Category Archives: Statistics

Visualizing operating characteristic curve with TI Nspire

In the study of quality control, sampling is an important technique to assess the overall quality level of a lot of production run. Operating characteristic curve is a great tool to understand the quality profile of acceptance sampling.

In TI Nspire, the OC curve can be defined as following using binomial distribution as an alternative to hypergeometric distribution.

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With the function defined, visualizing of 10% failure rate and sampling size of 20 can be done by graphing this function.

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Interesting applications of Generative Adversarial Network to crack CAPTCHA

Interesting results from a recent paper presented at the 25th ACM conference on Computer and Communications Security shown advances in Generative Adversarial Network (GAN). In particular the paper focused on tackling Captcha with GAN. GANs take a game theory approach in the training of network and during the deep learning process two entities compete in a game that one trying to fool the other while the other strives not to be fooled.

Comparison of performance of machine learning the probability distributions are usually considered as metrics for benchmark. One such commonly used is the Jensen–Shannon Divergence and a generalization can be given as

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Visualizing Volatility Sensitivity in Delta hedged gains with TI Nspire

The TI Nspire calculator is a great platform for visualizing data via interactive graphs. The built-in facility like input slider for variable value adjustment allowed dynamic visualization to complex equations, like the volatility sensitivity in delta-hedged gains used financial investment. Since this strategy involved a single call option, the volatility exposure equals the vega value of the option.

The following setup on the Nspire provided the functions to calculate the vega values.
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This spreadsheet input screen stores the spot prices and the calculated Black Scholes vega values.
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Finally, with the data plotting screen the graph of Delta hedged gains of volatility sensitivity is completed. An additional slider control can easily be added on it to adjust an offset variable so as to visualize scenarios under different spot price.
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Cryptographic roots in Blockchain technology

The Blockchain is expected to be the revolutionary technology to take the centre stage in our society where the traditional ledger system once dominates, from bitcoin that emerged in the finance sector to fields where transactions are dependent on authenticity, be it a paper document from bank, an import / export data exchange, or even documents in judicial systems, it is important to understand the principles of its fundamental roots in cryptography.

For example, to ensure the rightful spending of currency in bitcoins, there are a lot of technology being in place on the virtual money market. One being the Elliptic Curve Cryptography that is based on mathematics to ensure the identity of parties involved in any bitcoin transactions.

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