Showing papers by "University of Southern California published in 1970"
Book•
01 Jan 1970TL;DR: A reverse-flow technique is described for the solution of a functional equation arising in connection with a decision process in which the termination time is defined implicitly by the condition that the process stops when the system under control enters a specified set of states in its state space.
Abstract: By decision-making in a fuzzy environment is meant a decision process in which the goals and/or the constraints, but not necessarily the system under control, are fuzzy in nature. This means that the goals and/or the constraints constitute classes of alternatives whose boundaries are not sharply defined.
An example of a fuzzy constraint is: “The cost of A should not be substantially higher than α,” where α is a specified constant. Similarly, an example of a fuzzy goal is: “x should be in the vicinity of x0,” where x0 is a constant. The italicized words are the sources of fuzziness in these examples.
Fuzzy goals and fuzzy constraints can be defined precisely as fuzzy sets in the space of alternatives. A fuzzy decision, then, may be viewed as an intersection of the given goals and constraints. A maximizing decision is defined as a point in the space of alternatives at which the membership function of a fuzzy decision attains its maximum value.
The use of these concepts is illustrated by examples involving multistage decision processes in which the system under control is either deterministic or stochastic. By using dynamic programming, the determination of a maximizing decision is reduced to the solution of a system of functional equations. A reverse-flow technique is described for the solution of a functional equation arising in connection with a decision process in which the termination time is defined implicitly by the condition that the process stops when the system under control enters a specified set of states in its state space.
6,919 citations
TL;DR: In this article, structural identifiability is introduced to answer questions such as: To what extent is it possible to get insight into the internal structure of a system from input-output measurements? What experiments are necessary in order to determine the internal couplings uniquely?
Abstract: In this article we introduce a new concept, structural identifiability, which plays a central role in identification problems. The concept is useful when answering questions such as: To what extent is it possible to get insight into the internal structure of a system from input-output measurements? What experiments are necessary in order to determine the internal couplings uniquely? The definition of the concept of an identifiable structure is given. Criteria as well as certain identifiable structures are discussed. Particular emphasis is given to compartmental models.
774 citations
TL;DR: In this paper, the elastic scattering from one dimensional model potential containing barrier, using stabilization method, has been studied and the response energies of elastic scattering have been shown to be a function of the model potential.
Abstract: Resonance energies of elastic scattering from one dimensional model potential containing barrier, using stabilization method
575 citations
TL;DR: In this article, the structure of a steady one-dimensional isobaric deflagration is examined for the case of a direct first-order one-step irreversible exothermic unimolecular decomposition under Arrhenius kinetics.
Abstract: The structure of a steady one-dimensional isobaric deflagration is examined for the case of a direct first-order one-step irreversible exothermic unimolecular decomposition under Arrhenius kinetics. In particular, the eigenvalue giving the speed of propagation of the laminar flame into the unburned gas is sought for constant Lewis number of order unity. The method of matched asymptotic expansion is invoked in the physically interesting limit of activation temperature large relative to the adiabatic flame temperature. The leading approximation for the eigenvalue is found to be a generalization of the result given by Zeldovich, Frank-Kamenetski, and Semenov for Lewis number unity. The first two terms in the asymptotic expansion for the eigenvalue yield an expression superior to any previously published.
238 citations
225 citations
TL;DR: It is shown that portal pressure does not fall during the spontaneous loss of ascites and the appearance of sodium in the urine, and total plasma volume remains constant, suggesting that nonportal, or effective plasma volume does not contract when ascites is forming.
