• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.3
• /
• pp.451-458
• /
• 2001

In this paper, we propose speech control system for a various control device in the car with real time control speech. A real time speech control system is detected start-end points from speech data processing by A/D conversion, and recognize by one pass dynamic programming method. The results displays a monitor, and transports control data to control interfaces. The HMM model is modeled by a continuous control speech consists of control speech and digit speech for controlling of a various control device in the car The recognition rates is an average 97.3% in case of word & control speech, and is an average 96.3% in case of digit speech.

• The Journal of the Acoustical Society of Korea
• /
• v.14 no.1
• /
• pp.81-89
• /
• 1995

In this paper, we report the continuous speech recognition system using the continuous HMM with discrete duration control and the regression coefficients. Also, we do recognition experiment using One Pass DP method(for 25 sentences of robot control commands) with finite state automata context control. In the experiment for 4 connected spoken digits, the recognition rates are $93.8\%$ when the discrete duration control and the regression coefficients are included, and $80.7\%$ when they are not included. In the experiment for 25 sentences of the robot control commands, the recognition rate are $90.9\%$ when FSN is not included and $98.4\%$ when FSN is included.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.991-996
• /
• 2001

It is well known that there are two experimental errors on acoustic decay measurements. One is due to the influence of the band pass filter the other one is that of an averaging device. In this paper the influence of the filter is in detail investigated. To minimize the influence of filter, the product of the filter bandwidth Β (3㏈ bandwidth) and the reverberation time T$\sub$60/ of the room under test is at least 16. Moreover, if the initial part of an acoustic decay curve is important, the strong requirement, i.e. BT$\sub$60/＞ 64, must be satisfied. In this paper, the wavelet filter bank instead of the band pass filter bank is applied to obtain an acoustic decay curve. As results, the influence of filter is reduced and then the value of BT$\sub$60/ required for obtaining an acceptable decay curve is at least 4. The strong requirement for the initial part of a decay curve is also replaced by the BT$\sub$60/＞ 16 instead of BT$\sub$60/＞ 64.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.25 no.3
• /
• pp.171-177
• /
• 2005

Phase-shifting method using Fourier transform (PSM/FT) has been applied to measurement of in-plane displacement of a specimen. Thirty-two interference fringe patterns each of which has different phase of ${\pi}/16$ radian have been gathered from a specimen with in-plane displacement. Low-pass filtering by 2-D Fourier transform is used to suppress spatial noise of the fringe patterns. ${\alpha}-directional$ Fourier transform for PSM/FT is performed by use of the low-pass filtered 32 fringe patterns. Two kinds of specimens are used for experiment. One is a rectangular steel plate and the other one is a rectangular steel plate containing a circular hole at the center. In-plane displacement of each specimen is measured by PSM/FT, and calculated by finite element method (ANSYS) for comparison. The results are quite comparable, so that PSM/FT can be applied to measurement of in-plane displacement.

• Journal of Biosystems Engineering
• /
• v.27 no.6
• /
• pp.491-500
• /
• 2002

This study was carried out to investigate experimentally the effect of the tire inflation pressure of a tractor on soil compaction and tractive performance. Two kinds of field experiments were conducted using an agricultural tractor. One experiment is concerned with the tractive performance of the tractor at the three levels of tire inflation pressure; 50kpa, 100kpa and 200kpa, and the other one is about the soil compaction at the four levels of tire inflation pressure; 50kpa, 100kpa, 150kpa and 200kpa, at three different numbers of passes; 1, 3 and 5 passes. From the results of the field experiment, it was found that decreasing the tire inflation pressure decreased the motion resistance of tractor and increased the tractive force and tractive efficiency. The tractive and working performance of the tractor could be improved by the reduction of tire inflation pressure. Increasing the inflation pressure and the number of passes increased the soil compaction. Rate of compaction increased rapidly at the first pass and declined at subsequent passes. To reduce the effect of soil compaction for the whole field, it is recommended that tractor should follow the rut of the first pass from the subsequent passes, and decrease the inflation pressure of the driving tires up to allowable minimum level.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.3
• /
• pp.279-284
• /
• 2003

