Choosing the appropriate ISO layer for LAN interconnection

The authors discuss the technical ramifications involved in the choice between interconnecting local area networks with a layer 3 (ISO network layer) versus layer 2 (ISO data link layer) approach, that is, routers versus bridges. They consider the distinction between two layers and define routers and bridges. They then argue the case for each. They conclude that neither approach is better, in the sense that each has its appropriate problem space, and suggest a mixture of relays     

A model of decision-making involving two information processors

Two assumptions which are generally made in decision theory are: (a) all the information necessary for decision-making is available, and thus the decision problem reduces to utilizing the information to make the best decision possible, and (b) the decision-maker is human, and if he is assisted in decision-making, the assistance is provided by humans. In this paper, we propose a model which does not make either of these assumptions. In the model, we consider information acquisition to be an integral part of the decision problem. Moreover, we consider the issue of the human and computer working jointly towards solving decision problems. Thus, the model explicitly considers the issue of more than one agent's performing information-gathering actions. The model also considers the impact of a time constraint on decision-making.     

Elastographic dynamic range expansion using variable applied strains

In elastography, we want to image the entire range of stiffnesses of the elastic components found in inhomogeneous tissues. In order to achieve this, the elastographic dynamic range should equal the entire stiffness dynamic range in the target. Various sources of noise limit the dynamic range of elastography. The recently-defined strain filter concept offers an analytical and graphical way of observing these limitations. In this paper, we describe a method that achieves the expansion of the elastographic dynamic range. It involves the application of variable strains in combination with selective storage of strain data that have optimal elastographic signal-to-noise ratios. This expands the current dynamic range of elastography by orders of magnitude when compared to single compression elastography. The process is explained theoretically using the strain filter framework, and 1 D as well as 2D tissue simulations are used to corroborate the theory.     

Computer algorithms in power systems: from constructive methods totruncated fractals

It is shown that nonchaotic power system models can have complicated truncated fractal basin boundary structure. A brief survey of research in power system stability over the last five years is presented. Methods for assisting in teaching the basics of the theory with simple numerical examples at the senior level or a first year graduate course in engineering are outlined using computer techniques     

A theoretical framework for performance characterization of elastography: the strain filter

This paper presents a theoretical framework for performance characterization in strain estimation, which includes the effect of signal decorrelation, quantization errors due to the finite temporal sampling rate, and electronic noise. An upper bound on the performance of the strain estimator in elastography is obtained from a strain filter constructed using these limits. The strain filter is a term used to describe the nonlinear filtering process in the strain domain (due to the ultrasound system and signal processing parameters) that allows the elastographic depiction of a limited range of strains from the compressed tissue. The strain filter predicts the elastogram quality by specifying the elastographic signal-to-noise ratio (SNR(e)), sensitivity, and the strain dynamic range at a given resolution. The dynamic range is limited by decorrelation errors for large tissue strain values, and electronic noise for low strain values. Tradeoffs between different techniques used to enhance elastogram image quality may also be analyzed using the strain filter.     

Prognostic factors in erythrodermic mycosis fungoides and the Sézary syndrome

BACKGROUND AND DESIGN: There are no large studies evaluating patients with erythrodermic mycosis fungoides and Sézary syndrome to determine the important prognostic factors that may influence survival. This is important since new treatment modalities have been proposed as superior to existing primary therapies. We performed a retrospective cohort study of 106 patients with erythrodermic mycosis fungoides and Sézary syndrome, followed up in the Stanford (Calif) Mycosis Fungoides Clinic, to define the important prognostic factors in this group. RESULTS: Patients younger than 65 years have a more favorable survival profile than those 65 years or older (P < .005). Longer duration of symptoms before diagnosis ( > or = 10 years) tends to be associated with more favorable prognosis (p = .055). Lymph node stage is significantly correlated with survival; patients with overall stage III disease have more favorable prognosis than those with stage IV disease (P < .001). Patients with circulating Sézary cells in their blood have a significantly worse prognosis than those without (P < .005). Patient sex or race had no significant effect on overall survival outcome. Three distinct prognostic groups were identified, "favorable," "intermediate," and "unfavorable," according to the number of unfavorable prognostic factors (P < .005). The median survival in each group is 10.2, 3.7, and 1.5 years, respectively. CONCLUSIONS: In patients with erythrodermic mycosis fungoides and Sézary syndrome, the important prognostic factors are patient age at presentation, the overall stage, and peripheral blood involvement. Survival varies widely, depending on these variables. These prognostic factors should be evaluated when analyzing survival and/or treatment efficacy data of these patients.     

