Weapons systems analysis,Part III: Warfare gaming,tactics and techniques

Survivability has an expensive price tag. The reliability and continuing improvements in accuracy, cost effectiveness (cost/kill) and speed of precision guided munitions (PGM) will ultimately change warfare gaming tactics and techniques in the near future. This paper identifies, analyzes and classifies various warfare campaigns with respect to strategy, techniques and tactics.     

Heat and mass transfer from a laminar humid air stream to a plate at subfreezing temperature

Processes involving the transfer of heat from a humid air stream in laminar flow to a horizontal plate with the simultaneous deposition of frost is of importance in a variety of refrigeration equipment. The accumulating frost layer impedes the heat flow to the cooling surface. The present study is carried out to determine both theoretically and experimentally the factors that influence, frost formation on a cold surface and to correlate the Nusselt and Sherwood numbers with these factors.Experiments were conducted on a 600 mm long, flat horizontal plate, the Reynolds number and the relative humidity of the impinging air stream were varied from 30 000 to 140 000 and from 40% to 60% respectively, while the average surface temperature was near - 18°C. Empirical correlations of the Nusselt number and Sherwood number are presented.     

System effectiveness criteria for the analysis of MX basing modes

Due to the increased accuracy of the Soviet Strategic Rocket Forces, the present U.S. silo based missiles are becoming more vulnerable to attack. One reason for creating MX missiles in the first place is to avoid this vulnerability of silos. It is imperative now that basing of MX missiles be reconsidered before committing billions of dollars to a defensive system that may turn out to be a Maginot line for the 1980s. This paper puts forward criteria such as survivability, cost, operational readiness, technical feasibility, etc., and methodologies that can be used for the analysis and evaluation of various basing modes which might keep the deployment of MX missiles effective.     

Development of an on-line stabilization method for local power systems with large-capacity generation plants

This paper presents an on-line stabilization control method developed with the aim of maintaining transient stability in a local power system which includes large-capacity generation plants. The characteristics of this method are that the power/angle curve is estimated from the on line active and reactive power measured at the generator terminal, and the optimum generation shedding for stabilization is determined by applying the equal area method to this curve. Simulation tests using detailed models of the power system confirmed that the optimum generation shedding for stabilization could be computed for various fault conditions, both symmetrical or asymmetrical. It was also determined that the on-line data could be sampled for several tens of milliseconds after clearing the fault. Thus, this method provides effective control logic for practical stabilizing systems.     

Group routing without group routing tables: an exercise in protocol design

We present a group routing protocol for a network of processes. The task of the protocol is to route data messages to each member of a process group. To this end, a tree of processes is constructed in the network, ensuring that each group member is included in the tree. To build this tree, the group routing protocol relies upon the local unicast routing tables of each process. Thus, group routing is accomplished by composing two protocols: an underlying unicast routing protocol, whose detailed behavior is unknown but its basic properties are given, and a protocol that builds a group tree based upon the unicast routing tables. The group routing protocol is developed in three steps. First, a simple protocol is obtained, and is proven correct. Then, the protocol is refined twice. Each refined protocol improves upon its predecessor by satisfying all of the predecessor's properties plus some additional stronger properties. The final protocol has the property of adapting the group tree to changes in the unicast routing tables without compromising the integrity of the group tree, even in the presence of unicast routing loops.     

Block acknowledgment: redesigning the window protocol

A window protocol based on the block acknowledgment method, in which acknowledgment message has two numbers, m and n, to acknowledge the reception of all data messages with sequence numbers ranging from m to n, is discussed. In the window protocol, message sequence numbers are taken from a finite domain and both message disorder and loss can be tolerated. An initial version of the protocol that uses a simplified timeout action and unbounded sequence numbers is presented, the simplified timeout action in the protocol is replaced by a sophisticated one without disturbing the protocol's correctness, and the unbounded sequence numbers are replaced by bounded ones while preserving the protocol's correctness. Remarks concerning other variations of the protocol are also presented     

A new model to assess staphylococcal adhesion to intraocular lenses under in vitro flow conditions

Adhesion of staphylococcal cells to intraocular lenses coated with heparin was studied under in vitro flow conditions (280 microl min(-1)) at 37 degrees C. The intraocular lenses were incubated with human cerebrospinal fluid for 1 h or with cerebrospinal fluid including 0.50% plasma for 12 h, prior to bacterial challenge. Two strains of Staphylococcus epidermidis selected for this study, were isolated from biomaterial-associated infections. Bacterial adhesion was quantitated by bioluminescence and visualized by fluorescence microscopy of acridine orange stained bacteria. Surface coating with heparin significantly decreased bacterial adhesion of both strains after incubation with cerebrospinal fluid including 0.50% plasma for 12 h (p = 0.0209). However, no difference in bacterial adhesion was obtained between intraocular lenses with and without heparin, after incubation with cerebrospinal fluid for 1 h (p = 0.327). Microscopy showed that more bacteria were present on intraocular lenses without heparin than on intraocular lenses with heparin. The results show that preincubation with a proteinaceous fluid influences subsequent bacterial adhesion to the polymer surface. The results suggest that IOLs with heparin coating may be less prone to bacterial adhesion under perfusion conditions after surface conditioning in human CSF with 0.50% plasma and a preincubation period of 12 h. Heparin coating might be a valuable tool to decrease implant-associated bacterial endophthalmitis.     

Optimization of strength in cement pastes

It has been demonstrated that porosity is by far the dominant controlling factor limiting strength of hydrated cement paste. Mechanical means have been employed in the present study to minimize this porosity, “hot pressing” under rather modest temperatures and pressures, producing materials having very low porosity and unusually high strength. A new relationship to describe the interrelation of strength and porosity is given, and the effect of maturity of specimens, composition and microstructure are illustrated. Though theoretical density has not yet been achieved, the cement pastes have compressive strengths (as well as tensile and shear strengths) an order of magnitude higher than in normally hydrated cements, are stable and durable, and have dense interpenetrating microstructures.     

Modelling the repairability function by the first passage time distribution of Brownian motion

This paper puts forward the first passage time distribution of Brownian motion as a repairability model. The paper fits the model to observed active repair data of radar systems, obtaining as a result estimates of the mean first passage time, drift and diffusion parameters of the associated Brownian motion. Hypothesizing the first passage time distribution of Brownian motion for active repair time data of radar systems, the Kolmogorov-Smirnov test shows that the model is accepted and can be chosen as the parent population.