Showing papers by "Stanford University published in 1983"
TL;DR: Several models are formulated in which the security of protocols can be discussed precisely, and algorithms and characterizations that can be used to determine protocol security in these models are given.
Abstract: Recently the use of public key encryption to provide secure network communication has received considerable attention. Such public key systems are usually effective against passive eavesdroppers, who merely tap the lines and try to decipher the message. It has been pointed out, however, that an improperly designed protocol could be vulnerable to an active saboteur, one who may impersonate another user or alter the message being transmitted. Several models are formulated in which the security of protocols can be discussed precisely. Algorithms and characterizations that can be used to determine protocol security in these models are given.
5,145 citations
Book•
01 Jul 1983TL;DR: In this article, the piedmont: textile mills and times of change, and the teaching of how to talk in Trackton and Roadville, are discussed, as well as the teachers as learners and the townspeople.
Abstract: Photographs, maps, figures, tables, texts Acknowledgments Prologue Note on transcriptions Part I. Ethnographer Learning: 1. The piedmont: textile mills and times of change 2. 'Gettin' on' in two communities 3. Learning how to talk in Trackton 4. Teaching how to talk in Roadville 5. Oral traditions 6. Literate traditions 7. The townspeople Part II. Ethnographer Doing: 8. Teachers as learners 9. Learners as ethnographers Epilogue Epilogue - 1996 Notes Bibliography Index.
4,564 citations
TL;DR: It is shown that the optimal transmitter adapts its signal to the state S rather than attempting to cancel it, which is also the capacity of a standard Gaussian channel with signal-to-noise power ratio P/N.
Abstract: A channel with output Y = X + S + Z is examined, The state S \sim N(0, QI) and the noise Z \sim N(0, NI) are multivariate Gaussian random variables ( I is the identity matrix.). The input X \in R^{n} satisfies the power constraint (l/n) \sum_{i=1}^{n}X_{i}^{2} \leq P . If S is unknown to both transmitter and receiver then the capacity is \frac{1}{2} \ln (1 + P/( N + Q)) nats per channel use. However, if the state S is known to the encoder, the capacity is shown to be C^{\ast} =\frac{1}{2} \ln (1 + P/N) , independent of Q . This is also the capacity of a standard Gaussian channel with signal-to-noise power ratio P/N . Therefore, the state S does not affect the capacity of the channel, even though S is unknown to the receiver. It is shown that the optimal transmitter adapts its signal to the state S rather than attempting to cancel it.
4,130 citations
TL;DR: In this article, a new institutionalism emphasizes the relative autonomy of political institutions, the possibilities for inefficiency in history, and the importance of symbolic action to an understanding of politics.
Abstract: Contemporary theories of politics tend to portray politics as a reflection of society, political phenomena as the aggregate consequences of individual behavior, action as the result of choices based on calculated self-interest, history as efficient in reaching unique and appropriate outcomes, and decision making and the allocation of resources as the central foci of political life. Some recent theoretical thought in political science, however, blends elements of these theoretical styles into an older concern with institutions. This new institutionalism emphasizes the relative autonomy of political institutions, possibilities for inefficiency in history, and the importance of symbolic action to an understanding of politics. Such ideas have a reasonable empirical basis, but they are not characterized by powerful theoretical forms. Some directions for theoretical research may, however, be identified in institutionalist conceptions of political order.
3,248 citations
TL;DR: The conjunction rule as mentioned in this paper states that the probability of a conjunction cannot exceed the probabilities of its constituents, P (A) and P (B), because the extension (or the possibility set) of the conjunction is included in the extension of their constituents.
Abstract: Perhaps the simplest and the most basic qualitative law of probability is the conjunction rule: The probability of a conjunction, P (A&B) cannot exceed the probabilities of its constituents, P (A) and P (B), because the extension (or the possibility set) of the conjunction is included in the extension of its constituents. Judgments under uncertainty, however, are often mediated by intuitive heuristics that are not bound by the conjunction rule. A conjunction can be more representative than one of its constituents, and instances of a specific category can be easier to imagine or to retrieve than instances of a more inclusive category. The representativeness and availability heuristics therefore can make a conjunction appear more probable than one of its constituents. This phenomenon is demonstrated in a variety of contexts including estimation of word frequency, personality judgment, medical prognosis, decision under risk, suspicion of criminal acts, and political forecasting. Systematic violations of the conjunction rule are observed in judgments of lay people and of experts in both between-subjects and within-subjects comparisons. Alternative interpretations of the conjunction fallacy are discussed and attempts to combat it are explored.
