Ali, K, Horsfall, C & Lister, R 1989, 'Towards knowledge-based identification of mineral mixtures from reflectance spectra', Knowledge-Based Systems, vol. 2, no. 1, pp. 5-13.
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GOLD/M is an expert system that identifies some mineral mixtures in rocks by searching for characteristic features in the infrared reflectance spectra of the rocks. Some of these minerals indicate subsurface gold deposits. The system is implemented in a shell based on subjective Bayesian reasoning, as used in the Prospector expert system. An earlier system, called GOLD, could identify only the one mineral in a pure sample. GOLD/M identifies up to two minerals in a rock consisting of a mixture of minerals. This paper discusses the extensions made to cope with mineral mixtures, and discusses problems that emerged with the Prospector formalism. © 1989.
Donnelly, IJ & Watterson, PA 1989, 'Ion-matrix sheath structure around cathodes of complex shape', Journal of Physics D: Applied Physics, vol. 22, no. 1, pp. 90-93.
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Haseyama, M, Nagai, N, Miki, N & Miyanaga, Y 1989, 'Normalized ARMA lattice filter and its terminal conditions', Electronics and Communications in Japan (Part III: Fundamental Electronic Science), vol. 72, no. 2, pp. 1-13.
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AbstractIn this paper it is shown that covariant data of a synthesized signal corresponds to the covariant data of a real signal.This occurs when an ARMA lattice synthesis filter is used and the minimum mean square value of the estimation error is zero.Hence, a new terminal condition of the ARMA lattice filter is derived so that the covariant data of the synthesized signal will always correspond to the covariant data of a real signal.To this end, a design method for the normalized ARMA lattice filter is presented in this paper, and normalized estimation errors are derived. Finally, the starting condition and design for the normalized ARMA lattice filter is given.
Huang, MZ & Waldron, KJ 1989, 'An Efficient Rate Allocation Algorithm in Redundant Kinematic Chains', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 111, no. 4, pp. 545-554.
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This paper addresses a basic problem which arises in the coordination of serial chain manipulators, namely, that of decomposing a given end effector velocity state into a set of joint rates. Such a problem is indeterminate for manipulators with kinematic redundancy. A novel method of solving the rate distribution problem for the class of fully revolute-jointed, serial manipulators is developed. The technique is an extension of the axial field solution scheme developed initially for solving the force allocation problem in a statically indeterminate parallel chain system. The basis of the solution method lies in the dualities of velocity and force systems between series and parallel mechanisms. The method offers an efficient means of rate coordination and is especially useful in the control of manipulators with high degrees of redundancy. Two examples have been given for illustration. It is shown that the minimum norm solution, obtainable commonly from pseudoinverse, can also be achieved using this new efficient algorithm.
Kumar, V & Waldron, KJ 1989, 'Actively coordinated vehicle systems', Journal of mechanisms, transmissions, and automation in design, vol. 111, no. 2, pp. 223-231.
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The use of independent actuation of suspension and locomotion degrees of freedom offers significant potential for improved performance vehicles. In this paper, the mathematics of active coordination of such systems is explored. Two different, actively coordinated mobility system configurations are used as examples to elucidate the principles involved.
Kumar, V & Waldron, KJ 1989, 'Actively Coordinated Vehicle Systems', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 111, no. 2, pp. 223-231.
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The use of independent actuation of suspension and locomotion degrees of freedom offers significant potential for improved performance vehicles. In this paper, the mathematics of active coordination of such systems is explored. Two different, actively coordinated mobility system configurations are used as examples to elucidate the principles involved.
Kumar, V & Waldron, KJ 1989, 'Suboptimal algorithms for force distribution in multifingered grippers', IEEE Transactions on Robotics and Automation, vol. 5, no. 4, pp. 491-498.
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Kumar, VR & Waldron, KJ 1989, 'Adaptive gait control for a walking robot', Journal of Robotic Systems, vol. 6, no. 1, pp. 49-76.
