Multiple-input soft-switching power converters

A multiple-input power converter transferring energy from multiple input sources to a load comprises a plurality of voltage inputs. The power converter implements soft-switching techniques thereby reducing the converter switching losses and increasing the converter efficiency while using fewer components than presently designed multiple-input power converters. Such a power converter may include multiple input sources, where serially connected switches are coupled to one of the multiple input sources in an input leg. A voltage blocking capacitor is inserted between these input legs. Furthermore, the power converter includes a transformer for isolating the load from the multiple input sources, where the voltage blocking capacitor is connected to the primary winding of the transformer.Board of Regents, University of Texas Syste

One size does not fit all : accelerating OLAP workloads with GPUs

GPU has been considered as one of the next-generation platforms for real-time query processing databases. In this paper we empirically demonstrate that the representative GPU databases [e.g., OmniSci (Open Source Analytical Database & SQL Engine,, 2019)] may be slower than the representative in-memory databases [e.g., Hyper (Neumann and Leis, IEEE Data Eng Bull 37(1):3-11, 2014)] with typical OLAP workloads (with Star Schema Benchmark) even if the actual dataset size of each query can completely fit in GPU memory. Therefore, we argue that GPU database designs should not be one-size-fits-all; a general-purpose GPU database engine may not be well-suited for OLAP workloads without careful designed GPU memory assignment and GPU computing locality. In order to achieve better performance for GPU OLAP, we need to re-organize OLAP operators and re-optimize OLAP model. In particular, we propose the 3-layer OLAP model to match the heterogeneous computing platforms. The core idea is to maximize data and computing locality to specified hardware. We design the vector grouping algorithm for data-intensive workload which is proved to be assigned to CPU platform adaptive. We design the TOP-DOWN query plan tree strategy to guarantee the optimal operation in final stage and pushing the respective optimizations to the lower layers to make global optimization gains. With this strategy, we design the 3-stage processing model (OLAP acceleration engine) for hybrid CPU-GPU platform, where the computing-intensive star-join stage is accelerated by GPU, and the data-intensive grouping & aggregation stage is accelerated by CPU. This design maximizes the locality of different workloads and simplifies the GPU acceleration implementation. Our experimental results show that with vector grouping and GPU accelerated star-join implementation, the OLAP acceleration engine runs 1.9x, 3.05x and 3.92x faster than Hyper, OmniSci GPU and OmniSci CPU in SSB evaluation with dataset of SF = 100.Peer reviewe

Characteristics of burned area and susceptibility assessment of post-fire debris flow of Chongqing wildfire in August, 2022

In August, 2022, forest fires occurred in Jiangjin District, Banan District, and Beibei District in Chongqing, respectively, with a total burned area of approximately 35 km2. After the wildfire, an ash layer with a thickness of 1～5 cm was deposited on the slope, and the vegetation and soil structure of the burned area were devastated. Affected by concentrated rainfall, it will pose a serious threat to the infrastructure of nearby villages and towns and residents’ lives and properties once the post-fire debris flow occurs. Based on the remote sensing, field investigation, and in-situ tests, the distribution characteristics of burned areas after the fire were identified. The measured data including the thickness of the ash layer, and the saturated hydraulic conductivity of the soil were derived. The severe, moderate, and low burned areas accounted for 9.6%, 34.0%, and 56.4% of the entire area, respectively, with the corresponding average thickness of ash and soil disturbance layer of 15.10 cm, 3.28 cm, and 1.15 cm. According to the prediction model based on expert experience, a total of 95 potential debris flow gullies in burned areas were evaluated for the susceptibility of post-fire debris flow, of which 1 was of high susceptibility, 43 were of medium susceptibility, 44 were of low susceptibility, and 7 were not prone to occur, contributing to 1.05%, 45.26%, 46.32%, and 7.37% of the total, respectively. Considering that a large number of loose solid sources besides ash and sediment still exist in the moderate and severe burned areas within watersheds under the current conditions, with strong water repellency of burned soil, once the medium and high susceptibility gullies are affected by concentrated rainfall in the rainy season, there is a relatively high probability for the post-fire debris flow occurrence. This study provides basic information for the prevention and risk management of post-fire debris flows

Study on maneuver control design method of dual aircraft air combat with constraints

Aiming at the situation constraint problem in air combat trajectory control, a constrained backstepping flight control law is proposed. This method considers the constraints of the amplitude and bandwidth of the state variables in the traditional flight process. At the same time, it also introduces the situation information of the two aircraft air combat into the control law. The correction error is defined in the control law error, and the angle situation information is used to update the correction error. When the situation is dominant, the system can perform the maneuver task normally, and the correction error converges to 0 quickly When it is a disadvantage, the correction error becomes larger, and affects the maneuver, so that the situation changes to the advantage. The simulation results show that the method can effectively make the situation change in a favorable direction during maneuvering flight.</jats:p

Studying the impact of young age on prognosis and treatment in laryngeal squamous cell carcinomas using the SEER database

Background Laryngeal squamous cell carcinoma (LSCC) in young patients was reported to be more aggressive and associated with poorer survival than in older patients. However, very few studies contained sufficient cases to permit meaningful statistical analysis. It is still unknown whether less aggressive method like radical radiotherapy (RT) is comparable to total laryngectomy (TL) in survival rate among young patients. Methods This study extracted patient data from the surveillance, epidemiology, and end results database from 2004 to 2015. The findings for 304 patients (1.2%) below the age of 40 were compared with those for 24,827 patients (98.8%) aged 40 or older. Results The younger cohorts contained a higher proportion of female patients (33.6% vs. 19.1%, respectively), had more cases of glottic involvement (64.5% vs. 53.1%), and were less likely to have distant metastasis (0.7% vs.3.2%). A total of 5-year overall survival and cancer-specific survival rates (CSS) in the younger patients were 86.3% and 88.8%, respectively, significantly better than for older patients (53.8% and 67.6%). Significant differences were still observed when stratified for tumor stage (stage I–IV). The negative independent prognostic factors in younger patients were advanced tumor stage, degree of nodal involvement, and status of distant metastasis. Treatment with surgery and/or RT all produced excellent outcomes in stage I–IV diseases, and radical RT resulted in survival rates equal to those for TL in locally advanced LSCC among young patients (5-year CSS: 90% vs. 91.5%, p = 0.99). Conclusion LSCC is less aggressive and has significantly better survival in younger patients. For younger patients, advanced nodal involvement is the most important independent prognostic factor, and larynx preservation is comparable to TL in survival rate. </jats:sec