Showing papers by "Ford Motor Company published in 1984"

Practical cone-beam algorithm

Abstract: A convolution-backprojection formula is deduced for direct reconstruction of a three-dimensional density function from a set of two-dimensional projections. The formula is approximate but has useful properties, including errors that are relatively small in many practical instances and a form that leads to convenient computation. It reduces to the standard fan-beam formula in the plane that is perpendicular to the axis of rotation and contains the point source. The algorithm is applied to a mathematical phantom as an example of its performance.

Congestion control in IP/TCP internetworks

Abstract: Congestion control is a recognized problem in complex networks. We have discovered that the Department of Defense's Internet Protocol (IP), a pure datagram protocol, and Transmission Control Protocol (TCP), a transport layer protocol, when used together, are subject to unusual congestion problems caused by interactions between the transport and datagram layers. In particular, IP gateways are vulnerable to a phenomenon we call congestion collapse, especially when such gateways connect networks of widely different bandwidth. We have developed solutions that prevent congestion collapse.These problems are not generally recognized because these protocols are used most often on networks built on top of ARPANET IMP technology. ARPANET IMP based networks traditionally have uniform bandwidth, identical switching nodes, and are sized with substantial excess capacity. This excess capacity, and the ability of the IMP system to throttle the transmissions of hosts has for most IP/TCP hosts and networks, been adequate to handle congestion. With the recent split of the ARPANET into two interconnected networks and the growth of other networks with differing properties connected to the ARPANET, however, reliance on the benign properties of the IMP system is no longer enough to allow hosts to communicate rapidly and reliably. Improved handling of congestion is now mandatory for successful network operation under load.Ford Aerospace and Communications Corporation, and its parent company, Ford Motor Company, operate the only private IP/TCP long-haul network in existence today. This network connects six facilities (one in Michigan, two in California, one in Colorado, one in Texas, and one in England) some with extensive local networks. This net is cross-tied to the ARPANET but uses its own long-haul circuits; traffic between Ford facilities flows over private leased circuits, including a leased transatlantic satellite connection. All switching nodes are pure IP datagram switches with no node-to-node flow control, and all hosts run software either written or heavily modified by Ford or Ford Aerospace. Bandwidth of links in this network varies widely, from 1200 to 10,000,000 bits per second. In general, we have not been able to afford the luxury of excess long-haul bandwidth that the ARPANET possesses, and our long-haul links are heavily loaded during peak periods. Transit times of several seconds are thus common in our network.Because of our pure datagram orientation, heavy loading, and wide variation in bandwidth, we have had to solve problems that the ARPANET/MILNET community is just beginning to recognize. Our network is sensitive to suboptimal behavior by host TCP implementations, both on and off our own net. We have devoted considerable effort to examining TCP behavior under various conditions, and have solved some widely prevalent problems with TCP. We present here two problems and their solutions. Many TCP implementations have these problems; if throughput is worse through an ARPANET/MILNET gateway for a given TCP implementation than throughput across a single net, there is a high probability that the TCP implementation has one or both of these problems.

Congestion Control in IP/TCP Internetworks.

