Spam and mail filtering technology
Spam has always been one of the persistent problems of the Internet. Spam not only wastes network resources, but may also cause huge negative social impacts. Therefore, research on anti-spam technology is imperative.
The application research of artificial immune system in the field of engineering has brought new hope for preventing spam. At present, the mail filtering technology based on the artificial immune system has gradually gained the attention of academia, and there have been anti-spam products based on the principle of artificial immune in foreign countries.
Filter design
2.1 System model of the filter The working principle of the filter is shown in Figure 1. The gene pool mimics the human bone marrow, randomly generating initial B cells at a constant rate and adding antibodies
In the network. The health of B cells also decreases at a certain rate. When it is 0, B cells will die and be automatically pruned from the network. This mechanism reflects the characteristics of antibody network competition learning, and can ensure the diversity and stability of B cell populations.
Figure 1 Flow chart of the mail filter system
The structure of the gene bank is based on the collected spam samples, respectively, subject (Subject) field, sender (Sender) field and body (Message) field feature extraction, remove duplicates and some common keywords (such as and, of, etc. ), Three sets of feature items are formed, and these three sets together constitute the gene bank.
Design of mail filter based on antibody network
In the rectifier circuit; the use of diodes in series can increase the back pressure withstand value (usually the sum of the back pressure of all diodes, but it is best to use diodes of the same specification).
In the voltage stabilization circuit; the series connection of the diode is equal to the sum of the voltage stabilization value of the diode. The use of diodes in parallel is theoretically the sum of rated currents, but considering that it is impossible to be absolutely symmetrical, they can only be used below 80% of the total.
TVS transient suppressor diodes work in the same way as regulator diodes, but there are structural differences.The biggest difference is that the PN junction area composed of the general regulator diode is very small, it can withstand the reverse current is small.
Transient Voltage Suppressor,Transient Voltage Suppressor Diode,Series diode
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