Showing papers by "Ford Motor Company published in 1995"
15 Oct 1995
TL;DR: In this article, the authors present a model for dynamic control systems based on Adaptive Control System Design Steps (ACDS) with Adaptive Observers and Parameter Identifiers.
Abstract: 1. Introduction. Control System Design Steps. Adaptive Control. A Brief History. 2. Models for Dynamic Systems. Introduction. State-Space Models. Input/Output Models. Plant Parametric Models. Problems. 3. Stability. Introduction. Preliminaries. Input/Output Stability. Lyapunov Stability. Positive Real Functions and Stability. Stability of LTI Feedback System. Problems. 4. On-Line Parameter Estimation. Introduction. Simple Examples. Adaptive Laws with Normalization. Adaptive Laws with Projection. Bilinear Parametric Model. Hybrid Adaptive Laws. Summary of Adaptive Laws. Parameter Convergence Proofs. Problems. 5. Parameter Identifiers and Adaptive Observers. Introduction. Parameter Identifiers. Adaptive Observers. Adaptive Observer with Auxiliary Input. Adaptive Observers for Nonminimal Plant Models. Parameter Convergence Proofs. Problems. 6. Model Reference Adaptive Control. Introduction. Simple Direct MRAC Schemes. MRC for SISO Plants. Direct MRAC with Unnormalized Adaptive Laws. Direct MRAC with Normalized Adaptive Laws. Indirect MRAC. Relaxation of Assumptions in MRAC. Stability Proofs in MRAC Schemes. Problems. 7. Adaptive Pole Placement Control. Introduction. Simple APPC Schemes. PPC: Known Plant Parameters. Indirect APPC Schemes. Hybrid APPC Schemes. Stabilizability Issues and Modified APPC. Stability Proofs. Problems. 8. Robust Adaptive Laws. Introduction. Plant Uncertainties and Robust Control. Instability Phenomena in Adaptive Systems. Modifications for Robustness: Simple Examples. Robust Adaptive Laws. Summary of Robust Adaptive Laws. Problems. 9. Robust Adaptive Control Schemes. Introduction. Robust Identifiers and Adaptive Observers. Robust MRAC. Performance Improvement of MRAC. Robust APPC Schemes. Adaptive Control of LTV Plants. Adaptive Control for Multivariable Plants. Stability Proofs of Robust MRAC Schemes. Stability Proofs of Robust APPC Schemes. Problems. Appendices. Swapping Lemmas. Optimization Techniques. Bibliography. Index. License Agreement and Limited Warranty.
4,378 citations
TL;DR: Pulmonary embolism is common in a general hospital, and the frequency of unsuspected PE in patients at autopsy has not diminished, and even among patients who die from PE, the PE is usually unsuspected.
610 citations
TL;DR: In this paper, the authors describe some of the technical issues that must be considered if the automotive industry is to utilize these lightweight materials in larger volumes, and conclude with a cost-benefit perspective for typical light-metal applications in automotive industry.
581 citations
TL;DR: It is found that the amount of microdamage present in femoral compact bone increases dramatically with increasing age, and matrix microdamage in composite materials like bone will result in a profoundly reduced resistance to fracture.
529 citations
TL;DR: The presence and anatomical location of cells exhibiting DNA fragmentation after transient MCA occlusion suggest that apoptosis contributes to the development of ischemic infarct and suggests that apoptotic isChemic brain damage is a dynamic ongoing process.