Abstract: Renal sodium retention, ascites, and portal hypertension coexist in cirrhosis. It is generally held that renal sodium retention results from ascites formation. According to this belief, ascites is initiated by portal hypertension through leakage of excessive lymph from a congested liver, causing effective plasma volume to contract and renal sodium retention to follow as a consequence of this contraction. We would like to propose an alternate theory: that ascites formation in cirrhosis is a consequence of plasma volume expansion, and that renal sodium retention helps to promote this expansion. In this overflow theory of ascites formation portal hypertension is considered to expand mechanically the splanchnic bed, creating the condition for ascites to form as plasma volume expands further with the development of renal sodium retention. Such a theory reopens the question of what is the ultimate stimulus for renal sodium retention in cirrhosis with ascites. We first questioned the traditional reason given for renal sodium retention in cirrhosis when we confirmed the findings of many investigators that total plasma volume is elevated in the presence of ascites.1 We presented evidence that this elevation was not an artifact due to leakage of radioactively tagged albumin into ascites or the thoracic duct lymph space during the period of equilibration of this material in the plasma. Portal hypertension appeared to be the cause of the plasma volume expansion because the plasma volume correlated well with wedged hepatic vein pressure and fell following relief of portal hypertension by means of a portacaval anastomosis. Subsequently, we showed that portal pressure does not fall during the spontaneous loss of ascites and the appearance of sodium in the urine, and total plasma volume remains constant, suggesting that nonportal, or effective plasma volume does not contract when ascites is forming. 2 Recently, we have made two additional observations which are the subject of this communication: ( 1 ) The rate of ascites formation does not increase tollowing paracentesis nor does the plasma volume fall, both of which should occur if the traditional concept of ascites formation is correct. (2) Ascites could be made to reform in a patient with cirrhosis by administering a sodium-retaining hormone. This observation indicates that it is possible for ascites to form as a consequence of plasma-volume expansion in cirrhosis.
208 citations
TL;DR: Prenatal inoculation of cat and dog foetuses is particularly effective in tumour transmission and postnatal dogs bearing FSV induced fibrosarcomas provide antisera suitable for detecting the feline C-type RNA tumour virus antigens in the complement fixation test.
Abstract: An infectious C-type feline sarcoma virus (FSV), isolated from a naturally occurring fibrosarcoma of a domestic house cat, produces fibrosarcomas in kittens and puppies and induces cell transformation in feline embryo fibroblasts. Prenatal inoculation of cat and dog foetuses is particularly effective in tumour transmission. Postnatal dogs bearing FSV induced fibrosarcomas provide antisera suitable for detecting the feline C-type RNA tumour virus antigens in the complement fixation test.
150 citations
TL;DR: The results indicate that the classification should be satisfactory for many epidemiologic purposes, but it is clear that further improvement in definitions and in the standard films might be expected to improve the agreement between readers.
138 citations
TL;DR: It is shown how the Kronecker product can be mathematically defined and efficiently implemented using a matrix factorization method and a generalized spectral analysis is suggested, and a variety of examples are presented displaying various properties of the decompositions possible.
Abstract: A technique is presented to implement a class of orthogonal transformations on the order of pN log p N operations. The technique is due to Good [1] and implements a fast Fourier transform, fast Hadamard transform, and a variety of other orthogonal decompositions. It is shown how the Kronecker product can be mathematically defined and efficiently implemented using a matrix factorization method. A generalized spectral analysis is suggested, and a variety of examples are presented displaying various properties of the decompositions possible. Finally, an eigenvalue presentation is provided as a possible means of characterizing some of the transforms with similar parameters.
123 citations
TL;DR: Incontrovertible evidence of intravascular coagulation seems necessary before heparin therapy can be recommended for the treatment of hemorrhage in patients with cyanotic congenital heart disease.
TL;DR: Aminopeptidase A was proved to be an “angiotensinase” after purification from human serum indicated that this enzyme preferentially hydrolyzes N-terminal dicarboxylic amino acids.
TL;DR: In this article, an image force lowering of the potential energy barrier is included in a theoretical calculation of current transport in metal-semiconductor (Schottky barrier) contacts.