Surface adsorption and anticorrosive behavior of benzimidazolium inhibitor in acid medium for carbon steel corrosion

Corrosion inhibition property of a newly synthesized 3-(4-chlorobenzoylmethyl) benzimidazolium bromide inhibitor against carbon steel corrosion in 1 N hydrochloric acid solution was studied and analyzed utilizing various electrochemical methods. Electrochemical impedance study inferred that the inhibition efficiency increased with increasing inhibitor concentration and give 93.5% at 250 ppm. Potentiodynamic polarization study emphasized that inhibitor acted as a mixed type inhibitor and the adsorption of inhibitor on the metal surface followed Langmuir adsorption isotherm. The noise results were in good correlation with other electrochemical results obtained. The increase of inhibition efficiency with concentrations of inhibitor is attributed to the blocking of the active area by the inhibitor adsorption on the metal surface. The thermodynamic parameter values were calculated and discussed to explain the adsorption mechanism of inhibitor in an acidic medium. The protective surface morphology governed by the inhibited medium was investigated using the scanning electron microscopic technique. The surface roughness of the sample in the absence and presence of inhibitor was obtained using atomic force microscopic study. The effect and reactivity of the inhibitor are further clarified with quantum chemical analysis. Finally, the corrosion protection mechanism is proposed on the ground of experimental and theoretical studies.

Graphical abstract

     

Low cost anodic bonding for MEMS packaging applications

Anodic bonding of Pyrex 7740 glass to bare silicon and oxidized silicon wafer is presented for micro electro mechanical systems (MEMS) device packaging. Experimentally it has been observed that anodic bonding process parameters are varying with different 3D structures. The effects of bonding temperature and voltage are discussed by keeping the temperature constant and varying the voltage. The bonding interface has been studied by scanning electron microscope observations. Effective parameters for MEMS structure such as bonding temperature, voltage has been discussed.     

Melt rheology and elasticity of natural rubber—ethylene–vinyl acetate copolymer blends

The melt rheology of blends of natural rubber (NR) and ethylene–vinyl acetate copolymer (EVA) has been studied with reference to the effects of blend ratio, cross-linking systems, shear stress, and temperature. When EVA formed the dispersed phase, the viscosity of the blends was found to be a nonadditive function of the viscosities of the component polymers at lower shear region, i.e., a positive deviation was observed. This behavior has been explained based on structural buildup of dispersed EVA domains in the continuous NR matrix. The effect of the addition of silica filler on the flow characteristics of the blends has been investigated. The melt elasticity parameters such as die swell, principal normal stress difference, recoverable shear strain, and elastic shear modulus of NR–EVA blends were also evaluated. © 1993 John Wiley & Sons, Inc.     

A Heavy Lift Planning System for Crane Lifts

This paper presents the work done toward developing a computerized heavy lift planning system (HELPS) for planning crane lifts. Initially, a survey of the industry was carried out to define the heavy lift planning process and identify the developments necessary to improve the process. This survey identified eight tasks in the lift planning process. Based on these tasks, a logical framework representing the planning process was developed. The scope of the current work was limited to developing a tool for planning three of these tasks. A visualization environment—Walkthru—was selected to implement the heavy lift planning system. Although Walkthru provided many of the features required for the system, critical functions had to be added. The developmental work for this study focused on (1) developing a shell that could control the visualization environment and related files to provide seamless access to the library of cranes and (2) providing features to perform critical lift planning functions. The resulting prototype system was tested on sample lifts, and all the functions worked as designed.