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AbstractWalking vehicles have the potential to emulate the superior off‐road mobility of biological systems. However, it is important to make the walking machine terrain adaptive and versatile, and to minimize man's role as an operator in order to realize this potential. Terrain adaptive locomotion involves intelligent foothold selection and the control of gait to produce the desired motion. This requires a departure from the idealized, structured stepping patterns for statically stable gaits which have been the object of considerable research. A modified wave gait is used to demonstrate that it is possible for the vehicle velocity to be varied continuously in accordance with higher level commands even with irregular, asymmetric, and changing support patterns, A varying duty factor is employed to enable optimal leg cycling frequencies. Implementation of gait control algorithms and results from a computer simulation are also presented.
Kwan, PYK & Shannon, AG 1989, 'Objective tests and latent trait theories', International Journal of Mathematical Education in Science and Technology, vol. 20, no. 3, pp. 457-467.
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After a discussion about objectivity in measurement, this paper describes some linear and logistic models for the implementation of latent trait theory. The aim is to consider those mathematical and educational issues pertinent to learning more about the topic and using those standardized tests which utilize the Rasch and similar models of assessment. © 1989 Taylor and Francis Group, LLC.
Ohkama, H, Miki, N, Nagai, N & Miyanaga, Y 1989, 'A parallel processing architecture for parameter estimation with recursive least squares', Electronics and Communications in Japan (Part III: Fundamental Electronic Science), vol. 72, no. 9, pp. 105-114.
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AbstractThe recursive least‐squares method (RLS) is often employed in the identification of the linear discrete‐time system, in which the parameters are time‐varying. This paper aims at producing the output which is an estimation of the system parameters, and derives a new algorithm which minimizes the RLS criterion with (time‐variable) forgetting factor. A parallel architecture is proposed which executes the algorithm. the derived algorithm is composed of two‐step processes, which are the Agee‐Turner PD factorization update theorem and the forward‐substitution for solving linear triangular systems. the proposed parallel architecture is composed of a large number of processing elements (PE) connected in a regular way. the communication is performed only between adjacent PE, and the architecture can easily be implemented by VLSI. It can be considered as a systolic array composed of PE with a queue (FIFO memory). By introducing PE with a queue, the two‐step processes can be executed in parallel for the first time. It is shown that by employing the proposed parallel architecture composed of (N2 + 5N − 2)/2 PE in the real‐time processing, the estimated parameters for any time can be produced as the output, in a processing time independent of the number of parameters of the estimation, even though the computational complexity is of the order of square of the number of estimated parameters.
Sheng, D, Knutsson, S & Axelsson, K 1989, 'Verification and application of a numerical model for frost front penetration', Frost in geotechnical engineering. International symposium, Saariselka, 1989. Vol. 1, pp. 401-414.
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A PC-version of a numerical model for calculation of the frost front penetration and the temperature distribution in frozen and unfrozen soils has been developed. The model is described and so are the results from the application of the model to a field test. -from Authors
Stewart, MG & Melchers, RE 1989, 'Checking Models in Structural Design', Journal of Structural Engineering, vol. 115, no. 6, pp. 1309-1324.
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A large proportion of structural failures are due to human error in the design stage of a structural engineering project and many of these failures could have been averted if there had been adequate design checking Results are reported herein from surveys investigating the effectiveness of three typical design-checking processes: self-checking independent detailed design checking and overview checking Following a review of current work in this area appropriate mathematical models which examine the effects of error magnitude time and experience are proposed for each design checking process These are compared to the limited data obtained from the surveys Although preliminary the results have interesting implications for practitioners. © ASCE.
Stewart, MG & Melchers, RE 1989, 'Decision model for overview checking of engineering designs', International Journal of Industrial Ergonomics, vol. 4, no. 1, pp. 19-27.
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Overview checking occurs whenever an engineering design is reviewed by another engineer without specifically carrying out checking calculations or following through the design process in detail. Results are reported herein of a survey examining the effectiveness of overview checking. The respondents were requested to assess whether a structural design should be considered 'undersized', 'correct' or 'oversized'. Using the responses as a basis, a decision model is proposed for the effectiveness of overview checking as a function of error magnitude and of checker's experience. It is concluded that correct assessment of a design as 'safe' is not a function of experience. However, it appears that more experience is beneficial in selecting economical designs. © 1989.
