vs. a permanent dwelling/residence, assuming that by
"discontinuous " they mean not continual/not permanent
instead of "incongruous" (that vary in shape, size, diversified, inconsistent) - see the definition below: more text would help
:o)

in·con·gru·ous Audio Help /ɪnˈkɒŋgruəs/ Pronunciation Key - Show Spelled Pronunciation[in-kong-groo-uhs] Pronunciation Key - Show IPA Pronunciation
–adjective 1. out of keeping or place; inappropriate; unbecoming: an incongruous effect; incongruous behavior.
2. not harmonious in character; inconsonant; lacking harmony of parts: an incongruous mixture of architectural styles.
3. inconsistent: actions that were incongruous with their professed principles.


--------------------------------------------------
Note added at 8 hrs (2008-09-03 00:28:22 GMT)
--------------------------------------------------

If they live..and work in the streets, they are technically "homeless" or "Transients".
A dwelling place means

WordNet - Cite This Source - Share This dwelling

noun
housing that someone is living in; "he built a modest dwelling near the pond"; "they raise money to provide homes for the homeless"
abitazione/dimora in Italian (disctionary.com)

American Heritage Dictionary - Cite This Source - Share This tran·si·ent Audio Help (trān'zē-ənt, -zhənt, -shənt) Pronunciation Key
adj.
Passing with time; transitory: "the transient beauty of youth" (Lydia M. Child).
Remaining in a place only a brief time: transient laborers.