Extreme Data-rate Scheduling for the Data Center

Designing scalable and cost-effective data center interconnect architectures based on electrical packet switches is challenging. To overcome this challenge, researchers have tried to harness the advantages of optics in data center environment. This has resulted in exploration of hybrid switching architectures that contains an optical circuit switch to serve long bursts of traffic along with an electrical packet switch serving short bursts of traffic. The performance of such hybrid switching architectures in data center is dependent on the schedulers. Building hybrid schedulers is challenging because of varying properties of data center traffic, increasing network demands, requirements imposed by hybrid network architecture etc. Slow schedulers can negatively impact the performance of the data center network because of poor resource utilization. With future demands, this problem is going to escalate motivating the need for faster schedulers. One approach to do this would be to use a hardware based scheduler. In this paper we propose a framework that can be used to explore and evaluate hardware based hybrid schedulers.This project is supported by the EPSRC INTERNET Project EP/H040536/1.This is the author accepted manuscript. The final version is available from ACM via http://dx.doi.org/10.1145/2785956.279001

NetFPGA: Rapid Prototyping of Networking Devices in Open Source

The demand-led growth of datacenter networks has meant that many constituent technologies are beyond the budget of the wider community. In order to make and validate timely and relevant new contributions, the wider community requires accessible evaluation, experimentation and demonstration environments with specification comparable to the subsystems of the most massive datacenter networks. We demonstrate NetFPGA, an open-source platform for rapid prototyping of networking devices with I/O capabilities up to 100Gbps. NetFPGA offers an integrated environment that enables networking research by users from a wide range of disciplines: from hardware-centric research to formal methods.This work was jointly supported by EPSRC INTERNET Project EP/H040536/1, National Science Foundation under Grant No. CNS-0855268, and Defense Advanced Research Projects Agency (DARPA) and Air Force Research Laboratory (AFRL), under contract FA8750-11-C-0249. The views, opinions, and/or findings contained in this report are those of the authors and should not be interpreted as representing the official views or policies, either expressed or implied, of the National Science Foundation, Defense Advanced Research Projects Agency or the Department of Defense.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1145/2785956.279002

Influence of nutritive media and low temperatures on broomrape seed germination

The germination of broomrape seeds on different nutritive media and at low temperatures was tested. Broomrape seed was collected from three localities in Northern part of Serbia. Nutritive media which were used are: water agar, water agar with gibberelic acid and water agar with biological agent Trifender. Temperature regimes were: without cooling, and in the fridge for 7, 14 and 21 days at + 4°C. The highest number of germinated seeds was observed on the agar medium with gibberelic acid in presence of sunflower roots. Cooling of broomrape seeds on 4°C during 21 day leads to stimulation of their germination and average radicle length. The effect of bio-agent Trifender should be further investigated

Dosadašnja istraženost i novi podaci o Fitozeidama i Tideidama (Acari: Phytoseiidae, Tydeidae) za faunu Srbije i Crne Gore

Thirty two (32) species of phytoseiids and six (6) species of tydeids (Acari Phytoseiidae and Tydeidae) are known from Serbia and Montenegro. To add to that knowledge five (5) phytoseiid species namely: Neoseiulus californicus N. marginatus, N. bicaudus, Typhlodromus phialatus, Phytoseius canadensis and four (4) tydeids namely: Tydeus caudatus, Lorryia parainfatus, L. obliqua and Metatriophtydeus sp. are recorded for the first time.U radu je dat pregled vrsta fitozeida i tideida (Acari: Phytoseiidae Tydeidae) koje su u periodu 1975-2001. registrovane na teritoriji Srbije i Crne Gore. Fitozeide su do sada bile umereno istražena grupa u našoj zemlji sa ukupno 32 nađene vrste, od kojih 20 u Srbiji a 19 u Crnoj Gori. Kod nas je ranije nađeno svega 6 vrsta tideida, od čega u Srbiji svih šest, a u Crnoj Gori samo jedna vrsta. Usled nedostatka naših specijalista za tideide ova grupa grinja je do danas ostala neistražena. U radu su izneti podaci o devet novih vrsta fitozeida i tideida za našu akarofaunu. Na teritoriji Srbije registrovano je pet vrsta fitozeida: Neoseiulus califomicus, N. marginatus, N. bicaudus, Typhlodromus phialatus i Phytoseius canadensis. U Srbiji su nađene i tri nove vrste tideida - Tydeus caudatus, Lorryia obliqua i Metatriophtydeus sp. Jedna vrsta tideide nađena je Crnoj Gori - L. parainflatus