Abstract: Congestion control is a recognized problem in complex networks. We have discovered that the Department of Defense's Internet Protocol (IP), a pure datagram protocol, and Transmission Control Protocol (TCP), a transport layer protocol, when used together, are subject to unusual congestion problems caused by interactions between the transport and datagram layers. In particular, IP gateways are vulnerable to a phenomenon we call congestion collapse, especially when such gateways connect networks of widely different bandwidth. We have developed solutions that prevent congestion collapse.These problems are not generally recognized because these protocols are used most often on networks built on top of ARPANET IMP technology. ARPANET IMP based networks traditionally have uniform bandwidth, identical switching nodes, and are sized with substantial excess capacity. This excess capacity, and the ability of the IMP system to throttle the transmissions of hosts has for most IP/TCP hosts and networks, been adequate to handle congestion. With the recent split of the ARPANET into two interconnected networks and the growth of other networks with differing properties connected to the ARPANET, however, reliance on the benign properties of the IMP system is no longer enough to allow hosts to communicate rapidly and reliably. Improved handling of congestion is now mandatory for successful network operation under load.Ford Aerospace and Communications Corporation, and its parent company, Ford Motor Company, operate the only private IP/TCP long-haul network in existence today. This network connects six facilities (one in Michigan, two in California, one in Colorado, one in Texas, and one in England) some with extensive local networks. This net is cross-tied to the ARPANET but uses its own long-haul circuits; traffic between Ford facilities flows over private leased circuits, including a leased transatlantic satellite connection. All switching nodes are pure IP datagram switches with no node-to-node flow control, and all hosts run software either written or heavily modified by Ford or Ford Aerospace. Bandwidth of links in this network varies widely, from 1200 to 10,000,000 bits per second. In general, we have not been able to afford the luxury of excess long-haul bandwidth that the ARPANET possesses, and our long-haul links are heavily loaded during peak periods. Transit times of several seconds are thus common in our network.Because of our pure datagram orientation, heavy loading, and wide variation in bandwidth, we have had to solve problems that the ARPANET/MILNET community is just beginning to recognize. Our network is sensitive to suboptimal behavior by host TCP implementations, both on and off our own net. We have devoted considerable effort to examining TCP behavior under various conditions, and have solved some widely prevalent problems with TCP. We present here two problems and their solutions. Many TCP implementations have these problems; if throughput is worse through an ARPANET/MILNET gateway for a given TCP implementation than throughput across a single net, there is a high probability that the TCP implementation has one or both of these problems.

Shape Matching of Two-Dimensional Objects

Abstract: In this paper we present results in the areas of shape matching of nonoccluded and occluded two-dimensional objects. Shape matching is viewed as a ``segment matching'' problem. Unlike the previous work, the technique is based on a stochastic labeling procedure which explicitly maximizes a criterion function based on the ambiguity and inconsistency of classification. To reduce the computation time, the technique is hierarchical and uses results obtained at low levels to speed up and improve the accuracy of results at higher levels. This basic technique has been extended to the situation where various objects partially occlude each other to form an apparent object and our interest is to find all the objects participating in the occlusion. In such a case several hierarchical processes are executed in parallel for every object participating in the occlusion and are coordinated in such a way that the same segment of the apparent object is not matched to the segments of different actual objects. These techniques have been applied to two-dimensional simple closed curves represented by polygons and the power of the techniques is demonstrated by the examples taken from synthetic, aerial, industrial and biological images where the matching is done after using the actual segmentation methods.

Representation and Shape Matching of 3-D Objects

Abstract: A three-dimensional scene analysis system for the shape matching of real world 3-D objects is presented. Various issues related to representation and modeling of 3-D objects are addressed. A new method for the approximation of 3-D objects by a set of planar faces is discussed. The major advantage of this method is that it is applicable to a complete object and not restricted to single range view which was the limitation of the previous work in 3-D scene analysis. The method is a sequential region growing algorithm. It is not applied to range images, but rather to a set of 3-D points. The 3-D model of an object is obtained by combining the object points from a sequence of range data images corresponding to various views of the object, applying the necessary transformations and then approximating the surface by polygons. A stochastic labeling technique is used to do the shape matching of 3-D objects. The technique matches the faces of an unknown view against the faces of the model. It explicitly maximizes a criterion function based on the ambiguity and inconsistency of classification. It is hierarchical and uses results obtained at low levels to speed up and improve the accuracy of results at higher levels. The objective here is to match the individual views of the object taken from any vantage point. Details of the algorithm are presented and the results are shown on several unknown views of a complicated automobile casting.

Spectral-domain analysis of frequency selective surfaces comprised of periodic arrays of cross dipoles and Jerusalem crosses

Abstract: A full-wave analysis for the problem of scattering frequency selective surfaces from (FSS) comprised of periodic arrays of cross dipoles and Jerusalem crosses is presented. The formulation is carried out in the spectral domain where the convolution form of the integral equation for the induced current is reduced to an algebraic one. The equation is then solved using the Galerkin's procedure applied in the spectral domain. A set of entire-domain type "junction basis functions," which, is demonstrated in this paper to be essential to account correctly for the discontinuous nature of the induced current at the junction of the cross, is included in the expansion for the unknown induced current. This analysis is computationally efficient, and its accuracy is verified by the agreement between the computed theoretical data and the experimental results reported by other authors.

