A STATISTICAL-ECONOMIC FRAMEWORK FOR EVALUATING THE EFFECT OF ROBOT REPEATABILITY ON PROFIT

This paper presents a statistical-economic model for evaluating robot precision as measured by its positional repeatability. The model formulated assumes that repeatability follows a Rayleigh distribution. An economic measure maximizing the expected profit per unit time is developed, leading to an optimal velocity solution for a given task. Additional properties of the solution and sensitivity analyses are also provided. Finally, the model is validated by an empirical study of a simulated multi-station assembly operation with a PUMA robot that meets a random set of task requirements.     

A new empirical model to retrieve soil moisture and roughness from C-band radar data

A new empirical model for the retrieval, at a field scale, of the bare soil moisture content and the surface roughness characteristics from radar measurements is proposed. The derivation of the algorithm is based on the results of three experimental radar campaigns conducted under natural conditions over agricultural areas. Radar data were acquired by means of several C-band space borne (SIR-C, RADARSAT) or helicopter borne (ERASME) sensors, operating in different configurations of polarization (HH or VV) and incidence angle. Simultaneously to radar acquisitions, a complete ground truth data base was built up with different surface condition measurements of the mean standard deviation (rms) height s, the correlation length l, and the volumetric surface moisture M_v. This algorithm is more specifically developed using the radar cross-section σ⁰ (HH polarization and 39° incidence angle off nadir), namely, σ_0HH,39, and the differential (HH polarization) radar cross-section Δσ₀=σ_0,23°−σ_0,39° in terms of an original roughness parameter, Z_s, namely Z_s=s²/l, and M_v. A good agreement is observed between model outputs and backscattering measurements over different test fields. Eventually, an inversion technique is proposed to retrieve Z_s and M_v from radar measurements.     

Comparison between Supercritical CO2 Extraction and Hydrodistillation for Two Species of Eucalyptus: Yield,Chemical Composition,and Antioxidant Activity

In this work, 2 Eucalyptus species extracts (Eucalyptus cinerea and Eucalyptus camaldulensis) were prepared by hydrodistillation (HD) and supercritical carbon dioxide extraction (SCE) techniques. The best yields of E. cinerea and E. camaldulensis (27.5 and 8.8 g/kg, respectively) were obtained using SCE at 90 bar, 40 °C compared to HD (23 and 6.2 g/kg, respectively). Extracts were quantified by gas chromatography‐flame ionization detection and identified by gas chromatography‐mass spectrometry. 1,8‐cineole and p‐menth‐1‐en‐8‐ol were the major compounds of E. cinerea essential oil obtained by HD (64.89% and 8.15%, respectively) or by SCE (16.1% and 31.87%, respectively). Whereas, in case of E. camaldulensis, 1,8‐cineole (45.71%) and p‐cymene (17.14%) were the major compounds obtained by HD, and 8,14‐cedranoxide (43.79%) and elemol (6.3%) by SCE. Their antioxidant activity was assessed using 2 methods: 2,2‐azino‐di‐3‐ethylbenzothialozine‐sulphonic acid radical cation (ABTS^?+) and 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH^?). In the SCE extracts from both E. cinerea and E. camaldulensis, a promising radical scavenging activity was observed with ABTS^?+, (65 and 128 mg/L, respectively). The total phenolics composition of the extracts was measured and the range was 2 to 60 mg of gallic acid equivalent/g dry plant material. The SCE method was superior to HD, regarding shorter extraction times (30 min for SCE compared with 4 h for HD), a low environmental impact, allows production of nondegraded compounds and being part of green chemistry.     

Optimizing Graphene Oxide Encapsulated TiO2 and Hydroxyapatite; Structure and Biological Response

Nanocomposites based on hydroxyapatite (HAP) are fabricated with/without combining titanium oxide (TiO₂) and graphene oxide. Structure investigation was done for all compositions using X-ray diffraction (XRD), Fourier-transform infrared in addition to X-ray photoelectron to study the chemical compositions of the obtained nanocomposites. The surface morphology investigation was done with the scanning electron microscope and transmission electron microscope. In this regard, TiO₂ nanoparticles were exhibited in spherical shapes, while HAP was detected as nanorods. The dimensions of HAP have been decreased from 53 and 18 to 27 and 10 nm for length and diameter, respectively. The crystallite sizes obtained from XRD data are around 15 and 33 nm for HAP and TiO₂ respectively. Moreover, the diameter of TiO₂ reached 80 nm. Further, the average roughness parameter (R_a) improved from 9.2 to 11.1 nm from HAP to TNC. Besides, the root mean square (R_q), maximum height of the roughness (R_t), and maximum roughness valley depth (R_v) increased to 14.7, 104, and 55.9 nm, respectively. Furthermore, cell viability enhanced from 96.3?±?3 to 102.4?±?3%. Besides, the antibacterial behavior improved to be 15.3?±?1.3 and 14.2?±?0.9 mm for TNC against E. coli and S. aureus respectively.