Stewart, MG & Melchers, RE 1989, 'Error control in member design', Structural Safety, vol. 6, no. 1, pp. 11-24.
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Available evidence suggests that design checking can significantly reduce the incidence of structural failures resulting from human errors in the design process. Since 'real-world' experimentation is not possible, it is of interest to develop a model to simulate the effects of human error on a typical design task and also to model typical checking procedures. The development and analysis of these models is described in the present paper. The design task considered is that of member design for a rafter of a steel portal frame building. It was found that checking efficiencies between 0.6 and 0.9 are most effective in increasing structural reliability and that, often, only two separate design checks are necessary to virtually eliminate the incidence of structural failure due to human error. © 1989.
Stewart, MG & Melchers, RE 1989, 'Optimization of Structural Design Checking', Journal of Structural Engineering, vol. 115, no. 10, pp. 2448-2460.
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It is generally acknowledged that design checking reduces the incidence of structural failure. Because checking is often seen as nonproductive and costs money, the optimal degree of design checking is of interest. In the present paper, a decision model is developed to determine the optimal level of design checking. It is applied to the design of a steel rafter for a portal frame building. The model incorporates the effect of either an insured or an uninsured designer. Optimization was achieved by maximizing the expected utility. Using the model, it was found that the use of thorough self-checking and overview checking only is the optimal strategy, unless the consequences of failure are expected to be catastrophic, in which case one independent “design check” is also necessary. © ASCE.
Vigneswaran, S & Chang, JS 1989, 'Experimental testing of mathematical models describing the entire cycle of filtration', Water Research, vol. 23, no. 11, pp. 1413-1421.
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Two mathematical models developed based on different concepts to describe the entire cycle of filtration were tested with experimental results. The concept of Model I is based on the detachment of deposited particles. The degree of detachment was assumed proportional to the hydraulic gradient and number of particles already retained on the filter grain. Model II is based on the concept that there exists a maximum limit on particle deposition on the filter grain. It was found that Model I, based on the detachment assumption, can simulate better than Model II does. This may be an experimental proof for the concept of detachment which is now agreed by most of the researchers. The ultimate specific deposit was estimated experimentally for different filtration velocities to give a qualitative justification on the applicability range of the proposed models. © 1989.
Vigneswaran, S & Mora, JC 1989, 'Energy recovery considerations for membrane separation process', RERIC International Energy Journal, vol. 11, no. 1, pp. 1-15.
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This paper gives an overview of different membrane processes like reverse osmosis ultrafiltration with direct and indirect energy recovery systems. The feasibility of using direct and indirect energy recovery in each membrane process and a few examples are presented. The importance of cogeneration technology and pervaporation, and principles and examples are also introduced.
Vigneswaran, S, Muttamara, S & Srianandakumar, K 1989, 'Low waste technologies in selected industries', ENVIRON. SANIT. REV., no. 27, pp. 1-86.
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Expectations of increasingly higher living standards along with rapid industrial developments have resulted in a dramatic rise in the level of pollution of the natural environment. At the same time it is generally accepted that a healthy life requires good quality environment and hence the control of pollution. Today, environmental scientists are in the process of combining all these three aspects (industrialization, clean environment and healthy life) based on the principle of using low and non-waste technology. The philosophy behind this is 'to produce better while polluting less'. In practice, this technology and its application go by many names such as low and non-waste technology (LNWT), clean technology, pollution prevention, waste reduction, waste recycling, resource utilization, etc. The basic goal of LNWT is to eliminate the by-product formation that is discarded as waste. The objectives of LNWT are therefore to avoid inefficiencies in production which result in excess of waste and to recover the useful components of the waste in such a way that they can either be reused or recycled to minimize the emission of pollutants to the environment. LNWT alleviates disposal costs, liability risk and resource cost.
Vigneswaran, S, Muttamara, S, Srianandakumar, K & Ben Aim, R 1989, 'Low waste technologies in selected industries', Environmental Sanitation Reviews, no. 27.