Abstract: We measured the temporal profile and anatomic distribution of cells exhibiting DNA fragmentation at various durations of reperfusion after middle cerebral artery (MCA) occlusion in the rat. Focal cerebral ischemia was induced in male Wistar rats (n = 62) using an intraluminal monofilament blockade of the MCA. After 2 h of MCA occlusion, the animals were killed at different durations of reperfusion (0.5, 3, 6, 9, and 12 h and 1, 2, 4, 7, 14, 21, and 28 days, n = 4 per time point). Sham-operated rats (n = 4) and normal rats not subjected to any surgical procedure (n = 4) were used as controls. Coronal brain sections (5 microns) were analyzed, using an in situ ApopTag kit, hematoxylin and eosin, and immunohistochemical double-staining methods. Six rats subjected to 2 h of MCA occlusion were killed at 24 h for measurement of DNA fragmentation by gel electrophoresis. Our data indicate that within a coronal section, DNA fragmentation was present in zero to three cells in each hemisphere of normal and sham-operated rats as well as in the contralateral hemisphere of ischemic rats. The number of cells exhibiting DNA fragmentation increased as early as 0.5 h (8 +/- 6), peaked at 24-48 h (213 +/- 59), and persisted for 4 weeks (10 +/- 2) after onset of reperfusion (p 95% neurons) were located primarily in the inner boundary zone of the infarct. With use of gel electrophoresis, purified DNA obtained from the ischemic tissue exhibited the characteristic nucleosome ladder pattern associated with apoptosis.(ABSTRACT TRUNCATED AT 250 WORDS)
483 citations
TL;DR: The paper presents the control design for antilock braking systems via the sliding mode approach and considers the friction force as an output of the dynamic system which includes mechanical motion equations and the hydraulic circuit equations.
Abstract: The paper presents the control design for antilock braking systems via the sliding mode approach. In this study the authors formulate the problem as that of extremum searching in a highly uncertain situation. The authors consider the friction force as an output of the dynamic system which includes mechanical motion equations and the hydraulic circuit equations. This setting is complicated by the optimized function being a priori unknown, and the input (slip) not being measurable. >
480 citations
TL;DR: M Males and females with nicotine dependence had increased odds for alcohol and illicit drug disorders, major depression, and anxiety disorders, compared with nondependent smokers and nonsmokers combined, and major depression and any anxiety disorder were associated specifically with nicotine addiction.
Abstract: Recent epidemiologic studies have revealed that comorbidity of psychiatric disorders is far more pervasive than previously suspected. Strong associations have been reported between specific substance use disorders and between any mental disorder and any substance use disorder. This report focuses on comorbidity of nicotine dependence, a substance use disorder on which little epidemiologic information is available. Data come from an epidemiologic study of approximately 1000 young adults in southeast Michigan, in which the NIMH-DIS, revised according to DSM-III-R, was used. Lifetime prevalence of nicotine dependence was 20%. Males and females with nicotine dependence had increased odds for alcohol and illicit drug disorders, major depression, and anxiety disorders, compared with nondependent smokers and nonsmokers combined. Major depression and any anxiety disorder were associated specifically with nicotine dependence. Increased odds for alcohol or illicit drug disorders were observed also in nondependent smokers, compared to nonsmokers. History of early conduct problems increased the odds for nicotine dependence among smokers. Potential mechanisms in the comorbidity of nicotine dependence are discussed.
397 citations
TL;DR: The results suggest that the higher occurrence of anxiety disorders in females than males beginning early in life might explain in large part the higher female risk for major depression.
Abstract: The role of anxiety disorders in the development of sex differences in major depression is analyzed. Data come from a longitudinal epidemiologic study of young adults in the Detroit, Michigan area. The Diagnostic Interview Schedule, revised according to DSM-III-R, was used at baseline to measure lifetime psychiatric disorders and at follow-up to measure psychiatric disorders during the 3.5-year interval since baseline assessment. Consistent with previous reports, the lifetime prevalence of major depression was nearly two-fold higher in females than in males. The sex difference was primarily in major depression comorbid with anxiety disorders. Results from Cox-proportional hazards models, with time-dependent covariates, showed that prior anxiety disorder increased the risk for subsequent major depression in both sexes, with no evidence of an interaction. History of anxiety disorder, including number of prior anxiety disorders, accounted for a considerable part of the observed sex difference in major depression. Controlling for prior anxiety reduced by more than 50% the coefficient that estimates the association between gender and major depression. The results suggest that the higher occurrence of anxiety disorders in females than males beginning early in life might explain in large part the higher female risk for major depression. They emphasize the need for further research on sex differences in anxiety disorders.
