Decentralized Personal Health Records with Interacting Physician Apps and Intelligent Agents on Blockchain and Smart Contract Technologies (Preprint)

BACKGROUND The Health Avatar Platform (HAP) provides a mobile health environment with interconnected patient Avatars, physician apps, and intelligent agents (IoA3) for data privacy and participatory medicine. However, its fully decentralized architecture has come at the expense of decentralized data management and data provenance. OBJECTIVE The introduction of blockchain and smart contract (SC) technologies to the HAP legacy platform with a clinical metadata registry (MDR) remarkably strengthens decentralized health data integrity and immutable transaction traceability at the corresponding data-element level in a privacy-preserving fashion. A crypto-economy ecosystem was built to facilitate secure and traceable exchanges of sensitive health data. METHODS HAP decentralizes patient data in appropriate locations with no central storage, i.e., on patients’ smartphones and on physicians’ smart devices. We implemented an Ethereum-based hash chain for all transactions and SC-based processes to guarantee decentralized data integrity and to generate block data containing transaction metadata on-chain. Parameters of all types of data communications were enumerated and incorporated into three SCs, in this case a health data transaction manager, a transaction status manager, and an API transaction manager. The actual decentralized health data are managed in off-chain manner on their appropriate smart devices and authenticated by hashed metadata on-chain. RESULTS Metadata of each data transaction are captured in a HAP blockchain node by the SCs. We provide workflow diagrams each of the three use cases of data push (from a physician app or an intelligent Agents to a patient Avatar), data pull (requested to a patient Avatar by other entities), and data backup transactions. Each transaction can be finely managed at the corresponding data-element level rather than at the resource or document levels. Hash chained metadata support data element-level verification of the data integrity in subsequent transactions. SCs can incentivize transactions for data sharing and intelligent digital healthcare services. CONCLUSIONS HAP and IoA3 provide a decentralized blockchain ecosystem for health data that enables trusted and finely tuned data sharing and facilitates health value-creating transactions by SCs.

ALGORITMA ROCC

Algoritma concurrency control merupakan algoritma pengendalian akses konkurensi pada sistem sehingga objek yang diakses bersifat konsisten. Penelitian tentang concurrency control sudah dilakukan sejak 30 tahun lalu dan sudah banyak algoritma yang dihasilkan. Algoritma yang dihasilkan umumnya menggunakan asumsi bahwa Transaction Manager adalah satu-satunya modul yang digunakan pengguna untuk mengakses objek. Sekarang ini akses terhadap objek dilakukan orang tidak hanya melalui Transaction Manager, tetapi juga melalui aplikasi internet. Pola tingkah laku transaksi melalui aplikasi internet berbeda dengan aplikasi tradisional. Algoritma concurrency control yang ada seperti two phase locking kurang tepat dan berkinerja buruk pada aplikasi internet. Untuk itu dibutuhkan suatu algoritma concurrency control baru yang sesuai dengan aplikasi internet. Shi dan Perizzo memperkenal algoritma ROCC (Read-commit Order Concurrency Control). Banyak peneliti menilai algoritma ini sangat sesuai dengan aplikasi internet, tetapi algoritma ini melakukan restart yang tidak perlu. Penulis mencoba memperbaiki algoritma proses validasi sehingga restart dilakukan hanya pada akses atau transaksi yang tidak konsisten. Penelitian ini juga melakukan simulasi dalam upaya melihat perbedaan kinerja antara algoritma ROCC dan algoritma ROCC yang sudah diperbaiki.