CAR-Miner: An efficient algorithm for mining class-association rules

Building a high accuracy classifier for classification is a problem in real applications. One high accuracy classifier used for this purpose is based on association rules. In the past, some researches showed that classification based on association rules (or class-association rules – CARs) has higher accuracy than that of other rule-based methods such as ILA and C4.5. However, mining CARs consumes more time because it mines a complete rule set. Therefore, improving the execution time for mining CARs is one of the main problems with this method that needs to be solved. In this paper, we propose a new method for mining class-association rule. Firstly, we design a tree structure for the storage frequent itemsets of datasets. Some theorems for pruning nodes and computing information in the tree are developed after that, and then, based on the theorems, we propose an efficient algorithm for mining CARs. Experimental results show that our approach is more efficient than those used previously.     

A Comprehensive Approach for Estimating Hydraulic Quantities in a Multi-branched Estuarine System

Despite many previous investigations, there is no theoretically justifiable equation to determine the freshwater discharge, tidal velocity, and salinity in a complex estuary that contains several branches. In this study, the longitudinal distributions of freshwater and salinity concentration in multi-branched estuaries are investigated using a mathematical model, considering the energy balance by frictional head loss and the salt balance by diffusion and advection in a one-dimensional steady-state condition. We attempt to obtain the time-mean freshwater discharge rate quantitatively at a junction where the main flow separates into two branches. The salinity distribution along each branch is calculated by following the dispersion coefficient equation previously proposed for a single estuary. The salinity field is divided into the near-coast region and the upstream region, because in each segment the inland velocity varies according to the tidal flux. For computing the tidal velocity, we propose the Burgers equation and the Hoph-Cole transformation. The theoretical results obtained by these equations were found to be in good agreement with a set of observed data in the Red River estuary system.     

Performance evaluation of multi-hop csma/ca networks in fading environments

The performance of multi-hop CSMA/CA networks has in most cases been evaluated via simulations, or analytically using a perfect collision channel model. Using such methods, one can neither have access to the capture nature of the terminals nor evaluate the performance of the network in a fading environment. In this paper a new analytical framework that takes into account these capture and fading effects is presented. The network investigated in this paper has an infinite number of nodes which is assumed to be spatially Poisson distributed. The approach is to develop analytical expressions for the transition probabilities between states of nodes in the network by approximating these states as a Markov chain. A fast algorithm to solve these equations is also given. Numerical results show that the model agrees with simulation results for both omni-directional networks and networks employing beamforming.     

Corrosion protection of molybdate doped polypyrrole film prepared in succinic acid solution

ABSTRACT

Polypyrrole (PPy) was prepared on the mild steel substrate by electrochemical polymerisation in the solution containing pyrrole monomer and succinic acid. The mild steel surface could be passivated before and during electropolymerisation by molybdate. The morphology and structure of the PPy film were studied with SEM. The typical cauliflower structure of PPy was observed. Raman and IR spectroscopy showed that the obtained PPy was in an oxidised state. The thermal stability of PPy was investigated by the thermal gravimetric analysis, showing that PPy was stable at higher than 480°C. The electrochemical property of the PPy film was performed by open circuit potential, polarisation curves (I/E), and electrochemical impedance spectroscopy. The corrosion behaviour of mild steel (CT3) with PPy film in solution NaCl 3% was studied.

This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).     

Efficient optimization of network protection design with <Emphasis Type="Italic">p</Emphasis>-cycles

The purpose of this paper is to consider network survivability designs that utilize the p-cycle, and to propose a novel ILP formulation for capacity design based on network fundamental cycles, as well as the available straddling links. Concepts of visible and hidden straddling links—which are essential components of the model presented herein—are also introduced. The proposed model caters for the case of joint optimization of a p-cycle network that can be solved without enumerating p-cycle candidates. In addition, the complexity of the proposed model is much less than any conventional model dealing with large size networks and suitable for the design of networks having multiple quality of protection (MQoP) service classes using mixed protection techniques.     

The Chitinolytic Activities of Streptomyces sp. TH-11

Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by β-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy.     

Effects of HZSM-5 crystallite size on stability and alkyl-aromatics product distribution from conversion of propanal

The conversion of propanal on large (2–5 µm) and small (0.2–0.5 µm) crystallite HZSM-5 at 400 °C and atmospheric pressure has been studied. Improved catalyst stability was observed on small crystallites due to faster removal of products with the shorter diffusion path length, reducing the formation of coke precursors. As previously shown, C₉ aromatics are the initial aromatics produced from propanal via aldol condensation followed by cyclization and these have less opportunity to crack to lighter aromatics on the small crystallites. Thus, a higher ratio of C₉/(C₈+ C₇) aromatics was observed on the small crystallites. The main isomer of the C₈ aromatic products observed on small crystallites was the initial cracking product of the C₉ aromatics, and thermodynamically preferred, meta-xylene, while the shape-selective preferred para-xylene was the predominant product on large crystallites. The higher internal diffusion rate of the para isomer results in greater shape selectivity with the longer path of the large crystallite zeolite. It is concluded that the use of smaller crystallite HZSM-5 improves results for production of alkyl aromatics from light oxygenates at mild conditions that may prove useful for bio-oil upgrading.     

Linear Size Optimal $q$-ary Constant-Weight Codes and Constant-Composition Codes

An optimal constant-composition or constant-weight code of weight w has linear size if and only if its distance d is at least 2w-1. When d ? 2w, the determination of the exact size of such a constant-composition or constant-weight code is trivial, but the case of d=2w-1 has been solved previously only for binary and ternary constant-composition and constant-weight codes, and for some sporadic instances. This paper provides a construction for quasicyclic optimal constant-composition and constant-weight codes of weight w and distance 2w-1 based on a new generalization of difference triangle sets. As a result, the sizes of optimal constant-composition codes and optimal constant-weight codes of weight w and distance 2w-1 are determined for all such codes of sufficiently large lengths. This solves an open problem of Etzion. The sizes of optimal constant-composition codes of weight w and distance 2w-1 are also determined for all w ? 6, except in two cases.     

Hydrogen Generation from CO2 Reforming of Biomass-Derived Methanol on Ni/SiO2 Catalyst

Topics in Catalysis - CO2 reforming of methanol for producing hydrogen was experimentally carried out in a fixed-bed reactor on 10%Ni/SiO2. The 10%Ni/SiO2 was completely reduced during H2...