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The paper examines the need for low and non-waste technology. The methods to achieve low-waste technology are given. Selected unit operations are discussed for suspended solids removal and dissolved solids removal. The applications in selected industries include: pulp and paper mill industry; tapioca starch industry; palm oil refinery wastewater treatment; food industry; textile industry; electroplating industry; distillery industry.
Visvanathan, C, Aim, RB & Vigneswaran, S 1989, 'Application of cross-flow electro-microfiltration in chromium wastewater treatment', Desalination, vol. 71, no. 3, pp. 265-276.
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Cross-flow microfiltration (CFMF) was experimentally studied for the separation of precipitates of chromium hydroxide. Although this process enables one to obtain chromium-free filtrate, a disadvantage is that the filtration flux declines rapidly due to membrane fouling. In order to avoid this fouling problem and increase the filtration flux, an electric field was applied across the membrane as an antifouling technique (cross-flow electro-microfiltration-CFEMF). The surface charges of the precipitates were modified by adding a dispersant. The experimental results indicate that this modified process of CFEMF is highly effective in reducing the membrane fouling, which eventually leads to a remarkable filtration flux increase. The application of this antifouling technique of CFEMF is cited only for the suspensions containing charged particles and colloids. Nevertheless, the process of modification of surface charge with a dispersant permits us to use this technique with a wide variety of suspensions. © 1989.
Waldron, KJ, Raghavan, M & Roth, B 1989, 'Kinematics of a Hybrid Series-Parallel Manipulation System', Journal of Dynamic Systems, Measurement, and Control, vol. 111, no. 2, pp. 211-221.
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In this paper we first derive the coordinate transformations associated with a three-degree-of-freedom in-parallel-actuated micro-manipulator. Then we combine these results with the transformations associated with an in-series three-axis wrist on which the in-parallel micro-manipulator is mounted. The results are the basic transformation equations between joint-space position variables and end-effector (or task space) position variables for a hybrid series/parallel six-degree-of-freedom manipulator system. This structural combination results in a manipulator which exhibits desirable fine and gross motion characteristics as both a stand-alone device or as a sub-system of a more complex system with redundant degrees of freedom. The forward and inverse position kinematics and rate and force decomposition for this hybrid six-degree-of-freedom linkage are presented.
Watterson, PA 1989, 'Child-Langmuir sheath structure around wedge-shaped cathodes', Journal of Physics D: Applied Physics, vol. 22, no. 9, pp. 1300-1307.
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The steady state Child-Langmuir sheath around a wedge-shaped cathode immersed in a plasma is calculated numerically. The ions drawn from the plasma may be employed to sputter material from the cathode, or may implant into the cathode, depending upon the magnitude of the applied negative voltage. The ion impact rate onto the cathode reaches 2.2 times higher near a square edge and 3.6 times higher near a knife edge than the rate for planar surfaces of the cathode. However, for a knife edge the rate falls to zero at the edge. All the ions strike the cathode with the same kinetic energy, but the angle of impact is nonperpendicular near the edge, which could reduce the implantation depth and increase sputtering. © 1989 IOP Publishing Ltd.
Young, W, Hadgraft, R, Friday, R, Prior, M, Sharpe, R, Spencer, WJ, Szwed, N, Taylor, MAP, Walker, D & Wigan, M 1989, 'Knowledge based systems in civil engineering', Civil Engineering Systems, vol. 6, no. 1-2, pp. 3-4.
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BALL, JE, OLOUGHLIN, GG & COUNCIL, AWR 1970, 'APPROPRIATE MODELS FOR URBAN STORM-SEWER SYSTEMS', WATERCOMP 89, 1ST AUSTRALASIAN CONF ON TECHNICAL COMPUTING IN THE WATER INDUSTRY ( PREPRINTS ), INST ENGINEERS AUSTRALIA, MELBOURNE, AUSTRALIA, pp. 131-135.
Braun, RM 1970, 'Multi-dimensional median filtering for processing network and spectrum analyzer information', pp. 85-89.
