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Mobile virtualization introduces extra layers in software stacks, which leads to performance degradation. Especially, each I/O operation has to pass through several software layers to reach the NAND-flash-based storage systems. This paper targets at optimizing I/O for mobile virtualization, since I/O becomes one of major performance bottlenecks that seriously affects the performance of mobile devices...
Embedded systems are becoming increasingly popular due to their widespread applications. Hardware/software partitioning with reliability in consideration is becoming one of the most crucial steps in the design of complex embedded systems, especially for safety critical applications. In this paper, a reliability-centric approach is proposed to increase the reliability and decrease the potential errors...
A fire-fighting control system, which is usually implemented through programmable logic controllers, is a typical type of safety-critical cycle physical system. It has been widely used in currently complex industrial applications. So it is significant for a fire-fighting control system to conduct safety checking. There have been many methods to check safety of a fire-fighting control system so far,...
Three-dimensional (3D) stacked memory module based on TSV is becoming an attractive alternative. Chips are assembled through micro bumps, which will bring additional thermo-mechanical stress, as well as the channel resistance and interconnection reliability problem. In this paper, we leverage thermal cycles to assess the mechanical and electrical reliability of a bump-less wafer-on-wafer integration...
Multi-threaded programs play an increasingly important role in current multi-core environments. Exposing concurrency bugs and debugging such multi-threaded programs have become quite challenging due to their inherent non-determinism. In order to eliminate such non-determinism, many approaches such as record-and-replay and other similar bug reproducing systems have been proposed. However, those approaches...
We consider a new type of distinct element counting problem in dynamic data streams, where (1) insertions and deletions of an element can appear not only in the same data stream but also in two or more different streams, (2) a deletion of a distinct element cancels out all the previous insertions of this element, and (3) a distinct element can be re-inserted after it has been deleted. Our goal is...
I/O is becoming one of major performance bottlenecks in NAND-flash-based smartphones. Novel NVMs (nonvolatile memories), such as PCM (Phase Change Memory) and STT-RAM (Spin-Transfer Torque Random Access Memory), can provide fast read/write operations. In this paper, we propose an unified NVM/flash architecture to improve the I/O performance. A transparent scheme, vFlash (Virtualized Flash), is also...
Similarity measurement for spectral clustering has been well-studied in recent years due to its crucial role on describing the intrinsic structure of data points. In this paper, we propose a hybrid attributes similarity measure method to process the Gaussian kernel affinity matrix. Compared with traditional global or local scale methods, our new similarity measurement has a rather robustness to reflect...
Identifying hot items have been found useful in many network monitoring applications to detect network anomalies. There are different variants of this problem and we work on a special case where the traffic of the hot items are distributed in multiple dynamic data streams. Most of the existing methods for identifying hot items do not work for our problem, except one which used Group Testing based...
Multiple features have been employed for content-based medical image retrieval. To reduce curse of dimensionality, subspace learning techniques have been applied to learn a low-dimensional subspace from multiple features. Most of the existing methods have two drawbacks: first, they ignore the fact that multiple features have complementary properties, and thus have different contributions to construct...
Mobile virtualization introduces extra layers in software stacks, which leads to performance degradation. Especially, each I/O operation has to pass through several software layers to reach the NAND-flash-based storage systems. Among all the I/O operations, a large percentage is updating metadata. Frequent updating metadata not only degrades overall I/O performance but also severely reduces flash...
This paper present an optical system for Cs atomic fountain clock that is located on a 1.2 m×1.2 m optical table. Taking advantage of this system, we trap about 108 cesium atoms in the magneto-optic trap (MOT) and get the Ramsey fringe of the fountain by scanning the microwave frequency of the interrogation cavity. The full-width at half-maximum of the central fringe (FWHM) is 1.4 Hz.
Sambot is a module robot system, with the advantages of self-assembly. A target robotic configuration can be organized by a group of Sambots. A novel motion planning method for Sambot configuration using model checking is presented in this paper. This hierarchical method contains two layers. The abstract logic layer is responsible for the discrete planning of Sambots configuration. The robot and the...
In designing robot control systems, simulation is still the primary approach to verifying the functions of circuit descriptions written in hardware design language. The validity of the verification depends on the coverage metric. But not all state spaces can be specified in a simulation. Model checking can overcome the shortcomings of simulation, because all of the state spaces can be traversed. Robot...
Direct volume rendering (DVR) is commonly employed for the medical visualization. Multi-dimensional transfer functions are used in DVR to emphasize the region of interest in details. However, it is impractical to interact directly with the functions in more than three dimension. This paper proposes a novel framework called geometry constrained sparse embedding (GCSE) for dimensionality reduction (DR)...
Possessing two manipulators heightens the ability of dual-arm robots (DAR) to conduct complex tasks, while raising hazard that the two manipulators might collide with each other or with other objects. DARs are usually equipped with a collision-free motion planning algorithms (CFMPA) to prevent the two manipulators from colliding. The CFMPA searches the motion paths of robot manipulators, which are...
The control system for Cesium atomic fountain clock is described in detail in this paper. It consists of five parts, automatic digital frequency locking system of extended cavity diode laser (ECDL), the time serial control system, the data acquisition system, the microwave frequency synthesizer control system and the servo control system. With automatic digital frequency locking system, the frequency...
In this paper we present experimental results on the laser power stabilization of the detection system in Cs fountain clock. In order to stabilize the laser power, we have constructed a feedback loop by using an acousto-optic modulator, a photodetector, and a servo controller. The control-loop can make the relative intensity noise of the laser beam reduce from 1.33×10−4 Hz−1/2 to 7.16×10−6 Hz−1/2...
Recently, the open-source robot operating system (ROS) has been growing rapidly in the robotics community. However, the ROS runs on Linux, which does not provide timing guarantees for robot motion. This paper present a hybrid real-time ROS architecture on multi-core processor “RGMP-ROS”, which consists of two parts including the non-real-time subsystem “GPOS (General Operating system)” and the real-time...
We reported a wafer level through-stack-via (TSV) integration approach for stacked memory module using onetime bottom-up copper filling. This bumpless TSV integration approach simplified the fabrication process and provided better reliability compared with solder based technologies. Silicon wafer with blind vias was first bonded to a carrier wafer face to face with pre-patterned BCB, and then thinned...
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