Automated development of Tarski's geometry

Tarski's geometry, a complete first-order axiomatization of Euclidean plane geometry, is developed within the automated reasoning system OTTER. Proofs are obtained and performance statistics supplied for most of the challenge problems appearing in the literature. Few of these problems have been previously solved by any clause-based reasoning system. Further challenges are offered.     

Fuzzy decision tables for expert systems

The use of fuzzy decision tables as a programming language for representing both the knowledge and the procedures in expert systems is discussed. Examples of their use for the generation of procedural code and for the generation of if-then rules are given.     

Ventilatory and arterial blood gas tension adjustments to strenuous exercise in standardbreds

Five healthy, fit Standardbreds (mean +/- SEM, 490.4 +/- 15.0 kg, 4.0 +/- 0.5 years) were studied during a standardized test carried out on a treadmill. The test consisted of an 8-minute warm-up and a 9-minute exercise period (1 minute at 1.7, 4, 7, 8, 9, and 10 m/s; 2 minutes at 4 m/s; and a 1-minute walk at a 6% slope). Respiratory airflow, tidal volume (V(T)), and respiratory frequency (f) were continuously recorded, using 2 ultrasonic pneumotachographs connected to a face mask and mass spectrometer. Oxygen uptake, carbon dioxide output, and expired minute volume (V(E)) were obtained on a breath by breath basis. Arterial blood was tested at the end of each step for O2 and CO2 partial pressures. Heart rate was continuously recorded, using a heart rate recording system. Stride frequency was measured at each step, and the stride frequency-to-f ratio was calculated. Venous blood was tested for plasma lactate concentration be fore and 2 minutes after completion of the test. Some horses had a locomotion-respiration coupling (LRC), but this coupling was occasional and intermittent. The f was lower and V(T) was higher than values reported for thoroughbreds working under similar experimental conditions. Nevertheless, maximal V(E) did not overshoot maximal V(E) reported in Thoroughbreds. All horses were hypoxemic and hypercapnic, but there was wide variability between subjects. The horses with the highest oxygen uptake and the lowest plasma lactate concentration were more hypoxemic and hypercapnic. The Standardbreds, studied under our laboratory conditions, did not have constant LRC and had lower f with higher V(T) than did Thoroughbreds under similar experimental conditions. Despite these differences in breathing strategy, the Standardbreds did not have higher V(E) than did Thoroughbreds, and they were hypoxemic and hypercapnic. The fact that these Standardbreds, which obviously freely selected their breathing strategy, were unable or unwilling to adopt compensatory hyperventilation reinforces the hypothesis that, in strenuous exercising horses, there could be a physiologic limit to ventilation, most probably related to mechanical factors, but independent of any LRC.     

为检验和调试串行数据信号完整性选择最佳工具

以往决定使用实时示波器还是等时“取样”示波器非常简单,测量高速信号取决于示波器的带宽。但是,由于实时示波器现在提供了双位带宽,所以用带宽决定使用实时示波器还是顺序取样示波器不再那么明显。现在,这两种仪器在工作范围方面有着很大的重叠,仅仅根据测量带宽制订决策会漏掉选择中许多微秒的利害关系。但     

Biodegradability study of copolyesteramides based on diacid chlorides,diamines, and diols

Copolyesteramides were synthesized by polycondensation of diacid chlorides, diamines, and diols of varying methylene group chain length. The composition of the synthesized polymer was determined with nuclear magnetic resonance (NMR) analysis. The biodegradation of the polymers was evaluated both with enzymatic hydrolysis and activated sludge test. The polymers were hydrolyzed with lipases from Rhizopus arrhizus, Rhizopus delemar, Candida cylindracea, and an esterase from hog liver, whereas trypsin and α‐chymotrypsin did not have any apparent effect upon them. Enzymatic hydrolysis was found to be greatly affected by the polymer composition and structure. The degradation results obtained from the activated sludge test were in satisfactory agreement with those from enzymatic hydrolysis. The water‐soluble parts of hydrolyzed products were more susceptible to degradation of their ester bonds rather than their amide bonds. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 774–784, 2002     

Arson detection model

The authors discuss the development of a mathematical model to be utilized for fire scene classification and improved detection of arson. The analysis covers all fires from 1975 to 1979 in Dade County, Florida. Note: This research was supported by Grant No. DF-80-AX-0011 awarded by the Law Enforcement Assistance Administration to the Office of the Dade-Miami Justice Council. Points of view or opinions stated in this article are those of the authors and do not represent the official position or policies of L. E. A. A.     

Toward a Discipline of Cyber Security: Some Parallels with the Development of Software Engineering Education

Coordinated programs of education are a powerful engine for social change. That is where the parallel between the evolution of software engineering education and the emerging discipline of cybersecurity is so instructive. This article traces the development of a commonly accepted curriculum for cybersecurity in reference to the emergence of software engineering as an academic discipline. Based on the parallels, it is concluded that cybersecurity is presently at an encouraging watershed.     

Changes in lignocellulosic supramolecular and ultrastructure during dilute acid pretreatment of Populus and switchgrass

Dilute acid pretreatment (DAP) is commonly employed prior to enzymatic deconstruction of cellulose to increase overall sugar and subsequent ethanol yields from downstream bioconversion processes. Typically optimization of pretreatment is evaluated by determining hemicellulose removal, subsequent reactivity towards enzymatic deconstruction, and recoverable polysaccharide yields. In this study, the affect of DAP on the supramolecular and ultrastructure of lignocellulosic biomass was evaluated. A series of dilute acidic pretreatments, employing ～0.10–0.20 mol/m³ H₂SO₄ at ～160–180 °C, for varying residence times were conducted on both Populus and switchgrass samples. The untreated and pretreated biomass samples were characterized by carbohydrate and lignin analysis, gel permeation chromatography (GPC) and ¹³C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. GPC analysis shows a reduction in the molecular weight of cellulose and change in its polydispersity index (PDI) with increasing residence time, indicating that pretreatment is actually degrading the cellulose chains. ¹³C CPMAS and non-linear line-fitting of the C₄ region in the carbon spectrum of the isolated cellulose not only showed that the crystallinity index increases with residence time, but that the lateral fibril dimension (LFD) and lateral fibril aggregate dimension (LFAD) increase as well.