Two-Stream Action Recognition-Oriented Video Super-Resolution

We study the video super-resolution (SR) problem for facilitating video analytics tasks, e.g. action recognition, instead of for visual quality. The popular action recognition methods based on convolutional networks, exemplified by two-stream networks, are not directly applicable on video of low spatial resolution. This can be remedied by performing video SR prior to recognition, which motivates us to improve the SR procedure for recognition accuracy. Tailored for two-stream action recognition networks, we propose two video SR methods for the spatial and temporal streams respectively. On the one hand, we observe that regions with action are more important to recognition, and we propose an optical-flow guided weighted mean-squared-error loss for our spatial-oriented SR (SoSR) network to emphasize the reconstruction of moving objects. On the other hand, we observe that existing video SR methods incur temporal discontinuity between frames, which also worsens the recognition accuracy, and we propose a siamese network for our temporal-oriented SR (ToSR) training that emphasizes the temporal continuity between consecutive frames. We perform experiments using two state-of-the-art action recognition networks and two well-known datasets--UCF101 and HMDB51. Results demonstrate the effectiveness of our proposed SoSR and ToSR in improving recognition accuracy.Comment: Accepted to ICCV 2019. Code: https://github.com/AlanZhang1995/TwoStreamS

Design Of Silicon Controlled Rectifers Sic] For Robust Electrostatic Discharge Protection Applications

Electrostatic Discharge (ESD) phenomenon happens everywhere in our daily life. And it can occurs through the whole lifespan of an Integrated Circuit (IC), from the early wafer fabrication process, extending to assembly operation, and finally ending at the user‟s site. It has been reported that up to 35% of total IC field failures are ESD-induced, with estimated annual costs to the IC industry running to several billion dollars. The most straightforward way to avoid the ICs suffering from the threatening of ESD damages is to develop on-chip ESD protection circuits which can afford a robust, low-impedance bypassing path to divert the ESD current to the ground. There are three different types of popular ESD protection devices widely used in the industry, and they are diodes or diodes string, Grounded-gate NMOS (GGNMOS) and Silicon Controlled Rectifier (SCR). Among these different protection solutions, SCR devices have the highest ESD current conduction capability due to the conductivity modulation effect. But SCR devices also have several shortcomings such as the higher triggering point, the lower clamping voltage etc, which will become obstacles for SCR to be widely used as an ESD protection solutions in most of the industry IC products. At first, in some applications with pin voltage goes below ground or above the VDD, dual directional protection between each two pins are desired. The traditional dual-directional SCR structures will consume a larger silicon area or lead to big leakage current issue due to the happening of punch-through effect. A new and improved SCR structure for low-triggering ESD iv applications has been proposed in this dissertation and successfully realized in a BiCMOS process. Such a structure possesses the desirable characteristics of a dual-polarity conduction, low trigger voltage, small leakage current, large failing current, adjustable holding voltage, and compact size. Another issue with SCR devices is its deep snapback or lower holding voltage, which normally will lead to the latch-up happen. To make SCR devices be immunity with latch-up, it is required to elevate its holding voltage to be larger than the circuits operational voltage, which can be several tens volts in modern power electronic circuits. Two possible solutions have been proposed to resolve this issue. One solution is accomplished by using a segmented emitter topology based on the concept that the holding voltage can be increased by reducing the emitter injection efficiency. Experimental data show that the new SCR can posses a holding voltage that is larger than 40V and a failure current It2 that is higher than 28mA/um. The other solution is accomplished by stacking several low triggering voltage high holding voltage SCR cells together. The TLP measurement results show that this novel SCR stacking structure has an extremely high holding voltage, very small snapback, and acceptable failure current. The High Holding Voltage Figure of Merit (HHVFOM) has been proposed to be a criterion for different high holding voltage solutions. The HHVFOM comparison of our proposed structures and the existing high holding voltage solutions also show the advantages of our work

Ultrasound assisted low-temperature synthesis of TiB2 and Al3Ti particulates in molten aluminum

In situ formed TiB2 and Al3Ti are two typical representatives of ceramic and intermetallic reinforcements in the in situ particulate reinforced Al composites. TiB2 particulates can be synthesized in molten Al via the mixed-salts reaction by adding mixed K2TiF6 and KBF4 salts into the Al melt at high temperatures. Al3 Ti particulates can be produced by the direct-melt reaction between solid Ti powders and liquid Al at high temperatures. Generally, a high reaction temperature is always needed to obtain both reinforcements. Some issues, however, such as high cost and burning loss of alloying elements in Al alloys, are usually associated with high manufacturing temperatures. Specifically, a higher temperature can lead to the formation of larger-sized particulates, which severely degrades the mechanical properties of composite materials. Therefore, exploring the low-temperature synthesis of TiB2 and Al3Ti particulates is meaningful for practical productions. Also, the formation mechanisms for both particulates are still unclear, especially at lower synthesizing temperatures.^ This research is developed the following studies based on the above topics. The influences of reaction temperature and time on the mixed-salts reaction were studied. An ultrasound assisted technique was applied to the reaction at 700°C. Results show that a higher temperature can lead to a higher yield of TiB2 with a shorter reaction time, but the size of TiB 2 produced becomes larger. With a 10-min reaction time, the yield of TiB2 can reach 89.50 % and the size of most of TiB2 is in the range of 300-800 nm at 900 °C; Most TiB2 synthesized at 700 °C are smaller than 300 nm, but the yield is just 28.10 %. By using ultrasound, a high yield (90.40 %) of TiB2 particulates with smaller size (smaller than 300 nm) can be obtained at 700 °C. The formation mechanism of TiB2 was studied through a static experiment. At a higher temperature (900 °C), the synthesis of TiB2 mainly follows the precipitation-growth process at the reaction interface. At a lower temperature (700 °C), the precipitation-growth process and dissolution reaction between AlB2 and Al3Ti both contribute to the formation of TiB2. As the reaction time is prolonged, TiB2 particulates with a smaller size can be formed. Ultrasound has remarkable effects on the formation of TiB2 particulates, which can lead to accelerated mass transfers of [Ti] and [B] from salts to reaction interface and a high nucleation rate of TiB2. These two effects contribute to the low-temperature synthesis of TiB2. For the direct-melt reaction, a reaction-peeling model is proposed to explain the formation of small blocky Al3Ti particulates. Ultrasound is able to effectively accelerate the reaction-peeling process. The reaction time for a completed synthesis of Al3Ti can be shortened significantly. Most importantly, the formation of inclusions containing solid Ti powders can be avoided in the ultrasonic fields, allowing for the realization of a lower-temperature synthesis of Al3Ti at 700 °C

The BSD Socket API for Simulator

BSD Socket API for Simulator is a project to run untouched Real World Application (RWA) binaries on the powerful modern general-purpose network simulators. BSD Socket API for Simulator is designed to eliminate most of the drawbacks of previous works. It is simulator independence, so it can make use of the powerful functionality and versatile tools provided by modern general-purpose simulators such as NS-2. It is fully compatible with BSD Socket API, so RWA can be run on it without re-linking and re-compiling. It is transparent to the RWA, so RWAs are run on BSD Socket API for Simulator as they are on normal operating systems. BSD Socket API for Simulator is built on the concept of message redirecting. It has two critical parts: shared library and customized simulator application. The shared library is loaded into the address space of RWA. On one hand, messages sent by RWA are captured by the shared library and redirected to the customized simulator application. On the other hand, messages from simulator are redirected by the customized simulator application to the shared library. BSD Socket API for Simulator has been intensively tested. The test results show that it functions as expected and it has an acceptable performance