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1. FAIR and Interactive Data Graphics from a Scientific Knowledge Graph

   https://doi.org/10.1038/s41597-022-01352-z  

   Deagen, Michael E.; McCusker, Jamie P.; Fateye, Tolulomo; Stouffer, Samuel; Brinson, L. Cate; McGuinness, Deborah L.; Schadler, Linda S. (May 2022, Scientific Data)

   Abstract Graph databases capture richly linked domain knowledge by integrating heterogeneous data and metadata into a unified representation. Here, we present the use of bespoke, interactive data graphics (bar charts, scatter plots, etc.) for visual exploration of a knowledge graph. By modeling a chart as a set of metadata that describes semantic context (SPARQL query) separately from visual context (Vega-Lite specification), we leverage the high-level, declarative nature of the SPARQL and Vega-Lite grammars to concisely specify web-based, interactive data graphics synchronized to a knowledge graph. Resources with dereferenceable URIs (uniform resource identifiers) can employ the hyperlink encoding channel or image marks in Vega-Lite to amplify the information content of a given data graphic, and published charts populate a browsable gallery of the database. We discuss design considerations that arise in relation to portability, persistence, and performance. Altogether, this pairing of SPARQL and Vega-Lite—demonstrated here in the domain of polymer nanocomposite materials science—offers an extensible approach to FAIR (findable, accessible, interoperable, reusable) scientific data visualization within a knowledge graph framework. 

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2. Debugging Distributed Systems with Why-Across-Time Provenance

   https://doi.org/10.1145/3267809.3267839  

   Whittaker, Michael; Teodoropol, Cristina; Alvaro, Peter; Hellerstein, Joseph M. (January 2018, Proceedings of the ACM Symposium on Cloud Computing)

   Systematically reasoning about the fine-grained causes of events in a real-world distributed system is challenging. Causality, from the distributed systems literature, can be used to compute the causal history of an arbitrary event in a distributed system, but the event's causal history is an over-approximation of the true causes. Data provenance, from the database literature, precisely describes why a particular tuple appears in the output of a relational query, but data provenance is limited to the domain of static relational databases. In this paper, we present wat-provenance: a novel form of provenance that provides the benefits of causality and data provenance. Given an arbitrary state machine, wat-provenance describes why the state machine produces a particular output when given a particular input. This enables system developers to reason about the causes of events in real-world distributed systems. We observe that automatically extracting the wat-provenance of a state machine is often infeasible. Fortunately, many distributed systems components have simple interfaces from which a developer can directly specify wat-provenance using a technique we call wat-provenance specifications. Leveraging the theoretical foundations of wat-provenance, we implement a prototype distributed debugging framework called Watermelon. 

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3. Distributed Asynchronous Array Computing with the JetLag Environment

   https://doi.org/10.1109/PyHPC51966.2020.00011  

   Brandt, Steven R.; Hasheminezhad, Bita; Wu, Nanmiao; Sakin, Sayef Azad; Bigelow, Alex R.; Isaacs, Katherine E.; Huck, Kevin; Kaiser, Hartmut (November 2020, 2020 IEEE/ACM 9th Workshop on Python for High-Performance and Scientific Computing (PyHPC))

   null (Ed.)

   We describe JetLag, a Python-based environment that provides access to a distributed, interactive, asynchronous many-task (AMT) computing framework called Phylanx. This environment encompasses the entire computing process, from a Jupyter front-end for managing code and results to the collection and visualization of performance data.We use a Python decorator to access the abstract syntax tree of Python functions and transpile them into a set of C++ data structures which are then executed by the HPX runtime. The environment includes services for sending functions and their arguments to run as jobs on remote resources.A set of Docker and Singularity containers are used to simplify the setup of the JetLag environment. The JetLag system is suitable for a variety of array computational tasks, including machine learning and exploratory data analysis. 

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4. Quill: A Declarative Approach for Accelerating Augmented Reality Application Development

   Codi Burley, Ritesh Sarkhel (September 2022, A Quarterly bulletin of the Computer Society of the IEEE Technical Committee on Data Engineering)

   Sudeepa Roy and Jun Yang (Ed.)

   Data we encounter in the real-world such as printed menus, business documents, and nutrition labels, are often ad-hoc. Valuable insights can be gathered from this data when combined with additional information. Recent advances in computer vision and augmented reality have made it possible to understand and enrich such data. Joining real-world data with remote data stores and surfacing those enhanced results in place, within an augmented reality interface can lead to better and more informed decision-making capabilities. However, building end-user applications that perform these joins with minimal human effort is not straightforward. It requires a diverse set of expertise, including machine learning, database systems, computer vision, and data visualization. To address this complexity, we present Quill – a framework to develop end-to-end applications that model augmented reality applications as a join between real- world data and remote data stores. Using an intuitive domain-specific language, Quill accelerates the development of end-user applications that join real-world data with remote data stores. Through experiments on applications from multiple different domains, we show that Quill not only expedites the process of development, but also allows developers to build applications that are more performant than those built using standard developer tools, thanks to the ability to optimize declarative specifications. We also perform a user-focused study to investigate how easy (or difficult) it is to use Quill for developing augmented reality applications than other existing tools. Our results show that Quill allows developers to build and deploy applications with a lower technical background than building the same application using existing developer tools. 

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5. OKAPI: In Support of Application Correctness in Smart Home Environments

   https://doi.org/10.1109/FMEC.2019.8795349  

   Melissaris, Themis; Shaw, Kelly; Martonosi, Margaret (June 2019, Fourth International Conference on Fog and Mobile Edge Computing (FMEC))

   Typical Internet of Things (IoT) and smart home environments are composed of smart devices that are controlled and orchestrated by applications developed and run in the cloud. Correctness is important for these applications, since they control the home's physical security (i.e. door locks) and systems (i.e. HVAC). Unfortunately, many smart home applications and systems exhibit poor security characteristics and insufficient system support. Instead they force application developers to reason about a combination of complicated scenarios-asynchronous events and distributed devices. This paper demonstrates that existing cloud-based smart home platforms provide insufficient support for applications to correctly deal with concurrency and data consistency issues. These weaknesses expose platform vulnerabilities that affect system correctness and security (e.g. a smart lock erroneously unlocked). To address this, we present OKAPI, an application-level API that provides strict atomicity and event ordering. We evaluate our work using the Samsung SmartThings smart home devices, hub, and cloud infrastructure. In addition to identifying shortfalls of cloud-based smart home platforms, we propose design guidelines to make application developers oblivious of smart home platforms' consistency and concurrency intricacies. 

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