MATHEMATICS OF THE DISCRETE FOURIER TRANSFORM (DFT) WITH AUDIO APPLICATIONS SECOND EDITION
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@hellolixian-blog
MATHEMATICS OF THE DISCRETE FOURIER TRANSFORM (DFT) WITH AUDIO APPLICATIONS SECOND EDITION
Numpy Study Notes
An ndarray is a multidimensional container for homogeneous data; that is, all of the elements must be the same type.
data.shape, a tuple indicating the size of each dimension
data.dtype, a object describing the data type of the array
data.ndim, number of array dimensions
Create ndarray
Use the array function, np.array()
Unless explicitly specified, np.array tries to infer a good data type for the array that it creates
np.zeros() & np.ones() create arrays of 0' or 1', with a given length or shape
np.empty() creates an array without initializing its values to any particular value
To create a higher dimensional array with these methods, pass a tuple for the shape, e.g. np.empty((2,3,2))
np.arange() is an array-valued version of the built-in python range function
Install Scientific Python Package on Mac using Brew
http://penandpants.com/2013/04/04/install-scientific-python-on-mac-os-x/
btw, brew doctor is quite useful. Problem solved.
lixian$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers with debugging if you file an issue. If everything you use Homebrew for is working fine: please don't worry and just ignore them. Thanks!
Warning: Xcode 7 lacks the 10.10 SDK which can cause some builds to fail. We recommend installing the Command Line Tools with: xcode-select --install to resolve this issue.
Warning: Your Xcode (5.1.1) is outdated Please update to Xcode 6.4. Xcode can be updated from the App Store. lixian$ xcode-select --install
It's my DAY!
CSV Processing by Python
http://pymotw.com/2/csv/
Mathematics for Acoustic Application
https://ccrma.stanford.edu/~jos/mdft/Complex_Numbers.html
After so many years, it's really hard to pick up complex mathematics. Well, sometimes you just have to shut up and suck it up...
PMP Concept Notes
A project is based on a unique set of interdependent tasks and estimates of how long each task should take, various resources and assumptions about the availability and capability of those resources, and estimates of the costs associated with the resources.
The successful accomplishment of the project objective could be constrained by many factors, including scope, quality, schedule, budget, resources, risks, and customer satisfaction.
Good planning and communication are essential to prevent problems from occurring or to minimize their impact on the achievement of the project objective when they do occur.
In the initiating phase, projects are identified and selected. They are then authorized, using a document referred to as a project charter, which might include the rationale or justification for the project objective and expected benefits; general requirements and conditions such as amount of funds authorized, required completion date, major deliverables, and required reviews and approvals; and key assumptions. If the organization deciders to use external resources ( a contractor) to perform the project, the organization will prepare a document called a request for proposal (RFP). Through RFP, the sponsor or customer asks contractors to submit proposals on how they might address the need and the associated costs and schedule to do so.
The planning involves determining what needs to be done (scope, deliverables), how it will take (durations, schedule), how much it will cost (budget), and what the risks are.
Participation builds commitment.
The full scope of the work and deliverables were completed according to the specifications, within budget, and on time.
The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis throughout the performing phase and take any needed corrective action immediately.
A change control system needs to be established to define how changes will be documented, approved, and communicated. Agreement must be reached between the sponsor or customer and the project manager or contractor, as well as between the project manager and the project team, regarding to the way changes will be handled.
The later in the project that changes are identified, the greater their effect on accomplishing the project objective.
The performing phase of the project life cycle ends when he sponsor or customer is satisfied that the project objective has been accomplished and that the requirements have been met, and accepts the project deliverables.
The process of closing the project involves various actions, including collecting and making final payments, evaluating and recognizing staff, conducting a post-project evaluation, documenting lessons learned, and archiving project documents.
.wav File Format
The wave file is one of the RIFF specifications. The structure is consisted of 3 structs: WaveRIFFHeader, FormatChunk, and DataChunk.