365 citations
TL;DR: It is shown that the discrete Newton method, properly interpreted, yields an asymptotic observer for a large class of discrete-time systems, while the continuous Newton method may be employed to obtain a global observer.
Abstract: This paper focuses on the development of asymptotic observers for nonlinear discrete-time systems. It is argued that instead of trying to imitate the linear observer theory, the problem of constructing a nonlinear observer can be more fruitfully studied in the context of solving simultaneous nonlinear equations. In particular, it is shown that the discrete Newton method, properly interpreted, yields an asymptotic observer for a large class of discrete-time systems, while the continuous Newton method may be employed to obtain a global observer. Furthermore, it is analyzed how the use of Broyden's method in the observer structure affects the observer's performance and its computational complexity. An example illustrates some aspects of the proposed methods; moreover, it serves to show that these methods apply equally well to discrete-time systems and to continuous-time systems with sampled outputs. >
364 citations
TL;DR: Among young adults, those with less education, blacks, and those with high neuroticism and extroversion scores are more likely than others to be exposed to traumatic events and are thus at greater risk for PTSD.
Abstract: Objective The authors previously identified suspected risk factors for traumatic events related to posttraumatic stress disorder (PTSD) on the basis of data gathered retrospectively. In this study, they tested that model prospectively. Method A random sample of 1,200 persons was drawn from all 21- to 30-year-old members of a large health maintenance organization. In 1989, 1,007 of these persons were interviewed, and suspected risk factors were measured. In 1992, 979 were reinterviewed, and the 3-year incidence of exposure to traumatic events was ascertained. Results Nineteen percent of the sample reported traumatic events during the 3-year follow-up. A history of past exposure to traumatic events signaled an increase in the liability to exposure during follow-up, independent of suspected risk factors. Two predictors of exposure, neuroticism and extroversion, identified retrospectively, also predicted exposure prospectively. The odds for exposure among males and persons with less than a college education were marginally significant. Early misconduct and a family history of psychiatric disorder-predictors of exposure in the retrospective data-were not significant predictors at 3-year follow-up. Blacks had a higher incidence of exposure during follow-up than whites. An exploratory reanalysis suggested that the discrepancy between the retrospective and prospective results may be explained by the inclusion of childhood exposure in the lifetime retrospective inquiry. Conclusions The assumption that PTSD-related traumatic events are random phenomena was unsupported. Among young adults, those with less education, blacks, and those with high neuroticism and extroversion scores are more likely than others to be exposed to traumatic events and are thus at greater risk for PTSD.
350 citations
TL;DR: Ischemic cell damage is promoted by postischemic inflammatory response after 2 hours of transient MCA occlusion, and ischemiccell damage is reduced by administration of an anti-ICAM-1 antibody during reperfusion.
Abstract: Background and Purpose Postischemic cerebral inflammation may contribute to ischemic cell damage. Intercellular adhesion molecule–1 (ICAM-1) is a glycoprotein expressed on endothelial cells that facilitates leukocyte adhesion. We investigated the effect of administration of an anti–ICAM-1 antibody (1A29) on ischemic cell damage after transient (2-hour) or permanent middle cerebral artery (MCA) occlusion in the Wistar rat. Methods Groups studied were as follows: (1) transient MCA occlusion: rats were subjected to 2 hours of MCA occlusion, and after 1 hour of reperfusion they were treated with 1A29 (n=11) or an isotype control antibody (n=9); and (2) permanent MCA occlusion: rats were treated with 1A29 (n=9) or an isotype control antibody (n=7) 2 hours after onset of MCA occlusion. All animals were killed 1 week after onset of ischemia. Brain sections were stained with hematoxylin and eosin for histological evaluation. Results Significant reductions (P<.05) in both volume (44%) of the ischemic lesion and we...
