Multicasting in All-Optical WDM Networks

n this dissertation, we study the problem of (i) routing and wavelength assignment, and (ii) traffic grooming for multicast traffic in Wavelength Division Multiplexing (WDM) based all-optical networks. We focus on the 'static' case where the set of multicast traffic requests is assumed to be known in advance. For the routing and wavelength assignment problem, we study the objective of minimizing the number of wavelengths required; and for the traffic grooming problem, we study the objectives of minimizing (i) the number of wavelengths required, and (ii) the number of electronic components required. Both the problems are known to be hard for general fiber network topologies. Hence, it makes sense to study the problems under some restrictions on the network topology. We study the routing and wavelength assignment problem for bidirected trees, and the traffic grooming problem for unidirectional rings. The selected topologies are simple in the sense that the routing for any multicast traffic request is trivially determined, yet complex in the sense that the overall problems still remain hard. A motivation for selecting these topologies is that they are of practical interest since most of the deployed optical networks can be decomposed into these elemental topologies. In the first part of the thesis, we study the the problem of multicast routing and wavelength assignment in all-optical bidirected trees with the objective of minimizing the number of wavelengths required in the network. We give a 5/2-approximation algorithm for the case when the degree of the bidirected tree is at most 3. We give another algorithm with approximation ratio 10/3, 3 and 2 for the case when the degree of the bidirected tree is equal to 4, 3 and 2, respectively. The time complexity analysis for both these algorithms is also presented. Next we prove that the problem is hard even for the two restricted cases when the bidirected tree has (i) depth 2, and (ii) degree 2. Finally, we present another hardness result for a related problem of finding the clique number for a class for intersection graphs. In the second part of the thesis, we study the problem of multicast traffic grooming in all-optical unidirectional rings. For the case when the objective is to minimize the number of wavelengths required in the network, given an 'a'-approximation algorithm for the circular arc coloring problem, we give an algorithm having asymptotic approximation ratio 'a' for the multicast traffic grooming problem. We develop an easy to calculate lower bound on the minimum number of electronic components required to support a given set of multicast traffic requests on a given unidirectional ring network. We use this lower bound to analyze the worst case performance of a pair of simple grooming schemes. We also study the case when no grooming is carried out in order to get an estimate on the maximum number of electronic components that can be saved by applying intelligent grooming. Finally, we present a new grooming scheme and compare its average performance against other grooming schemes via simulations. The time complexity analysis for all the grooming schemes is also presented

Evaluation of Opportunities and Challenges of Using INRIX Data for Real-Time Performance Monitoring and Historical Trend Assessment

In recent years there has been a growing desire for the use of probe vehicle technology for congestion detection and general infrastructure performance assessment. Unlike costly traditional data collection by loop detectors, wide-area detection using probe-sourced traffic data is significantly different in terms of measurement technique, pricing, coverage, etc. This affects how the new technology is applied and used to solve current traffic problems such as traffic incident management and roadway performance assessment. This report summarizes the experiences and lessons learned while using probe data for traffic operations and safety management in the state of Nebraska and makes recommendations for opportunities to maximize the use of probe data in light of its limitations. A detailed analysis of performance monitoring and historical trend analysis, including identification of the top 10 congested segments, congestion per mile across metro areas, congested hour(s) during summer and winter months, and yearly travel time reliability, for Interstate 80 segments in Nebraska were performed. Two main conclusions can be drawn from this study. First, there is almost always a speed bias between data streaming from probes and traditional infrastructure-mounted sensors. It is important to understand the factors that influence these biases and how to cope with them. Second, lack of confidence score 30 (real-time) probe data is a critical issue that should be considered precisely for incident detection, roadway performance assessment, travel time estimation, and other traffic analyses. Ultimately, the authors present several recommendations that will help transportation agencies gain the best value from their probe data

Interesting Examples of IBGP Configuration

In this paper we give examples to show that if an Internal Border Gateway Protocol (IBGP) configuration using route reflections violates even one of the four conditions mentioned in the theorem given in a previous work, then there may be persistent oscillations or forwarding loops

Utilizing Path Diversity via Asynchronous and Asymmetric Wakeups in Sensor Networks

We present an asynchronous wakeup policy for wireless sensor networks that exploits the available path diversity for maximizing the expected network lifetime. We assume a random traffic generation model such that the rate is constant in time. Each node is assumed to have a set of forwarding neighbors, any of which may be used for forwarding its traffic to the sink. A node having data packet to send, transmits the packet to the first available node in its forwarding set. In order to maximize the network lifetime, we balance the power dissipation at the network nodes by adjusting the wakeup parameters at various nodes. Allowing different nodes to wakeup with different rates makes the scheme asymmetric. For ease of analysis, we restrict ourselves to static, open-loop policies. We show that the optimization problem is a Signomial Program (SP), that can be well approximated as a Geometric Program (GP). By extensive simulations, we compare the asymmetric policy thus obtained to the best possible symmetric policy obtained from the same optimization setup but ensuring additionally that the wakeup rates at all the nodes are the same (in which case the optimization problem is shown to be exactly a GP). The simulations show that allowing asymmetry can extend the network lifetime by effectively exploiting the available path diversity. Moreover, we also prove that, in case of symmetric policies, no piecewise static policy can beat the simple static policy that we use for comparison in our results. This shows that in the space of open-loop, asynchronous wakeup policies, employing the static, asymmetric policy presented in this paper is much more profitable than even the best piecewise static, symmetric policy.Research partially supported by the NSF under grant CNS-051955

