Low-cost,Concurrent Checking of Pointer and Array Accesses in C Programs

Illegal pointer and array accesses are a major cause of failure for C programs. We present a technique called ‘guarding’ to catch illegal array and pointer accesses. Our implementation of guarding for C programs works as a source-to-source translator. Auxiliary objects called guards are added to a user program to monitor pointer and array accesses at run time. Guards maintain attributes to catch out of bounds array accesses and accesses to deallocated memory. Our system has found a number of previously unreported errors in widely-used Unix utilities and SPEC92 benchmarks. Many commonly used programs have bugs which may not always manifest themselves as a program crash, but may instead produce a subtly wrong answer. These programs are not routinely checked for run-time errors because the increase in execution time due to run-time checking can be very high. We present two techniques to handle the high cost of run-time checking of pointer and array accesses in C programs: ‘customization’ and ‘shadow processing’. Customization works by decoupling run-time checking from original computation. A user program is customized for guarding by throwing away computation not relevant for guarding. We have explored using program slicing for customization. Customization can cut the overhead of guarding by up to half. Shadow processing uses idle processors in multiprocessor workstations to perform run-time checking in the background. A user program is instrumented to obtain a ‘main process’ and a ‘shadow process’. The main process performs computations from the orignal program, occasionally communicating a few key values to the shadow process. The shadow process follows the main process, checking pointer and array accesses. The overhead to the main process which the user sees is very low – almost always less than 10%. © 1997 by John Wiley & Sons, Ltd.     

Manufacturing quality density,control and maintenance

The purpose of this paper is to define conceptually and operationally, a measure of quality density in manufacturing. This is expressed in terms of a manufacturing process propensity to ‘output’ units which are defectives, as a function of the manufactured production output, the manufacturing deterioration process, maintenance, quality control, and generally the risks a manufacturing process is subjugated to. Particularly, we assume that the production process induces ‘shocks’ which lead to poorer manufactured quality, while maintenance efforts are continually being employed to restore the process propensity to produce units of better quality. Quality control is used then to monitor the output quality of units produced. Using a methodology of level crossing in stochastic point processes, the stationary probability distribution of a manufactured output quality is defined. Applications to production quality management, combined quality and maintenance management, as well as quality control are considered. Finally, an exponential shock model is resolved analytically.     

FILTER INLET VELOCITY REDISTRIBUTION WITH FILTER LOADING

ABSTRACT

Previous flow visualizations and laser Doppler anemometer velocity measurements have shown that clean engine air filters are presented with very non-uniform velocity distributions when tested in the SAE universal panel Filter test housing. Experiments were conducted to measure the changes that occur in the velocity distribution in the plane 12.7 mm upstream of the filter as it is loaded with dust. Laser Doppler anemometer measurements of velocity profiles were performed for a production engine air Filter in the SAE universal panel filter test housing. Test conditions corresponded to a clean Filter, and dust-loaded Filters at additional pressure drops corresponding to 50 percent, 100 percent, and 150 percent of the design terminating pressure value. The results show that dust loading does make the velocity profiles less non-uniform, but that the changes are not dramatic. The inlet velocity profiles for the design capacity Filter remain very non-uniform.     

Formation of vitisin A during red wine fermentation and maturation

During alcoholic fermentation the formation of vitisin A occurred mainly in the period between 20% and 85% glucose utilisation, when the concentrations of the precursors, malvidin-3-glucoside and pyruvic acid were at a maximum. The maximum rate of vitisin A synthesis of 11 mg/Lh occurred when 57% of glucose had been utilised and 440 mg/L malvidin-3-glucoside, 114 mg/L pyruvic acid and 3.1 mg/L measured oxygen were present. During maturation, production of vitisin A appeared to be linked with the availability of a suitable oxidant. Synthesis of vitisin A continued for approximately 6 months of maturation in air-tight bottles while the precursors were available. In wines that underwent malolactic fermentation, the malolactic bacteria consumed pyruvic acid and thereby limited the production of vitisin A. At the end of a 12 month maturation period, the concentration of vitisin A declined in wines made without any malolactic fermentation, even though malvidin-3-glucoside and pyruvic acid were still present. This indicated that there was a shortage of a suitable oxidant required to complete the reaction.     