Abstract: Image force lowering of the potential energy barrier is included in a theoretical calculation of current transport in metal-semiconductor (Schottky barrier) contacts. Thermionic and thermionic-field (tunnel) emission are analyzed in a normalized formulation to yield the current (I) vs. voltage (V) relationship. Quantum-mechanical reflection of carriers near the top of the image force rounded barrier is included in the theory by the use of Kemble's transmission probability which incorporates the one-dimensional WKB-type tunneling approximation into a transmission probability applicable both above and below the top of the barrier. Carrier distributions in the semiconductor and in the metal are described by Maxwell-Boltzmann statistics. For any given combination of three dimensionless input parameters E b kT , kT E 00 , and E 00 E 11 , which correspond to bias, temperature and donor concentration respectively, two dimensionless output parameters I f I m (current) and the diode n value (inverse slope of the semilog I vs. V relationship) are determined. Computer solutions are presented in both graphical and tabular form. The results permit a straightforward calculation of the barrier height and the semiconductor donor concentration from experimental I−V data. In comparison with the predictions of current transport models that neglect image force lowering, the present work shows that inclusion of image force leads to a significant increase in the predicted magnitude of the current density and to minor changes in the magnitude of the diode n value. Corrections to the predictions of models that neglect image force arise primarily from enhanced thermionic emission over the image force lowered barrier rather than from enhanced tunnel emission through the image force narrowed barrier. The Kemble transmission probability may be defined in terms of a characteristic transmission energy, Et, which is useful when thermionic emission dominates the conduction process to the extent that quantum-mechanical tunneling and reflection may be considered as a perturbation on thermionic emission. When this occurs Et can be used to estimate the magnitude of the perturbation.
TL;DR: Warmeling of samples of marine sediments to room temperatures prior to the extraction of interstitial water accounts for the apparent enrichments of potassium ion and chloride ion and depletions of magnesium ion and calcium ion.
Abstract: Warmeling of samples of marine sediments to room temperatures prior to the extraction of interstitial water accounts for the apparent enrichments of potassium ion (13.3 percent) and chloride ion (1.4 percent) and depletions of magnesium ion (2.5 percent) and calcium ion (4.9 percent). These differences are the result of changes in ion-exchange selectivity as a function of temperature.
[...]
TL;DR: Findings are consistent with the possibility that lipid peroxidation is a mechanism of ozone toxicity and associated with a greater susceptibility to lethal levels of ozone.
Abstract: Vitamin E deficiency in rats is associated with a greater susceptibility to lethal levels of ozone. Exposure of rats to sublethal ozone concentrations produces an accelerated decline in serum vitamin E levels. These findings are consistent with the possibility that lipid peroxidation is a mechanism of ozone toxicity.
TL;DR: The contraceptive effect of 50, 100, 200 and 400 mg doses of medroxyprogesterone acetate (MPA) in silastic cylindrical vaginal rings (75 mm outside diameter, 7 mm thick) molded around metal springs and placed in diaphragm position was investigated in 19 non-contracepting, regularly-cycling women (7 of whom were placebo controls) over two pretreatment control cycles, 1 treatment cycle (rings inserted for 3 weeks) and 1 post-treatment recovery cycle.
TL;DR: In this paper, the pseudopotential scheme of Lin and Kleinman was used to calculate the energy bands of PbTe, PbSe and PbS in very good agreement with experiment.
TL;DR: A method for the estimation of dihydrotestosterone in human peripheral plasma using diluted plasma from an estrogen treated or pregnant patient and Duplicate samples can be measured with an error of 10% for male and 13% for female samples is described.
Abstract: A method is described for the estimation of dihydrotestosterone (5α-androstan- 17β-ol-3-one) in human peripheral plasma. An aliquot of 5–10 ml of plasma with 3H indicator is extracted with solvent and chromatographed on low residue, methanol washed paper in the Bush B-3 system for 2–3 hr. The sample is then assayed by a displacement technique using diluted plasma from an estrogen treated or pregnant patient. Separation of bound from free steroid is obtained with small Sephadex G-25 columns. The % bound of the sample is converted to mass by comparison with a standard curve and corrected for recovery. Testosterone and dihydrotestosterone can be assayed simultaneously. Duplicate samples can be measured with an error of 10% for male and 13% for female samples and there is no indication for the presence of systematic errors. The nonspecific blank is 0.15±0.05 (sd) ng/sample. Prepubertal plasma did not contain measurable amounts of dihydrotestosterone. Adult male values are 54±19 (sd) and female plasma...
