Steroid OpenFlow Service Scalability Analysis

Modern cloud applications are hosted on data centers across vast geographical scopes and exchange large amounts of data continuously. Transmission Control Protocol (TCP) is the most popular protocol for reliable data transfer; however, due to TCP’s congestion control mechanism, maximum achievable throughput across a large bandwidth-delay product (BDP) network is limited. Various solutions exist to enhance data transfer throughput but they usually require non-trivial and explicit installation and tuning of specialized software on both sides which makes deployment limited. A software defined networking (SDN) based solution Steroid OpenFlow Service (SOS) was developed that utilizes multiple parallel TCP connections to transparently enhance network performance across a large BDP network. OpenFlow is used to transparently redirect user traffic to nearby service machines called SOS agent and these agents use multiple TCP connections to transfer data fast across large BDP network. While SOS has shown significant improvements in data transfer throughput, there are multiple factors which affect its performance. This study focuses on SOS scalability analysis targeting four critical factors: CPU utilization of SOS agents, sockets used for parallel TCP connections, how OpenFlow is used and network configurations. Through this study, the SOS agent code was revamped for performance improvements. Experiments were conducted on the National Science Foundation’s CloudLab platform to assess the effect of the above-mentioned factors on SOS performance. Results have shown improvement in throughput per SOS session from 10.96Gbps to 12.82Gbps by removing CPU bottleneck on 25Gbps network. SOS deployment over an InfiniBand network has shown a linear increase in throughput to 23.22Gbps with optimal network configurations. Using OpenFlow to support multiple client connections to the same server have increased throughput from 12.17Gbps to 17.20Gbps. The study showed that with code-level improvements and optimal network configurations, SOS performance can be improved substantially

Dynamics of Germ Cell Specific Stable Transcriptional Complexes in Xenopus Oocytes

Early animal development depends largely on the activation/expression of genes, and this often depends on the binding of transcription factors to genomic DNA sequences on which they act. This is particularly true of genes that determine cell fate; for example, Asc1-1 leads to neural differentiation and MyoD for muscle. In early development, different genes need to be activated in sequence by appropriate transcription factors. It is commonly believed that a transcription factor has only a very short dwell time of seconds or minutes on its appropriate DNA sequence. On the other hand, differentiated cell strains retain their differentiated state for many years. Does this mean that a transcription factor molecule must be exchanged for another molecule of the same kind, or could it be that a transcription factor dwell time might be significantly prolonged in stably differentiated cells, as are most non-dividing adult cell types? I have investigated the dwell time of the neurogenic transcription factor Asc1-1 by injecting mRNAs or DNAs into the non-dividing oocyte of Xenopus. Transcription factor proteins can be introduced by mRNA injection and DNA sequences to which they bind, when required; induced gene expression is monitored by expression of fluorescent reporter genes. I have used competition experiments with differently marked transcription factor proteins and DNA binding sequences to measure dwell time in living oocytes. I find that the dwell time of the factor proteins on the DNA or chromatin to which they specifically bind is much longer than is generally believed. This unexpected stability may contribute to the strength of cell differentiation in normal development. Several aspects of the regulation of transcription in non-dividing cells have been studied. Xenopus oocyte can form stable transcriptional complexes on an injected DNA template. Once formed, these transcriptional complexes stay stable for several rounds of transcription, which can last for days without letting any other DNA compete for the mRNA expression. The nature of these complexes has been thought to be tightly bound to their template DNA. However, a new mechanism governing this phenomenon of stabilised transcription in Xenopus oocyte has been proposed. According to this phenomenon, stabilised mRNA expression by a DNA template in Xenopus oocyte is established by local transcription factors' entrapment. RNA polymerase II factors have been shown to enable the formation of stabilised nuclear compartments. This finding proposes a new way of how the non-dividing cells can maintain their gene expression for a prolonged time.Trinity College, University of Cambridge. Chief Minister Merit Scholarship, PEEF Government of Pakistan

