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

Etiology and early detection of nasopharyngeal carcinoma : an epidemiological approach

Nasopharyngeal carcinoma (NPC) is a rare malignancy worldwide, but it is endemic in a few areas including southern China, Southeast Asia, North Africa, and the Arctic. The underlying mechanisms behind this remarkable geographic distribution remain unclear. Although Epstein-Barr virus (EBV) infection has been suggested as a necessary cause of undifferentiated NPC, EBV itself is not sufficient to cause this malignancy. Other co-factors, such as environmental risk factors, and/or genetic susceptibility, may interact with EBV to play a role in the carcinogenesis of NPC. Survival rates differ significantly between NPC patients in early stages and late stages. Due to the close associations between EBV infection and NPC risk, EBV-related biomarkers have been used for early detection and screening for NPC has been conducted in a few high-incidence areas. However, the cost-effectiveness of this approach has not been demonstrated. Pilot efforts have highlighted that identification of additional biomarkers is needed to improve early detection rate and reduce the mortality rate of NPC in high-incidence populations. The aim of this thesis is to study the association of early-life social environment, oral hygiene, and family history with the risk of NPC, and to utilize an affinity proteomic approach to identify biomarkers that can potentially facilitate the early detection. In Study I, we investigated associations between childhood family structure, in terms of sibship size and number of older/younger siblings, and the risk of NPC or infectious mononucleosis (IM, another EBV-associated disease) in Sweden, an NPC low-incidence area. For each outcome, a nested case-control study was conducted within the Swedish national health and population registers, including 251 NPC cases, 11,314 IM cases, and five population controls per case matched by sex and year of birth. Clearly contrasting findings were observed between NPC and IM risk. We detected a monotonically increased risk of NPC with a larger sibship size (P trend = 0.006), especially with an increasing number of older siblings. For example, the odds ratio (OR) of NPC for those with three or more siblings compared with no siblings was 2.03 (95% confidence interval [CI]: 1.23, 3.35). In contrast, we detected a lower risk of IM among subjects with a larger sibship size, and more older/younger siblings. We concluded that early-life social environment could contribute to NPC pathogenesis in non-endemic areas. Earlier infection with EBV might be associated with an elevated risk of NPC, which is further supported by the clearly contrasting findings between NPC and IM. In Study II, we estimated the associations between oral hygiene and NPC risk in a high-incidence area. We conducted a population-based case-control study in southern China between 2010 and 2014, with a total of 2528 newly diagnosed NPC cases aged 20-74, and 2596 randomly selected controls. Controls were frequency matched to the age and sex distribution of the cases by geographic region. Based on questionnaire information, we found an increased risk of NPC with a higher number of filled teeth. Compared with those having no filled teeth, subjects having 1 to 3 and more than 3 filled teeth had adjusted ORs of 1.25 (95% CI: 1.06, 1.49) and 1.55 (95% CI: 1.13, 2.12), respectively (P trend = 0.002). In contrast, more frequent tooth brushing was inversely associated with the risk of NPC. We concluded that poor oral health could be associated with an elevated risk of NPC. Prospective cohort studies with a comprehensive measurement on oral health condition are needed to confirm our findings and explore the underlying mechanisms. Absolute NPC risks in the general population with and without a family history of NPC in NPC-endemic geographic regions, where the great majority of NPC cases occur worldwide, are largely unknown. In Study III, we utilized family data from the aforementioned population-based case-control study in southern China and found that subjects with a first-degree family history of NPC were at a greater than 4-fold higher risk for NPC, compared to those without such a history, whereas a family history of other malignancies did not confer an increased risk of NPC. The excess risk was higher for a maternal than a paternal history and slightly stronger for a sibling than a parental history, and for a sororal than a fraternal history. Among first-degree relatives of cases, the cumulative risk of NPC up to age 74 years was 3.7%, whereas that among relatives of controls was 0.9%. Cumulative risk was higher in siblings than in parents among relatives of cases, whereas no such difference was noted among relatives of controls. The affinity proteomic approach is valuable for biomarker validation and identification. In Study IV, we utilized plasma samples from 174 NPC cases and 175 community-based controls from Taiwan to identify biomarkers that could potentially facilitate early detection of NPC. We established a panel of eight such biomarkers, including proteins encoded by the genes CCNB1, KDR, PDGFB, LGALS1, HAS1, LY6K, IL2RA, and CXCL10. The combination of these eight markers showed promising value to distinguish early-stage NPC patients from controls (areas under the receiver operating characteristic curves = 0.808, 95% CI: 0.745, 0.871). Additional studies with prospectively collected biospecimens are warranted to examine the use of these plasma biomarkers in the early detection of NPC

