from the same dataset, which has a lot of recordings of each digit, but using only 4 voices. It’s quite possible that there are patterns found in the voices that would not exist in other voices. This would make it great using a random sample from the original dataset, but possibly useless for someone else. There’s also the problem of noise, which MFCC is strongly affected by. So naturally, I recorded my own voice speaking digits and ran it with the model. Unfortunately, I could only manage approximately 50% accuracy, although it is consistently accurate with digits 0, 1, 2, 4 and 6. Much better than chance, at least!

This is a very simple model, which allows you to extract only MFCCs from an audio recording of a spoken digit (0 through 9) and plug it into the model to get an answer. But MFCCs may not tell the whole story, so the next step will be to use additional extracted features to get this model to perform better. There is also much more tweaking I can do with the model to see if I can obtain better results.

I’d like to step through the actual code next week and describe the steps taken to achieve this result. In the meantime, I have a lot more tweaking and refactoring to do.

I would like to mention a very important concept that I studied this week in the context of DSP: convolution. With the help of Allen Downey’s ThinkDSP and related lecture, I learned a bit more detail on filtering of signals. Convolution is essentially sweeping one signal over another to get a new signal. In DSP, this is used for things such as low-pass filters and adding echo to audio.

Think of an impulse as an instantaneous tone consisting of many (or all) frequencies. If you record this noise in a room, you will get a recording of the “impulse response”. That is, how all of the frequencies are affected by the room over time. The discrete Fourier transform of this response is essentially a filter, because it gives the amplitude of each frequency in the impulse response, including all echos and any muffling. Multiplying these amplitudes by the DFT of an entirely different audio signal will modify each frequency in the exact same way. And thus, to the human hear, this different audio signal will sound like it does in the same room. If this concept is interesting, I encourage you to watch the lecture and work through the examples in the book.

I think these topics may come in handy if I need to pre-process recordings, in the event that noise is in fact causing errors in the above model.

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.

Learn How You Fail

All the big CEO’s and entrepreneurs will give you trite advice on their LinkedIn pages: you need to fail a lot in order to succeed a lot.

I can’t be too hard on anyone who wants to get this message out, because I had to hear it at some point too. Failure meant incompetence to me, not part of the path to success. But what if failures don’t stop? The “Learn How You Fail” apprenticeship pattern attempts to solve the problem of lingering failures despite increased success.

This is likely due to something you are repeatedly doing that causes the failures. Hone in on these behaviors, because changing them is the only way to stop failing. Furthermore, you may simply not be good at some things, and finding these things can prevent wasted time and effort.

A potential problem with this pattern is that a lot of failure is likely due to blind spots in our perception of ourselves, so it’s likely not easy to solve the problem of uncovering the cause of our failures. But as software developers, our skills in pattern recognition should be top notch. Carefully documenting your failures and how they connect should reveal the patterns.

A coworker asked me years ago what my chosen superpower would be. I answered that I would want to know everything. Omniscience. Besides briefly earning me the nickname “know-it-all”, this reflects my own desire to fix my unfixable flaws. Now, I do think significant effort should be put into things that you are especially bad at. But this pattern is a good reminder to let go of the things that you’ve tried to do and simply haven’t worked out.

Success is many cases is figuring out what you are good at, not about fixing all of your weaknesses. This is the reasons the US President has a cabinet, Congress has subcommittees, companies have divisions, and software team members have roles. We can’t all do everything.

My biggest issue with this pattern going forward will be striking a balance. There will always be a desire to learn as much as possible. Gaining more skill and broadening horizons may be tempting, but knowing when to give up in a specific area is the challenge. The CEOs who credit their success to past failures knew what to give up on within their chosen field. Almost always, this doesn’t mean choosing a brand new career; it means finding what you’re doing wrong in the current one.

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.

Share What You Learn: Sharing is caring

While applying this pattern to my experience feels a little presumptuous, considering people do not “look to [me] as a source of knowledge”, I have tried to share what little knowledge I have as I gain in hopes of helping my classmates with any troubles they may have. Like Kindred Spirits before, I have had good luck attacking a new topic in our individual ways first then comparing notes and filling in the gaps in our knowledge others have covered. As well, this topic reminds me of Breakable Toys as well and my misunderstanding of it, where I concluded that writing a wiki may be a helpful personal learning tool but through the lens of this pattern, sharing it could provide a collective learning tool. While I have yet to go as far as creating that wiki, I have been willing to share any knowledge I have with my classmates.