Journal Article•
TL;DR: Brains from eight rats subjected to transient focal ischemia and reperfusion revealed an ultrastructural appearance of apoptosis and light microscopic features of cells exhibiting DNA fragmentation, which may contribute to the development of infarct after transient focal cerebral ischemies.
Abstract: Brains from eight rats subjected to transient focal ischemia (2 hours) and reperfusion (22 hours) revealed an ultrastructural appearance of apoptosis and light microscopic features of cells exhibiting DNA fragmentation. The number of cells exhibiting DNA fragmentation was significantly higher (P < 0.01) in the ipsilateral hemisphere (216 +/- 43 per section) than in the contralateral hemisphere and in normal (n = 4) and sham operated (n = 4) rats (0 to 3 positive cells per section in controls). Cells exhibiting DNA fragmentation were primarily located in the inner boundary zone to the infarct. Cells exhibiting DNA fragmentation provided morphological information of apoptosis. Apoptosis may contribute to the development of infarct after transient focal cerebral ischemia.
TL;DR: The presence and anatomic location of apoptotic cells exhibiting DNA fragmentation after transient cerebral occlusion indicate that apoptosis accompanies neuronal necrosis.
Abstract: Background and Purpose The induction of neuronal necrosis has been studied after various durations of transient middle cerebral artery (MCA) occlusion in the rat. The objective of the present study was to measure the numbers and anatomic distribution of cells exhibiting apoptotic bodies as an indication of DNA fragmentation and apoptotic cell death as a function of duration of transient MCA occlusion in the rat.
Methods The MCA of male Wistar rats (n=24) was occluded for 10, 20, 30, 60, 90, and 120 minutes (n=4 per group) with the use of an intraluminal monofilament, and reperfusion was instituted for 48 hours. DNA fragmentation was measured in paraffin sections with the use of a terminal deoxynucleotidyl- transferase (TdT)-mediated dUTP-biotin nick end-labeling (TUNEL) method. Adjacent sections were stained with hematoxylin and eosin for analysis of ischemic cell damage, and immunohistochemical double staining methods were used for cell identification. Sham-operated rats (n=4) and normal rats not subjected to any surgical procedure (n=4) were used as controls for apoptosis detection.
Results Within 5-μm-thick coronal sections, DNA fragmentation was present in 0 to 3 apoptotic cells in each hemisphere of normal, sham-operated rats as well as in the contralateral hemisphere of ischemic rats. After 10 to 20 minutes of MCA occlusion, apoptotic cells exhibiting DNA fragmentation (10 to 20) increased in the regions of selective neuronal necrosis in the preoptic area and in the striatum. After 30 to 60 minutes of ischemia, scattered apoptotic cells (30 to 60) exhibited DNA fragmentation and expanded into areas of selective neuronal necrosis in the cortex. After 90 to 120 minutes of occlusion, groups of apoptotic cells (70 to 200, >95% neurons) were primarily localized to the inner boundary zone of the infarct.
Conclusions A range of mild to severe ischemia-reperfusion stimuli induce internucleosomal DNA cleavage. The presence and anatomic location of apoptotic cells exhibiting DNA fragmentation after transient cerebral occlusion indicate that apoptosis accompanies neuronal necrosis.
Patent•
27 Sep 1995TL;DR: An automatic transmission for an automotive vehicle includes multiple planetary gear units, each including a sun gear, a ring gear surrounding the sun gear and a set of planet pinions continually engaged with the sun and ring gear.
