Neural Networks Overfitting

Overfitting pada Neural Network

Sampai saat ini, model sapu jagad yang kami pergunakan untuk berbagai aplikasi yang rumit dan sangat nonlinier adalah Jaringan Syaraf Tiruan /JST atau Artificial Neural Network/ANN yang terkadang hanya disebut sebagai NN. Satu neuron adalah persamaan jumlah seluruh input kali pembobotnya dikalikan fungsi aktifasi. Model NN sebenarnya adalah multi equation yang disusun secara series-paralel, dimana bobot-nya diupdate dalam rangka menyamakan output prediksi dan data aktual saat fase training. Tentunya data serumit apapun akan termodelkan dengan baik bila dimasukkan dalam fase training ini, semakin banyak neuron dan hidden layer semakin akurat model yang terbentuk, yang tercermin dari semakin kecil harga RMSE training.

Namun model yang terlalu akurat untuk data yang ditrainingkan akan menjadi model yang terlalu eksklusif. Akan menghasilkan output yang baik untuk data yang ditrainingkan saja, tapi tidak bisa menghasilkan output yang baik untuk data validasi (data yang tidak termasuk dalam fase training). Fenomena ini disebut overfitting, yang merupakan masalah terbesar dalam pemodelan menggunakan NN.

Sebenarnya tidak hanya model yang terlalu besar (banyaknya hidden neuron dan hidden layer) yang menyebabkan overfitting, Jumlah observasi data yang terlalu sedikit, jumlah variabel input yang terlalu sedikit, kualitas data (outlier data, noise, konsistensi, korelasi input dan output, sebaran data), pembagian data yang untuk training dan validasi serta pemilihan fungsi aktifasi.

Source: Totok R Biyanto's Weblog

You might also like:

How to share Mac OS X Leopard files on a Windows Vista Network
How to share Mac OS X Leopard files on a Windows Vista Network
Tech : (Its iPad!) Apples iSlate, iPad or iTablet?
Tech : (Its iPad!) Apples iSlate, iPad or iTablet?
Mac OS X Core Networking and Network Troubleshooting
Mac OS X Core Networking and Network Troubleshooting

Monday prosper reading material...

2008-08-25 09:22:48 by grativo

1. This loan will provide the necessary capital to purchase software, marketing materials and entrepreneurial educational tool taught by master entrepreneur and CEO of Nouveau Riche University, Jim Piccolo. With the ability to now focus full-time as opposed to free-time I expect to increase my income to a respectable $1,800/month.
2. Seriously folks, this loan will be used to take my Forex Trading Strategy, which is working very well, to the next level. Look at the picture in the listing. Over 150% profit in 13 days of active, 24 hour, automated trading using my software. (Turns out never traded for real money)
3. This loan will be used to help me invest 10k into a forex managed account investment fund. I am a good candidate for this loan because I am investing my own money...

No Loss Trading Plan that really works for your.

2008-01-18 20:41:56 by bfnnrgn

Are you in the Dallas, TX area? I have a trading plan that is non speculative, non directional, and generates a very high rate of return. It works everyday - all the time - with no losses - (yes) it "really" works. I have been trading the financial markets for 30 years and I understand exactly what I am doing. As a demo, I started trading a friends Forex account of just $6,000.00 on 12/20/07 and I generated a 100% return in just three weeks using leverage with no losses. Luck was not part of the success. A properly funded brokerage account will never have losses. I know it sounds unlikely but I can demonstrate and prove it "is" true. It took me most of my life to develop this technique and it did not come cheap to me. I call it my zero sum no loss trading plan and it will beat any...

Pay one way or another

2005-09-04 14:25:42 by o-lOl-o

$2000 for an online course huh. If it works for you. A few weeks is really good to actually begin to profit in live trading. Staying consistant over the long hual is the trick now. That takes discipline. Avoid the blowout sessions where a trader chases good money after bad trying to recoup losses. Or greedily jumps into a trade with little research.
I home schooled myself over about a year period. I didn't have the money to trade at the time so it really didn't matter. I was content to learn and save till I had it. I had some expenses that was a priority over forex. When I did have the extra cash not swallowed by life I had been profiting for over 6 months on paper and the transition to live was relatively seemless.
I'm getting nice returns now for almost a year live. From...

Will we ever… simulate the human brain?  — BBC News
Markram says he wants to build the cells as they are – gloriously detailed branching networks, full of active genes and electrical activity. He wants to simulate them down to their ion channels – the molecular gates that allow neurons to build up a ...

How I used alien quantum Internet medicine on my cat  — Ars Technica
Portal Access Key™ unlocks a quantum portal developed by ZAG that allows bioinformation to flow from ZAG's quantum computer directly to the neural network of your brain, another quantum computer, via quantum teleportation. This quantum data delivers ...

Related posts:

  1. Neural network forecasting
  2. Neural Networks for Excel
  3. Neural networks using C
  4. Neural Networks or Gate
  5. Neural Networks in Trading