I also got a great opportunity to brush up on our major’s most difficult subject and then test my knowledge of it by being a peer assisted learning mentor for Data Structures. I realized how much I missed the first time I took the class, and when explaining it I had to shed to convenient mental tools I used for more thorough methods that I could then share with the students. I remember specifically trying to explain how to rank program running times, without taking the derivative of the function that represented the run time; as many of the students had not, and likely would not, take calculus. By the end I did feel as though I was better acquainted with the material but felt sometimes like I needed to go deeper as I had difficulties explaining some concepts well.

Another time, I remember having to give a mock lecture to another student who missed a lecture. It really pushed my understanding of the material to the limit because I could recite what I had copied into my notebook but if he needed to ask a question I could have fallen apart had I not been confident in the material, or had a good understanding of it. The book says that you may feel that “someone more experienced [should] put themselves forward”. However, many people can feel intimidated by professionals and may not be willing to ask vital questions for fear of looking foolish; as opposed to the camaraderie of peers. I think that pushing ourselves to interrogate our own knowledge of material in the presences of peers offers an excellent opportunity for growth.

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.

Apprenticeship Pattern Review 8: Find Mentors

The “Find Mentors” pattern from Apprenticeship Patterns by Oshineye and Hoover is one that has relevance no matter how far along on your software craftsman journey you are. Whether you are opening an IDE for the first time or are a seasoned veteran who has contributed endless amounts of knowledge to the field of software development, it is important to seek and learn from those who’ve been through the trials and tribulations that you have yet to face. There is a stereotype that programmers are these hermit-like creatures that rarely see the light of day and seldom speak to other humans. In their dark caves, they churn out program after program in a vacuum-like environment. This is simply not the case and every single person who calls themselves a software developer can benefit from collaboration, specifically seeking out those who have already made the mistakes and can expedite the growing process for them.

All of the patterns that were carefully curated to appear in Apprenticeship Patterns have relevancy in practically all software developers’ professional careers. “Find Mentors” is no different as the knowledge that can be learned from a mentor can potentially be far greater than that learned alone because of the simple fact that they have walked the road and generally know the “path of least resistance” in their given field of expertise. This is why I feel this pattern is so important. Not only do mentors hold massive amounts of knowledge waiting to be tapped into for your benefit, having a mentor that you can show your work to can force you to hold yourself to much higher standards than otherwise. I think the realism the authors bring to the pattern when they explain that “no one knows everything” is important because it can be tempting to rely on a mentor too much and lose confidence in them when they don’t have an answer to a given problem. They are only human too, therefore they have gaps in their knowledge just like the rest of us. Note also that the mentors one needs throughout their career change and shifts just as much as one’s own knowledge does.

This pattern has made me desperately want to seek out people I can learn from who are further along in their careers. The benefit of having mentors to obtain guidance from is far greater than the fear of ridicule that has been generally holding me back from finding mentors that can help me excel in my career.

 

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

Read Constantly

Reading consistently give you ability to happen our mind.

And when reading connately about good programming, it will build you knowledge and would open more understanding of programming.

“If you read even one good programming book every two months, roughly 35 pages a week, you’ll soon have a firm grasp on the industry and distinguish yourself from nearly everyone around you.”

Books are the key component for growing. Not even book, just the articles or some options on a certain programing tasks you are doing. 

I like how this section cover the need of reading the words. looking at the word and understanding it. We as a software developer should not only be doing readings on the language tat we are familiar with but also on other languages that is some how connected it the pervious one.

The similarity will connect the broad perfection of a different but yet similar languor. For example,  HTML and CSS are quite similar, java and javascript function and calls are similar but are implemented differently. 

From the blog CS@Worcester – Tech a Talk -Arisha Khan by ajahan22 and used with permission of the author. All other rights reserved by the author.

Final Project pt.1

For my final project in my Software construction, design, and architecture class, my partner and I had the idea of creating a web page that was able to access data of a SQLite database. The structure of this project was to connect to a database using Java as a backend and use Rest api to send out sql commands. We needed to run the backend on a server using a Spring Boot framework available to us. Once our connection was setup and our backend methods to access the database was ready we had to create the front end. We used Typescript and Java Angular to create our front end, or in other words our web page. The typescript code had to connect to the Java rest api so our chain of connections from the top goes; Typescript and Angular -> Java Rest api -> SQLite database. 

