An empirical approach to evaluating dependency locality in hierarchically structured software systems

In software development, especially component-based software development, dependency locality states that relevant software components should be at shorter distances than irrelevant components. This principle is used together with modularity and hierarchy to guide the design of large-scale complex software systems. In previous work, dependency locality and its correlation with design quality were studied by statically measuring the interactions between software components. This paper presents an empirical approach to evaluating the hierarchical structure of software systems through mining their revision history. Two metrics, spatial distance and temporal distance, are adapted to measure the dependencies between software components. The correlation of spatial distance and temporal distance between software components represents a factor that influences system design quality. More specially, a well designed system hierarchy should have a significant positive correlation while a non-significant positive correlation or a negative correlation would signify design flaws. In an application of this approach, we use Mantel test to study the dependency locality of six software systems from Apache projects.     

Analysis of network processing workloads

Network processing is becoming an increasingly important paradigm as the Internet moves towards an architecture with more complex functionality in the data path. Modern routers not only forward packets, but also process headers and payloads to implement a variety of functions related to security, performance, and customization. It is important to get a detailed understanding of the workloads associated with this processing in order to be able to develop efficient network processing engines. We present a tool called PacketBench, which provides a framework for implementing network processing applications and obtaining an extensive set of workload characteristics. For statistics collection, PacketBench provides the ability to derive a number of microarchitectural and networking related metrics. We show a range of workload results that focus on individual packets and the variation between them. The understanding of workload details of network processing has many practical applications. We discuss how PacketBench results can be used to estimate network processing delay that are very close to those obtained from measurement.     

1-O-acyl derivatives of glucose as non-penetrating inhibitors of glucose transport by hamster small intestine in vitro

1-O-acyl derivatives of glucose are not transported by the hamster small intestine in vitro. These derivatives, however, are potent inhibitors of the glucose transport system. 1-O-Decanoyl glucose is a competitive inhibitor of beta-methyl glucoside transport.     

Role of Biomaterials and Controlled Architecture on Tendon/Ligament Repair and Regeneration

Engineering synthetic scaffolds to repair and regenerate ruptured native tendon and ligament (T/L) tissues is a significant engineering challenge due to the need to satisfy both the unique biological and biomechanical properties of these tissues. Long-term clinical outcomes of synthetic scaffolds relying solely on high uniaxial tensile strength are poor with high rates of implant rupture and synovitis. Ideal biomaterials for T/L repair and regeneration need to possess the appropriate biological and biomechanical properties necessary for the successful repair and regeneration of ruptured tendon and ligament tissues.     

Ohmic Heating Behaviour of Cabbage and Daikon Radish

Shredded cabbage (50 % v/v) and Daikon radish cubes (57 % v/v) with different salt concentrations (0.15, 0.5, 1, 1.5, and 1.85 %) were heated from 30 to 70 °C in a static ohmic heating cell at different voltages (65, 80, 100, 120, and 135 V) and frequencies (60, 2070, 5030, 7990, and 10,000 Hz) to evaluate their ohmic heating behaviour. Radish heated under 1.5 % salt, 120 V and 7990 Hz or 1 % salt, 135 V and 5030 Hz conditions gave the shortest heating time of 6 min from 30 to 70 °C, and cabbage gave the longest time of 128 min at 0.15 % salt, 100 V, and 5030 Hz. Regression models of heating rate as a quadratic function of the sample temperature gave R² >0.98. The general trend observed was that the magnitude of the heating rate increased with frequency at high voltage but decreased at low voltage for cabbage, while the opposite trend was observed for radish. Heating was more efficient at higher salt concentration and applied voltage. Radish heated more rapidly than cabbage. A slight slope change was observed in all cases between 50 and 60 °C. The response surface models revealed linear, cross products and quadratic effects to be significant with R ² over 0.98.     

Magnetic resonance imaging of water freezing in packed beds cooled from below

Full-field quantitative visualization of freezing interfaces requires the introduction of high resolution noninvasive methods. Magnetic resonance imaging (MRI) is a versatile tool for mapping the distribution of liquids (primarily water) in three-dimensional space, and is the only practical solution in systems that are strongly refracting or opaque to visible light. MRI is employed to visualize ice formation in water-saturated packed beds consisting of spherical beads packed in a cylindrical cavity and cooled from below. Imaging of the stagnant interstitial water is accomplished by exploiting the strong contrast in proton spin density signal between interstitial ice and liquid water. Our implementation of MRI allows fully three-dimensional reconstruction of the solidification front and adequate time resolution to quantify the freezing of pore water. The effect of pore space heterogeneity near the lateral walls of the cavity, as expressed by the ratio of bed to bead diameter, is examined with respect to the shape and propagation rate of the freezing interface. A modification of the test section also allows the study of freezing in pure water which is used for comparison. The present work demonstrates the kind of extra provisions in terms of design and choice of materials of the test section that are necessary in order to accommodate the special environment of the MRI scanner in heat transfer applications.     

Method to Characterize the Air Flow and Water Removal Characteristics during Vacuum Dewatering. Part I—Experimental Method

An experimental method using a novel design to characterize the air flow and water removal during vacuum dewatering in paper manufacturing is discussed. The experimental setup involves the intermittent application of vacuum, similar to commercial systems, using a rotating disk with slot opening arrangement. The system is capable of commercially realistic residence times of the order of milliseconds. The intermittent application of vacuum simulates vacuum dewatering on commercial paper machines. The air flow rate is calculated from changes in pressure and temperature in the vacuum tank underneath the sample. The role and importance of air flow during vacuum dewatering is studied by accurately measuring the air flow, properly taking into account the leaks during vacuum dewatering. The method described here provides for the first time accurate air flow and water removal data during vacuum dewatering. Methods of analysis of the experimental data are also presented. This information can be used to better understand the water removal process as well the role and importance of air flow during vacuum dewatering.