Abstract: An automatic transmission for an automotive vehicle includes multiple planetary gear units, each including a sun gear, a ring gear surrounding the sun gear, a set of planet pinions continually engaged with the sun gear and ring gear, and a planet carrier rotatably supporting the planet pinions. Various brakes selectively hold elements of the gear units against rotation and several clutches releasably interconnect elements of the, gear units. A torque converter is adapted to produce a hydrokinetic drive connection between the crankshaft of an engine and the input shaft of the transmission, or to mechanically connect those components when a bypass clutch of the torque converter is engaged. Various elements of the planetary gear units are permanently driveably connected mutually.
TL;DR: In this article, an improved mechanism for the formation of lubricant-derived antiwear films, which accounts for a substantial body of experimental data, together with some unique observations resulting from their own investigations, was proposed.
TL;DR: The data suggest that in dogs with chronic HF, constituent myocytes of LV regions which manifest severe RIF may be subjected to chronic hypoxia; a condition that can adversely impact the function and viability of the collagen encircled cardiocyte.
Abstract: Progressive deterioration of left ventricular (LV) function is a characteristic feature of the heart failure (HF) state. The mechanism or mechanisms responsible for this hemodynamic deterioration are not known but may be related to progressive intrinsic dysfunction, degeneration and loss of viable cardiocytes. In the present study, we tested the hypothesis that accumulation of collagen in the cardiac interstitium (reactive interstitial fibrosis, RIF), known to occur in HF, results in reduced capillary density (CD=capillary/fiber ratio) and increased oxygen diffusion distance (ODD) which can lead to hypoxia and dysfunction of the collagen encircled myocyte. Studies were performed in LV tissue obtained from 10 dogs with chronic HF (LV ejection fraction 26±1%) produced by multiple sequential intracoronary, microembolizations. In each dog, CD and ODD were evaluated in LV regions that manifested severe RIF (volume fraction 16±2%) and in LV regions of little or no RIF (volume fraction 4±1%). In regions of severe RIF, CD was significantly decreased compared to regions of no RIF (0.92±0.02 vs. 1.05±0.03) (P<0.03). Similarly, ODD was significantly increased in regions of severe RIF compared to regions of no RIF (15.3±0.4 vs. 12.2±0.3 μm) (P<0.001). These data suggest that in dogs with chronic HF, constituent myocytes of LV regions which manifest severe RIF may be subjected to chronic hypoxia; a condition that can adversely impact the function and viability of the collagen encircled cardiocyte.
Patent•
09 Mar 1995TL;DR: A finger follower type rocker arm has an outer body that engages the stem of an engine valve and a pivotally mounted inner arm engaged and moved by the cam lobe of the engine camshaft.
Abstract: A finger follower type rocker arm has an outer body that engages the stem of an engine valve. Within the body is pivotally mounted an inner arm engaged and moved by the cam lobe of an engine camshaft. A latching pin normally causes the inner arm and outer body to act as an integral unit to activate the engine valve in a conventional manner. Selective withdrawal of the latching pin permits the cam lobe to move the inner arm in a free-wheeling manner without effecting movement of the outer body or valve stem, thus disabling the engine valve.
Patent•
28 Jun 1995TL;DR: In this paper, the authors proposed a method for detecting an electrical conductivity leakage path in a vehicle having a plurality of batteries coupled in series and having a chassis ground, which includes the steps of measuring the voltage at the first voltage divider output with the switchable electrical connection between that voltage dividers output and chassis ground closed.
Abstract: The present invention provides a method for detecting an electrical conductivity leakage path in a vehicle having a plurality of batteries coupled in series and having a chassis ground. The method comprises the step of (a) providing a voltage divider for each of the batteries, each voltage divider having an output having a voltage at a potential between the potentials of the positive and negative terminals of the voltage divider's respective battery. The method also includes the step of (b) providing a plurality of electrical connections, each switchable between open and closed, each between a voltage divider output and chassis ground. Furthermore, the method comprises the steps of (c) closing the switchable electrical connection between the first voltage divider output and chassis ground. In addition, the method includes the steps of (d) measuring the voltage at the first voltage divider output with the switchable electrical connection between that voltage divider output and chassis ground closed; and (e) opening the switchable electrical connection between the first voltage divider output and chassis ground.