     

The Capacitated p-facility Location Problem on the Real Line

The problem we address involves locating p new facilities to service a set of customers or fixed points on the real line such that a measure of total cost will be minimized. A basic form of this problem was investigated by Love (1976), who observed that the fixed points must be allocated in sequence to the new facilities in an optimal solution, and thus, the problem can be solved by a dynamic programming algorithm. Since then, other forms of the model have been investigated; however, in all cases it is assumed that the new facilities have unlimited capacity so that customer flows are always allocated to the nearest facility. The objective of this paper is to analyze the effect of capacity constraints on the optimal locations of the new facilities. A general fixed-cost function is also included to account for practical considerations such as zoning regulations, and to permit the facilities to be located anywhere on the line instead of only at the fixed vertices. A dynamic programming method is formulated to solve the problem when the variable cost components are increasing convex functions of travel distance. The problem is shown to be NP-hard under more general cost structures.     

Remote sensing and developing countries,training and technology transfer Europe-Africa

The use of space remote sensing is certainly important for developing countries, but the questions still remain of how to introduce it effectively and in the long term and what the contribution of training is.

This paper attempts to provide analysis on efforts in space remote sensing from developing countries, particularly Europe and Africa. It highlights two essential points: 1. The training. 2. The actual state of space remote sensing applications.

The study shows that the actual use of this technology in Africa is still rare in comparison to the number of trained participants. It also shows that there is no direct correlation between the percentages of those trained and the number of ongoing national projects.

It appears that a national and global policy is essential to ensure durability. Demonstrations, financial analysis and assessments are needed to sensitize the government decision-makers.     

The kinetic modelling of a steam distillation unit for the extraction of aniseed (Pimpinella anisum) essential oil

A simplified model that considered the oil constituents as one constituent, anethole, the major component, was used to describe the mass transfer of steam extraction of aniseed essential oil. The model can be used to optimise and control the process. Depending on the oil content, two mass transfer regimes were identified (i) the first one corresponds to an unsaturated surface extraction and (ii) the second corresponds to the slower transfer of oil from the deeper parts of the material to the surface, which may be due to concentration gradients and chemical bonding. The model was validated by experimental data obtained from a pilot‐plant system. Solid‐steam mass transfer coefficients were determined and a critical oil content was found to limit the two mass transfer regimes. The value for this critical oil concentration (x_B) was found to be 0.011 (g oil g^?1 solid). In addition, an optimal operating pressure of 200 kPa was found to give maximum extraction yield. Copyright © 2005 Society of Chemical Industry     

A decision analysis view of the effect of robot repeatability on profit

The purpose of this paper is to view recent developments in non-von Neumann and Morgenstern utility functions (vNM) via a stationary statistical-economic model. Such a model is suggested in the literature for evaluating robot precision, assuming that repeatability follows a Rayleigh distribution. Various vNM and non-vNM utility forms are discussed and illustrated for the robot evaluation and selection problem. The approach suggested here may be applicable for companies operating under profit centers where market systematic risk data are not available and decisions are based on the decision maker's (DM) attitude toward risk. Although the numerical illustrations demonstrate a consistency among the expected profit measure for most utility forms that were investigated, the analysis provides an extended framework for dealing with risky production problems. Furthermore, it illustrates the sensitivity of robot operational decisions such as speed and of both the output rate per time unit and the product quality to the DM's attitude toward risk. It allows the DM to analyze and explain decisions as affected by the selection of the utility form, as well as the technological and economic parameters and measures describing the problem, particularly the technical risk involved in the determination of a robot operational problem.     

An extended continuous maximal covering location problem with facility placement

In this paper we will discuss a formulation of the maximal covering problem when the facilities can be placed anywhere on the set R². A selection of such problems is given. In each case we shall see that the set of locations for facility placement can be reduced to a finite set. Lastly, one of the problems is then solved using an integer program formulation.