3,221 citations
TL;DR: This paper reviewed the nonparametric estimation of statistical error, mainly the bias and standard error of an estimator, or the error rate of a prediction rule, at a relaxed mathematical level, omitting most proofs, regularity conditions and technical details.
Abstract: This is an invited expository article for The American Statistician. It reviews the nonparametric estimation of statistical error, mainly the bias and standard error of an estimator, or the error rate of a prediction rule. The presentation is written at a relaxed mathematical level, omitting most proofs, regularity conditions, and technical details.
3,146 citations
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TL;DR: In this article, the authors explore why organizations tend to be increasingly and inevitably homogeneous in their forms and practices, and suggest that organizational fields are structured into an organizational field by powerful forces that lead them to become similar.
Abstract: Instead of examining why organizations are dissimilar, this study explores why organizations tend to be increasingly and inevitably homogenous in their forms and practices. Organizations in a similar line of work are structured into an organizational field by powerful forces that lead them to become similar. Rather than the causes of rationalization and bureaucratization suggested by Max Weber, including competition and the need for efficiency, institutional similarity is due to the structuration of organizational fields, a process caused largely by the state and the professions, which are the great rationalizers of the late 20th century. In highly structured organizational fields, rational efforts of individuals aggregately lead to structural, cultural, and output homogeneity. Homogenization is best captured by the concept of isomorphism, the process whereby one element in a population resembles others that confront the same environmental conditions. The two types of isomorphism are competitive and institutional. Three processes lead to organizational similarity: (1) coercive isomorphism stemming from political influence and the problem of legitimacy; (2) mimetic isomorphism resulting from uniform responses to uncertainty; and (3) normative isomorphism associated with professionalism. While these isomorphic processes improve organizational transactions, they do not necessarily increase internal efficiency. Twelve hypotheses are offered for further research about which organizational fields will be most homogenous. These hypotheses relate the impact of resource centralization and dependency, goal ambiguity and technical uncertainty, and professionalism and structuration on isomorphic change. Finally, useful implications of the study for theories of organizations and social change are offered. (TNM)
2,879 citations
TL;DR: In this paper, an algorithm, called RATTLE, for integrating the equations of motion in molecular dynamics calculations for molecular models with internal constraints is presented. But it is based on the Verlet algorithm and retains the simplicity of using Cartesian coordinates for each of the atoms to describe the configuration of a molecule with internal constraint.
2,669 citations
TL;DR: In this article, the authors build on the theory of irreversible choice under uncertainty to explain cyclical investment fluctuations and show that when individual projects are irreversible, agents must make investment timing decisions that trade off the extra returns from early commitment against the benefits of increased information gained by waiting.
Abstract: This paper builds on the theory of irreversible choice under uncertainty to give an explanation of cyclical investment fluctuations. The key observation is that, when individual projects are irreversible, agents must make investment timing decisions that trade off the extra returns from early commitment against the benefits of increased information gained by waiting. In an environment in which the underlying stochastic structure is itself subject to random change, events whose long-run implications are uncertain can create an investment cycle by temporarily increasing the returns to waiting for information.
2,352 citations
TL;DR: An adaptive psychometric procedure that places each trial at the current most probable Bayesian estimate of threshold is described, taking advantage of the common finding that the human psychometric function is invariant in form when expressed as a function of log intensity.
Abstract: An adaptive psychometric procedure that places each trial at the current most probable Bayesian estimate of threshold is described. The procedure takes advantage of the common finding that the human psychometric function is invariant in form when expressed as a function of log intensity. The procedure is simple, fast, and efficient, and may be easily implemented on any computer.
2,334 citations
TL;DR: In this paper, a prediction rule is constructed on the basis of some data, and then the error rate of this rule is estimated in classifying future observations using cross-validation.
Abstract: We construct a prediction rule on the basis of some data, and then wish to estimate the error rate of this rule in classifying future observations. Cross-validation provides a nearly unbiased estimate, using only the original data. Cross-validation turns out to be related closely to the bootstrap estimate of the error rate. This article has two purposes: to understand better the theoretical basis of the prediction problem, and to investigate some related estimators, which seem to offer considerably improved estimation in small samples.
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TL;DR: In this article, the authors examined how major firms utilize R&D activities to create new businesses through internal corporate venturing (ICV) using a qualitative method, which was done for one large, U.S.-based high-technology firm.
