Decentralized access control for smart buildings using metadata and smart contracts

In this paper, we present a methodology based on blockchain smart contracts to describe, grant, and revoke fine-grained permissions for building users in a decentralized fashion. This method supports access control using resource description framework (RDF) graphs and implements two APIs for client applications. Leveraging the metadata of a real building, we have applied the proposed method to manage privileges in some realistic use-cases and shown that it can greatly reduce the administration overhead while providing fine-grained access control.

Optimizing serverless computing: introducing an adaptive function placement algorithm

The main concept behind serverless computing is to build and run applications without the need for server management. It refers to a fine-grained deployment model where applications, comprising of one or more functions, are uploaded to a platform and then executed, scaled, and billed in response to the exact demand needed at the moment. While elite cloud vendors such as Amazon, Google, Microsoft, and IBM are now providing serverless computing, their approach for the placement of functions, i.e. associated container or sandbox, on servers is oblivious to the workload which may lead to poor performance and/or higher operational cost for software owners. In this paper, using statistical machine learning, we design and evaluate an adaptive function placement algorithm which can be used by serverless computing platforms to optimize the performance of running functions while minimizing the operational cost. Given a fixed amount of resources, our smart spread function placement algorithm results in higher performance compared to existing approaches; this will be achieved by maintaining the users' desired quality of service for a longer time which prevents premature scaling of the cloud resources. Extensive experimental studies revealed that the proposed adaptive function placement algorithm can be easily adopted by serverless computing providers and integrated to container orchestration platforms without introducing any limiting side effects.

Executability of Python Snippets in Stack Overflow

Online resources today contain an abundant amount of code snippets for documentation, collaboration, learning, and problem-solving purposes. Their executability in a "plug and play" manner enables us to confirm their quality and use them directly in projects. But, in practice that is often not the case due to several requirements violations or incompleteness. However, it is a difficult task to investigate the executability on a large scale due to different possible errors during the execution. We have developed a scalable framework to investigate this for SOTorrent Python snippets. We found that with minor adjustments, 27.92% of snippets are executable. The executability has not changed significantly over time. The code snippets referenced in GitHub are more likely to be directly executable. But executability does not affect the chances of the answer to be selected as the accepted answer significantly. These properties help us understand and improve the interaction of users with online resources that include code snippets.

Emprirical Analysis on Public Docker Images

A Large-scale Emprirical Analysis on Public Docker Images

This work has been submitted as a paper for peer review, and it is still under review. Details will be available soon.

Security Enhancement for Cyber-physical systems

This work has been submitted as a paper for peer review, and it is still under review. Details will be available soon.

Design and Implementation of Admittance Testing System for Solar Cells with Automatic Data Retrieval

consuming and laborious, but also has some human factors affecting the test results. Based on practical demands of Advanced Optoelectronic Technology Laboratory of East China Normal University, an admittance testing system for solar cells with automatic data retrieval is designed and implemented. This work presents the realization of instrumentation, automated data acquisition and control systems . The development of testing software, such as software used for voltage/frequency Vs capacity testing and software used for temperature/frequency Vs capacity testing, is also presented . The system can automatically perform admittance testing according parameters given by users, r etrieve and visualize data in real time and process data and obtain results by algorithms. The system has high robustness and expansibility, which greatly improves the efficiency and accuracy of testing, and provides, to some extent, technical reference fo r realization of instrumentation, automated data acquisition and control systems for other instruments.