TL;DR: Evaluated the utility of the alveolar-arterial (A-a) oxygen gradient in the diagnosis of acute pulmonary embolism among patients who participated in the Prospective Investigation of Pulmonary Embolism Diagnosis (PIO-PED).
TL;DR: A significant neuroprotective effect of rNIF with continuous treatment for 48 hours following 2 hours of MCAO is demonstrated, correlated with a reduced number of neutrophils within the ischemic tissue.
Abstract: We tested the neuroprotective potential of neutrophil inhibitory factor (rNIF), a novel 41-kd recombinant glycoprotein derived from a hookworm, in a model of focal cerebral ischemia in the rat. Male Wistar rats were assigned to treatment with rNIF and vehicle. Middle cerebral artery occlusion (MCAO) for 2 hours was induced by insertion of an intraluminal suture. Infusion of the drug was initiated at the onset of reperfusion. Infarct volume was determined 48 hours after reperfusion. Neutrophils were measured within the ischemic tissue by myeloperoxidase (MPO) staining. Treatment with rNIF resulted in a 48% reduction in cerebral infarction compared with control animals (p < 0.01). Neutrophil accumulation in the ischemic brains of rNIF-treated rats was reduced significantly (p < 0.01) compared with control animals. The number of neutrophils within the infarcted tissue correlated positively with the size of the area of infarction (p < 0.001, r = 0.6) within representative cerebral coronal sections. We demonstrated a significant neuroprotective effect of rNIF with continuous treatment for 48 hours following 2 hours of MCAO. The neuroprotective effect was correlated with a reduced number of neutrophils within the ischemic tissue. These results demonstrate potential therapeutic properties of rNIF in the management of stroke.
01 Apr 1995-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this paper, the minimum zone solution of a set of datapoints sampled from a part is computed, given adequate initial conditions, and the final implementable formulation solves a sequence of linear programs that converge to a local optimal solution.
Abstract: Most inspectors measure form tolerances as the minimum zone solution, which minimizes the maximum error between the datapoints and a reference feature. Current coordinate measuring machines verification algorithms are based on the least-squares solution, which minimizes the sum of the squared errors, resulting in a possible overestimation of the form tolerance. Therefore, although coordinate measuring machines algorithms successfully reject bad parts, they may also reject some good parts. The verification algorithms developed in this set of papers compute the minimum zone solution of a set of datapoints sampled from a part. Computing the minimum zone solution is inherently a nonlinear optimization problem. This paper develops a single verification methodology that can be applied to the cylindricity and straightness of a median line problems. The final implementable formulation solves a sequence of linear programs that converge to a local optimal solution. Given adequate initial conditions, this solution will be the minimum zone solution. This methodology is also applied to the problems of computing the minimum circumscribed cylinder and the maximum inscribed cylinder. Experimental evidence that the formulations are both robust and efficient is provided.
Patent•
31 Jul 1995TL;DR: A low quiescent current wake-up interface and method for awakening an automotive electronics module from its inactive state was proposed in this article, where the wakeup interface comprises at least one wakeup input switch interface circuitry (30A-I, 36A -I) for generating a first current transient when one of the input switches (28A-II, 38A -II) is closed, and wake-ups sense circuitry (40) responsive to the first current transceiver signal for providing a wakeup command signal.
Abstract: A low quiescent current wake-up interface and method for awakening an automotive electronics module from its inactive state. In one particular aspect of the invention, the wake-up interface comprises at least one wake-up input switch (28A-I, 38A-I); wake-up input switch interface circuitry (30A-I, 36A-I) for generating a first current transient when one of the input switches (28A-I, 38A-I) is closed; and wake-up sense circuitry (40) responsive to the first current transient for providing a wake-up command signal. Preferably the wake-up sense circuitry (40) includes a first latch (102) for detecting the first current transient, a second latch (172) responsive to the first latch (102) for providing the wake-up command signal, and timing circuitry (128) for providing a time delay. In another aspect of the invention, a method for awakening an automotive electronics module having a microcontroller (32) and at least one wake-up input switch (38A-I) coupled thereto comprises the steps of: generating a first current transient when one of the input switches is closed; sensing the first current transient; and generating a wake-up command signal in response to the first current transient.
