There seems to be more than one artist named Silvia.

1) The German singer Silvia released a self titled album in 1982. The musical style is NDW (neue deutsche Welle" - "new german wave") in addition to minimalistic electro sounds.

2) The trance artist Silvia is more of an underground music maker. She composes most of her music using a YAMAHA keyboard and a few music programs, and composes both orchestral music as well as trance/techno. Her most popular pieces are her Vertex series: Vertex ALPHA, Vertex BETA, Vertex GAMMA, and the most recent one, Vertex DELTA.

http://www5e.biglobe.ne.jp/~silvia-s/index.html
http://www.muzie.co.jp/cgi-bin/artist.cgi?id=a004297

3) The Lithuanian singer. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.