Abstract: Examines how major firms utilize R&D activities to create new businesses through internal corporate venturing (ICV). Using a qualitative method, this analysis was done for one large, U.S.-based high-technology firm. This firm has a new venture division, which was formed in the early 1970s. Data were obtained from the study of six major projects that were ongoing at the time of the research. This data collection included interviews with 61 firm employees involved in the projects. The key and peripheral managerial activities of the grounded process model of ICV and the flow of these activities through four venture stages are presented. The four major processes in the model are definition, impetus, strategic context determination, and structural context determination. Among the findings: It is usually the autonomous strategic initiatives of individuals at the operational level that provide the ideas for much of corporate entrepreneurship. As a result of the very autonomous nature of these initiatives, management has difficulty deciding how to deal with the new initiatives and often ignores administrative issues through the entrepreneurial process. Middle-level managers are found to play a key role in linking these autonomous initiatives to the corporate strategy of these diversified major firms. (SRD)
TL;DR: A monoclonal antibody specific for a lymphocyte surface molecule that appears to mediate recognition of lymph node HEV and to be required for lymphocyte homing into lymph nodes in vivo is described.
Abstract: Lymphocytes migrate from the bloodstream by recognizing and binding to specialized endothelial cells lining the high endothelial venules (HEV) in lymph nodes and Peyer's patches. We describe here a monoclonal antibody, MEL-14, specific for a lymphocyte surface molecule that appears to mediate recognition of lymph node HEV, and to be required for lymphocyte homing into lymph nodes in vivo.
TL;DR: In this article, the authors present a model of the strategic process concerning entrepreneurial activity in large, complex organizations and make the following key points: First, firms need both diversity and order in their strategic activities to maintain their viability.
Abstract: This paper presents a model of the strategic process concerning entrepreneurial activity in large, complex organizations. Previous empirical and theoretical findings can be integrated in this new conceptual framework.
The paper makes the following key points. First, firms need both diversity and order in their strategic activities to maintain their viability. Diversity results primarily from autonomous strategic initiatives of participants at the operational level. Order results from imposing a concept of strategy on the organization. Second, managing diversity requires an experimentation-and-selection approach. Middle level managers play a crucial role in this through their support for autonomous strategic initiatives early on, by combining these with various capabilities dispersed in the firm's operating system, and by conceptualizing strategies for new areas of business. Third, top management's critical contribution consists in strategic recognition rather than planning. By allowing middle level managers to redefine the strategic context, and by being fast learners, top management can make sure that entrepreneurial activities will correspond to their strategic vision, retroactively. Fourth, strategic management at the top should be to a large extent concerned with balancing the emphasis on diversity and order over time. Top management should control the level and the rate of change rather than the specific content of entrepreneurial activity. Finally, new managerial approaches and innovative administrative arrangements are required to facilitate the collaboration between entrepreneurial participants and the organizations in which they are active.
TL;DR: The DNA sequences derived from the germ line JH-C mu region are found to be required for accurate and efficient transcription from a functionally rearranged VH promoter, and the Ig gene enhancer appears to act in a tissue-specific manner.
TL;DR: In this article, a model of the strategic process in large, complex firms is presented under which the propositions "structure follows strategy" and "strategy follows structure" can both be subsumed.
Abstract: Based on a review of previous landmark studies and in the light of findings of recent research on internal corporate venturing, a model of the strategic process in large, complex firms is presented under which the propositions “structure follows strategy” and “strategy follows structure” can both be subsumed. Current corporate strategy induces some strategic behavior but changes in corporate strategy follow other, autonomous, strategic behavior.
TL;DR: The identity of genes that specify the largest RNA polymerase II subunits, the 220-000- and 150,000-dalton polypeptides, was confirmed by competitive radioimmune assay.
Abstract: Genes encoding yeast RNA polymerase II subunits were cloned. Efficient isolation of these genes was accomplished by probing a phage lambda gt11 recombinant DNA expression library with polyvalent antibodies directed against purified yeast RNA polymerase II. The identity of genes that specify the largest RNA polymerase II subunits, the 220,000- and 150,000-dalton polypeptides, was confirmed by competitive radioimmune assay. Both of these genes exist in single copy in the yeast Saccharomyces cerevisiae.
TL;DR: In this paper, the origin of the observed scaling violations in the hadron spectra is investigated, and a simple parametrization for the heavy-quark fragmentation function is given which describes well recently measured charmed-meson spectra.
