I argue that Vygotsky’s theory of concept formation (1986) is a powerful framework within which to explore how an individual at university level constructs a new mathematical concept. In particular, this theory is able to bridge the divide between an individual’s mathematical knowledge and the body of socially sanctioned mathematical knowledge. It can also be used to explain how idiosyncratic u...

This paper aims to clarifyi the concept of business models, its usages, and its roles in the Information Systems domain. A review of the literature shows a broad diversity of understandings, usages, and places in the firm. The paper identifies the terminology or ontology used to describe a business model, and compares this terminology with previous work. Then the general usages, roles and poten...

The concept of Dynamic Spectrum Access (DSA) will allow the radio spectrum to be traded in a market like scenario allowing Wireless Service Providers (WSPs) to lease chunks of spectrum on a short-term basis. Such market mechanisms will lead to competition among WSPs where they not only compete to acquire spectrum but also attract and retain users. Currently, there is little understanding on how...

this study has investigated smallholder farmers’ household food security level in mazandaran province during the two times i.e pre-harvest period and post-harvest period. using krejcie and morgan’s detrmining sample table, 384 farmers selected as a sample. a multi-stage sampling technique was used to select preciously subjects. household food insecurity access scale (hfias) was the main tool fo...