290 research outputs found
On a Navier–Stokes–Ohm problem from plasma physics in multi connected domains
We consider a model from electro-magneto-hydrodynamics describing a plasma in bounded multi connected domains. A nontrivial solution exists for magnetic fields as the equilibrium of this model. Nonlinear stability of the nontrivial solution is proved based on time weighted maximal Lp-regularity
Strategic Input Price Discrimination with Horizontal Shareholding
Price discrimination has substantial social and policy implications and has received attention in the literature. However, prior research on input price discrimination has largely been limited to single-input situations. We explore the strategic desirability of uniform pricing, fill gaps in the prior literature regarding the “nondiscriminatory” aspect of input price discrimination, and contribute to the growing literature on perfectly complementary inputs in ver- tical markets. This study considers a vertically related market in which two symmetric upstream firms provide perfectly complementary inputs for two downstream manufacturers, one of which has a non-controlling interest in its rival. Each upstream firm can choose between two pricing regimes: discrim- inatory or uniform. This study shows that, although uniform pricing limits pricing flexibility, one upstream firm voluntarily chooses uniform pricing, and the other chooses discriminatory pricing in equilibrium. To our knowledge, this study is the first to demonstrate such an asymmetric pricing equilibrium. Furthermore, our findings have implications for policymakers deciding whether to prohibit discriminatory pricing
DBTSS: DataBase of Human Transcription Start Sites, progress report 2006
DBTSS was first constructed in 2002 based on precise, experimentally determined 5′ end clones. Several major updates and additions have been made since the last report. First, the number of human clones has drastically increased, going from 190 964 to 1 359 000. Second, information about potential alternative promoters is presented because the number of 5′ end clones is now sufficient to determine several promoters for one gene. Namely, we defined putative promoter groups by clustering transcription start sites (TSSs) separated by <500 bases. A total of 8308 human genes and 4276 mouse genes were found to have putative multiple promoters. Third, DBTSS provides detailed sequence comparisons of user-specified TSSs. Finally, we have added TSS information for zebrafish, malaria and schyzon (a red algae model organism). DBTSS is accessible at
Proposal and Demonstration of Free-Space Optical Communication Using Photonic Crystal Surface-Emitting Lasers
We propose and demonstrate free-space optical (FSO) communication using photonic crystal surface-emitting lasers (PCSELs). Unlike other types of conventional semiconductor lasers, such as edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs), PCSELs achieve much larger area single-mode coherent lasing, and this unique feature enables high-power (>watt) and lens-free operations at the same time. To date, these advantages have been recognized to be game changing, especially in light detection and ranging (LiDAR) and laser processing applications. In this work, we show that FSO communication can also benefit from these advantages of PCSELs; more specifically, conventional transmitters that include low-power semiconductor lasers, optical lenses, and fiber-based amplifiers could be replaced with a single PCSEL. Since fiber amplifiers usually consist of bulky components and have low conversion efficiencies, PCSELs can offer more space- and power-saving solutions. Moreover, the narrow beam divergence angles directly obtained from large-area single-mode PCSELs can also eliminate the need for lens systems on the transmitter side. To experimentally verify these potential advantages, we performed FSO transmission experiments based on PCSELs and successfully transmitted 480-MHz and 864-MHz orthogonal frequency division multiplexed (OFDM) signals over 1.1 m using a 500-μm PCSEL in a lens-free transmitter configuration. We believe that PCSELs open new possibilities and choices in FSO communication
Dynamic Virtual Network Reconfiguration Over SDN Orchestrated Multitechnology Optical Transport Domains
Network virtualization is an emerging technique that enables multiple tenants to share an underlying physical infrastructure, isolating the traffic running over different virtual infrastructures/tenants. This technique aims to improve network utilization, while reducing the complexities in terms of network management for operators. Applied to this context, software defined networking (SDN) paradigm can ease network configurations by enabling network programmability and automation, which reduces the amount of operations required from both service and infrastructure providers. SDN techniques are decreasing vendor lock-in issues due to specific configuration methods or protocols. Application-based Network Operations (ABNO) is a toolbox of key network functional components with the goal of offering application-driven network management. Service provisioning using ABNO may involve direct configuration of data plane elements or delegate it to several control plane modules. We validate the applicability of ABNO to multi-tenant virtual networks in multi-technology optical domains based on two scenarios, in which multiple control plane instances are orchestrated by the architecture. Congestion Detection and Failure Recovery, are chosen to demonstrate fast recalculation and reconfiguration, while hiding the configurations in the physical layer from the upper layer.Grant numbers : supported by the Spanish Ministry of Economy and Competitiveness through the project FARO (TEC2012-38119)
SDN-based Network Orchestration of Variable-capacity Optical Packet Switching Network over Programmable Flexi-grid Elastic Optical Path Network
A multidomain and multitechnology optical network orchestration is demonstrated in an international testbed located in Japan, the U.K., and Spain. The application-based network operations architecture is proposed as a carrier software-defined network solution for provisioning end-to-end optical transport services through a multidomain multitechnology network scenario, consisting of a 46–108 Gb/s variable-capacity OpenFlow-capable optical packet switching network and a programmable, flexi-grid elastic optical path network
Control orchestration protocol:unified transport API for distributed cloud and network orchestration
Control orchestration protocol:unified transport API for distributed cloud and network orchestration
In the context of the fifth generation of mobile technology (5G), multiple technologies will converge into a unified end-to-end system. For this purpose, software defined networking (SDN) is proposed, as the control paradigm will integrate all network segments and heterogeneous optical and wireless network technologies together with massive storage and computing infrastructures. The control orchestration protocol is presented as a unified transport application programming interface solution for joint cloud/network orchestration, allowing interworking of heterogeneous control planes to provide provisioning and recovery of quality of service (QoS)-aware end-to-end services. End-to-end QoS is guaranteed by provisioning and restoration schemes, which are proposed for optical circuit/packet switching restoration by means of signal monitoring and adaptive modulation and adaptive route control, respectively. The proposed solution is experimentally demonstrated in an international multi-partner test bed, which consists of a multi-domain transport network comprising optical circuit switching and optical packet switching domains controlled by SDN/OpenFlow and Generalized Multiprotocol Label Switching (GMPLS) control planes and a distributed cloud infrastructure. The results show the dynamic provisioning of IT and network resources and recovery capabilities of the architecture.Grant numbers : This work was partially supported by the Spanish MINECO project DESTELLO (TEC2015-69256-R)
Demonstration of Adaptive SDN Orchestration:A Real-time Congestion-aware Services Provisioning over OFDM-based 400G OPS and Flexi-WDM OCS
- …