Starting the project the very first obstacle we ran into was connection Java rest api to the SQLite database. It was something we had never done before, but thankfully there was helpful resources online. We found out that there was a series of Java imports to facilitate this function. A few imports needed are as follows:

import java.sql.*;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

Using these imports we were able to create an object of type ‘Connection’ in order to establish the actual connection to the database. Here is our method:

public static Connection getConnection() {

   if (conn == null) {

       try {

           conn = DriverManager.getConnection(“jdbc:sqlite:” + dbpath);

       } catch (SQLException e) {

           e.printStackTrace();

       }

   }

   return conn;

}

The set method to set our path:

DatabaseSQL.setPath(“C:/…(insert path here)…”);

We are now able to get the connection inside our Java rest api classes that contain our SQLite query methods using this statement:

Connection conn = DatabaseSQL.getConnection();

As I said this information can be found through many sources online so we were lucky such a function was available for us to use at our disposal. We needed the connection to be established before we could proceed with anything else because the entire project relied on accessing the database. However, in order to actually know if our connection was working we couldn’t rely on the absence of errors. We needed to create a rest api method to access the database and give us a result so that we could be sure.

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

Javascript vs. Typescript

As someone fairly new to coding, learning new languages is both fun and painful. When I heard we were going to be doing some web development, I figured Javascript would be involved, and I had a brief moment of panic. I am a frequenter of subreddits like /r/programmerhumor, or other humor-based tech blogs, and there is a lot of dogpiling on Javascript as a language. It gets a lot of flak for being very weakly typed, and for its default behaviors utilizing this weak typing leading to a lot of wacky and confusing results for people who aren’t deeply familiar with the language. A quick example:

When I discovered we would be using Typescript (And what Typescript was), it was a bit of a relief. The way that the language looks just feels more comfortable to me, especially as someone who has mostly been learning Java. I have been trying to expand my horizons as of late, and wanted to look into people that may feel the opposite. Maybe the verbosity and strictness of a strongly-typed object oriented language is bad if you know what you’re doing, and I found a very interesting blog expressing just that.

In the blog post “Shit Javascript Coders Say” by Dave Sag found here: https://medium.com/@davesag/shit-javascript-coders-say-7a2d2881228d,
he utilizes a very pointed and crass writing style to express his distaste for OOP and strong-typed languages in general compared to Javascript. He also does not like Typescript. One reason I find this funny is because in this Software Architecture class I am writing this blog for, there is a big focus on creating interfaces, organizing classes, and figuring out the best ways to group and create objects. These are all things, according to Dave Sag, that are not needed in Javascript, and that Typescript “encourages the use of these practices as a weak, wobbly crutch” (paraphrasing).

I found this juxtaposition very amusing, and would be very interested in going down the rabbit hole more and finding out about best pure Javascript practices, or if Mr. Sag’s views are commonly held in some communities (I found plenty of blog posts praising Typescript, for what it’s worth).

In my brief time with Typescript so far, I have found it a bit verbose and clunky (though I am certainly a neophyte coder). Hopefully as I continue to learn, these distinctions become more clear and I can post an updated perspective.

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

Getting Angular

The topic for my post this week is Angular. CS 343, Software construction, design, and architecture, introduced REST API frontend last week. I did not have a good grasp of what Angular is, so I read the article “Angular Tutorial: Getting Started With Angular 4”, by Shubham Sinha. The article breaks down Angular into easy to understand parts which are then explained thoroughly.

The article begins with describing the general history of
Angular and why it was designed. Originally AngularJS, Angular was designed for
the use in designing SPAs (Single-Page Application). SPAs are useful as they do
not require an entire page to be refreshed. Instead SPAs only refresh necessary
components. This allows for SPAs to act similarly to desktop applications.

The article then begins its tutorial, though I would describe
it as an overview of the details of Angular projects. The author goes into the
different parts of Angular and describing them each in detail.

  • Modules:                           
    Chunks of code with a specific task, such as classes.
  • Components:                   
    Code that use API to control sections of the screen. Contains instructions for
    client-side GUI.
  • Templates:                        
    HTML tags that describe how to render components.
  • Metadata:                          
    The code that informs Angular on how to process a class.
  • Data
    binding:                       
    The connection used to tie parts of a template to parts of a component. An easy
    connection for data state and data events.
  • Directives:                         
    Logic code for manipulating data: adding, removing, changing.
  • Services:                             
    A wide category for encompassing anything an application my need.
  • Dependency
    Injection: 
    Allows Angular to create new instances of a class with all its dependencies
    that can be “injected” into another class.

From what I understand, the page code will be divided into
modules. The page view will be divided into components that use templates and
metadata to determine how to display the component. Directives are logic code
that manipulate data. Data binding allows for easy access to a data’s state and
events. Dependency injection inserts an instantiation of a class with all its
dependencies. Finally, services are simply anything an application may need:
value, function, feature.