Abstract: The origin of the observed scaling violations in inclusive ${e}^{+}{e}^{\ensuremath{-}}$ annihilation is investigated. Perturbative jet evolution is not necessarily the only reason for scale breaking in the hadron spectra at present energies. Remnants of finite-transverse-momentum and mass effects are still important in nonperturbative, cascade-type, jet formation in the \ensuremath{\sim}10 GeV range. Heavy-quark fragmentation has a strong impact on hadronic inclusive spectra. A simple parametrization for the heavy-quark fragmentation function is given which describes well recently measured charmed-meson spectra. Taking these effects into account, good agreement with the observed scaling violations is obtained in cascade-type jet models with hard-gluon bremsstrahlung.
TL;DR: In this paper, the data are used through their rank order, allowing a nonparametric approach to the data bivariate distribution, which allows a risk-qualified estimation of local and global spatial distributions.
Abstract: The indicator approach, whereby the data are used through their rank order, allows a nonparametric approach to the data bivariate distribution. Such rich structural information allows a nonparametric risk-qualified, estimation of local and global spatial distributions.
TL;DR: In this paper, an experimental investigation of transport processes in the near wake of a circular cylinder at a Reynolds number of 140000 was performed using X-array hot-wire probes mounted on a pair of whirling arms, which increases the relative velocity component along the probe axis and decreases the relative flow angle to usable values in regions where fluctuations in flow velocity and direction are large.
Abstract: This paper describes an experimental investigation of transport processes in the near wake of a circular cylinder at a Reynolds number of 140000. The flow in the first eight diameters of the wake was measured using X-array hot-wire probes mounted on a pair of whirling arms. This flying-hot-wire technique increases the relative velocity component along the probe axis and thus decreases the relative flow angle to usable values in regions where fluctuations in flow velocity and direction are large. One valuable fringe benefit of the technique is that rotation of the arms in a uniform flow applies a wide range of relative flow angles to the X-arrays, making them inherently self-calibrating in pitch. An analog circuit was used to generate an intermittency signal, and a fast surface-pressure sensor was used to generate a phase signal synchronized with the vortex-shedding process. The phase signal allowed sorting of the velocity data into 16 populations, each having essentially constant phase. An ensemble average for each population yielded a sequence of pictures of the instantaneous mean flow field, with the vortices frozen as they would be in a photograph. In addition to globally averaged data for velocity and stress, the measurements yield non-steady mean data (in the sense of an average a t constant phase) for velocity, intermittency, vorticity, stress and turbulent-energy production as a function of phase for the first eight diameters of the near wake. The stresses were resolved into a contribution from the periodic motion and a contribution from the random motion at constant phase. The two contributions are found to have comparable amplitudes but quite different geometries, and the time average of their sum (the conventional global Reynolds stress) therefore has a quite-complex structure. The non-steady mean-vorticity field is obtained with good resolution as the curl of the non-steady mean-velocity field. Less than half of the shed circulation appears in the vortices, and there is a slow decay of this circulation for each shed vortex as it moves downstream. In the discussion, considerable emphasis is put on the topology of the non-steady mean flow, which emerges as a pattern of centres and saddles in a frame of reference moving with the eddies. The kinematics of the vortex-formation process are described in terms of the formation and evolution of saddle points between vortices in the first few diameters of the near wake. One important conclusion is that a substantial part of the turbulence production is concentrated near the saddles and that the mechanism of turbulence production is probably vortex stretching at intermediate scales. Entrainment is also found to be closely associated with saddles and to be concentrated near the upstream-facing interface of each vortex.
TL;DR: This report presents the first study of cardiac arrhythmias and conduction disturbance in a large group of patients with sleep apnea syndrome studied between 1974 and 1979 with 24-hour Holter electrocardiography and a simultaneously recorded polygraph during late afternoon or nocturnal sleep.
Abstract: This report presents the first study of cardiac arrhythmias and conduction disturbance in a large group (400 patients) with sleep apnea syndrome studied between 1974 and 1979 with 24-hour Holter electrocardiography and a simultaneously recorded polygraph during late afternoon or nocturnal sleep. Of the 400, 193 patients (48%) had cardiac arrhythmias during the recorded night. The mean number of apneic events, age, weight and lowest oxygen saturation during sleep were not significantly different in those with arrhythmias. The most significant abnormalities were unsustained ventricular tachycardia in 8 patients, sinus arrest that lasted for 2.5 to 13 seconds in 43 patients, and second-degree atrioventricular conduction block in 31. Seventy-five had frequent (greater than 2 beats/min) premature ventricular contractions during sleep. Fifty patients with significant arrhythmias had a tracheostomy and were monitored again after surgery. No arrhythmia was present in these patients except for premature ventricular contractions.
