Decimal floating-point is a relatively recent addition to the IEEE standard (IEEE Std 754-2008). There exist few verification techniques that can check whether software libraries or hardware designs are in compliance with the standard. Our work presents a verification method to verify implementations of the decimal floating-point square root operation. We present an effective simulation based verification technique using test cases that verify the corner cases of the operation. The test cases are generated by solving constraints describing these corner cases with a dedicated constraint solver. The generated test cases proved their usefulness by finding severe bugs in two well-tested designs.

Most of the previous researches which intended with the subject of virtual power plants (VPPs), focused on the study of VPPs from economical point of view: auctions, bidding, trading, markets, pricing, cost, profit, benefits, risk, investors … etc. Merely conjecture, all the VPPs' models presented are financial and economical models, with no one prescribed electrical model. In this paper, a generic VPP will be proposed and considered for the study. The proposed generic VPP will be modeled with a novel Electro-Economical Model (EEM). The proposed model was constructed on three steps: construction of electrical model, construction of economical model, and combining both electrical and economical models to form EEM of the proposed generic VPP. The proposed generic VPP consisting of four basic components: dispatchable power plant(s), flexible load(s), storage unit(s), and stochastic generating unit(s); was illustrated. This system model has been simulated. All simulation results will be demonstrated and discussed.

From about fifteen years passed, a new term was proposed for the first time by Dielmann and Velden: "Virtual Power Plant (VPP)", and they asked about if the VPPs can contribute as a reliable and environmentally oriented energy supply, or not?, at this moment, they considered some problems that must be examined to insure the success of this idea; like: management of such a system (optimal utilization), adaptation of VPP with the network connected to (reliability), markets (retail and wholesale) … etc. If these problems are solved, then the VPP has a large opportunity to deliver an important contribution as an economic, reliable and nonpolluting energy supply system. The market is the dominant factor for the success of VPPs being. Before the age of distributed generation (DG), the energy delivery pricing model was the cost against service. The model states that consume (buy) energy then pay -buy and pay-. When the age of renewables raised up, the model of buy and pay is shifted away to a new market based pricing model: pay at first and then buy. Another conceptual model starts to appear including active demand side participation using the transactive energy concept. In this paper, a new combined model for market and electrical performance of VPPs is presented; the electro-economical model (EEM). The model will include the four basic components of any VPP: dispatchable power plants, flexible loads, storage units, and stochastic generating units. Two main targets for the proposed modeling: optimal operation of VPPs, and active network energy management of VPPs. The VPP can earn profit from the market and as a result, its objective reduces to maximizing its profit (ρ). Energy management in a VPP or active network management means the optimal operation of this VPP in order to manage energy flow. Optimal operation is based on a stochastic basis of energy sources and multi-market framework.

n/a