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Stream clustering is an important data mining technique to capture the evolving patterns in real-time data streams. Today’s data streams, e.g., IoT events and Web clicks, are usually high-speed and contain dynamically-changing patterns. Existing stream clustering algorithms usually follow an online-offline paradigm with a one-record-at-a-time update model, which was designed for running in a single machine. These stream clustering algorithms, with this sequential update model, cannot be efficiently parallelized and fail to deliver the required high throughput for stream clustering. In this paper, we present DistStream, a distributed framework that can effectively scale out online-offline stream clustering algorithms. To parallelize these algorithms for high throughput, we develop a mini-batch update model with efficient parallelization approaches. To maintain high clustering quality, DistStream’s mini-batch update model preserves the update order in all the computation steps during parallel execution, which can reflect the recent changes for dynamically-changing streaming data. We implement DistStream atop Spark Streaming, as well as four representative stream clustering algorithms based on DistStream. Our evaluation on three real-world datasets shows that DistStream-based stream clustering algorithms can achieve sublinear throughput gain and comparable (99%) clustering quality with their single-machine counterparts. 

“Living” cell sheets or bioelectronic chips have great potentials to improve the quality of diagnostics and therapies. However, handling these thin and delicate materials remains a grand challenge because the external force applied for gripping and releasing can easily deform or damage the materials. This study presents a soft manipulator that can manipulate and transport cell/tissue sheets and ultrathin wearable biosensing devices seamlessly by recapitulating how a cephalopod’s suction cup works. The soft manipulator consists of an ultrafast thermo-responsive, microchanneled hydrogel layer with tissue-like softness and an electric heater layer. The electric current to the manipulator drives microchannels of the gel to shrink/expand and results in a pressure change through the microchannels. The manipulator can lift/detach an object within 10 s and can be used repeatedly over 50 times. This soft manipulator would be highly useful for safe and reliable assembly and implantation of therapeutic cell/tissue sheets and biosensing devices.