Kaons and antikaons in strong magnetic fields

The in-medium masses of the kaons and antikaons in strongly magnetized asymmetric nuclear matter are studied using a chiral SU(3) model. The medium modifications of the masses of these open strange pseudoscalar mesons arise due to their interactions with the nucleons and scalar mesons within the model. The proton, the charged nucleon, has effects from the Landau energy levels in the presence of the magnetic field. The anomalous magnetic moments (AMM) of the nucleons are taken into consideration in the present study and these are seen to be large at high magnetic fields and high densities. The isospin effects are appreciable at high densities. The density effects are observed to be the dominant medium effects, as compared to the effects from magnetic field and isospin asymmetry. ~Comment: 22 pages, 4 figures, version to be published in Eur. Phys. Jour. A. arXiv admin note: text overlap with arXiv:1712.0799

Determining the efficacy of ginger Zingiber officinale as a potential nutraceutical agent for boosting growth performance and health status of Labeo rohita reared in a semi-intensive culture system

A 120-day feeding trial was conducted in a pilot field setting to study the nutraceutical properties of ginger powder (GP), focusing on the growth performance and health status of Indian major carp L. rohita reared under a semi-intensive culture system. L. rohita fingerlings (average weight: 20.5 g) were divided into five groups and fed a diet with no GP supplementation (control), or a diet supplemented with GP at 5 g (GP5), 10 g (GP10), 15 g (GP15), and 20 g (GP20) per kg of feed. The study was carried out in outdoor tanks (20 m(2)) following a complete randomized design with three replicates for each experimental group. Dietary supplementation of GP at 15 g.kg(-1) (GP15) of feed caused a significant increase in the growth performances of the fish. Results also showed that feeding of GP15 diet led to a significant improvement in the health status of fish as indicated by a marked change in the tested haematological indices (i.e., higher RBC, WBC, Hb, and Ht values), oxidative status (increased SOD and decreased LPO levels), biochemical parameters (increased HDL, decreased cholesterol, and triglycerides levels), and activities of the liver enzymes (decreased AST and ALT). Overall results suggested that dietary supplementation of GP could positively influence the growth and health status of L. rohita fingerlings, and hence could be an important natural nutraceutical for sustainable farming of carp

Lasmiditan: new drug for acute migraine

Migraine is ranked by the World Health Organization as the world’s second leading cause of disability. The current state of knowledge suggests that migraine is a neuronal process involving activation and sensitization of the trigeminal nociceptors and the trigeminocervical complex, as well as cortical spreading depression and abnormal brainstem activity. The present non vascular etiological basis has opened a new horizon in the treatment of acute migraine targeting the trigeminal pathways. Lasmiditan, a highly selective 5-HT1F receptor agonist, acts on the trigeminal system without causing vasoconstriction because of its low affinity for 5-HT1B receptors. The compound belongs to a new class of drugs “ditans” and its mechanism of action is neuronal without evidence of vasoactive effects as seen with triptans. It lowers plasma protein extravasation decreasing the neurogenic inflammation of the dura and suppress neuronal firing within the trigeminal nucleus caudalis. Also, 5HT1F agonists have shown to decrease c-fos activity within trigeminal nucleus thereby reducing the level of synaptic activation. The onset of action of lasmiditan is fast, shows rapid absorption, oral bioavailability of 40% and linear pharmacokinetics. Most common adverse reactions seen are dizziness, paresthesia, somnolence, nausea, fatigue and lethargy with dizziness being the most recurrently reported adverse event. Clinical trials for lasmiditan to date have been positive, and maiden results suggest that lasmiditan may be a new safe and effective option for acute migraine treatment, especially for patients refractory to or unable to tolerate triptans, and/or for patients with pre-existing cardiovascular disease. With Eli Lilly and Co. having already applied for US FDA approval in Nov 2018, lasmiditan may soon be a new addition to the mounting armoury of drugs against migraine

Coloring Rooted Subtrees on a Bounded Degree Host Tree

We consider a rooted tree R to be a rooted subtree of a given tree T if the tree obtained by replacing the directed arcs of R by undirected edges is a subtree of T. In this work, we study the problem of assigning colors to a given set of rooted subtrees of a given host tree such that if any two rooted subtrees share a directed edge, then they are assigned different colors. The objective is to minimize the total number of colors used in the coloring. The problem is NP hard even in the case when the degree of the host tree is restricted to 3. This problem is motivated by the problem of assigning wavelengths to multicast traffic requests in all-optical tree networks. We present a greedy coloring scheme for the case when the degree of the host tree is restricted to 3 and prove that it is a 5/2-approximation algorithm. We then present another simpler coloring scheme and prove that it is an approximation algorithm for the problem with approximation ratio 10/3, 3 and 2 for the cases when the degree of the host tree is restricted to 4, 3, and 2, respectively