Free volume and the kinetics of aging of polymer glasses

Abstract: Application du modele stochastique decrit par Robertson a la recouvrance du volume de l'acetate polyvinylique. Comparaison avec les donnees de Kovacs

Filtration system for diesel engine exhaust-II

Abstract: A filtration system operative to remove oxidizable particulates from the exhaust gas of a diesel engine is disclosed. The system has a filter element to trap and collect particulates in the exhaust gas, ignition means supplied with energy for a period only sufficient to ignite a leading portion of the particulate collection, and means for conducting a flow of gas with excess oxygen thorough the filtration means immediately following ignition without addition of other energy, the flow of gas with excess oxygen being utilized to support the continued oxidation of the ignited particulate collection. The ignition means may comprise (a) apparatus for adding excess hydrocarbon fuel either to (i) the gas flow through the intake manifold of the engine, (ii) the exhaust gas exiting from the engine, or (iii) a separate supply of compressed air, and (b) a supplementary heated catalyst located between the exhaust manifold of the engine and the filter element for acting upon the hydrocarbon rich gas flow, the catalyst being effective to bring about ignition of the hydrocarbon rich gas and produce a heated exhaust gas high enough in temperature to ignite at least a portion of the particulates in the filter element.

Composite light pickup device

Abstract: A composite light pickup device for use in an automotive vehicle to collect light from both the ambient surroundings and from oncoming vehicles and employing separate optical fiber couplings of the collected light to a headlamp system that responsively activates the vehicle headlamps when the ambient light level is too low and switches the activated headlamps between high and low beams in response to receiving light from oncoming vehicle headlamps.

On failure modeling

Abstract: : A promising approach to failure modeling, in particular to developing failure-time distributions, is discussed. Under this approach, system state or wear and tear is modeled by an approximately chosen random process, eg, a diffusion process; and the occurrences of fatal shocks are modeled by a Poisson process whose rate function is state dependent. The system is said to fail when either wear and tear accumulates beyond in acceptable or safe level or a fatal shock occurs. This approach has significant merit. First it provides revealing new insights into most of the famous and frequently used lifetime distributions in reliability theory. Moreover, it suggests intuitively appealing ways for enhancing those standard models. Indeed, this approach provides a means of representing the underlying dynamics inherent in failure processes. Reasonable postulates for the dynamics of failure should lend credence to prediction and estimation of reliability, maintainability, and availability. In other words, accuracy of representation could lead to better, more reliable prediction of failure. (Author)

Attitude stabilization of flexible spacecraft during stationkeeping maneuvers

Abstract: This paper present s t h e a n a l y s i s and design o f r e a c t i o n j e t a t t i t u d e c o n t r o l system f o r a spacecraf t having l a r g e f l e x i b l e s a l a r a r rays . During t r a n s l a t i o n a l t h r u s t i n g maneuvers, t h e s o l a r a r r a y f l e x i b i l i t y s t r o n g l y i n t e r a c t s w i t h the Pulse-Width and Pulse-Frequency (PdPF) modulator. A simple t r a n s f e r f u n c t i o n model o f f l e x i b l e spacecra f t i s used f o r t h e p r e l im inary c o n t r o l design. The s t a t i c and dynamic charact e r i s t i c s o f the PWPF modulator a re discussed i n d e t a i l . Nonl inear s t a b i l i t y ana lys is i s performed us ing t h e descr ib ing f u n c t i o n o f the modulator. R e l a t i v e s t a b i l i t y margin w i t h respec t t o the l i m i t c y c l e c o n d i t i o n o f a s t r u c t u r a l mode i s used as a measure o f t h e non l inear c o n t r o l system robustness. The performance and s t a b i l i t y margin p r e d i c t e d by c l a s s i c a l s i n g l e a x i s design, a r e v e r i f i e d from t h e 3-ax is non l inear d i g i t a l s imulat i o n s .

A Biomechanical Analysis of Head, Neck, and Torso Injuries to Child Surrogates Due to Sudden Torso Acceleration

Abstract: The authors report on the injuries to the head, neck and thorax of fifteen child surrogates, subjected to varying levels of sudden acceleration. Measured response data in the child surrogate tests and in matched tests with a three-year-old child test dummy are compared to the observed child surrogates injury levels to develop preliminary tolerance data for the child surrogate. The data are compared with already published data in the literature.

