To Prove Four Color Theorem

In this paper, we give a proof for four color theorem(four color conjecture). Our proof does not involve computer assistance and the most important is that it can be generalized to prove Hadwiger Conjecture. Moreover, we give algorithms to color and test planarity of planar graphs, which can be generalized to graphs containing $K_x(x>5)$ minor. There are four parts of this paper: Part-1: To Prove Four Color Theorem Part-2: An Equivalent Statement of Hadwiger Conjecture when $k=5$ Part-3: A New Proof of Wagner's Equivalence Theorem Part-4: A Geometric View of Outerplanar GraphComment: The paper is further reduced, and each part is more self-contained, is the fina

Light axigluon and single top production at the LHC

The light axigluon model can explain the Tevatron $t\overline{t}$ forward-backward asymmetry and at the same time satisfy the constraints from the electroweak precision measurement and the $ATLAS$ and $CMS$ data, which induces the flavor changing ($FC$) couplings of axigluon with the $SM$ and new quarks. We investigate the effects of these $FC$ couplings on the s- and t-channel single top productions at the $LHC$ and the $FC$ decays $Z\rightarrow \overline{b}s+b\overline{s}$, $t\rightarrow c\gamma$ and $cg$. Our numerical results show that the light axigluon can give significantly contributions to single top production and the rare top decays $t\rightarrow c\gamma$ and $cg$.Comment: 22 pages, 8 figures; references added, contributions of new quarks to rare decay processes adde

A Cooperation-Driven ICN-based Caching Scheme for Mobile Content chunk Delivery at RAN

In order to resolve the tension between continuously growing mobile users’ demands on content access and the scarcity of the bandwidth capacity over backhaul links, we propose in this paper a fully distributed ICN-based caching scheme for content objects in Radio Access Network (RAN) at eNodeBs. Such caching scheme operates in a cooperative way within neighbourhoods, aiming to reduce cache redundancy so as to improve the diversity of content distribution. The caching decision logic at individual eNodeBs allows for adaptive caching, by taking into account dynamic context information, such as content popularity and availability. The efficiency of the proposed distributed caching scheme is evaluated via extensive simulations, which show great performance gains, in terms of a substantial reduction of backhaul content traffic as well as great improvement on the diversity of content distribution, etc

Shaping of molecular weight distribution using b-spline based predictive probability density function control

Issues of modelling and control of molecular weight distributions (MWDs) of polymerization products have been studied under the recently developed framework of stochastic distribution control, where the purpose is to design the required control inputs that can effectively shape the output probability density functions (PDFs) of the dynamic stochastic systems. The B-spline Neural Network has been implemented to approximate the function of MWDs provided by the mechanism model, based on which a new predictive PDF control strategy has been developed. A simulation study of MWD control of a pilot-plant styrene polymerization process has been given to demonstrate the effectiveness of the algorithms

Multilevel DC-AC Converter Interface with Solar Panels

This paper presents a single-phase 11-level (5 H-bridge) cascaded multilevel DC-AC converter that has implemented a Phase Locked Loop (PLL) and Maximum Power Point Tracking (MPPT) with 5 separate solar panel DC sources. This topology upgrades the conventional 3-level Pulse Width Modulation (PWM) controlled converter with advantages such as smoother output waveforms, more flexibility in voltage range, smaller filter size, and switching angle control. Simulation results of voltage synchronization using PLL and experimental setup and results implementing the entire converter interface are also presented

Identification and Mitigation of Information Leakage Caused by Side Channel Vulnerabilities in Network Stack

Keeping users sensitive information secure and private in todays network is challenging. Networks are large, complicated distributed systems and are subject to a wide variety of attacks, such as eavesdropping, identity spoofing, hijacking, etc. What is worse, encrypting data is often not enough in light of advanced threats such as side channel attacks, which enable malicious attackers to infer sensitive data from insignificant network information unexpectedly. For this purpose, we pro- pose series of techniques to prevent such information leakage at different layers in network stacks, and raise awareness of its severity. More specifically, 1) we propose a practical physical (PHY) layer security framework FOG, for effective packet header obfuscation using MIMO, to keep eavesdroppers from receiving any meaningful packet information; 2) we identify and fix a subtle yet serious pure off-path side channel vulnerability (CVE-2016-5696) introduced in both TCP specification and its implementation in Linux kernel, which prevents malicious attackers from exploiting it to indicate arbitrary connections state, reset the connection or even further hijack the connection; 3) we propose a principled TCP side channel vulnerability discovery solution based on model checking and program analysis, and automatically identify 12 new side channel vulnerabilities (and 3 old ones) from TCP implementation in Linux and FreeBSD kernel code. The ultimate goal is to help guide the future design and implementation of network stacks.Keeping users’ sensitive information secure and private in today’s network is challenging. Network nowadays are subject to a wide variety of attacks, such as eavesdropping, identity spoofing, denial of service, etc. What is worse, encrypting sensitive data is often not enough in light of advanced threats such as side channel attacks, which enable malicious attackers to infer sensitive data from “insignificant” network information unexpectedly. For this purpose, we propose series of techniques to prevent such information leakage at different layers in network stack, and raise awareness of its severity. In our first work, we propose a practical physical (PHY) layer security framework FOG, for effective packet header obfuscation using MIMO, to prevent eavesdroppers from receiving any packet headers to profile users. Secondly, we identify and fix a subtle yet serious pure off-path side channel vulnerability (CVE-2016-5696) introduced in both TCP specification and its implementation in Linux kernel. This vulnerability allows malicious attackers to indicate arbitrary TCP connection’s state, reset the connection or even further hijack the connection. Motivated by the fact that most previous TCP side channel vulnerabilities are manually identified, in our last work, we propose a principled TCP side channel vulnerability discovery solution based on model checking and program analysis. It automatically identifies 12 new side channel vulnerabilities (and 3 old ones) from TCP implementation in Linux and FreeBSD kernel code. The ultimate goal of my research is to help guide the future design and implementation of network stacks

Price credit and price risk simulation for Alaska natural gas pipleline project

Thesis (M.S.) University of Alaska Fairbanks, 2003This work describes the price risk involved in developing an Alaska Natural Gas Pipeline. Three alternatives were developed. They are an ALCAN Only 4.5 Bcf/day case, a Y-line case, and an ALCAN Only 5.5 Bcf/day case. The simulation result supports the conclusion that the ALCAN Only 4.5 Bcf/day case would be the most feasible and flexible choice for the long-run gas development with less commodity risk. Also, the price credit simulation was run based on the EIA natural gas price forecast. It shows how a Federal Tax Credit helps to reduce price risk making this marginal project more acceptable for participating oil companies. However it might not be revenue neutral for the Federal Government. The risk-assessment model was constructed in the Excel spreadsheet with a commercially purchased add-in feature (@RISK by Palisade Corp.) that performed the Monte Carlo simulation and the probabilistic outcomes. It was designed to be a dynamic tool that could estimate production performance with associated costs, and product prices to Yield an economic analysis. The model was specifically designed for the Alaska Natural Gas Pipeline. This work could be useful for government, companies, and any individual, who is currently involved with the Alaska Natural Gas Act