Comments on ‘The phenomenon of homeopathic instability in dynamical systems’

Less restrictive sufficiency conditions on system parameters are developed for the existence of homeopathic instability in the class of dynamical systems considered by Johnson. With these conditions, the results are consistent with the earlier work of Youla el at., in particular in terms of the pole-zero interpretation of the sufficiency conditions. A typographical error in the work by Johnson is also noted.     

Strong separation of learning classes

Abstract

Suppose LC ₁ and LC ₂ are two machine learning classes each based on a criterion of success. Suppose, for every machine which learns a class of functions according to the LC ₂ criterion of success, there is a machine which learns this class according to the LC ₂ criterion. In the case where the converse does not hold LC, is said to be separated from LC ₂. It is shown that for many such separated learning classes from the literature a much stronger separation holds: (?𝒞∈LC ₁) (?𝒞' ∈LC ₂ - LC ₁(( [' ?𝒞] It is also shown that there is a pair of separated learning classes from the literature for which the stronger separation above does not hold. A philosophical heuristic toward the design of artificially intelligent learning programs is presented with each strong separation result.     

Supervisory control for co-ordination of multiple robots†

This paper deals with a solution of supervisory control problem for co-ordination of multiple robots. The application of two or more robots employed in a co-operating mode can increase the level of flexibility and productivity in an automated manufacturing environment. However, as the number of robots or the intricacy of task to be performed increases, the control requirements also increase substantially. Co-operating robots can be used in typically complex assembly operations where the payload may be too heavy for a single arm to handle; the object to be manipulated may be irregularly shaped and provide only limited access for physical handling, or the two parts to be assembled together may require simultaneous orientation and unique positioning.

The co-ordination control strategies developed were applied to two IBM 7540 SCARA robots. Several control schemes were devised to achieve concurrent robot co-ordination and trajectory tracking. A digital computer program operable on an IBM PS/2 System 80 provided multiple concurrent programming of the two robots. Interactive control strategy and master-slave control strategy were designed, implemented, optimized, and tested. The results showed excellent trajectory adherence and repeatability for both control schemes     

Absolute stability results for non-linear systems using logarithmic plots

Absolute stability of non-linear systems is examined using the conventional techniques, and a representation of Popov line in the logarithmic gain and phase versus frequency plane. A grapho-analytical procedure is advanced for the Popov line transference to the Bode plane. The technique may be used either as an analytical tool for investigating absolute stability of systems with specified non-linearity sector, or as a synthesis technique for compensator design. The application of the proposed method for substantiating compensator design results is illustrated by two examples.     

On postponement strategies for product families with multiple points of differentiation

Several researchers have studied the benefits of product and process design that calls for delaying the differentiation of products. Previous research has focused on products having only one point of differentiation. However, in reality most product families have several points of differentiation. In this paper, we develop two models to study products with more than one point of differentiation. In each model, we examine the benefits of delayed differentiation at each of these points, and derive the necessary conditions when one type of delayed differentiation is more beneficial than the other. Our analysis indicates that demand variabilities, correlations and the relative magnitudes of the lead times play an important role in determining which point of differentiation should be delayed.     

EFFECT OF PAPAYA PULP ADDITION ON THE GROWTH OF LACTOBACILLUS ACIDOPHILUS

Effect of papaya pulp addition to skim milk on the growth characteristics of five strains of Lactobacillus acidophilus was investigated. All the strains tested exhibited higher viable counts, shorter generation time, increased acid production, greater sugar utilization and fall in pH upon addition of papaya pulp. The generation time, acid production, sugar utilization and pH values at the end of 18 h fermentation of skim milk by different strains were 150–200 min, 0.29–1.73%, 0.39–2.22 g/100 mL and 3.85–6.10, respectively. The corresponding values for 10% papaya pulp added skim milk blend were 120–143 min, 0.51–1.84%, 0.70–2.79 g/100 mL and 3.70–5.10, respectively. Organoleptic evaluation revealed that papaya pulp addition imparted firmness to the coagulum and thus enhanced the acceptability of the product by eliminating the problem of wheying-off and improved flavor.     

Component spectroscopic properties of light-harvesting complexes with DFT calculations

Photosynthesis is a fundamental process in biosciences and biotechnology that influences profoundly the research in other disciplines. In this paper, we focus on the characterization of fundamental components, present in pigment-protein complexes, in terms of their spectroscopic properties such as infrared spectra, nuclear magnetic resonance, as well as nuclear quadrupole resonance, which are of critical importance for many applications. Such components include chlorophylls and bacteriochlorophylls. Based on the density functional theory method, we calculate the main spectroscopic characteristics of these components for the Fenna-Matthews-Olson light-harvesting complex, analyze them and compare them with available experimental results. Future outlook is discussed in the context of current and potential applications of the presented results.     

The textural properties of soy paneer

Toned dairy milk and soy milk were mixed in different proportions and coagulated at various temperatures to produce paneer blends, and their textural properties were evaluated. As the soy milk proportion in the blend increased from 0% to 50%, hardness, cohesiveness and chewiness of the samples decreased initially, but further increase in the blend from 50% to 100% cause these values to increase slightly. The proportion of soymilk in the prepared paneer had a significant effect on hardness, cohesiveness, adhesiveness, chewiness and yield, whereas the coagulation temperature affected cohesiveness and yield. The process parameters did not show any effect on the springiness.     

Transmittance Study of a Tubular Cover Collector

Transmittance of a tubular cover collector has been calculated for a particular orientation. Tilt of the collector is optimised for the four typical days (two equinoxes and two solstices) at Delhi and Madras, a high and low latitude station respectively. Only the two nearest neighbouring tube elements are considered, in order to take into account the shadowing effect. In the present system, where the thickness of the tube and the flat glass sheets, has been taken to be the same, the transmittance of the tubular cover has been found to be comparitively less than that of a cover formed by two parallel sheets of window glass. However, because of its cylindrical geometry, very thin glass tubes can be used for all practical purposes, thereby, increasing the transmittance to a great extent. It has also been concluded that for all tubular covers including this system, hour angle instead of angle of incidence is an exact parameter to study the variation of effective transmittance. The difference in the mode of variation of transmittance with hour angle in the present system, with that in case of tubular collector, is attributed to the variation of average angle of incidence (local) with hour angle.