科研成果 by Type: Conference Paper

Atmospheric modeling is an essential issue in the study of climate change. However, due to the complicated algorithmic and communication models, scientists and researchers are facing tough challenges in finding efficient solutions to solve the atmospheric equations. In this paper, we accelerate a solver for the three-dimensional Euler atmospheric equations through reconfigurable data flow engines. We first propose a hybrid design that achieves efficient resource allocation and data reuse. Furthermore, through algorithmic offsetting, fast memory table, and customizable-precision arithmetic, we map a complex Euler kernel into a single FPGA chip, which can perform 956 floating point operations per cycle. In a 1U-chassis, our CPU-DFE unit with 8 FPGA chips is 18.5 times faster and 8.3 times more power efficient than a multicore system based on two 12-core Intel E5-2697 (Ivy Bridge) CPUs, and is 6.2 times faster and 5.2 times more power efficient than a hybrid unit equipped with two 12-core Intel E5-2697 (Ivy Bridge) CPUs and three Intel Xeon Phi 5120d (MIC) cards.

This paper studies how displaced royal families in the Roman principate speak about their royal ancestry. Gaius Julius Antiochus Epiphanes "Philopappos" and his sister Julia Balbilla, who were descendents of the Orontid dynasty of Commagene in northwestern Syria, are objects of this study. The kingdom of Commagene was twice incorporated into the Roman province of Syria, first upon the death of Antiochos III Epiphanes in 17 CE, then during Vespasian's reign in 72 CE. Philopappos and Balbilla were displaced and eventually integrated into the circle of the Roman senatorial élite. The two siblings are examples of displaced royal families "at work," creating their extraordinary status within the Roman principate through monumental and literary works that claim inheritance to their ancestral past.  This paper will first review relevant scholarship – such as David Braund on client kingship (1984), Joel Allen on hostage and hostage taking in the principate (2006), Paul Burton on Roman foreign relations in the Republic (2011) – to clarify the operating terms of amicitia, fides, and foedus that formed the socio-political context within which Philopappos and Balbilla operated. The second part of the paper will discuss how the visual and inscriptional programme of Philopappos' monument at Athens and Babilla's graffitti poetry on the statue of Memnon in Egyptian Thebes negotiate socio-political contexts. This paper argues that Philopappos' monument did not only speak to his extraordinary status as humbled royalty under Rome, but also his belonging to Athens, and how Commagenian royalty and Roman citizenship attributed to his sense of belonging. Similarly, Balbilla was a valued member of Hadrian and Sabina's court specifically because of her conscious pronouncement of her family's royal blood and their piety, which qualities were pronounced in her graffiti poetry. Together, Philopappos and Balbilla marks a change in the nature of client kingship from Trajan onwards, as royal members become valued not for their ability to govern kingdoms, but for their extraordinary status as royal Roman citizens.

This paper reports a normally-off high voltage hybrid Al203/GaN gate-recessed MOSFET fabricated on silicon substrate. The normally off operation was implemented by digital gate recess using an oxidation and wet etching based AlGaN barrier remove technique. The Al203/GaN MOSFET features a true normally off operation with a threshold voltage of 2 V extracted by the linear extrapolation of the transfer curve. The three terminal off-state breakdown voltage is 1650 V for the device with 30 gm gate-drain distance with floating Si substrate. The breakdown voltage is limited to 1000 V when the Si substrate is grounded. The on-resistance is 7.0 m Omega cm(2) for the device with 30 gm gate-drain distance and the power figure of merit is 388 MW/cm2. The small signal RF performance of the normally-off GaN MOSFET is also evaluated.

In this work, the performance of GaN-based MOS-Channel-HEMTs (MOSC-HEMTs) are shown to be greatly improved by a thin ALD-grown AlN interfacial layer inserted between the amorphous Al2O3 gate dielectric and GaN-channel. The single-crystalline AlN interfacial layer effectively blocks oxygen from the GaN surface and avoids the formation of detrimental Ga-O bonds. Frequency-dispersion in C-V characteristics has been effectively suppressed. The maximum drain current and field-effect mobility are boosted from 410 mA/mm and 98 cm(2)/V.s in a conventional Al2O3/GaN MOSC-HEMT to 660 mA/mm and 165 cm(2)/V.s in an Al2O3/AlN/GaN MOSC-HEMT, owing to improved interface quality. The devices also deliver a high ON/OFF current ratio of similar to 10(10), and significantly reduced dynamic on-resistance degradation.