The One Pass Method (OPM) previously presented for the identification of single input single output systems is used to estimate the parameters of a Decentralized Control System (DCS). The OPM is a linear and therefore a simple estimation method. All of the calculations are performed in one pass, and no initial parameter guess, iteration, or powerful search methods are required. These features are of interest especially when the parameters of multi input-output model are estimated. The benefits of the OPM are revealed by comparing its results against those of two recently published methods based on pulse testing. The comparison is performed using two databases from the literature. These databases include single and multi input-output process transfer functions and relevant disturbances. The closed loop responses of these processes are roughly captured by the previous methods, whereas the OPM gives much more accurate results. If the parameters of a DCS are estimated, the OPM yields the same results in multi or single structure implementation. This is a novel feature, which indicates that the OPM is a convenient and practice method for the parameter estimation of multivariable DCSs.

• Journal of Industrial Technology
• /
• v.30 no.A
• /
• pp.17-23
• /
• 2010

Recently, a large number of open-pit mines are planning to change their mining method to underground types because the environmental concerns and legal regulations are increased with a rise in the standard of living. The K silica mine, which is one of them and located in Kyunggi province, is planning the establishment of a vertical shaft which will be used for ore-pass channel in their new glory hole mining method. This vertical shaft will be designed to join with a horizontal gangway excavated from the ground level. In this new mining system, the excavated ore particles will be stored inside a shaft and transported out with a help of a conveyor belt. Therefore the hang-up of ore particles in a shaft, the control of gate at the bottom of a shaft, the installation of dog-leg at the gate should be investigated identically. In this study, the PFC-2D code which is one of the discrete element numerical methods has been applied to simulate the particle flow mechanism in a shaft, and the optimum mine design has been proposed to maximize the productivity and to minimize the system damage.

• Korean Journal of Applied Biomechanics
• /
• v.13 no.2
• /
• pp.115-122
• /
• 2003

The purposes of this study were to analyze the muscle activities and the characteristics of muscle recruting patterns of lower limb for crouching start technique using four elite splint. The EMG technique was used to record muscle activities of both right and left sides of retus femoris, vastus medialis, biceps femoris, and gastrocnemius. Eight surface electrodes were placed on the surface of the selected muscles and one ground electrode was also attached on the back of neck(C7). One video camera was also used to record the crouching start motion to define 6 events and 5 phases for further analysis. The raw EMG data were filtered with band pass filter(10-350) to remove artifacts and then low pass filtered(4Hz) to find the linear envelope which resemble muscle tension curve. This filter EMG data were normalized to MVIC for the purpose of comparison between right and left sides muscle. The results of this study were as follows. All four subjects showed that vastus medialis muscle activity was comparatively higher than those of retus femoris, biceps femoris, gastrocnemius. And left side of muscle activity was comparatively higher than right side of muscle activity. Therefore, when the subjects starting out crouching start position, we recognized that the muscle of lower limb showed interaction effect by each muscle.

• Safety and Health at Work
• /
• v.13 no.4
• /
• pp.500-506
• /
• 2022

This study evaluated the consistency between two quantitative fit test devices with different methods of ambient aerosol counting. Three types of respirators (N95, half mask, and full facepiece) were worn by 50 participants (male, n = 25; female, n = 25), PortaCount (Pro+ 8038) and MT (05U) were connected to one probe to one mask, and fit factors (FFs) were measured simultaneously with the original and modified protocols. As a result of comparing MT FFs with PortaCount FFs as references and by applying for the pass/fail criteria (FF = 100), the consistency between the two devices for half masks and full facepieces was very high. N95 was somewhat weaker than the two type of respirators in the consistency; however, the correlation between the two devices was very strong (p < 0.0001). The results showed that an FF of 100 as measured by PortaCount was likely to be measured as 75 by the MT. Therefore, when performing the fit test for N95 using the MT and pass level of FF 100, a certain level of adjustment is necessary, whether end-user or putting a scaling factor by manufacturer.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1155-1160
• /
• 2011

The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. Duplexing methode uses FDD to transmit and receive broadband data at the same time. In the case of FDD we assign a private use channel each with the transmission at the receiving. In this paper, We implement multiple access wireless OFDM transceiver. We verified that one ground transceiver communicates with two car transceiver at the same time.