Research

wordlNESLabOngoing and past research is described here. See also the Publications page for further info!

Mobile drone computing. Unmanned aerial vehicles, ground robots, and aquatic rovers are revolutionising mobile sensing applications. Compared to mobile phones or connected cars that can only opportunistically sense, these platforms offer directly control over where to sample the environment: the application can explicitly instruct them on where to move. They can thus implement sensing functionality that were previously unimaginable, such as collecting high-resolution imagery of civil infrastructures where satellite views cannot reach, or inspecting the sea floor to gain fine-grained environmental data. We are researching how to build the software that powers these systems and how to enable its efficient and dependable execution. Work in collaboration with Kamin Whitehouse (University of Virginia). [MOBISYS16 (Best Paper Award), DRONET16 (Best Paper Award)SENSYS14]

System support for transiently-powered computing. We are developing software techniques to support applications that may be unpredictably interrupted because of energy shortages and must later resume as soon as energy is newly available. Examples are in the domains of smart buildings and wearable devices, whose energy provisioning may be assisted through ambient energy harvesting and wireless energy transfer. Because energy availability will be erratic, shutdowns and reboots will frequently happen. To ameliorate this, we are seeking answers to three questions. First is how to enable checkpointing of the program state on stable storage with minimal latency and energy consumption. Second is how to determine when and how to intertwine checkpointing with the main application’s processing. Third is what support to offer to developers to manage the possibility that applications be interrupted for a non-negligible amount of time. The work is partly funded through the Google Faculty Award we received in 2015. [IPSN17TOSN16, EWSN16]

The wireless bus networking abstraction. Cyberphysical systems (CPS) are employed at the core of many safety-critical sophisticated applications in a range of domains, from manufacturing to healthcare. Because of this, they need to operate dependably, efficiently, and in real-time.  Low-power wireless communications bring unquestionable advantages as underlying networking substrate for CPS, yet current low-power wireless protocols only focus on a few of the performance goals and fundamental qualities useful to the design and operation of CPS. Together with Marco Zimmerling (TU Dresden, Germany) and Prof. Lothar Thiele (ETH Zurich, Switzerland), we are developing the wireless bus: a networking abstraction and underlying implementation able to serve the needs of CPS applications with respect to predictable behaviors, adaptiveness against changing application requirements and network dynamics, as well as efficient run-time operation. [TCPS17SRDS13, MASCOTS13, SENSYS12, IQ2S12]

Directional transmissions in low-power wireless. Smart antennas may greatly improve the performance of low-power wireless communications; for example, by reducing channel contention as the antenna steers the radiated energy only towards the intended receivers, and by extending the communication range at little additional energy cost. Their potential, however, is largely untapped as existing low-power wireless protocols are built on the old adage of omni-directional transmissions. We are designing new networking solutions that, by modifying existing designs or by applying a clean-slate approach, are able to fully harness the benefits the  of directional transmissions and, at the same time, we are investigating the limitations of this technology in a low-power multi-hop setting. Work in collaboration with Ambuj Varshney (Uppsala University, Sweden), Thiemo Voigt (SICS Swedish ICT), and Gian Pietro Picco (University of Trento, Italy). [MASS16SENSYS15, SECON13, EWSN13, REALWSN13, REALWSN10]

Software adaptation in CPS. Cyberphysical systems (CPS) place a computing and communication core in the environment to gather data from, and possibly take actions on the real world. Because of the intimate interactions between the system and the physical world it is immersed in, CPS software is chiefly required to self-adapt against the many and unpredictable environment dynamics. This is difficult to achieve in general, and even more so whenever adaptation decisions are subject to time constraints or developers are to battle against the resource limitations of many existing CPS platforms. We are studying design concepts, language abstractions, and verification approaches to tackle this challenge on a range of different platforms, from tiny sensor nodes to autonomous robot drones. [REACTION16CORCS14, DCOSS14]

Dependability in wireless sensor networks. Because of cost and minimal invasiveness, wireless sensors networks are created out of resource-constrained devices that tend to be brittle and fragile. The environment bears great influence on the their functioning, and yet its dynamics are partly not even understood and in general difficult to predict. This makes it challenging to achieve dependable system operation. We are investigating how to improve the dependable behavior of wireless sensor networks without sacrificing other key performance objectives, such as energy consumption. This requires studying the problem from different angles, including finding ways to understand the fundamental limitations, adapting existing dependable computation models, as well as increasing the system’s predictability and resilience to the environment dynamics. Work in collaboration with Arshad Jhumka (University of Warwick, UK) [TOSN16, EWSN16, SRDS13, EWSN10, SRDS09]