Construction of FASR subsystem testbed and application for solar burst trajectories and RFI study

The construction of the Frequency Agile Solar Radiotelescope (FASR) Subsystem Testbed (FST) and observational results are described. Three antennas of Owens Valley Solar Array (OVSA) have been upgraded with newly designed, state of art technology. The 1-9 GHz RF signal from the antenna feed is transmitted via broadband (45 MHz-9.5 GHz) optical fiber links to the control room. The RF is then downconverted to a 500 MHz, single-sideband signal that can be tuned across the 1-9 GHz RF band. The data are sampled with an 8-bit, 1 GHz sampling-rate digitizer, and further saved to a computer hard disk. The full-resolution time-domain data thus recorded are then correlated through offline software to provide phase and amplitude spectra. An important feature of this approach is that the data can be reanalyzed multiple times with different digital signal-processing techniques (e.g., different bit-sampling, windowing, and RFI excision methods) to test the effects of different designs. As a prototype of the FASR system, FST provides the opportunity to study the design, calibration and interference-avoidance requirements of FASR. In addition, FST provides, for the first time, the ability to perform broadband spectroscopy of the Sun with high spectral, temporal and moderate spatial resolution. With this three-element interferometer, one has the ability to determine the location of simple sources with spectrograph-like time and frequency resolution. The large solar flare of 2006 December 6 was detected by the newly constructed FASR Subsystem Testbed, which is operating on three antennas of Owens Valley Solar Array. This record-setting burst produced an especially fine set of fiber bursts--so-called intermediate-drift bursts that drift from high to low frequencies over 6-10 s. According to a leading theory (Kuijpers 1975), the fibers are generated by packets of whistler waves propagating along a magnetic loop, which coalesce with Langmuir waves to produce escaping electromagnetic radiation in the decimeter band. With this three element interferometer, for the first time fiber burst source locations can be determined relative to the background even though the absolute location is still unkown for the lack of phase calibration information. The radio information over a 500 MHz band (1.0-1.5 GHz) was used to determine the trajectories of the bursts. Since the digital data are recorded with full resolution and processed offline, a key advantage of it is that one can process the data in different ways in order to simulate and test hardware implementations. FST data provides a unique testbed for studying methods of RFI excision. RFI is observed to be present in every one of the 500 MHz bands, and the high time and frequency resolution provided by FST allows one to characterize it in great detail. The use of time-domain kurtosis, and a variant of the kurtosis method in the frequency domain were explored to identify the presence of RFI and flag bad channels in simulated real time (i.e., we play back the raw, full-resolution recorded data and flag the bad channels during play-back just as a real-time system would do). The ability to select alternate RFI excision algorithms during play-back allows one to compare algorithms on an equal basis. From the same data set, the two kurtosis (time domain and frequency domain) RFI excision algorithms were compared. The results are compared quantitatively to show that the spectral kurtosis is more effective than time domain kurtosis algorithm for detecting the RFI contamination, as expected from theoretical considerations

Phylogeny, biogeography, and revision of the subfamily Dallatorrellinae (Hymenoptera, Liopteridae)

A recent cladistic study suggested that the parasitoid wasp subfamily Dallatorrellinae is a monophyletic clade within the cynipoid family Liopteridae. The subfamily currently includes only four known species belonging to two genera, i.e., the monotypic genus Mesocynips Cameron, 1903 and the genus Dallatorrella Kieffer, 1911 . The present study presents a revision of the subfamily, including descriptions of five new species in the genus Dallatorrella: D. maculata, D. maxima, D. pulla, D. ronquisti and D. sinica. A key to the species of the subfamily is provided. Cladistic analysis of the subfamily at species level is undertaken and the biogeographic history of the subfamily Dallatorrellinae is reconstructed with respect to phylogeny. Contrary to an earlier assumption that the Dallatorrellinae originated in the Australian region, the phylogeny indicates that the Dallatorrellinae originated in southeastern Asia and dispersed to Australia at a later date. Consequently, the divergence between the Dallatorrellinae and the stem species of two other liopterid subfamilies, Liopterinae and Oberthuerellinae, corresponds with the separation between Laurasia and Gondwanalan

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