Security analysis of the micro transport protocol with a misbehaving receiver

BitTorrent is the most widely used Peer-to-Peer (P2P) protocol and it comprises the largest share of traffic in Europe. To make BitTorrent more Internet Service Provider (ISP) friendly, BitTorrent Inc. invented the Micro Transport Protocol (uTP). It is based on UDP with a novel congestion control called Low Extra Delay Background Transport (LEDBAT). This protocol assumes that the receiver always gives correct feedback, since otherwise this deteriorates throughput or yields to corrupted data. We show through experimental investigation that a misbehaving uTP receiver, which is not interested in data integrity, can increase the bandwidth of the sender by up to five times. This can cause a congestion collapse and steal large share of a victim’s bandwidth. We present three attacks, which increase the bandwidth usage significantly. We have tested these attacks in a real world environment and show its severity both in terms of number of packets and total traffic generated. We also present a countermeasure for protecting against the attacks and evaluate the performance of that defence strategy

Measurement of Partial Discharge Inside Metal Enclosed Power Apparatus using Internal Sensor

Partial discharge detection by detecting the released energy in form of electromagnetic wave during discharge using Ultra-High Frequency (UHF) antenna is one method to determine insulation system quality in high voltage system. UHF PD detection method has several advantages over conventional PD detection system such as IEC 60270 method. The advantages of UHF PD detection system are the capability to directly detect PD signal without firstly shut down, the installation system and their immunity from environmental noise. Nowadays most of electrical equipment are in form of metal enclosed model. This paper deals with measurement of PD occurrences inside metal enclosed equipment using internal sensor. The loop antenna is used for PD measurement. The experimental results show that the presence of metal box gives significant change on the PD signal detected by using loop antenna. Without metal box, the measurement sensitivity decreases because of the high level of background noise. The metal box acts as electromagnetic wave shielding and reduces the external noise. When the loop antenna placed inside metal box, the measurement sensitivity increases because of the low level of background noise inside metal box

A Microprocessor-based multivariable interactive control system

This study outlines the various types of control systems and reviews the necessary mathematical techniques to solve the problem of multivariable interactive control. The characteristics as well as the state representation for control processes involving either p or v type canonical structures are discussed. Next, the characteristics of multivariable interactive discrete control systems are discussed in detail. The advantages of flexibility and speed of microprocessors are used as powerful tools to implement a microprocessor-based system can be employed to control discrete processes. To demonstrate a practical application of a microprocessor-based system in a multivariable interactive discrete process, the algorithm and software (Assembly Language) is developed for a special engine control system selected as the model

Application of Ultra-Wideband Double Layer Printed Antenna for Partial Discharge Detection

Partial discharge (PD) is a local electrification phenomenon that partially connects insulation between the conductors and occurs either on the surface of the conductor or inside the insulation (void). During the PD there are several phenomena that accompany the occurrence of PD, such as impulse currents, heat radiation, electromagnetic waves, mechanical waves and chemical processes. This phenomenon is detected and measured to know the existence of PD. One of the PD measurements is ultra high frequency (UHF) method, by measuring the waves generated by PD using antenna. One of antenna having good characteristics is UWB double layer printed antenna. In this paper the application of ultra-wideband double layer printed antenna for partial discharge detection is reported. The application of antenna on PD measurement, shows that the antenna is able to detect PD. The characteristics of PD: PDIV, PDEV, PD waveform are measured using this antenna. Ultra-wideband (UWB) double layer printed antenna is an antenna developed from a square microstrip antenna with symmetrical T-shaped tethering. The proposed antenna is implemented on Epoxy FR-4 substrate with permittivity of 4.3, thickness of 1.6mm, and 72.8mm x 60.0mm in size. The VNA testing of the antenna shows that the antenna bandwidth is from 50MHz to 2.30GHz. The measured results of PD wave are PDIV, PD waveform and PDEV

Determination of Appropriate Overhead Line Insulator in Sumatra due to Contamination Severity

Insulator is one of the important equipment to support electrical power delivery which flow through the transmission line. Considering its very important role, the selection of insulators must be certainly based on deep analysis so that the insulator we choose works properly. There are several standards that can be used in selecting isolators, but in this paper the standards that will be used for case study analysis are IEC and IEEE standards. Case studies that will be used for the selection of insulators are for Sumatra that located in Indonesia which is a tropical country and certainly has special environmental characteristics that can influence the selection parameters of an insulator. There are several parameters that are commonly used in selecting overhead isolators those are power frequency voltage, environmental condition (contamination), switching over voltage, and lightning over voltage. Using environmental condition, it is found that the pollution category of Sumatra area is heavy, which influence the selection of insulation material