Abstract: In recent years, real-time spatial applications, like
location-aware services and traffic monitoring, have become more
and more important. Such applications result dynamic environments
where data as well as queries are continuously moving. As a result,
there is a tremendous amount of real-time spatial data generated
every day. The growth of the data volume seems to outspeed the
advance of our computing infrastructure. For instance, in real-time
spatial Big Data, users expect to receive the results of each query
within a short time period without holding in account the load
of the system. But with a huge amount of real-time spatial data
generated, the system performance degrades rapidly especially in
overload situations. To solve this problem, we propose the use of
data partitioning as an optimization technique. Traditional horizontal
and vertical partitioning can increase the performance of the system
and simplify data management. But they remain insufficient for
real-time spatial Big data; they can’t deal with real-time and
stream queries efficiently. Thus, in this paper, we propose a novel
data partitioning approach for real-time spatial Big data named
VPA-RTSBD (Vertical Partitioning Approach for Real-Time Spatial
Big data). This contribution is an implementation of the Matching
algorithm for traditional vertical partitioning. We find, firstly, the
optimal attribute sequence by the use of Matching algorithm. Then,
we propose a new cost model used for database partitioning, for
keeping the data amount of each partition more balanced limit and
for providing a parallel execution guarantees for the most frequent
queries. VPA-RTSBD aims to obtain a real-time partitioning scheme
and deals with stream data. It improves the performance of query
execution by maximizing the degree of parallel execution. This affects
QoS (Quality Of Service) improvement in real-time spatial Big Data
especially with a huge volume of stream data. The performance of
our contribution is evaluated via simulation experiments. The results
show that the proposed algorithm is both efficient and scalable, and
that it outperforms comparable algorithms.
Abstract: In this letter, we demonstrate high-performance AlGaN/GaN planar Schottky barrier diodes (SBDs) on the silicon substrate with field plate structure for increasing breakdown voltage VB. A low turn-on resistance RON (3.55 mΩ-cm2), low reverse leakage current (< 0.1 µA) at -100 V, and high reverse breakdown voltage VB (> 1.1 kV) SBD has been fabricated. A virgin SBD exhibited a breakdown voltage (measured at 1 mA/mm) of 615 V, and with the field plate technology device exhibited a breakdown voltage (measured at 1 mA/mm) of 1525 V (the anode–cathode distance was LAC = 40 µm). Devices without the field plate design exhibit a Baliga’s figure of merit of VB2/ RON = 60.2 MW/cm2, whereas devices with the field plate design show a Baliga’s figure of merit of VB2/ RON = 340.9 MW/cm2 (the anode–cathode distance was LAC = 20 µm).
Abstract: The newest semiconductor devices on the market are MOSFET transistors based on the silicon carbide – SiC. This material has exclusive features thanks to which it becomes a better switch than Si – silicon semiconductor switch. There are some special features that need to be understood to enable the device’s use to its full potential. The advantages and differences of SiC MOSFETs in comparison with Si IGBT transistors have been described in first part of this article. Second part describes driver for SiC MOSFET transistor and last part of article represents SiC MOSFET in the application of buck converter (step-down) and design of simple RC snubber.
Abstract: Field study was conducted to determine the post field soil fertility status responses of pawpaw (Carica papaya L.) var. homestead selection and sunrise-solo orchards to organo-mineral fertilizer (OMF) rates applied at 10, 20 40 t/ha where both the zero t/ha OMF and NPK 15:15:15 at 50 g/plant/month served as control. The result showed that all pawpaw orchards treated with OMF rates recorded significantly (p≤0.01) higher % P, % K, Na and % organic matter in soil compared to applied NPK which recorded lower Na. However, while orchards plated with sole pawpaw were higher in soil bulk density (SBD), orchards with homestead mixture were lower in SBD and significantly lower % organic matter compared to obtainable under sunrise crop mixture which recorded lower Na and Mg. In conclusion, as a result of loosening effect on soil particles, the homestead pawpaw probably due to more rooting activities as well as the addition of organic fertilizer to soils both had significant influence leading to lower SBD.
Abstract: Typical Intelligent Decision Support System is 4-based, its design composes of Data Warehouse, Online Analytical Processing, Data Mining and Decision Supporting based on models, which is called Decision Support System Based on Data Warehouse (DSSBDW). This way takes ETL,OLAP and DM as its implementing means, and integrates traditional model-driving DSS and data-driving DSS into a whole. For this kind of problem, this paper analyzes the DSSBDW architecture and DW model, and discusses the following key issues: ETL designing and Realization; metadata managing technology using XML; SQL implementing, optimizing performance, data mapping in OLAP; lastly, it illustrates the designing principle and method of DW in DSSBDW.