• Speech Sciences
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• 제8권1호
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• pp.77-91
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• 2001

This paper investigates the timing of Korean spoken in a news-reading speech style in order to improve the naturalness of durations used in Korean speech synthesis. Each segment in a corpus of 671 read sentences was annotated with 69 segmental and prosodic features so that the measured duration could be correlated with the context in which it occurred. A CART model based on the features showed a correlation coefficient of 0.79 with an RMSE (root mean squared prediction error) of 23 ms between actual and predicted durations in reserved test data. These results are comparable with recent published results in Korean and similar to results found in other languages. An analysis of the classification tree shows that phrasal structure has the greatest effect on the segment duration, followed by syllable structure and the manner features of surrounding segments. The place features of surrounding segments only have small effects. The model has application in Korean speech synthesis systems.

• Korean Journal of Optics and Photonics
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• 제4권4호
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• pp.452-456
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• 1993

The quantum efficiencies of photomultiplier tubes were measured by counting the coincidence photon pairs generated in the process of spontaneous parametric down-conversion. They were measured within 3% accuracy over the range of wavelength from 560 to 850 nm without any standard light source or detector. The values for 633 nm correspond to those obtained with a calibrated laser power meter within the measurement error.

• Journal of the Korean Operations Research and Management Science Society
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• 제31권1호
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• pp.55-71
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• 2006

We perform a computational study on 0-1 knapsack problems generated under explicit correlation induction. A total of 2000 100-variable test problems are solved. We use two solution methods: (1) a well known heuristic and (2) a representative branch and bound type algorithm. Two different performance measures are considered: (1) the number of nodes needed to find an optimal solution and (2) the relative error of the heuristic solution. We also examine the effect of different joint probability mass functions (pmfs) for the coefficient values on the performance of the solution procedure.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.865-866
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• 2006

The aim of this study was to implement the system that could evaluate the function of urinary tract with noninvasive and comfort methods. There for in this study hardware device and computer software have been developed that enables the analysis of the urine flow rate and vesical pressure signal measured during voiding. These signals were recorded simultaneously and transmitted to the PC. For the measurement system evaluation, the model system for the lower urinary system of men was designed. From the evaluation of the model system, vesical pressure was correlated with the occlusion degree. In a pilot study on 5 male subjects, means of standard deviation was 1.06, average error rate was 2.09 and coefficient variation was 2.09.

• Journal of the Korea Institute of Military Science and Technology
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• 제12권1호
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• pp.44-50
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• 2009

In this study, the relationship between military pilot's spatial ability and unusual attitude recovery was investigate. MRT(Mental Rotation Test) was measured with spatial ability whereas recovery time and error rates were mearsured with respect to 11 unusual attitudes. Eight fighter pilots and eight rear cockpit pilots of F-4E participated in this study. The results showed that MRT response time was significantly correlated with unusual attitude recovery time. The regression equation showed that unusual attitude recovery time was linearly related to MRT response time and could be explained by MRT response time more than 66%. In conclusion, it is recommended that a training is needed to improve the mental rotation ability in a visually restricted environments during maneuvering.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권5A호
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• pp.487-493
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• 2008

In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

• Journal of the Korean Society of Safety
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• 제17권4호
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• pp.126-132
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• 2002

By using the reference data, the empirical equations which describe the interrelationships of explosion properties and physical properties of n-chlorinated hydrocarbons have been derived. The properties which have been correlated are the lower and upper explosive limits, the stoichiometric coefficients, the heats of combustion, the carbon numbers. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosive limits(LEL) of chlorinated hydrocarbons on the basis of the literature data are proposed. The fire and explosion properties calculated by the proposed equations in this research were a good agrement with literature data within a few A.A.P.E.(Average Absolute Percent Error) and A.A.D.(Average Absolute Deviation.) From a given explosive properties, by using the proposed equations, it is possible to predict to the fire and explosion characteristics for the other chlorinated hydrocarbons.

• Proceedings of the KSRS Conference
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.312-316
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• 2002

Satellite radar interferometry data shows a strong coherent signal on oyster sea farms where artificial structures installed on the bottom. We obtained 21 highly coherent interferograms from eleven JERS-1 SAR data sets despite of large orbital baseline (~2 km) or large temporal baseline (~l year). The phases observed in sea farms are probably induced by double bouncing on sea surface, and consequently reveal a tide height variation. To restore the absolute sea level changes we counted the number of wrapping by exploiting the intensity of backscattering. Backscattering intensity is closely correlated with the change in water surface height, while interferometry gives the detailed variation within the limit of 2$\pi$ (or 15.3 cm). Comparing the radar measurements with the tide gauge records yielded a correlation coefficient of 0.96 and an ms error of 6.0 cm. The results demostrate that radar interferometry is promising to measure sea level.

• Electrical & Electronic Materials
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• 제8권5호
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• pp.633-639
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• 1995

Dropouts in magnetic media are a primary quality deficiency which is detrimental to magnetic signal quality and thus the major impediment to error-free recording, especially in high density digital recorders. The specific form of defects and causes found to be responsible for signal dropouts occurring in magnetic tape were studied. Dropout occurred when the RF signal falls to low level due to the various types of surface defects. However, the fall in the level of the RF signal in gravure roll coated tapes was most often caused by foreign particles adhering to the magnetic tape. It was also shown from the present study that scattered particles trapped under the tape surface or put on the top can lift it as it crosses the head, creating a spherical tent shaped defect and causing a temporary signal drop. Dropout producing substances were identified through optical and microchemical analyses. The results were correlated with measured electrical signal losses combined with analytical microscopy to clarify source identification of defects.

• Communications for Statistical Applications and Methods
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• 제22권5호
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• pp.445-462
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• 2015

This article deals with the problem of estimation of the population mean in presence of multi-auxiliary information in two occasion rotation sampling. A multivariate exponential ratio type estimator has been proposed to estimate population mean at current (second) occasion using information on p-additional auxiliary variates which are positively correlated to study variates. The theoretical properties of the proposed estimator are investigated along with the discussion of optimum replacement strategies. The worthiness of proposed estimator has been justified by comparing it to well-known recent estimators that exist in the literature of rotation sampling. Theoretical results are justified through empirical investigations and a detailed study has been done by taking different choices of the correlation coefficients. A simulation study has been conducted to show the practicability of the proposed estimator.