TL;DR: Five instances of tumors arising in extragonadal sites which the authors believe are properly classified as yolk sac tumors are presented and the histogenesis is discussed and compared with that of testicular and ovarian y egg sac tumors.
Abstract: Five instances of tumors arising in extragonadal sites which we believe are properly classified as yolk sac tumors are presented. One of these tumors constituted the malignant component of a mediastinal teratoma; one represented the development of malignancy in a sacrococcygeal cyst; a third started in the broad ligament; and two others have to be classified simply as pelvic extragonadal. All five patients died of their tumors. The histogenesis of these tumors is discussed and compared with that of testicular and ovarian yolk sac tumors.
TL;DR: A survey of several techniques for the identification of dynamic systems using computer techniques, including spectral analysis, search and gradient methods, quasi-linearization, and stochas tic approximation, particularly suited to digital or hybrid computer implementation.
Abstract: This paper presents a survey of a number of techniques for the identification of dynamic systems using computer techniques. The techniques discussed are particularly suited to digital or hybrid com...
TL;DR: Gravimetric and isotopic determinations of the respiratory and water metabolism of Perognathus formosus in the laboratory are in substantial agreement with values which are known from other heteromyid species obtained under similar conditions.
TL;DR: Group of mice were raised in social isolation or were subjected to prolonged and increased social interaction, and the catecholamine synthesizing and metabolizing enzymes were examined in the adrenal glands of these mice.
Abstract: THE important role of catecholamines in behaviour has been recognized1. Increased adrenaline and noradrenaline excretion has been observed in anxiety-provoking situations and in states of anger and aggression2,3. Drugs used in affective disorders cause marked changes in uptake, storage, release and metabolism of the neurotransmitter noradrenaline in the peripheral and central nervous systems4,5. Because of the growing understanding of the implication of catecholamines in behavioural changes, we examined the effect of psychosocial stimulation and deprivation on the activity of the enzymes involved in the biosynthesis and metabolism of catecholamines. Groups of mice were raised in social isolation or were subjected to prolonged and increased social interaction, and the catecholamine synthesizing (tyrosine hydroxylase and phenylethanolamine N-methyltransferase) and metabolizing (monoamine oxidase and catecholamine-O-methyl transferase) enzymes were examined in the adrenal gland. We wish to report marked changes in enzymes involved in catecholamine synthesis and metabolism in the adrenal glands of these mice.
TL;DR: A fresh approach toward the solution of many of the debatable problems in complete denture construction consists of simply recording the extent of the downward and forward mandibular movements made during speech, which automatically restores the patient's original horizontal and vertical overlaps which can be used to control seven factors of occlusion.
Abstract: A fresh approach toward the solution of many of the debatable problems in complete denture construction consists of simply recording, as guided by muscle memory, the extent of the downward and forward mandibular movements made during speech. This automatically restores the patient's original horizontal and vertical overlaps which can be used to control seven factors of occlusion. The values derived by progressive function refinement of this information, through the controlled use of diagnostic treatment dentures incorporating tissue treatment material, and a free running occlusal scheme have been reviewed.
TL;DR: The authors review some classical and some contemporary approaches to the problem of generations, and order these perspectives in a typology reflecting some underlying dimensions of the social-psychological investigation of generations.
Abstract: Of those phenomena on which social scientists gather data and write analyses, there are few of more popular relevance today than discussions of the “generation gap.” It is of course true that the problem of generations is one of the older issues in modem sociology; despite this, very few thorough studies have yet been made to illuminate the nature and extent of continuity or differences between age groups today. Even more importantly, there have been no empirical attempts to analyze the effect on social structure of such differences between generations. Indeed, all too often the discussion of such issues has been impressionistic, speculative, and even apocalyptic-not only in the popular press, but also in the pages of scholarly books and journals. The purpose of this paper is to review some classical and some contemporary approaches to the problem of generations, and t o order these perspectives in a typology reflecting some underlying dimensions of the social-psychological investigation of generations.
