Knowledge Bases with Output

In this paper we shall propose a knowledge representation method, the deduction process in a knowledge representation and reasoning system using this method and therefore the answer function of such a system. This is an algebraic method because some concepts of universal algebra are used. More precisely, we introduce the concept of knowledge base with output (KBO), the central structure being that of labeled stratified graph. For such a base we distinguish a structure and two kinds of computations. The structure is described by a labeled stratified graph and an output space. The computations in a KBO are represented by two levels: syntactic and semantic. Both the syntactic and the semantic computations in a KBO are described in this paper. Finally, we exemplify all the concepts and we apply the method to solve a given problem in travel scheduling. All the theoretical results are proved in a separate section. Received 17 May 1999 / Revised 30 January 2000 / Accepted 5 April 2000     

Effect of subcutaneous recombinant human erythropoietin in cancer patients receiving radiotherapy: final report of a randomized, open-labelled, phase II trial

The purpose of this study was to determine the safety, efficacy and impact on quality of life of recombinant human erythropoietin (r-HuEPO) for cancer patients undergoing radiotherapy (RT). An open-labelled randomized design was used, with patients randomized to either treatment or control arms. Patients in the treatment arm received r-HuEPO given by subcutaneous injection at a dose of 200 units kg(-1) day(-1) plus oral iron supplements (ferrous sulphate 325 mg p.o. t.i.d.). Entry was restricted to patients with carcinoma of the lung, uterine cervix, prostate or breast who presented for RT with anaemia parameters reflective of 'the anaemia of chronic disease'. Radiotherapy policies (portals, doses, fraction size, etc.) were determined by the site and stage of disease. Complete blood counts (CBCs) were obtained weekly. The target level of haemoglobin was 15 g dl(-1) for men and 14 g dl(-1) for women. Quality of life (QOL) was assessed weekly by using an analogue scale to judge energy, activities of daily living and overall quality of life. Forty-eight patients were entered in the study, 24 in the treatment arm and 24 in the control arm. The prerandomization demographic characteristics and mean laboratory values were comparable in both arms. The mean haemoglobin at completion was 13.6 g dl(-1) for r-HuEPO-treated patients compared with 11.0 g dl(-1) for control subjects (P = 0.0012). Patients who received r-HuEPO demonstrated a mean weekly haemoglobin increase of 0.41 g dl(-1) compared with a decrease in mean haemoglobin level in controls for 6 of the 7 weeks of the study (mean weekly decrease of 0.073 g dl(-1)). Target levels of haemoglobin were achieved by 41.6% of r-HuEPO-treated patients compared with none of the control subjects. The mean platelet count declined in both arms of the study with RT but the decline from pretreatment was less rapid in r-HuEPO-treated patients (11.2% decrease) compared with controls (26.3% decrease) and was statistically significant during weeks 4-6. Toxicity was minor with only mild irritation at the injection site. Mean quality of life end points were superior in the treatment arm but not statistically significant. r-HuEPO had a beneficial effect on weekly haemoglobin levels in patients undergoing RT with response rates similar to other studies. There was also a less rapid decline in weekly platelet counts in r-HuEPO-treated patients compared with control subjects. Further studies are needed to address the optimum dose and scheduling as well as the impact of r-HuEPO on clinical outcomes.     

Emissions of a diesel engine using B20 and effects of hydrogen addition

The blended biodiesel with up to 20% biodiesel in petroleum diesel (B20) is considered nowadays as available in production. Previous studies investigating the effect of B20 on engine emissions led to some contradictory results. The present study continued the investigation on B20, 20% biodiesel (rapeseed methyl esters) blend effects and was also extended on B20 enriched with hydrogen. It was conducted on a conventional tractor diesel engine running alternatively with B20 and petroleum diesel at various speeds and full load and then, with the same fuels enriched with hydrogen, at 60% load and two speeds.     

Magnetic and dielectric properties of Co–Zn ferrite

Nanocrystalline powders of Co substituted Zn ferrite with the chemical formula Co_xZn_1−xFe₂O₄ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) were synthesized by sol–gel autocombustion method using tartaric acid as fuel agent. The samples were sintered in static air atmosphere for 7 h at 773 K, 7 h at 973 K and 10 h at 1173 K. The organic phase extinction and the spinel phase formation were monitored by means of Fourier transform infrared spectroscopy. The X-ray diffraction patterns analysis confirmed the spinel single phase accomplishment. Crystallite size, average grains size, lattice parameter and cation distribution were estimated. Magnetic behavior of the as-obtained samples by means of M-H hysteresis measurements was studied at room temperature. Permeability and dielectric permittivity at room temperature versus frequency was the subject of a comparative study for the Co_xZn_1−xFe₂O₄ series. In agreement with the proposed cation distribution the sample with Co_0.8Zn_0.2Fe₂O₄ formula exhibits the optimal magnetic and dielectric properties.     