I found that after reading this article I have a better
understanding of Angular. Angular can be used for client-side rendering of
data. By separating the page into several different components, Angular can create
SPAs that are dynamic and responsive. This article is informative and accessible,
I highly recommend this article to anybody who is getting acquainted to
Angular.

Referenced Article:
https://www.edureka.co/blog/angular-tutorial/

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.

If It’s Broke Don’t Fix it: Treating Bugs Like Buddha

For my last blog for this course instead of taking one
particular course subject, summarizing it, and theorizing about what actual
implementations may look like – I’d like to look at the whole course and do the
same. More specifically, I would like to cover how bugs or defects are actually
addressed, or not, in Software Development and Testing. To do this I have found
some interesting blog posts which argue that 100% of bugs may be able to be
fixed, but shouldn’t be. Instead, one should focus on serving the vast majority
of users under expected circumstances.

           Both blogs
focus on how impractical, and expensive, maintaining 100% stability or up-time
is. In the first focusing on bugs specifically they give many reasons why this
goal is unadvisable. The first is the prevalence of Agile Development,
dominating nearly the entire software development landscape. As such, the constraints
of this fast-paced development style limit the ability to do traditional QA testing;
if a program can have several revisions in a week, maybe even a day, then how
could a team reasonable test all these iterations. Instead, the author suggest
a stability monitoring tool to automatically test each revision.

           In
addition, they suggest that eliminating 100% of bugs would eliminate many which
users would never see, so why waste resources addressing them? Even if you
could fix everything how could you possibly know? This focus is reinforced when
considering the truly incredible breadth of devices that one may have consider,
and specifically in mobile development: where they cite the over 24,000
different android devices on the market. One must focus on the average expected
user experience and not waste time fussing with the outliers until, presumably,
a bug report is filed.

The second blog discusses
defects in systems in a similar way, covering more or less the same points, although
mentioning a rather obscure possibility: being legally challenged for claiming
that your product has no defects. Instead, what I believe they are trying to emphasize
is that products are always fallible, and the amount of resources required to
get them even close is impossible or impractical. As a result, as we move
forward in this class and towards graduation I think we should resist the impulse
to try for complete perfection and instead focus on what is achievable and
provides the best experience for the majority of users.

Sources

Not all bugs are worth fixing and that’s okay
The Zero Defect Fallacy

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.

Understanding Typescript

Let’s start by discussing javascript a bit. Javascript is currently a must know programming language in the computer science world. It is widely used for web development on both front-end and back-end development. Javascript can also be found in many other fields of development including mobile apps, desktop apps, and game development. 

Javascript language is quite user friendly and can even be considered easy to learn but it doesn’t come without its concerns of course. The same code you’ve written may work differently when used in different browsers such as Google Chrome versus explorer, or safari, for example. Javascript is also very stripped down so it can be easy to create errors by mistake especially for beginners. An example of this is that Javascript is dynamically typed. Programs don’t know the types of variables until they are assigned at runtime and then they must do an awful lot of referencing to figure out the type depending on the size of the program. Since types are not required there are no compiling errors or messages to tell you what you are doing wrong. It leaves a hard traced error if or not careful when working with your code. 

Now moving on to Typescript!

Typescript is a superset of Javascript which means it contains all the same functionality of Javascript as well as added features. Typescript compiles to plain Javascript so any code you write in Javascript will run just fine in Typescript, as long as you have written it correctly of course. The big additions of Typescript are type annotations, interfaces, and classes. 

As opposed to Javascript, which is dynamically typed, Typescript uses static typing. Static typing means that things like variable types can be checked at compile time since variable annotations are available. The code will still run if you have an error but you will receive a message warning you about the specific error that was detected. Also depending on your IDE it may offer the function of displaying errors to the user while they are typing. If you want to take advantage of this functionality then you can check out the Visual Studio Code IDE, which contains that function.

I chose to blog about this subject because I am a newcomer to this language and material. I figured if I did some research on my own and actually typed out the words then it would all become more clear to me what the relationship of Typescript was to Javascript and what they are used for in the real world. I feel now that I have this general overview and understanding of the language and its use that I can now conceptualize my own uses for it. I’m looking forward to implementing what I have learned about Typescript into my own projects.

Lease, Diana. “TypeScript: What Is It & When Is It Useful?” Medium, Frontend Weekly, 31 Jan. 2018, medium.com/front-end-weekly/typescript-what-is-it-when-is-it-useful-c4c41b5c4ae7.

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