• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.6
• /
• pp.1157-1164
• /
• 2007

In this paper, we implement a PDA(Personal Digital Assistant)-based audiometric system in order to estimate hearing threshold by adopting both pure-tone sound and speech audiometric test system. To estimate a subject's hearing threshold in an ambulatory audiometric test environment, an efficient sound calibration scheme between a PDA and a headphone device is proposed by appling polynomial fitting algorithms in 8-banded frequency ranges.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.10
• /
• pp.2299-2304
• /
• 2010

A sensorless vector control of an induction motor provides a good performance in the middle and high speed region. However, in the low speed region, it is very difficult to implement the sensorless vector controller because the feeding voltage measured by the motor is very low. In this paper, we designed the sensorless vector controller of an induction motor using the estimate of the slip frequency. To verify the performance of the proposed controller, an experiment has been performed.

• Structural Engineering and Mechanics
• /
• v.45 no.4
• /
• pp.423-437
• /
• 2013

Complex structures are usually assembled from several substructures with joints connecting them together. These joints have significant effects on the dynamic behavior of the assembled structure and must be accurately modeled. In structural analysis, these joints are often simplified by assuming ideal boundary conditions. However, the dynamic behavior predicted on the basis of the simplified model may have significant errors. This has prompted the researchers to include the effect of joint stiffness in the structural model and to estimate the stiffness parameters using inverse dynamics. In the present work, structural joints have been modeled as a pair of translational and rotational springs and frequency equation of the overall system has been developed using sub-structure synthesis. It is shown that using first few natural frequencies of the system, one can obtain a set of over-determined system of equations involving the unknown stiffness parameters. Method of multi-linear regression is then applied to obtain the best estimate of the unknown stiffness parameters. The estimation procedure has been developed for a two parameter joint stiffness matrix.

• Korean Management Science Review
• /
• v.29 no.3
• /
• pp.1-11
• /
• 2012

This paper considers a localization problem in time difference of arrival (TDOA)-based radio frequency identification (RFID) systems. To estimate the position of a target tag, this paper suggests three localization algorithms that use benchmark tags. The benchmark tags are the same type as the target tag, but either the locations or distance of the benchmark tags are known. Two algorithms use the benchmarks for auxiliary information to improve the estimation accuracy of the other localization algorithms such as least squared estimator (LSE). The other one utilizes the benchmarks as essential tags to estimate the location. Numerical tests show that the localization accuracy can be improved by using benchmark tags especially when an algorithm using the LSE is applied to the localization problem. Furthermore, this paper shows that our benchmark algorithm is valuable when the measurement noise is large.

• Proceedings of the KOSOMBE Conference
• /
• v.1995 no.11
• /
• pp.205-208
• /
• 1995

Analysis of Heart Rate Variability has been studied to estimate autonomic nervous system. PR interval represents conduction time from atrium to ventricle. PR interval variability(PRV) is also can be used to estimate autonomic nervous system. We have acquired two-state ECGs of children who are before vagal stimulation and after vagal stimulation. We applied chaotic theory to each ECG in order to analyze PRV, and compared the results from frequency domain analysis. The correlation dimension of PRV of pre-stimulated children is higher than that of post-stimulated children.

• Journal of Positioning, Navigation, and Timing
• /
• v.6 no.4
• /
• pp.135-140
• /
• 2017

This paper proposes a signal merging algorithm to increase the signal-to-noise ratio (SNR) of a GPS correlator output to estimate the roll angle of a rotating vehicle in a weak GPS signal environment. Rotation Locked Loop (RLL) algorithm is used to estimate a roll angle using the characteristics that the power of the GPS signal measured at the receiver of a rotating vehicle varies periodically. First, delay times are calculated to synchronize GPS signals using satellites' and receiver's positions and the rotation frequency of a vehicle, and then correlator outputs are delayed in time and merged with each other, resulting in the increase of an SNR in a correlator output. Finally, simulations are conducted and the performance of the proposed algorithm is validated.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 1994.10a
• /
• pp.79-84
• /
• 1994

The purpose of this study is to find out the relation between the outdoor activity and independent behavior of infant and the physical charater of the intermediate-territory. Another purpose is to find out the estimate of infant smother to the intermediate-territory as the space of the infant's outdoor life. As the result of this study, the following points are confirmed :1) The outdoor activity. cognition. independent behavior of infant is affected by the physical character of the intermediate-territory.2) The time and frequency of outdoor activity is affected by the physical character of the intermediate-territory. 3) The cognition and the boundary of outdoor activity are affected by the physical character of the intermediate-territory.4) The time of independent behavior is affected by the physical character of the intermediate-territory.5) The estimate of infant's mother to the intermediate-territory as the space of infant’s activity is very bad. Therefore the physical environment of intermediate-territory is very poor.

• Journal of the Korean housing association
• /
• v.6 no.2
• /
• pp.43-49
• /
• 1995

The purpose of this study is to find out the relation between the outdoor activity and independent behavior of infant and the physical charater of the intermediate-territory. Another purpose is to find out the estimate of infant's mother to the intermediate-territory as the space of the infant's outdoor life. As the result of this study, the following points are confirmed: 1) The outdoor activity, cognition, independent behavior of infant is affected by the physical character of the intermediate-territory. 2) The time and frequency of outdoor activity is affected bu the physical character of the intermediate-territory. 3) The cognition and the boundary of outdoor activity are affected by the physical character of the intermediate-territory. 4) The time of independent behavior is affected by the physical character of the intermediate-territory. 5) The estimate of infant's mother to the intermediate-territory as the space of infant's activity is very bad. The physical environment of intermediate-territory is very poor.

• Journal of Industrial Technology
• /
• v.30 no.B
• /
• pp.99-108
• /
• 2010

This study was intended to estimate the soil runoff at the basin of Mandaechun where the measure needs to be taken to deal with the increasing muddy water resulting from soil runoff during wet season and torrential rain at the high reaches of the Soyang lake where highland vegetables are cultivated and soil replacement for improvement is carried out every two to three years. The study was carried out in such a way of identifying the topographic factors using geographical spatial data from Water Management Information System (WAMIS) and ARC-VIEW program and estimating the soil runoff by rainfall frequency using Revised Universal Soil Loss Equation (RUSLE), and furthermore, evaluating the soil runoff contribution at the basin of Mandaechun based on estimate of the soil runoff by section.

• Journal of the Korean Society of Safety
• /
• v.10 no.1
• /
• pp.56-63
• /
• 1995

Two methods of the numerical method of CPQRA(Chemical Process Quantitative Risk Analysis) and the manual method of IAEA(International Atomic Energy Agency) were used to estimate the individual risk and societal risk around the chemical plant. Where, the CPQRA is introduced to verify the theoritical background of the manual of international atomic energy agency. The Gaussian plume model which has a weather stability class D with velocity of 5m/s was applied to calculate dispersion of hazard material. Also, 8-point method was employed to the effects of accidents for wind distribution. Furthermore, historical record, FTA(Fault Tree Analysis) and ETA(Event Tree Analysis) were used to estimate the probability or frequency of accidents. Eventually, the individual risk shows isorisk contour and the societal risk shows F-N curve around hazard facility, especially in chemical plants. Caulculated results, which both individual and societal risk, by using IAEA manual show simillar results to those of calculation by numerical method of CPQRA.