Pain Sensations Associated with Electrocutaneous Stimulation

This paper discusses the results of experiments carried out to determine the feasibility of using electrocutaneous stimulation in sensory substitution systems. The sharp, pricking pain often associated with electrocutaneous stimulation has been found to be a result of thermal damage to the corneal layer of the skin. The high-energy densities required to create this damage often occur, even at moderate stimulation currents, because of the highly nonhomogeneous nature of the skin-electrode interface. However, this pain can be controlled without resorting to electrode pastes by adopting a simple procedure for applying the electrode. The dynamic range and the stability of the sensation magnitude have been measured under paste-free conditions and the conclusion is reached that electrocutaneous stimulation would be a viable alternative to mechanical stimulation in certain sensory substitution applications.     

Optimal Switch-Concentrator Location for a Telephone Network

This paper considers the problem of the optimal introduction of digital switching equipment into an existing analog local telephone network. The criterion used is the present worth of annual charges. Using certain plausible assumptions, this multilocation dynamic problem is shown to reduce to an equivalent static problem. The latter can be expressed as a classical plant location problem for which several solution techniques are available in the operations research literature.     

Fiberoptic circuit network design under reliability constraints

A general mathematical model for a network design problem with reliability constraints and a revised formulation which seems particularly appropriate for fiber-optics networks is presented. Upper and lower bounding procedures based on continuous relaxations of this modified formulation are described. Preliminary computational results are reported. Limited computational results indicate a good performance of the algorithm, producing a gap between lower and upper bounds that is sufficiently small for a branch-and-bound procedure to be applicable     

An approximate performance model for a multislot integratedservices system

An approximate model (with finite or infinite waiting room) is presented for an integrated service system with three types of traffic: a first-offered narrowband traffic, an overflow narrowband traffic, and a wideband traffic. A narrowband call requires a single server, while the number of servers required to serve a wideband call is N. The blocked narrowband calls are lost while the blocked wideband calls are delayed in a finite or infinite waiting room. Based on two assumptions with regard to the characteristics of the system, the system is resolved by decomposition. The corresponding improvements in numerical efficiency as well as in computational storage requirements are significant enough to enable use of the model within network optimization algorithms. The model provides a very good approximation for the system performance, i.e. the blocking probabilities of the two narrowband traffics, the loss probability (in the case of finite waiting room), the probability of nonwaiting, and the average waiting time of wideband traffic     

Speed in test performance in depressed patients.

Compared the performance of 2 groups of nonschizophrenic, nonorganic, psychiatric patients—25 depressed (mean age 41.4 yrs) and 25 nondepressed (mean age 37.8 yrs) Ss—on several tests, including the Quick Test, the WAIS, and 10 speed tests and measures of ambiguous figure reversal rates. The 2 groups of Ss were matched for general psychopathology, sex, age, and education. No difference in the performance on power-cognitive (i.e., intelligence) tests was found. Depressed patients performed more slowly on psychomotor speed tests, confirming an earlier study comparing depressed patients and normal controls. Findings generally confirm those of the 1st author et al (1972) and those of several earlier studies summarized by W. R. Miller (see record 1975-20082-001). (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Law,Exposed

To help resolve a wider spectrum of disputes, Brazil enacted its first Mediation Law on June 26, to take effect in 180 days.