EFFECT OF SPLEEN IN RESTRUCTURED BEEF

Boneless beef chucks were converted to restructured beef steaks and formulated with 1% NaCl and 0.25% sodium tripolyphosphate (STP). Experimental treatments included (1) control-frozen, (2) control-5 days storage at 0°C, (3) 1% spleen pulp-frozen and (4) 1% spleen pulp-5 days storage at 0°C. Treatments 2 and 4 were evaluated only after storage for 5 days; whereas, treatments 1 and 3 were studied at 5 and 70 days. Spleen pulp enhanced (P<0.05) color development during frozen storage for a short period but offered no (P>0.05) contribution to color preservation during prolonged storage. Visual color and overall appearance were affected more by storage time and conditions than by the addition of spleen pulp. Spleen pulp had no effect (P>0.05) on product cohesiveness, texture, tenderness and flavor of frozen restructured beef steaks but improved the tenderness of unfrozen samples.     

Specific Heat, Thermal Conductivity, Density, and Thermal Diffusivity of Mexican Tortillas Dough

A split-split unit experiment was conducted and analyzed to determine the specific heat, thermal conductivity, density, and thermal diffusivity of Mexican corn-based tortillas dough (MCTD) as a function of processing time, temperature, and moisture content (wb). The data indicated that thermal conductivity and thermal diffusivity were significantly influenced by processing time, and respective components of temperature and moisture content. Specific heat and density varied with levels of moisture content and temperature. Thermal conductivity, specific heat, density, and thermal diffusivity could each be predicted separately by a polynomial equation.     

PREDICTION OF FLOUR EXTRACTION RATE IN HARD RED WINTER WHEAT USING THE SINGLE KERNEL CHARACTERIZATION†

Flour extraction rate is a key determinant in milling efficiency and profitability and can be useful in projecting flour output from a mill. Wheat is generally purchased based upon a small group of traditionally measured physical characteristics. This article explores the use of the Single Kernel Characterization System (SKCS) to predict flour extraction rate. Regression analysis was performed using the SKCS parameters and test weight against flour extraction rate for over 600 observations from multiple years from the hard red winter wheat production areas of the U.S. The regression equation had an R²of 0.81. The data suggest that the SKCS 4100 and test weight can be used to predict flour extraction rate in hard red winter wheat. Using the regression equation as a tool, mill buyers may be able to make better decisions regarding their wheat purchases and prediction of flour output.     

Reduction of Bitterness and Tartness in Grapefruit Juice with Florisil

Treatment of commercial grapefruit juice with Florisil (activated magnesium silicate) simultaneously reduced the content of citric acid and the bitter compounds limonin and naringin. Ascorbic acid concentration and °Brix (total soluble solids) were not altered by the Florisil treatment. Experienced taste panelists were able to differentiate between the nontreated and Florisil-treated juice on the basis of bitterness and tartness (acidity). The panelists indicated a preference for the Florisil-treated juice.     

Variation in Myoglobin Denaturation and Color of Cooked Beef, Pork, and Turkey Meat as Influenced by pH, Sodium Chloride, Sodium Tripolyphosphate, and Cooking Temperature

This study investigated the effects of pH (5.50–7.00), sodium chloride concentration (0.0–3.0%), and sodium tripolyphosphate concentration (0.0 and 0.5%) on the percent myoglobin denatured (PMD) in beef, pork and turkey muscle when heated to temperatures between 55 and 83°C. At most temperatures studied, the presence of sodium chloride and sodium tripolyphosphate increased the PMD. In contrast, high pH markedly decreased the PMD (P<0.05). The effect of pH on PMD was similar for all three species studied and, in all cases, was sufficient to produce obvious color differences in the cooked muscles.     

Mechanically Separated Spleen: Its Composition and Protein Efficiency Ratio

Beef spleens were freed of undesirable capsular and internal connective tissue by passage through a Beehive Model AU 4171 deboner fitted with a desinewing head. The resulting product (called mechanically separated spleen or MSS) was recovered at a 79% yield and contained 17.0% protein, 2.9% fat and 762 ppm iron. The effect of mechanical separation on protein quality was determined by protein efficiency ratio (PER). Rats fed MSS and whole spleen diets exhibited significantly greater weight gains than those fed casein. PER values for whole spleen (2.4) and MSS (2.3) were not significantly different. The PER value for casein (2.5) was significantly higher than that of MSS but not whole spleen.