TL;DR: Ambulatory function is possible with an unfixed healing fracture of the distal part of the femur when appropriate total-contact support to the limb is provided and an environment of function for the healing fracture is considered.
Abstract: 1. A total-contact, lower-extremity plaster device incorporating brace-joints at the knee has been described for the early ambulatory care of healing fractures in the distal part of the femur.
2. Prospective study of consecutive cases has demonstrated no non-unions or refractures in 150 patients treated with traction followed by early mobilization in a cast-brace and a mean healing time of 14.5 weeks. In a similar but smaller group of fractures treated in the traditional manner by preliminary traction and then immobilized in a spica cast, there were three non-unions, and three refractures occurred after longer periods of immobilization.
3. The factor considered most important for rapid and efficient fracture healing is an environment of function for the healing fracture. Ambulatory function is possible with an unfixed healing fracture of the distal part of the femur when appropriate total-contact support to the limb is provided.
TL;DR: In this article, the authors show that the activity levels and complexity of new interorganizational networks are observable consequents of prior degrees of social integration defined in organizational terms, and they test this proposition in terms of the flow of poverty funds from Federal agencies to and among organizations within the 130 largest American cities.
Abstract: The activity levels and complexity of new interorganizational networks are observable consequents of prior degrees of social integration defined in organizational terms. This proposition was specified and tested in terms of the flow of poverty funds from Federal agencies to and among organizations within the 130 largest American cities. The city's extralocal integration was measured by the number of national associational headquarters it contained, and integration among its local units by the incidence of communitywide civic associations as well as degree of control by its municipal government. With some exceptions, the extralocal variable predicted the level of interorganizational activity, while local integration predicted complexity within a portion of the interorganizational network. Expedient or normative demand, inferred from poverty rates and other forms of deprivation, only made positive contributions to such prediction where the prior levels of integration were high. The study provides empirical support of an interorganizational level of analysis; it outlines directions for further research in urbanized social systems; and it demonstrates the need to employ both additive and multiplicative models of social organization.
01 Jun 1970
TL;DR: In this paper, a review of the theory of filtering for stochastic processes is provided, in particular the sequential theory of linear filtering and the nonlinear filtering theory of non-linear filtering.
Abstract: This paper provides a review of the theory of filtering for stochastic processes. In particular, the sequential theory of linear filtering is reviewed as well as the theory of nonlinear filtering.
TL;DR: The utility of the basic structures of modern mathematics for chemistry is discussed; general set theory, topology, and group theory are shown to pervade almost all static and dynamic aspects of chemistry.
Abstract: The utility of the basic structures of modern mathematics for chemistry is discussed; general set theory, topology, and group theory are shown to pervade almost all static and dynamic aspects of chemistry. Chemical analogy, the systematic classification of molecules and a corresponding nomenclature system, conformational transformations, polyhedral rearrangements, and the relations between starting materials, transition complexes, and final products of chemical reactions are examples of where we apply the elements of modern mathematics to the solution of chemical problems.
TL;DR: Eighteen instances of ovarian tumor with microscopic pattern similar to that of the testicular tumors which the authors termed yolk sac or vitelline are presented and two of the 18 subjects with ovarian tumors appear to have survived their neoplasms; one of these was 7 and the other 15 at the time of surgery.
Abstract: Eighteen instances of ovarian tumor with microscopic pattern similar to that of the testicular tumors which we termed yolk sac or vitelline are presented. In the ovary, though not in the testis, this pattern has often been called “Schiller mesonephroma.” Reasons are given for our preference for the term yolk sac tumor to that of mesonephroma for these neoplasms. The ovarian tumors, though occurring in young individuals, unlike the testicular tumors are not concentrated in early infancy. Moreover, the ovarian tumors do not exhibit the striking age-prognosis relationship which characterized the testicular tumors. Two of the 18 subjects with ovarian tumors appear to have survived their neoplasms; one of these was 7 and the other 15 at the time of surgery. The remaining 16 subjects have died of their neoplasms.