I am having Vivitar Electronic Flash (model 283) with Automatic Thyristor Exposure Control. Can I use this flash with Canon or Nikon DSLR cameras directly or with some other way.
The center pin will fire the flash on any camera. To be safe use a High Voltage Sync Regulator.
Here is a link to one on B+H: http://www.bhphotovideo.com/c/product/245292-REG/Wein_W990560_Safe_Sync_Hot_Shoe_to.html
This is the first one I found and I'm sure they're are other brands that will work just as well. I used to have one a few years ago, but where it is now, and what brand it was are a mystery.
It all depends on the sync voltage of your particular copy. The Vivitar 283 was made for a long period of time, and there were various changes to the model over the years. Some vintage 283s have been found to fire with a sync voltage of over 300V, which can fry the hotshoe of most digital cameras. Nikon's hotshoe sync voltage limit is 250V.
There are, however, 283s that have digital-safe sync voltages, so if you can measure the sync voltage, that's the easiest way to tell if it's compatible, or if you need to limit the voltage on the hotshoe.
In addition, as I'm sure you know, you cannot use TTL, "smart" optical slaving, FP/HSS, etc. etc. with it. And it has no explicit manual flash ratio (1, 1/2, 1/4, etc.) power controls, but depends on either an autothyristor and the flash calculator, or doing math in your head to get the right guide number.
Today, there are a lot of inexpensive flashes (say in the $60-$200 range) that offer a lot more features and are safe for dSLRs, so it may be a better choice, depending on how you want to use the 283, to look at getting a newer unit from, say, LumoPro, Godox, or Yongnuo.
The original Vivitar 283/285 flashes (made way back in the 1980s) used a high voltage trigger. Wasn't a problem on the largely mechanical sync mechanisms in cameras then, will likely destroy a modern digital camera.
The HV series (283HV and 285HV) used a low voltage trigger and are completely compatible with any modern camera.
The 283 and 285 are excellent flashes, the 285 being one of the most powerful hotshoe flashes ever made. I used one for many years. It's battery hungry, but it's also capable of accepting a 500 volt (!) battery pack for near-instant recharges.
However, that only applies to the original made-by-Vivitar models. The ones on sale today are NOT made by Vivitar - the original company's founders died of old age and the company name has been sold a couple of times. The current 283/285 flashes have the same name and case, but also have a reputation for rather low quality. They are basically a cheap knock-off riding the reputation of their predecessors. Use at your camera's risk.