Each chunk starts with the name of the chunk, followed by the length of the chunk, followed by more data as following:
WaveRIFFHeader
The ChunkID is RIFF (0x 52 49 46 46). And ChunkSize equals to 36 + Subchunk2Size. In addition, Format will be 'WAVE', 0x 57 41 56 45, and indicates two sub-chunks, 'fmt' and 'data'.
Format Sub-chunk
It describes the format of sound data. The ID chunk is fmt (space) (0x 66 6D 74 20), 4 bytes. SubChunkSize, 0x 10 00 00 00, stands for the size of the rest of the SubChunk which follows this number. AudioFormat
VM under Linux
http://www.turnkeylinux.org/blog/qemu-kvm-rules
Computing History
http://www.columbia.edu/cu/computinghistory/
Air-pollution Mask Selection
There is serious air pollution in China. So, I'm buying face masks for my families. News mentioned it needs protection from PM2.5 particles. Since that, I did little research to understand what kind of mask I should order.
In US, NIOSH, the National Institute for Occupational Safety and Health is the U.S. federal agency that conducts research and makes recommendations to prevent worker injury and illness. Particulate respirators are divided to 3 categories: N-, R-, and P-, which stand for not resistant to oil, resistant to oil, and oil proof. Besides that, it has different filter efficiency (i.e., 95%, 99%, or 99.97%). Of course, the higher efficiency it is, the more money it asks for. Refer to: http://www.theworldofchinese.com/2013/04/whered-you-get-that-mask/
Following content gives me little brief of brand selection:
http://www.theworldofchinese.com/2013/04/whered-you-get-that-mask/
I personally ordered 3M 9211 for your reference.
My German Note
I started taking German class starting from this September. Following is my refreshing note:
https://docs.google.com/document/d/1lV5kNZCj_fAGX8Klc7ABB2Bc99y5cd3P_2SyPW-Io_E/edit?usp=sharing
The UNIX system was developed by researchers who needed a set of modern computing tools to help them with their projects. The system allowed a group of people working together on a project to share selected data and programs while keeping other information private.
In 1975, Bell Labs offered it to educational institutions at nominal cost. UNIX System V (SVR 4) descended from versions developed and maintained by AT&T and UNIX system Laboratories.
In 1977, the Computer Systems Research Group(CSRG) at the UC Berkeley made significant additions and changes to it. In fact, it made so many popular changes that one version of the system is called Berkeley Software Distribution (BSD) of the UNIX system. Mac OS X inherits much more strongly from BSD branch.
In 1983, GNU project's initial announcement: http://www.gnu.org/gnu/initial-announcement.html
In 1988, for System V POSIX (Portable Operating System Interface for Computer Environments) is a group of IEEE standards that define API, shell, and utility interfaces for an OS.
In 1969, Ken Thompson wrote the UNIX OS in PDP-7 assembly language. To make it portable, Thompson developed B programming language, a machine-independent language, from the BCPL language. Dennis Ritchie developed C programming language by modifying B and rewrote UNIX in C in 1073 with Thompson.
In late 1980s, ANSI defined a standard version of C language, commonly referred to ANSI C or C89. Ten years later the C99 standard was published is mostly supported by GNU Project's C compiler, names gcc.
Error 1015
All the experience with Genius Bar sucks. Bringing iphone back and figuring out on my own is better option.
http://everythingapplepro.net/?p=506
Instruction of Installing Java on Ubuntu
http://www.wikihow.com/Install-Oracle-Java-on-Ubuntu-Linux
gdb with STL
For some reason, it's hard for gdb to print STL content. I used the very first solution. It works fine.
http://sourceware.org/gdb/wiki/STLSupport
Topological Sorting
DAG is is a directed graph with no directed cycles. That is, it is formed by a collection of vertices and directed edges, each edge connecting one vertex to another, such that there is no way to start at some vertex v and follow a sequence of edges that eventually loops back to v again.
DAGs may be used to model:
1) A collection of tasks that must be ordered into a sequence, subject to constraints that certain tasks must be performed earlier than others, may be represented as a DAG with a vertex for each task and an edge for each constraint; algorithms for topological ordering may be used to generate a valid sequence.
2) Processes in which information flows in a consistent direction through a network of processors