QuickCast: Fast and Efficient Inter-Datacenter Transfers using Forwarding Tree Cohorts

Large inter-datacenter transfers are crucial for cloud service efficiency and are increasingly used by organizations that have dedicated wide area networks between datacenters. A recent work uses multicast forwarding trees to reduce the bandwidth needs and improve completion times of point-to-multipoint transfers. Using a single forwarding tree per transfer, however, leads to poor performance because the slowest receiver dictates the completion time for all receivers. Using multiple forwarding trees per transfer alleviates this concern--the average receiver could finish early; however, if done naively, bandwidth usage would also increase and it is apriori unclear how best to partition receivers, how to construct the multiple trees and how to determine the rate and schedule of flows on these trees. This paper presents QuickCast, a first solution to these problems. Using simulations on real-world network topologies, we see that QuickCast can speed up the average receiver's completion time by as much as $10\times$ while only using $1.04\times$ more bandwidth; further, the completion time for all receivers also improves by as much as $1.6\times$ faster at high loads.Comment: [Extended Version] Accepted for presentation in IEEE INFOCOM 2018, Honolulu, H

DCCast: Efficient Point to Multipoint Transfers Across Datacenters

Using multiple datacenters allows for higher availability, load balancing and reduced latency to customers of cloud services. To distribute multiple copies of data, cloud providers depend on inter-datacenter WANs that ought to be used efficiently considering their limited capacity and the ever-increasing data demands. In this paper, we focus on applications that transfer objects from one datacenter to several datacenters over dedicated inter-datacenter networks. We present DCCast, a centralized Point to Multi-Point (P2MP) algorithm that uses forwarding trees to efficiently deliver an object from a source datacenter to required destination datacenters. With low computational overhead, DCCast selects forwarding trees that minimize bandwidth usage and balance load across all links. With simulation experiments on Google's GScale network, we show that DCCast can reduce total bandwidth usage and tail Transfer Completion Times (TCT) by up to $50\%$ compared to delivering the same objects via independent point-to-point (P2P) transfers.Comment: 9th USENIX Workshop on Hot Topics in Cloud Computing, https://www.usenix.org/conference/hotcloud17/program/presentation/noormohammadpou

RCD: Rapid Close to Deadline Scheduling for Datacenter Networks

Datacenter-based Cloud Computing services provide a flexible, scalable and yet economical infrastructure to host online services such as multimedia streaming, email and bulk storage. Many such services perform geo-replication to provide necessary quality of service and reliability to users resulting in frequent large inter- datacenter transfers. In order to meet tenant service level agreements (SLAs), these transfers have to be completed prior to a deadline. In addition, WAN resources are quite scarce and costly, meaning they should be fully utilized. Several recently proposed schemes, such as B4, TEMPUS, and SWAN have focused on improving the utilization of inter-datacenter transfers through centralized scheduling, however, they fail to provide a mechanism to guarantee that admitted requests meet their deadlines. Also, in a recent study, authors propose Amoeba, a system that allows tenants to define deadlines and guarantees that the specified deadlines are met, however, to admit new traffic, the proposed system has to modify the allocation of already admitted transfers. In this paper, we propose Rapid Close to Deadline Scheduling (RCD), a close to deadline traffic allocation technique that is fast and efficient. Through simulations, we show that RCD is up to 15 times faster than Amoeba, provides high link utilization along with deadline guarantees, and is able to make quick decisions on whether a new request can be fully satisfied before its deadline.Comment: World Automation Congress (WAC), IEEE, 201

Analytical Modelling of Power Efficient Reliable Operation of Data Fusion in Wireless Sensor Network

Irrespective of inclusion of Wireless Sensor Network (WSN) in majority of the research proposition for smart city planning, it is still shrouded with some significant issues. A closer look into problems in WSN shows that energy parameter is the origination point of majority of the other problems in resource-constrained sensors as well as it significant minimizes the reliability in standard sensory operation in adverse environment. Therefore, this manuscript presents a novel analytical model that is meant for establishing a well balance between energy efficiency over multi-path data forwarding and reliable operation with improved network performance. The complete process is emphasized during data fusion stage to ensure data quality too. A simulation study has been carried out using benchmarked test-bed of MEMSIC nodes to find that proposed system offers good energy conservation process during data fusion operation as well as it also ensure good reliable operation in comparison to existing system

Identification of polymorphic microsatellite loci in the queenless, ponerine ant Diacamma ceylonense

Diacamma ceylonenseis a queenless, ponerine ant whose colonies are headed by a single, mated, egg-laying worker referred to as the gamergate. Thus, new colonies are a result of dispersal by wingless gamergates. This is expected to influence patterns of colony dispersal and spatial distribution of genetic variablity. In order to facilitate the study of population genetic structure we have identified six unique, polymorphic, microsatellite loci. We have used fluorescence tagged primers to detect polymorphism at these loci

Reversal of abscisic acid induced stomatal closure by benzyl adenine

Benzyl adenine enhanced stomatal opening in isolated epidermal strips of Commelina benghalensis and Tridax procumhens. The stimulation was maximum at a concentration of 5×10−5 M BA. But kinetin had no remarkable effect on stomatal opening. The activity of benzyl adenine was observed over a narrow range of concentrations, from 10−5 M to 10−4 M. The increase in stomatal aperture was more pronounced in Commelina than in Tridax. Presence of benzyl adenine in the medium prevented the stomatal closure expected from abscisic acid and could reverse considerably the stomatal closure induced earlier by abscisic acid. It is felt that the balance between abscisic acid and cytokinins can possibly control the stomatal aperture effectively

Combined Approach for Tooth Whitening: A Case Report

The discolored, non-vital anterior tooth is a common aesthetic concern for many patients.  Discolored non-vital teeth are frequently compromised owing to previous trauma, caries, endodontic therapy and failed restorations. Destructive invasive treatment options are likely to weaken the remaining tooth structure. This can reduce the prognosis and challenge the long-term viability of the tooth, thereby initiating further prosthetic predicaments. This paper discusses modern approaches to the treatment of discolored teeth. The paper presents a case on inside/outside bleaching techniqu

A comparative study of laser posterior cordotomy and vocal cord lateralization

AbstractIntroductionThe treatment of bilateral vocal cord paralysis continues to be a challenge to the otolaryngologist, head and neck surgeon even today. Numerous surgical procedures have been proposed to improve the patient’s airway insufficiency without leaving the patient with a breathy, weak voice or an incompetent larynx. In this study we compared the outcome of laser posterior cordotomy and vocal cord lateralization in a group of bilateral abductor palsy patients.MethodRetrospective as well as a prospective study of 25 patients was carried out. The total of 25 patients was divided into 2 groups, group 1 consisted of 15 patients who underwent vocal cord lateralization with SUTUPAK suture and group 2 consisted of 10 patients who underwent laser assisted posterior partial cordotomy.ResultsThyroidectomy was the commonest cause for bilateral vocal fold paralysis i.e. 80% (20) of cases. Patients who underwent laser posterior cordotomy had 100% successful decannulation rate as compared to 92.8% for vocal cord lateralization patients. Comparison between pre and post operative voice assessment data by WILCOXON SIGNED RANKS test revealed that excepting the parameter of fluctuations/s in F0, all other parameters were statistically not significant.ConclusionLaser cordotomy is a superior, reliable and viable alternative to the other lateralization procedures for bilateral vocal fold paralysis