Multi-tenancy architecture (MTA) is often used in Software-as-a-Service (SaaS) and

the central idea is that multiple tenant applications can be developed using compo

nents stored in the SaaS infrastructure. Recently, MTA has been extended where

a tenant application can have its own sub-tenants as the tenant application acts

like a SaaS infrastructure. In other words, MTA is extended to STA (Sub-Tenancy

Architecture ). In STA, each tenant application not only need to develop its own

functionalities, but also need to prepare an infrastructure to allow its sub-tenants to

develop customized applications. This dissertation formulates eight models for STA,

and proposes a Variant Point based customization model to help tenants and sub

tenants customize tenant and sub-tenant applications. In addition, this dissertation

introduces Crowd- sourcing to become the core of STA component development life

cycle. To discover fit tenant developers or components to help building and com

posing new components, dynamic and static ranking models are proposed. Further,

rank computation architecture is presented to deal with the case when the number of

tenants and components becomes huge. At last, an experiment is performed to prove

rank models and the rank computation architecture work as design.