On-line monitoring of airborne chemistry in levitated nanodroplets: in situ synthesis and application of SERS-active Ag-Sols for trace analysis by FT-Raman spectroscopy

We report a new strategy for on-line monitoring of chemical reactions in ultrasonically levitated, nanoliter-sized droplets by Raman spectroscopy. A flow-through microdispenser connected to an automated flow injection system was used to dose picoliter droplets into the node of an ultrasonic trap. Taking advantage of the flow-through characteristics of the microdispenser and the versatility of the automated flow system, a well-defined sequence of reagents could be injected via the microdispenser into the levitated droplet placed in the focus of the collection optics of the Fourier transform Raman spectrometer. In that way, chemical reactions could be carried out and monitored on-line. The developed system was used for fast, reproducible, in situ synthesis of a highly active surface enhanced Raman scattering (SERS) sol resulting from the reduction of silver nitrate with hydroxylamine hydrochloride in basic conditions. With this chemical system, SERS substrate preparation could be achieved at room temperature and in short time. The in situ prepared silver sol was used for trace analysis of several organic test molecules that were injected into the levitated SERS-active droplet again using the microdispenser. The concentration dependence of the SERS spectra was studied using 9-aminoacridine, revealing that down to the femtogram region high-quality SERS spectra could be obtained. Additionally, SERS spectra of 6-mercaptopurine, thiamine, and acridine were recorded in the levitated drop as well.     

Pulse propagation in finite elastic inhomogeneous media

The transfer matrix of a finite elastic bar is derived and the reflection and transmission functions are obtained. The matrix formalism is combined with Fourier component decomposition and applied to simulate acoustic pulse propagations in elastic inhomogeneous periodic and finite media. The numerical results are compared with experimental data to conclude about the validity of this method.     

Dynamisches Knicken des geraden Trägers unter Biegebeanspruchung

Zusammenfassung Ein frei aufliegender, in seiner Mitte von einer periodisch ver?nderlichen Einzellast in lotrechter Richtung beanspruchter Tr?ger führt nicht nur lotrechte Biegeschwingungen, sondern auch seitliche Biegeschwingungen und Drehschwingungen des Querschnitts aus. Wird die angreifende Kraft zu gro?, so tritt seitliches Knicken des Tr?gers ein. Aus einer Untersuchung des Schwingungsvorgangs in Verbindung mit einer Stabilit?tsbetrachtung lie? sich ein Stabilit?tsdiagramm herleiten, aus dem man entnehmen kann, unter welchen Bedingungen sich der Tr?ger stabil verh?lt.     

Complex Precursors for Doped Lanthanum Chromite Synthesis

Doped lanthanum chromites are investigated as ceramic interconnect materials to be used in high-temperature solid oxide fuel cells (SOFCs). This paper deals with the preparation of LaCr_1–x M _x O₃ (M = Ni, Cu, x = 0 – 0.2) from complex precursors isolated in the La(NO₃)₃-Cr(NO₃)₃-M(NO₃)₂-urea system. The isolated complex precursors were characterized by atomic absorption spectrometry, electronic, and FT-IR spectra, as well as, by thermal analysis. Doped lanthanum chromites, LaCr_1–x M _x O₃ (M = Ni, Cu) were prepared by calcining of corresponding urea-based precursors at 1000-1200°C for 2 h. Doped mixed-oxide samples were characterized by X-ray diffraction (XRD), Scanning electron-microscopy-energy-dispersive X-ray analysis (SEM-EDX), electrical conductivity, as well as magnetic measurements.     

ITO thin films deposited by advanced pulsed laser deposition

Indium tin oxide thin films were deposited by computer assisted advanced PLD method in order to obtain transparent, conductive and homogeneous films on a large area. The films were deposited on glass substrates. We studied the influence of the temperature (room temperature (RT)-180 °C), pressure (1-6 × 10^− 2 Torr), laser fluence (1-4 J/cm²) and wavelength (266-355 nm) on the film properties. The deposition rate, roughness, film structure, optical transmission, electrical conductivity measurements were done. We deposited uniform ITO thin films (thickness 100-600 nm, roughness 5-10 nm) between RT and 180 °C on a large area (5 × 5 cm²). The films have electrical resistivity of 8 × 10^− 4 Ω cm at RT, 5 × 10^− 4 Ω cm at 180 °C and an optical transmission in the visible range, around 89%.     

Development of inverse dynamic model for a surgical hybrid parallel robot with equivalent lumped masses

Robotic-assisted surgery is a continuously developing field, as robots have demonstrated clear benefits in the operating room. This paper presents the inverse dynamic model (in the case of using the laparoscope as a surgical instrument) and some characteristics of a 5-DOF hybrid parallel robot designed for minimally invasive surgery. The new inverse dynamic model is obtained using the virtual work method on the basis of dynamically equivalent lumped masses. The simulation and numerical results have been obtained for the experimental model of the developed PARASURG-5M robot, showing that the analytical inverse dynamic model could be used in the control of the robot. Finally, a comparison between the simulation data obtained in Matlab (IDM) with the simulation data through a Multi-body Simulation software (MBS), namely Adams (MBS) has been performed.