Towards Understanding Spontaneous Speech: Word Accuracy vs. Concept Accuracy

In this paper we describe an approach to automatic evaluation of both the speech recognition and understanding capabilities of a spoken dialogue system for train time table information. We use word accuracy for recognition and concept accuracy for understanding performance judgement. Both measures are calculated by comparing these modules' output with a correct reference answer. We report evaluation results for a spontaneous speech corpus with about 10000 utterances. We observed a nearly linear relationship between word accuracy and concept accuracy.Comment: 4 pages PS, Latex2e source importing 2 eps figures, uses icslp.cls, caption.sty, psfig.sty; to appear in the Proceedings of the Fourth International Conference on Spoken Language Processing (ICSLP 96

Some recent results in aerospace vehicle trajectory optimization techniques

Algorithms and computation techniques for solving trajectory optimization problem

Central bank independence and the monetary instrument problem

We study the monetary instrument problem in a model of optimal discretionary fiscal and monetary policy. The policy problem is cast as a dynamic game between the central bank, the fiscal authority, and the private sector. We show that, as long as there is a conflict of interest between the two policy-makers, the central bank's monetary instrument choice critically affects the Markov-perfect Nash equilibrium of this game. Focusing on a scenario where the fiscal authority is impatient relative to the monetary authority, we show that the equilibrium allocation is typically characterized by a public spending bias if the central bank uses the nominal money supply as its instrument. If it uses instead the nominal interest rate, the central bank can prevent distortions due to fiscal impatience and implement the same equilibrium allocation that would obtain under cooperation of two benevolent policy authorities. Despite this property, the welfare-maximizing choice of instrument depends on the economic environment under consideration. In particular, the money growth instrument is to be preferred whenever fiscal impatience has positive welfare effects, which is easily possible under lack of commitment

Inflation dynamics under optimal discretionary fiscal and monetary policies

We examine the dynamic properties of inflation in a model of optimal discretionary fiscal and monetary policies. The lack of commitment and the presence of nominally risk-free debt provide the government with an incentive to implement policies which induce positive and persistent inflation rates. We show that this property obtains already in an environment with flexible prices and perfectly competitive product markets. Introducing nominal rigidities and imperfect competition has no qualitative but important quantitative implications. In particular, with a modest degree of price stickiness our model generates inflation dynamics very similar to those experienced in the U.S. since the Volcker disinflation of the early 1980s

Optimal Fiscal and Monetary Policy Without Commitment

This paper studies optimal fiscal and monetary policy in a stochastic economy with imperfectly competitive product markets and a discretionary government. We find that, in the flexible price economy, optimal time-consistent policy implements the Friedman rule independently of the degree of imperfect competition. This result is in contrast to the Ramsey literature, where the Friedman rule emerges as the optimal policy only if markets are perfectly competitive. Second, once nominal rigidities are introduced, the Friedman rule ceases to be optimal, inflation rates are low and stable, and tax rates are relatively volatile. Finally, optimal time-consistent policy under sticky prices does not generate the near-random walk behavior of taxes and real debt that can be observed under optimal policy in the Ramsey problem. A common reason for these results is that the discretionary government, in an effort to asymptotically eliminate its time-consistency problem, accumulates a large net asset position such that it can finance its expenditures via the associated interest earnings

Exploring the functional domain and the target of the tetanus toxin light chain in neurohypophysial terminals

The tetanus toxin light chain blocks calcium induced vasopressin release from neurohypophysial nerve terminals. Here we show that histidine residue 233 within the putative zinc binding motif of the tetanus toxin light chain is essential for the inhibition of exocytosis, in the rat. The zinc chelating agent dipicolinic acid as well as captopril, an inhibitor of zinc-dependent peptidases, counteract the effect of the neurotoxin. Synthetic peptides, the sequences of which correspond to motifs present in the cytoplasmic domain of the synaptic vesicle membrane protein synaptobrevin 1 and 2, prevent the effect of the tetanus toxin light chain. Our results indicate that zinc bound to the zinc binding motif constitutes the active site of the tetanus toxin light chain. Moreover they suggest that cleavage of synaptobrevin by the neurotoxin causes the inhibition of exocytotic release of vasopressin from secretory granules

Evaluation of the application of ERTS-1 data to the regional land use planning process

The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis

Out-of-plane magnetic domain structure in a thin film of La0.67Sr0.33MnO3 on SrTiO3 (001) observed by magnetic force microscopy

