The term "non-conventional" project or "project with non-conventional cash fl ows" was introduced into economic literature after the internal rate of return (IRR) was shown to have multiple values or not exist at all in some projects. A project is considered to be conventional if it has only one change in the cash fl ow sign, no matter whether minus to plus or vice versa. A conventional project has a unique IRR. However, not all projects with a multiple sign change in cash fl ow are non-conventional, i.e. have problems with IRR determination. To ascertain the project type, the generally accepted approach recommends investigating monotony of the net present value (NPV) depending on the discount rate in order to fi nd out how many IRRs the project has. On the other hand, neither the monotony of the NPV function nor a unique IRR guarantee that the project is conventional. The IRR is known to be a rate of return for a conventional investment project rather than a non-conventional project. Moreover, it was shown that the rate of return of a non-conventional project cannot be determined within the framework of the NPV method, and therefore the concept of profi tability cannot be formulated. The recently proposed generalized net present value (GNPV) method allows us to determine the rate of return of a non-conventional project. This paper presents a method to determine the rate of return for an investment project of any type and proves that in the case of a conventional project the rate of return is the IRR, while in the case of a non-conventional project it is the generalized internal rate of return (GIRR). The necessary and suffi cient conditions of conventional and non-conventional projects have been formulated.

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Different rules for weighting input vectors in high-order associative memory models are considered. Numerical simulation results are given showing the advantage of the pattern weighting in recognizing high-correlated patterns. An optoelectronic implementation of the inner-product associative memory with weighting method is presented.

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Investments are often justified and accepted based on the IRR as the main criterion of profitability. However, that criterion is hardly ever used to evaluate some financial instruments (e.g. short sales, options, futures and swaps). This is partially due to the fact that some instruments possess a cash flow describing a borrowing rather than an investment. Others have a non-conventional cash flow and, consequently, the IRR may be meaningless or impossible to determine. We describe a non-conventional cash flow of a financial instrument as a non-conventional project consisting of a sequence of single-period (simple) projects. Each simple project has only two cash flows with opposite signs therefore the IRR for the simple project is always determined. If there is a decomposition in which each simple project has the same IRR value, then that value is the IRR of the non-conventional project. If a decomposition of the non-conventional project into simple projects with the same IRR is impossible, the non-conventional project’s IRR does not exist. If a simple project is an investment then the IRR is a rate of return for an investor. If a simple project is a loan then the IRR is an interest rate for the borrower, but not for the investor. Therefore the NPV method estimates a non-conventional project for two different participants simultaneously that leads to problems with definition of IRR. In order the loan’s IRR would be a rate of return for the investor, but not an interest rate for the borrower, the sign of IRR should be replaced to opposite one. The paper discusses how to use the Generalized Net Present Value (GNPV) method to calculate a yield of the financial instrument with non-conventional cash flow. The function GNPV(r, p) depends on two rates: finance and reinvestment ones that determine a cost of funding and a rate of return, respectively. The equation GNPV (r, -r) = 0 is investigated in the paper. The solution of that equation is the Generalized Average Rate of Return (GARR). We suggest using the GARR as a new measure of a yield for evaluating financial instruments possessing a non-conventional cash flow and estimating a portfolio’s performance over period with contributions and withdrawals.