Course four, module three, Decentralized Application Platforms. We've been exploring various blockchain platforms, challenges in the vigorous development activities advancing the blockchain technology. Have you wondered about the practical application that illustrates the special features of blockchain technology? Namely, Decentralization, Disintermediation, and Distributed Immutable Ledger? Are their application that affect you and me? Yes there are. We'll explore two Dapp platforms; Auger and Grid Plus, which are both implemented on Ethereum. Ideas and plans for these applications have been in the development side by side with Ethereum. Auger and Grid Plus are layers above the smart contract, each opening up the blockchain and the smart contract layer to the vast expands of vertical domains. In this case, it is the prediction markets and the energy retailing, respectively. More importantly, you can be a participant in these Dapp platforms, if you wish to do so. Let's venture out and see how the blockchain technology is applied and utilized in these two Dapp platforms. So, where does the Dapp platform module fall in our specialization roadmap? Recall material from earlier courses. We've been developing these layers shown. Previously we've developed simple Dapps, whereas here, we'll explore a comprehensive platform for a vertical business domain and understand how smart contracts form a central role in these applications. Why did we choose these particular Dapp platforms? Auger and Grid Plus are chosen specifically to illustrate two very diverse uses of the blockchain. These applications have extended history, complex components, and operations. Provenance of transactions are critical in both applications. They are addressing real world problems, not hypothetical ones. They offer innovative models for other domains to adapt. On completion of this module, you will be able to discuss the architecture and working of Auger platform, list use cases for Auger, explain the architecture and working of Grid Plus platform, and explore how Grid Plus can be used.