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The author describes the use of median filtering to enhance the readability of the trace information of such instruments as network analyzers and spectrum analyzers. A class of mildly recursive median filters (MRMFs) is described, and application to a spectrum analyzer is demonstrated. The results show that a 41% improvement in Gaussian noise, using an MRMF with a window size of three samples, is possible. The MRMF turns out to have considerably better performance for very small window sizes than nonrecursive MFs.
HADGRAFT, RG & WIGAN, MR 1970, 'A POSSIBLE PROTOTYPE FOR A NEW AUSTRALIAN RAINFALL AND RUNOFF', HYDROLOGY AND WATER RESOURCES SYMPOSIUM 1989 : COMPARISONS IN AUSTRAL HYDROLOGY, 18TH SYMP ON HYDROLOGY AND WATER RESOURCES : COMPARISONS IN AUSTRAL HYDROLOGY ( PREPRINTS ), INST ENGINEERS AUSTRALIA, UNIV CANTERBURY, CHRISTCHURCH, NEW ZEALAND, pp. 481-482.
HADGRAFT, RG & WIGAN, MR 1970, 'ASSESSMENT AND IMPROVEMENT OF THE CODIFICATION AND DELIVERY OF ENGINEERING EXPERIENCE', WATERCOMP 89, 1ST AUSTRALASIAN CONF ON TECHNICAL COMPUTING IN THE WATER INDUSTRY ( PREPRINTS ), INST ENGINEERS AUSTRALIA, MELBOURNE, AUSTRALIA, pp. 160-164.
HADGRAFT, RG & WIGAN, MR 1970, 'TOWARDS EFFECTIVE FIELD SUPPORT AND RETRAINING FOR ENGINEERS WHO USE AUSTRALIAN RAINFALL AND RUNOFF', HYDROLOGY AND WATER RESOURCES SYMPOSIUM 1989 : COMPARISONS IN AUSTRAL HYDROLOGY, 18TH SYMP ON HYDROLOGY AND WATER RESOURCES : COMPARISONS IN AUSTRAL HYDROLOGY ( PREPRINTS ), INST ENGINEERS AUSTRALIA, UNIV CANTERBURY, CHRISTCHURCH, NEW ZEALAND, pp. 468-472.
Indraratna, B, Naguleswary, S & Balasubramaniam, AS 1970, 'Application of physical and mathematical modelling in underground excavations', 30th U.S. Symposium on Rock Mechanics, USRMS 1989, pp. 301-308.
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The scope of this paper is to introduce a mathematical model based on matrix algebra in order to determine similitude quantities, which can be arranged in specific formats to simulate the field conditions and associated behaviour. The formulation of a typical mathematical model applicable to Geomechanics is demonstrated here. The examples provided are intended to facilitate comprehension and application of the proposed model in practice.
Nanua, P & Waldron, KJ 1970, 'Direct kinematic solution of a Stewart platform', Proceedings - IEEE International Conference on Robotics and Automation, pp. 431-437.
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The Stewart platform is a fully parallel, six-degree-of-freedom manipulator mechanism. A solution of the direct kinematics problem for the Stewart platform is presented for the case in which the six limbs form three concurrent pairs at either the base or the hand member. The solution is shown to be reducible to a 24th-order polynomial equation in tan(φr/2). It is also shown that, for a given set of link lengths, the Stewart platform can be assembled in 24 different configurations.
Stauffer, LA & Slaughterbeck-Hyde, RA 1970, 'The Nature of Constraints and Their Effect on Quality and Satisficing', 1st International Conference on Design Theory and Methodology, ASME 1989 Design Technical Conferences, American Society of Mechanical Engineers.
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Abstract A taxonomy of constraints is presented based on design considerations, source, context, strength, and use. The taxonomy is developed from observations of two sets of real-time protocol data of mechanical designers, along with the work of other researchers. The taxonomy begins to explain the nature of constraints. A hypothesis of how introduced constraints affect design quality is also presented. Finally, a more specific definition of satisficing is developed based on an experiment demonstrating constraint satisfaction.