TL;DR: Upper and lower bounds for delay that are computationally simple are presented in this paper and can be used to bound the delay, given the signal threshold, and to certify that a circuit is "fast enough," given both the maximum delay and the voltage threshold.
Abstract: In MOS integrated circuits, signals may propagate between stages with fanout. The exact calculation of signal delay through such networks is difficult. However, upper and lower bounds for delay that are computationally simple are presented in this paper. The results can be used 1) to bound the delay, given the signal threshold, or 2) to bound the signal voltage, given a delay time, or 3) certify that a circuit is "fast enough," given both the maximum delay and the voltage threshold.
TL;DR: Simulations using a biochemically-based model of leaf photosynthesis make it possible to predict the distribution of leaf nitrogen contents that maximizes photosynthetic carbon gain over the canopy of an entire plant.
Abstract: Simulations using a biochemically-based model of leaf photosynthesis make it possible to predict the distribution of leaf nitrogen contents that maximizes photosynthetic carbon gain over the canopy of an entire plant. In general, the optimal nitrogen content increased with increasing daily photosynthetically active photon irradiance.
TL;DR: In this paper, the concept of student cognitive engagement and the manner in which classroom instruction may develop self-regulated learners are analyzed. But, since theory and research on academic motivation, to date only vaguely define the role of learning processes, and since studies of learning strategies rarely assess motivational outcomes, their analysis integrates these two streams of literature.
Abstract: The article analyzes the concept of student cognitive engagement, and the manner in which classroom instruction may develop self‐regulated learners. Since theory and research on academic motivation, to date only vaguely define the role of learning processes, and since studies of learning strategies rarely assess motivational outcomes, our analysis integrates these two streams of literature. We also identify specific features of instruction and discuss how they might influence the complex of student interpretive processes focal to classroom learning and motivation. Measurement issues and research strategies peculiar to the investigation of cognitive engagement are addressed.
TL;DR: In this paper, a causal modelling methodology is used to examine competing methodological and theoretical hypotheses concerning the effects of product quality on direct costs and business unit return on a business unit's performance.
Abstract: This study uses a causal modelling methodology to examine competing methodological and theoretical hypotheses concerning the effects of product quality on direct costs and business unit return on i...
TL;DR: The results indicate that differentiated mouse muscle nuclei can activate human muscle genes in the nuclei of a cell type in which they are not normally expressed, and that this activation occurs via the cytoplasm.
TL;DR: It is proved that there are properties of sequences that are not expressible in temporal logic, even though they are easily expressible using, for instance, regular expressions, and shown how temporal logic can be extended to express any property definable by a right-linear grammar and hence a regular expression.
Abstract: It is first proved that there are properties of sequences that are not expressible in temporal logic, even though they are easily expressible using, for instance, regular expressions. Then, it is shown how temporal logic can be extended to express any property definable by a right-linear grammar and hence a regular expression. Finally, a complete axiomatization and a decision procedure for the extended temporal logic are given and the complexity of the extended logic is examined.
TL;DR: In this paper, the partitioning of 25 trace elements between high-silica rhyolitic glass and unzoned phenocrysts of potassic and sodic sanidine, biotite, augite, ferrohedenbergite, hypersthene, fayalite, titanomagnetite, ilmenite, zircon, and allanite has been determined by INAA on suites of samples from the mildly peralkaline lavas and tuff of the Sierra La Primavera, Mexico, and the metaluminous, compo
TL;DR: In this paper, the authors introduce a model of feedback effect equilibria in which an asymmetrically informed agent is motivated to communicate its privately known attribute but can do so only through channels or signals which convey directly useful information to competing agents.
Abstract: This paper introduces a model of "feedback effect equilibrium" i.e. equilibria in which an asymmetrically informed agent is motivated to communicate its privately known attribute but can do so only through channels or signals which convey directly useful information to competing agents. This revelation to the competition serves to reduce the value of the private information held by the first agent. Models of this kind are of obvious relevance to realistic theories of product or financial market disclosure policies of firms, patenting, and a host of related behavioural and regulatory issues. This model is developed in the context of a set of firms engaged in research and development rivalry, in which the value of privately held and disclosed information arises from its implications for the likelihood and timing of productive innovation.