# Abstract
## 5 Discussion and Outlook  
In data analytics, visual representations are important since they can provide constructs that intuitively assist with inferring new information and can also reduce individuals' cognitive burden. The introduction of adequate visual representations for ledger data enables a higher level of analytics and therefore augments the intuitiveness of auditing processes. Nevertheless, when designing analytics solutions, the level of abstraction needs careful consideration; higher level data can facilitate richer and quicker analytics. To apply these concepts, we designed two distributed ledger visual representations, i.e., transaction-oriented abstraction highlighting transactions history and structure while allowing tracing and tracking of assets, and an account-oriented abstraction focusing on interactions between entities and providing insights on inter-participant behaviors. To enable the implementation of these high-level visual representations, we proposed an abstraction layer architecture. Its main purpose it to provide coherent interfacing and aggregating functionalities allowing the production of readily consumable data. A comparison between the proposed approach and available abstraction services for HF is provided in Table 1. To illustrate the proposed visual concepts and application architecture, a use case based on a dashboard for the regulated sectors has been explored. Employing higher level abstractions to represent HF data enables better comprehension of entities' interactions and improves the auditability of the system in comparison to HE.  
As a result of their simplicity, the middleware and microservice architecture enable better maintainability and scalability of the system. The autonomous life-cycles of microservices allow them to be deployed at a relatively fast pace. However, due to their technical heterogeneity, a larger set of skills is required for their development and maintenance. In addition, to comply with the best practices, individual testing of the microservices needs to be performed. Both the necessary skill-set and the additional testing make this type of architecture less cost effective in the short term or at low scale compared to traditional monolithic applications. Yet, as a result of the high scalability and maintainability of the microservice architecture, this extra-cost can be recovered when developing and operating larger systems.  
Ultimately, a universal higher level query language could be designed on top of this abstraction layer, which sits on blockchains. In turn, just like what Structured Query Language (SQL) is to Relational Database Management System (RDBMS), such language  
Figure 7: Concept design of the network topology view of the RegNet dashboard. From the left to the right column: page selection, news feed, network topology visualization and transaction insights. The analytics used to populate the dashboard are based on the data of the HF network deployed as a proof-of-concept in the RegNet case scenario.  
with its compositional, pragmatic and rich semantics would make business level querying much easier.  
Future work will investigate the scalability and interoperability of such system. In addition, a user study could also be conducted to evaluate the usability and effectiveness of the proposed visualizations and dashboard concept.  
Conceptualization, L.V. and S.D.; methodology, L.V. and S.D.; software, L.V.; validation, L.V., S.D. and S.S.; investigation, L.V.; resources, S.D. and A.M.K.; writing, L.V.; review and editing, S.D.; visualization, L.V.; supervision, S.D. and S.S.; project administration, S.D.; funding acquisition, S.D. and A.M.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Innovate UK [application number 45079; project number 106159].  
Data Availability Statement: Data sharing is not applicable to this article.  
The authors declare no conflict of interest.