The room temperature out-of-plane magnetization of epitaxial thin films of La0.67Sr0.33MnO3 on SrTiO3 (001) has been investigated with magnetic force microscopy, using magnetic tips with very small coercivity, relative to the film. A clear magnetic pattern in the form of a checkerboard, with domain dimensions of a few hundred nanometers, was found for the thin, coherently strained films, which is approximately aligned along the maximum strain [110] and [1[overline 1]0] directions in the film. With increasing in-plane applied magnetic field, the magnetic contrast reduces, reflecting the rotation of the magnetization vector into the plane of the film. This process is reversible with the field. The out-of-plane magnetic pattern is not sensitive to rotation of the in-plane field. We attribute the observed out-of-plane magnetization component to an out-of-plane magnetic anisotropy, which is a remainder of the [111] magnetic easy axis in bulk La0.67Sr0.33MnO3 single crystal

Causes of prehospital misinterpretations of ST elevation myocardial infarction

Objectives: To determine the causes of software misinterpretation of ST elevation myocardial infarction (STEMI) compared to clinically identified STEMI to identify opportunities to improve prehospital STEMI identification. Methods: We compared ECGs acquired from July 2011 through June 2012 using the LIFEPAK 15 on adult patients transported by the Los Angeles Fire Department. Cases included patients ≥18 years who received a prehospital ECG. Software interpretation of the ECG (STEMI or not) was compared with data in the regional EMS registry to classify the interpretation as true positive (TP), true negative (TN), false positive (FP), or false negative (FN). For cases where classification was not possible using registry data, 3 blinded cardiologists interpreted the ECG. Each discordance was subsequently reviewed to determine the likely cause of misclassification. The cardiologists independently reviewed a sample of these discordant ECGs and the causes of misclassification were updated in an iterative fashion. Results: Of 44,611 cases, 50% were male (median age 65; inter-quartile range 52–80). Cases were classified as 482 (1.1%) TP, 711 (1.6%) FP, 43371 (97.2%) TN, and 47 (0.11%) FN. Of the 711 classified as FP, 126 (18%) were considered appropriate for, though did not undergo, emergent coronary angiography, because the ECG showed definite (52 cases) or borderline (65 cases) ischemic ST elevation, a STEMI equivalent (5 cases) or ST-elevation due to vasospasm (4 cases). The sensitivity was 92.8% [95% CI 90.6, 94.7%] and the specificity 98.7% [95% CI 98.6, 98.8%]. The leading causes of FP were ECG artifact (20%), early repolarization (16%), probable pericarditis/myocarditis (13%), indeterminate (12%), left ventricular hypertrophy (8%), and right bundle branch block (5%). There were 18 additional reasons for FP interpretation (<4% each). The leading causes of FN were borderline ST-segment elevations less than the algorithm threshold (40%) and tall T waves reducing the ST/T ratio below threshold (15%). There were 11 additional reasons for FN interpretation occurring ≤3 times each. Conclusion: The leading causes of FP automated interpretation of STEMI were ECG artifact and non-ischemic causes of ST-segment elevation. FN were rare and were related to ST-segment elevation or ST/T ratio that did not meet the software algorithm threshold

Risk of acquired drug resistance during short-course directly observed treatment of tuberculosis in an area with high levels of drug resistance.

BACKGROUND: Data on the performance of standardized short-course directly observed treatment (DOTS) of tuberculosis (TB) in areas with high levels of drug resistance and on the potential impact of DOTS on amplification of resistance are limited. Therefore, we analyzed treatment results from a cross-sectional sample of patients with TB enrolled in a DOTS program in an area with high levels of drug resistance in Uzbekistan and Turkmenistan in Central Asia. METHODS: Sputum samples for testing for susceptibility to 5 first-line drugs and for molecular typing were obtained from patients starting treatment in 8 districts. Patients with sputum smear results positive for TB at the end of the intensive phase of treatment and/or at 2 months into the continuation phase were tested again. RESULTS. Among 382 patients with diagnoses of TB, 62 did not respond well to treatment and were found to be infected with an identical Mycobacterium tuberculosis strain when tested again; 19 of these patients had strains that developed new or additional drug resistance. Amplification occurred in only 1.2% of patients with initially susceptible or monoresistant TB strains, but it occurred in 17% of those with polyresistant strains (but not multidrug-resistant strains, defined as strains with resistance to at least isoniazid and rifampicin) and in 7% of those with multidrug-resistant strains at diagnosis. Overall, 3.5% of the patients not initially infected with multidrug-resistant TB strains developed such strains during treatment. Amplification of resistance, however, was found only in polyresistant Beijing genotype strains. CONCLUSIONS: High levels of amplification of drug resistance demonstrated under well-established DOTS program conditions reinforce the need for implementation of DOTS-Plus for multidrug-resistant TB in areas with high levels of drug resistance. The strong association of Beijing genotype and amplification in situations of preexisting resistance is striking and may underlie the strong association between this genotype and drug resistance