The Transient Jupiter Trojan-Like Orbit of P/2019 LD2 (ATLAS)

Comet P/2019 LD2 has orbital elements currently resembling those of a Jupiter Trojan, and therefore superficially appears to represent a unique opportunity to study the volatile content and active behavior of a member of this population for the first time. However, numerical integrations show that it was previously a Centaur before reaching its current Jupiter Trojan-like orbit in 2018 July, and is expected to return to being a Centaur in 2028 February, before eventually becoming a Jupiter-family comet in 2063 February. The case of P/2019 LD2 highlights the need for mechanisms to quickly and reliably dynamically classify small solar system bodies discovered in current and upcoming wide-field surveys.Comment: 7 pages, 3 figures. Accepted for publication in Icaru

Reactor physics modelling of accident tolerant fuel for LWRs using ANSWERS codes

The majority of nuclear reactors operating in the world today and similarly the majority of near-term new build reactors will be LWRs. These currently accommodate traditional Zr clad UO2/ PuO2 fuel designs which have an excellent performance record for normal operation and most transients. However, the events at Fukushima culminated in significant hydrogen production and hydrogen explosions, resulting from high temperature Zr/steam interaction following core uncovering for an extended period. These events have resulted in increased emphasis towards developing more accident tolerant fuels (ATFs)-clad systems, particularly for current and near-term build LWRs. R&D programmes are underway in the US and elsewhere to develop ATFs and the UK is engaging in these international programmes. Candidate advanced fuel materials include uranium nitride (UN) and uranium silicide (U3Si2). Candidate cladding materials include advanced stainless steel (FeCrAl) and silicon carbide. The UK has a long history in industrial fuel manufacture and fabrication for a wide range of reactor systems including LWRs. This is supported by a national infrastructure to perform experimental and theoretical R&D in fuel performance, fuel transient behaviour and reactor physics. In this paper, an analysis of the Integral Inherently Safe LW R design (I2S-LWR), a reactor concept developed by an international collaboration led by the Georgia Institute of Technology, within a U.S. DOE Nuclear Energy University Program (NEUP) Integrated Research Project (IRP) is considered. The analysis is performed using the ANSWERS reactor physics code WIMS and the EDF Energy core simulator PANTHER by researchers at the University of Cambridge. The I2S-LWR is an advanced 2850 MWt integral PWR with inherent safety features. In order to enhance the safety features, the baseline fuel and cladding materials that were chosen for the I2S- LWR design are U3Si2 and advanced stainless steel respectively. In addition, the I S-LWR design adopts an integral configuration and a fully passive emergency decay heat removal system to provide indefinite cooling capability for a class of accidents. This paper presents the equilibrium cycle core design and reactor physics behaviour of the I2S-LWR with U3Si2 and the advanced steel cladding. The results were obtained using the traditional two-stage approach, in which homogenized macroscopic cross-section sets were generated by WIMS and applied in a full 3D core solution with PANTHER. The results obtained with WIMS/PANTHER were compared against the Monte Carlo Serpent code developed by VTT and previously reported results for the I2S-LWR. The results were found to be in a good agreement (e.g. < 200 pcm in reactivity) among the compared codes, giving confidence that the WIMS/PANTHER reactor physics package can be reliably used in modelling LWRs with ATFs.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1051/epjn/201601

Finite Size Giant Magnon

The quantization of the giant magnon away from the infinite size limit is discussed. We argue that this quantization inevitably leads to string theory on a Z_M-orbifold of S^5. This is shown explicitly and examined in detail in the near plane-wave limit