Debugging Finite Element Programs Input Data with Machine Learning

Abstract: Debugging of the input data of a structural analysis program is a troublesome task which is heavily dependent on empirical knowledge. The paper describes an effort that applies machine learning to build an expert system for debugging faults in structural analysis program input data. ID3 decision tree induction algorithm is employed to build the automatic learning mechanism. This method Oflkrs an attractive potential for knowledge acquisition in the civil engineering domain in which expertise plays a dominant role. This paper is novel in at least three aspects: (1) machine learning is employed to build expert systems automatically; (2) a novel impurity function is proposed for splitting the decision tree; (3) a formulated comparison is proposed for evaluating learning results.     

Home ownership policy in Singapore: An assessment

Since independence in 1965, housing conditions in the city‐state of Singapore, with a population of 2.6 million in 1988, have improved considerably. Much of the credit for this must be attributed to the government's policy of building homes for the lower income groups. One objective of the housing policy is 100 per cent home ownership for public housing. In pursuing this policy the political and social aspects are often emphasised. This paper attempts an economic evaluation of the 100 per cent home ownership target. It examines the demand and supply side policies that are employed to achieve the target. In analysing the economic implications of the policy, it is observed that such a policy distorts household expenditure, leads to overconsumption of housing and results in a thinner rental market and constrains tenure choice. These economic losses need to be recognised even while accepting the political and social importance of the policy.     

A best deadlock control for S3PMR to reach all states

This study proposes a new approach that recovers the system from deadlock states to its former live states, and reaches the same number of states as the original uncontrolled model by adding monitors (and control arcs) with no new problematic siphons. We further propose a lossless approach by coloring some arcs to avoid the material loss. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

A true-direction reconstruction of the quiet direct simulation method for inviscid gas flows

In this paper, a true-direction flux reconstruction of the second-order quiet direct simulation (QDS-2N) Smith et al. (2009)  [3] as an equivalent Euler equation solver, called QDS-N², is proposed. Because of the true-directional nature of QDS, where volume-to-volume (true-direction) fluxes are computed, as opposed to fluxes at cell interfaces as employed by traditional finite volume schemes, a volumetric reconstruction is required to reach a totally true-direction scheme. The conserved quantities are permitted to vary (according to a polynomial expression) across all simulated dimensions. Prior to the flux computation, QDS particles are introduced using properties based on weighted moments taken over the polynomial reconstruction of the conserved quantity fields. The resulting flux expressions are shown to exactly reproduce the existing second-order extension for a one-dimensional flow, while providing a means for true multi-dimensional reconstruction. The new reconstruction is demonstrated in several verification studies. These include a shock–bubble interaction problem, an Euler-four-shock interaction problem, and the advection of a vortical disturbance. These results are presented, and the increased computation time and the effect of higher-order extension are discussed in this paper. The results show that the proposed multi-dimensional reconstruction provides a significant increase in the accuracy of the solution. We show that, despite the increase in the computational expense, the computational speed of the proposed QDS-N² method is several times higher than that of the previously proposed QDS-2N scheme for a fixed degree of numerical accuracy, at least, for the test problem of the advection of vertical disturbances.     

Prototype system for pursuing firm’s core capability

Core capabilities are critical abilities that enhance and sustain an organization’s competitive advantage in extremely competitive environments. In today’s complex and dynamic business environment, companies are often prevented from effectively and efficiently evaluating relevant factors necessary for developing their core capability strategic systems. These systems, with inherent human decision-making processes, should be fully considered when creating a method for determining a firm’s suitable or required core capabilities. It is helpful to implement IT-based group decision support systems (GDSS) with soft computing algorithms to assist managers in determining the appropriate core capabilities for the firm. Therefore, this study develops a holistic group decision support system in which similarity measures, fuzzy set theory, and fuzzy mathematics programming are implemented to facilitate managers in making decisions. Through evaluations done in actual cases, we have found that this system creates a flexible and user-friendly environment that aids top management and other relevant staff members in evaluating all relevant factors related to core capabilities.     

Salt effect of lithium bromide on the solution polymerization of acrylonitrile

Abstract

In this paper, the salt effect of lithium bromide (LiBr) on the dimethyl formamid (DMF) solution polymerization of acrylonitrile was studied. From the experimental data, we proposed a possible mechanism and derived its rate expression to determine the kinetic parameters for this system. The results show that the values of k_v/k_tr (1.984～79.365) and k_t/k² _tr (3.311×l0²～3.156×l0⁵ sec·mole/1) of the DMF‐LiBr solution polymerization of acrylonitrile are larger than those of the DMF‐LiCl solution polymerization of acrylonitrile shown by Bamford and others. These results can be explained by the basicity of salt and the dissociation of polyacrylonitrile in the DMF‐LiBr solution.     

Model simulations for in situ aerobic cometabolism of trichloroethylene

BACKGROUND: While overall removal of trichloroethylene (TCE) can be estimated from in situ pilot studies of aerobic cometabolism, no quantitative information on the relative importance of the biodegradation and sorption processes is currently available. This paper presents a quantitative method to evaluate the dynamics and the individual removal efficiencies of cometabolic biodegradation and sorption processes using model simulations for in situ aerobic cometabolism. RESULTS: The first‐order rate constant of TCE cometabolism by aerobic toluene‐utilizing bacteria was around 0.2 to 0.3 L mg^?1 day^?1. The TCE partition coefficient of sorption was determined at 16.4 L kg^?1. The sorption process diminished as the sorption capacity of the aquifer solids became saturated. The sustainable TCE removal efficiency due to cometabolic biodegradation for the in situ pilot was determined at 25.8%, 51.8%, and 75.2% for residence times of 0.14 day, 0.57 day, and 1.16 day, respectively, after establishing an indigenous toluene‐degrading consortium. CONCLUSION: The agreement between model simulations and pilot results demonstrates the validity of a model that incorporates fundamental microbial and transport processes of advection, dispersion, and sorption onto the aquifer solids. The mathematical model aids the understanding of both the dynamics and the individual removal efficiencies of sorption and biodegradation processes of in situ bioremediation. Copyright © 2010 Society of Chemical Industry     

Purification and characterisation of two acidic peroxidase isoforms from the sheaths of bamboo shoots

Three isoforms of peroxidase (POD) were isolated from the sheaths of bamboo shoots by chromatofocusing on Polybuffer exchanger PBE 94. POD‐A was partially purified, and POD‐B and POD‐C were purified and characterised. POD‐A was a basic peroxidase, whereas POD‐B and POD‐C were acidic peroxidases with different isoelectric points. Using o‐phenylenediamine (OPD) as a hydrogen‐donor, the optimum temperatures for function of POD‐B and POD‐C were 55 and 45–55 °C, respectively, while both had the same optimum pH of 4.5. Both isoforms were stable between 30 and 60 °C and between pH 4.5 and 10. The activities of the POD isoforms towards hydrogen‐donors were both pH and concentration dependent. Under optimal conditions, POD‐B and POD‐C catalysed the oxidation of catechol, pyrogallol, and OPD at higher rates than guaiacol, o‐dianisidine and 2, 2’‐azino‐bis‐ (3‐ethylbenzothiazoline‐6‐sulphonic acid). Both isoforms were almost completely inhibited by chemical modification reagent diethyl pyrocarbonate (4.5 mM).