A three-dimensional model of anisotropic hardening in metals and its application to the analysis of sheet metal formability

Abstract: The hardening model proposed by Z. Mroz based on the uniaxial fatigue behavior of many metals is adopted to derive an incremental constitutive equation for general three-dimensional problems. This constitutive law is then employed in the analysis of metal forming problems to assess the influence of loading cycles, of the types involved in standard forming processes, on the ultimate formability of sheet metals. The predicted forming limit curves differ quantitatively from results obtained via an isotropie hardening model and differ qualitatively from those obtained via a kinematic model. Also investigated are the effects of such loading cycles on material response to simple tensile loading, which is often used to characterize a material. Significant differences between the present model and the other two models considered are observed in such characterizers of simple tensile behavior as the stress-strain curve, the anisotropy parameter and the uniform elongation. These differences suggest a rather simple experiment to identify the proper material model to be used in analyses of problems which involve loading cycles. Comparisons with some experimental results reveal that the employment of an anisotropic hardening model, such as the generalized Mroz model derived herein, is indeed crucial in accurately predicting material response to complicated loading histories.

Catalyst Deactivation Due to Glaze Formation from Oil-Derived Phosphorus and Zinc

Abstract: The deactivation of automotive catalysts by engine oil-derived components of phosphorus and zinc can occur by the formation of an amorphous zinc pyrophosphate (Zn/sub 2/P/sub 2/O/sup 7/) that is impervious to gas diffusion. The catalyst poison, derived from antiwear oil additive zinc dialkyl dithiophosphate (ZDP) in low-temperature exhaust environments, appears as glassy, amorphous deposits on catalysts as shown by scanning electron microscopy (SEM). Laboratory studies were performed to understand the effects of exhaust stoichiometry, temperature, rate of oil burn, and chemical form of P and Zn compounds on glaze formation. The formation of the amorphous deposits using a laboratory pulsator apparatus showed that non-combusted ZDP causes the glaze formation. Electron microprobe studies indicated the association of P with Zn on precious metal films exposed to ZDP combustion products. Secondary ion mass spectrometry (SIMS) confirmed a similar P to Zn correspondence on the vehicle-aged catalysts. Once formed, the amorphous zinc pyrophosphate glaze could only be removed under high-temperature, reducing conditions which sintered the catalyst with no significant improvement in activity. Guidelines are presented for exhaust temperatures necessary for catalyst operation and prevention of catalyst deactivation by the formation of Zn pyrophosphate glaze.

Multi-mode child restraint system

Abstract: A multi-mode child restraint system is disclosed, comprising a seat and a bolster adapted to receive and releasably engage the seat. The seat provides a seating unit and an impact shield pivotably mounted to the seating unit. The impact shield is rotatable rearwardly to form a support stand for the seating unit in a reclined position. The restraint seat, either with or without the bolster is adapted to be secured to a motor vehicle seat by a seat belt associated with such motor vehicle seat.

Spectral-domain analysis of circular patch frequency selective surfaces

Abstract: A computationally efficient method is presented for analyzing the scattering from frequency selective surfaces (FSS) comprised of circular metal patches. The formulation is carried out in the spectral domain where the convolution form of the integral equation for the induced current reduces to an algebraic one and the spectral-Galerkin technique is used to solve the resulting equation. Entire-domain basis functions that satisfy the edge condition are introduced to expand the unknown induced current on the metal patches. Calculated results using this procedure show good agreement with data reported by other authors.

Fuel economy opportunities with an uncooled Dl diesel engine

Abstract: Possibilites de realiser des economies de carburant avec un moteur diesel a injection directe non refroidi

Comparison of solvent extraction and thermal-optical carbon analysis methods: application to diesel vehicle exhaust aerosol.

