A COMPARISON OF EXTENDED SOURCE-FILTER MODELS FOR MUSICAL SIGNAL RECONSTRUCTION

China Scholarship Council (CSC)/ Queen Mary Joint PhD scholarship; Royal Academy of Engineering Research Fellowshi

A Color Dual Form for Gauge-Theory Amplitudes

Recently a duality between color and kinematics has been proposed, exposing a new unexpected structure in gauge theory and gravity scattering amplitudes. Here we propose that the relation goes deeper, allowing us to reorganize amplitudes into a form reminiscent of the standard color decomposition in terms of traces over generators, but with the role of color and kinematics swapped. By imposing additional conditions similar to Kleiss-Kuijf relations between partial amplitudes, the relationship between the earlier form satisfying the duality and the current one is invertible. We comment on extensions to loop level.Comment: 5 pages, 4 figure

Cost effective RISC core supporting the large sending offload

The Ethernet speed has increased sending and receiving frames from 40 to 100 Gbps after the IEEE P802.3ba released. The industry and academia have focused scaling up the TCP/IP protocol processing for 40-100 Gbps. LSO is a de facto standard, which is offloaded to network interface for sending packets up to 10 Gbps. It not clears whether a network interface can support such function for new 40-100 Gbps. The widely use of the hardware-based NIC such as the use of a fully customized logic based network interface can be due to the following reasons; Still it is not clear whether the General Purpose Processor (GPP) can provide the processing required for high-speed line beyond the 10 Gbps. Also, the limit of the GPP's clock in supporting the processing of network interfaces. However, using a RISC core engine for offloading the LSO function can deliver some important features to network interfaces design, such as simplicity, scalability, shorter developing cycle time. In this paper, we have investigated using a specialized RISC core to process the LSO functions for TCP/IP and UDP/IP for high-speed communications rate up to 100 Gbps. To achieve this, we have enhanced the LSO algorithm to scale it to 100 Gbps. A fast DMA is used to support transferring data in the network interface. The LSO processing methodology on the network has presented. In addition, the RISC's performance and data movements for high communication rate up to 100 Gbps have been measured. A 148 MHz RISC core can support the sending-side processing for up to 100 Gbps transmission speed for the TCP/IP and UDP/IP protocol when the MTU is applied (1500 bytes). A DMA with 3759 MHz is required to eliminate the idle cycles while transferring data over the 64-bit local bus

Realization of an all-optical zero to π cross-phase modulation jump

We report on the experimental demonstration of an all-optical π cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or π phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor

Quantitative analysis of the effects queuing has on a CCID3 controlled DCCP flow

While the Data Congestion Control Protocol (DCCP) shows much promise at becoming a protocol of choice for real-time applications in the future, there are relatively speaking, only a small number of academic papers purporting to its performance and its various nuances. This paper will describe the effects queuing and in particular queue sizes have on DCCP when CCID3 is selected as the congestion control mechanism. From results obtained through the experimentation described in this paper, a clear trade-off between packet loss rates and packet latency values was found to occur when different queue sizes were employed on the experimental network. It was found that employing small fixed sized queues on the network led to lower packet latencies but higher volumes of packet loss as a result of the queue size reaching its maximum threshold more frequently. Alternatively when large queue sizes were used, the number of packet loss events reduced significantly however, packet latency values increased. In addition to showing this impending trade-off empirically, this paper describes ways in which this phenomenon could potentially be exploited to allow DCCP to offer applications with a more tailored form of transportation protocol based on their particular needs

On Lorentz invariance and supersymmetry of four particle scattering amplitudes in SNR8S^N\R^8 orbifold sigma model

The $S^N\R^8$ supersymmetric orbifold sigma model is expected to describe the IR limit of the Matrix string theory. In the framework of the model the type IIA string interaction is governed by a vertex which was recently proposed by R.Dijkgraaf, E.Verlinde and H.Verlinde. By using this interaction vertex we derive all four particle scattering amplitudes directly from the orbifold model in the large $N$ limit.Comment: Latex, 23 page

FUSE Detection of Galactic OVI Emission in the Halo above the Perseus Arm

Background observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) toward l=95.4, b=36.1 show OVI 1032,1038 in emission. This sight line probes a region of stronger-than-average soft X-ray emission in the direction of high-velocity cloud Complex C above a part of the disk where Halpha filaments rise into the halo. The OVI intensities, 1600+/-300 ph/s/cm^2/sr (1032A) and 800+/-300 ph/s/cm^2/sr (1038A), are the lowest detected in emission in the Milky Way to date. A second sight line nearby (l=99.3, b=43.3) also shows OVI 1032 emission, but with too low a signal-to-noise ratio to obtain reliable measurements. The measured intensities, velocities, and FWHMs of the OVI doublet and the CII* line at 1037A are consistent with a model in which the observed emission is produced in the Galactic halo by hot gas ejected by supernovae in the Perseus arm. An association of the observed gas with Complex C appears unlikely.Comment: accepted for publication in ApJL, 11 pages including 3 figure