TL;DR: Brains from 5 mice subjected to focal ischemia revealed a significant increase (P < 0.01) in cells exhibiting DNA fragmentation in theipsilateral hemisphere compared to 0-3 per section found in the contralateral hemisphere and normal and sham operated mice.
TL;DR: The data indicate that NO is released in the brain after the onset of ischemia and NO levels can be modulated by administration of NO substrate and NO antagonists.
TL;DR: Results suggest that Cyto-D, through effects on cytoskeleton, induced cardiac Na+ channels to enter a mode characterized by a lower peak open probability but a greater persistent activity as if the inactivation rate was slowed.
Abstract: To investigate the role of the cytoskeleton in cardiac Na+ channel gating, the action of cytochalasin D (Cyto-D), an agent that interferes with actin polymerization, was studied by whole cell voltage clamp and cell-attached and inside-out patches from rat and rabbit ventricular cardiac myocytes. Cyto-D (20-40 microM) reduced whole cell peak Na+ current by 20% within 12 min and slowed current decay without affecting steady-state voltage-dependent availability or recovery from inactivation. Brief treatments ( 50% within 20 min, and long bursts of openings occurred. Washout of Cyto-D did not restore ensemble-averaged current amplitude, but burst duration decreased toward control values. Cyto-D also induced an additional slower component to open and closed times. These results suggest that Cyto-D, through effects on cytoskeleton, induced cardiac Na+ channels to enter a mode characterized by a lower peak open probability but a greater persistent activity as if the inactivation rate was slowed. The cytoskeleton, in addition to localizing integral membrane proteins, apparently also plays a role in regulating specific detailed functions of integral membrane proteins such as the gating of Na+ channels.
TL;DR: A two degree of freedom hand has been developed to demonstrate this concept and has been made sufficiently compact to allow users to gain experience with it.
Abstract: An important factor in the acceptance of a prosthesis is the ease with which the wearer can operate the device. Multiple degrees of freedom of a prosthesis are difficult to control independently and require a high level of concentration. If the control is arranged in a hierarchical manner and the lower levels' detailed control is performed by a microprocessor, it is possible to control a number of degrees with little direct intervention by the operator. A two degree of freedom hand has been developed to demonstrate this concept and has been made sufficiently compact to allow users to gain experience with it. >
TL;DR: The continued use of aspirin for 2 additional years after an initial year of aspirin therapy for the prevention of saphenous vein bypass graft occlusion showed no additional long-term benefit on graft patency at the end of the third year.
TL;DR: The frequency of PE on follow-up among patients with normal pulmonary angiograms is small, but there is a real and measureable rate of clinically important PE over the subsequent 12 months that is higher than reported in the general population of hospitalized patients.
TL;DR: In this paper, the authors analyse the property of improvability of a serial production line and derive appropriate indicators for improving performance in the process of continuous improvement, and show that in a well-designed system each buffer is on average half-full, and each intermediate machine has equal frequencies of blockages and starvations.
Abstract: A production system is described as improvable if the limited resources involved in its operation can be redistributed so that a performance measure is improved. In this paper the property of improvability is analysed for the case of a particular system, the serial production line. Improvability of the production rate with respect to machine efficiency and work-in-process distribution is analysed, appropriate indicators of improvability are derived, and their utilization in the process of continuous improvement is discussed. It is shown, in particular, that in a well-designed system each buffer is on average half-full, and each intermediate machine has equal frequencies of blockages and starvations