Abstract: Filter samples of particulate emissions from two diesel automobiles were analyzed by solvent extraction with a hot toluene/1-propanol mixture, by thermal-optical carbon analysis, and by X-ray fluorescence analysis On the average, carbon accounted for 83% of the particulate matter, and organic carbon comprised 70% of the extractable mass The ratio of elemental carbon as measured by the thermal-optical technique to unextractable mass was 105 +/- 004 For most of the filters the unextractable mass was predominantly elemental carbon However, for the filters with the largest amounts of unextracted material the elements Fe, S, Al, Si, and Ca were present in significant amounts (03-5% each of the unextractable mass when expressed as oxides) 29 references

Shear properties and a stress analysis obtained from vinyl-ester losipescu specimens

Abstract: The use of losipescu specimens for the determination of the shear properties of a vinyl-ester resin was investigated. The antisymmetric four-point bend and the Adams and Walrath fixtures were studied for their suitability in loading these specimens. Photoelastic and strain-gage data in addition to published finite-element results show that the latter fixture distorts the stress field in the gage section. The antisymmetric four-point bend fixture is found to give the purest shear-stress field in the gage section and to yield the most reliable shear-modulus values. A refined photoelastic analysis shows that the shear-stress distribution between the notch roots is essentially uniform with a relative maximum or minimum at the centroid depending on the depths of the notches. Also, stress risers of up to 30 percent are observed near the notch roots. Except at the roots, finite-element predictions are presented which are in excellent agreement with photoelastic data. The failure mode of this vinyl-ester resin is tensile and the corresponding tensile stress calculated from the average shear stress in the gage section of the losipescu specimen is in excellent agreement with failure data acquired in tension.

Automotive dispensing apparatus for fuel additive

Abstract: A dispensing apparatus is disclosed for adding a fluid agent to the fuel supply of an automotive engine, the agent is effective in depressing the ignition temperature of soot collected in an exhaust trap. The apparatus comprises: (a) a reservoir for containing a supply of the fluid agent such as copper octoate and hexane; (b) an electrically operated pulse pump for positively displacing a measured amount of the agent from the reservoir into the fuel supply; (c) register means for registering the amount of fuel replenished to the engine fuel supply and for transmitting an electrical signal proportional to the amount of fuel so added; and (d) control means responsive to the electrical signal to permit electrical operation of the pulse pump for a number of predetermined pulses to dispense a required amount of the agent for maintaining a desired uniform concentration of the agent throughout the fuel supply.

Carbon ignition temperature depressing agent and method of regenerating an automotive particulate trap utilizing said agent

Abstract: A carbon ignition temperature depressing agent is disclosed along with a method of regenerating an automotive particulate trap using the ignition temperature depressing agent. The agent is effective to promote oxidation of on-board collected carbonaceous particles extracted from the automobile exhaust. The agent comprises (a) an organometallic compound that upon heating (the combustion process of the engine) forms a readily reducible metal oxide which when finely divided promotes a carbonaceous ignition temperature in the range of as low as 450° F. and up to as low as 675° F., and (b) an aerosol-promoting liquid carrier effective to form a fine mist with the organometallic compound when sprayed, the carrier having a boiling point in the range of 176°-302° F. (80°-150° C.). The organometallic compound is one or more metal octoates having the metal selected from the group consisting of copper, nickel and cerium. The organometallic compounds are readily soluble and stable in the fuel supply used with an internal combustion engine such as an automotive diesel engine. The mixture is used in a volume amount of 10-50 milliliters per gallon of fuel or the organometallic compound is present in an amount of at least 0.15-0.5 gm/gal of fuel. The organometallic compound is proportioned to the carrier in a ratio of 1:2 to 1:10. The aerosol-promoting liquid carrier is selected from the group consisting of hexane, pentane and toluene and is effective to promote a droplet size for said mixture when sprayed of substantially less, on average, of one micron.

Proximity moisture sensor

Abstract: A device for detecting the presence of water includes a capacitance sensor coupled to a windshield to detect capacitance changes A multivibrator is coupled to the sensor to translate the detected capacitance change to the frequency domain A phase-locked loop coupled to the multivibrator produces a phase pulse in response to water causing a change in capacitance and, in turn, a change in the frequency of the multivibrator

Electrochemical photocatalytic structure

Abstract: A planar photoelectrochemical structure includes a thin, porous layer of semiconductor powder material on a catalytic film. Using incident light absorbed by the semiconductor, the structure is suited to photosensitizing redox reactions of substrates introduced to the structure in an aqueous gas-phase environment. Conducting catalyst films allow significant external electrical interaction with the photoelectrochemical process occurring in the layer.