Singular value decomposition in multidimensional arrays

In this paper, an attempt is made to extend the method of singular value decomposition (SVD) to multidimensional (m-D) arrays (tensors). For the sake of brevity the whole study refers to a 3-D array. The 3-D array is transformed to a 2-D array by unifying two dimensions into one. Then, the SVD method is applied to this 2-D array. Afterwards, the unified dimensions are separated and we apply new SVDs. Finally, decomposition of the 3-D array into three dimensions is achieved. An example showing the effectiveness of the method is also presented.     

Changing the way UK cities are built: The shifting urban policy and the adaptation of London’s housebuilders<Superscript>1</Superscript>

This paper summarises recent trends in UK housebuilding and tries to place them within the wider context of the changes in housing provision in the UK. Based on relevant management literature it argues that recent changes in British urban policy, related to the types of land released and types of development promoted, have significant effects on housing production in the UK. Some indications of those changes are already visible in the type of industry outputs and in the practices of emerging industry leaders.     

STRUCTURAL SHAPE OPTIMIZATION USING EVOLUTION STRATEGIES

The objective of this paper is to investigate the efficiency of combinatorial optimization methods and in particular algorithms based on evolution strategies, when incorporated into shape optimization problems. Evolution strategy algorithms are used either on a stand-alone basis, or combined with a conventional mathematical programming technique. The numerical tests presented demonstrate the computational advantages of the proposed approach which become more pronounced in large-scale optimization problems and/or parallel computing environment.     

Communication protocol for a local network based on code division multiplexing

A communication protocol for a local network that handles voice signals and uses ‘direct sequence spread spectrum’ techniques ( DS-SS), is presented. The control of the protocol is distributed among the network users, providing them with the capability for full-duplex communication and successful channel acquisition without data collisions. The access of the single communication channel by any user of the network and the routing of calls are based on the detection of the number of the decoded signal levels. The implementation of the network is simplified with the use of a single code per communication. The protocol operation ( including the call scheduling and signalling processes) that generates all the signals necessary for communication in the network ( ring, idle, busy) is described in detail.     

Spinodal Decomposition in Tetragonal Systems: SnO2-Tio2

Expressions are given for the coherency-strain elastic free energy of systems with tetragonal symmetry in the framework of the continuum theory. This theory is applied for SnO₂-TiO₂ and the results are compared with known experimental observations. Calculations for other tetragonal systems are also presented. Finally, the results of these calculations for systems of tetragonal symmetry are discussed in the light of the Cahn and Hilliard theory of spinodal decomposition.     

MAINTAINING POSTHARVEST QUALITY OF THE TOMATO FRUIT BY EMPLOYING METHYL JASMONATE AND ETHANOL VAPOR TREATMENT

ABSTRACT

The postharvest quality of tomato fruit (Lycopersicon esculentum L.) was evaluated after treatment with natural volatile compounds (methyl jasmonate [MJ] or ethanol) and storage at 13C during or following vapor exposure. The fruit treated with natural volatiles did not differ on fruit decay during vapor exposure, but following exposure and transfer to ambient air, the fruit had less decay at storage temperature. Volatile‐treated fruit tended to maintain firmness during exposure, and the effects were significant for ethanol‐treated fruit, following storage to ambient air. Sugar (i.e., fructose and glucose) concentration was stimulated in ethanol‐treated fruit following exposure and transfer to ambient air. Ascorbic acid concentration was stimulated in MJ‐treated fruit during exposure and persisted (including ethanol treatment) following transfer to ambient air. Total phenolics declined during vapor exposure and increased for MJ‐treated fruit after transfer to ambient air. Lycopene concentration did not differ during MJ exposure but increased following volatile exposure. The fruit samples treated with vapors had accelerated percentage weight loss compared with untreated fruit during ripening but without commercial interest, whereas citric acid content did not differ among the treatments. The results suggest that MJ and ethanol vapor may improve fruit quality‐related attributes on top of the well‐documented antimicrobial protection during fresh produce storage and transit.

PRACTICAL APPLICATIONS

The data presented in this work suggest that the use of natural volatiles is an innovative and useful tool as an alternative to the use of synthetic fungicides or other sanitation techniques in storage/packaging. Vapor enrichment may reduce disease development with a major contribution to limiting the spread of the pathogen by lowering the spore load (spore production) in the storage/transit atmospheres as well as the use of natural volatiles as an alternative food preservative. In addition to these, the improvement of fruit quality observed in the present work is of great market importance. The effects of natural compounds on individual microorganisms (fungi and bacteria), both responsible for spoilage and foodborne pathogens, as well as the minimum concentration to gain effectiveness without affecting fresh produce quality and storage deserve further research.

     

MODELING AND CONTROL OF CONTINUOUS DIGESTERS USING THE PLS METHODOLOGY

The partial least squares (PLS) methodology is a regression tool able to deal with two important problems in system identification: the noise contained in the industrial data and the correlations that are observed among the input variables. In this article, the PLS technique is applied on real industrial data to produce dynamical multi-input single-output (MISO) models of the behavior of the kappa number in a continuous digester with respect to the important input variables that can be measured on-line. The ultimate goal is the development of a model predictive control (MPC) scheme that can be used for keeping the kappa number of the produced pulp close to the desired set point. We show that a modification in the standard MPC algorithm is needed in order to take into account the correlations among the input variables.     

Wear Testing of Seals in Magneto-Rheological Fluids©

Magneto-rheological (MR) fluid-based dampers can be used in suspensions to modify ride, handling, and suspension frequencies in autos. We have developed a unique seal wear test method to simulate the wear of rod seals in Magneto-rheological fluid-based dampers. In this test, seal material samples in the form of rectangular coupons are immersed in a bath of MR fluid, and a section of the rod is brought into contact with the seal coupon. The rod is loaded against the coupon with a known normal force, and a variable-frequency reciprocating machine is used to stroke the rod back and forth across the material coupon surface. Test conditions such as normal load, frequency and amplitude of oscillation, and temperature are adjusted to simulate desired conditions. This bench test method ranks various seal materials qualitatively in the correct order (as determined in field tests with these seal materials) in terms of wear and abrasion resistance and constitutes a valid test procedure for the screening of seal materials, MR fluids, and rod surface coatings.