• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.341-343
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• 2005

This paper introduces a compression algorithm for power quality disturbance signal via the discrete wavelet transform, DWT. Algorithm to estimate a time delay from the power quality disturbance signal is proposed. Pseudo-stationary signal is constructed from the estimated time delay. A difference signal or nonstationary signal is obtained by removing a pseudo-stationary signal from a disturbance signal. DWT is applied to a difference signal. The threshold is applied to reduce a number of coefficients. Simulation results show the resonable compression ratio while keep low signal distortion.

• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1127-1134
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• 2002

The effects of pressure and temperature on the autoignition of propane and n-butane blends were investigated using a rapid compression machine (RCM) , which is widely used to examine the autoignition characteristics. The RCM was designed to be capable of varying the compression ratio between 5 and 20 and minimize the vortex formation on the cylinder wall using a wedge-shaped crevice. The initial temperature and pressure of the compressed gas were varied in range of 720∼900 K and 1.6∼ 1.8 MPa, respectively, by adjusting the ratio of the specific heat of the mixture by altering the ratio of the non-reactive components (N$_2$, Ar) under a constant effective equivalence ratio (ø$\_$f/= 1.0) The gas temperature after the compression stroke could be obtained from the measured time-pressure record. The results showed a two-stage ignition delay and a Negative Temperature Coefficient (NTC) behavior which were the unique characteristic of the alkane series fuels. As the propane concentration in the blend were increased from 20% and 40% propane, the autoignition delay time increased by approximately 41 % and 55% at 750 K. Numerical reduced kinetic modeling was performed using the Shell model, which introduced some important chemical ideas, represented by the generic species. Several rate coefficients were calibrated based on the experimental results to establish an autoignition model of the propane and n-butane blends. These coefficients can be used to predict the autoignition characteristics in LPG fueled Sl engines.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.169-176
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment, cold weather environment of curing temperature $5^{\circ}C$. Flash concrete tested slump, air contest, setting and Hardening concrete valuated setting period of form, day of age 3, 7, 28 compression strength in sealing curing. Underwater curing specimen compression strength of age 3. 7, 28day used strength change accordingly fly-ash concrete curing temperature. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Setting test result, fly-ash ratio of replacement higher delay totting time. Same volume of fly-ash ratio of replacement is lower fly-ash ratio of replacement fine aggregate delay setting time. Setting test in curing temperature $35^{\circ}C$ over twice fast setting in curing temperature $20^{\circ}C$ and all specimen setting delay in curing temperature $5^{\circ}C$. F40 specimen end of setting about 30 time. (2) Experiment result age 28day compression strength more fisher plan concrete then standard environment in curing temperature $20^{\circ}C$, cold weather environment in curing temperature $5^{\circ}C$, most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$ replacement binder 25%, fine aggregate 15%. (3) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.525-534
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• 2001

Generally, compression and encryption procedures are performed independently in lossless image compression and encryption. When compression is followed by encryption, the compressed-stream should have the property of randomness because its entropy is decreased during the compression. However, when full data is compressed using image compression methods and then encrypted by encryption algorithms, real-time processing is unrealistic due to the time delay involved. In this paper, we propose to combine compression and encryption to reduce the overall processing time. It is method decomposing gray-scale image by means of quadtree compression algorithms and encrypting the structural part. Moreover, the lossless compression ratio can be increased using a transform that provides an decorrelated image and homogeneous region, and the encryption security can be improved using a reconstruction of the unencrypted quadtree data at each level. We confirmed the increased compression ratio, improved encryption security, and real-time processing by using computer simulations.

• The Korean Journal of Emergency Medical Services
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• v.14 no.3
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• pp.71-81
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• 2010

Purpose: To minimize an interruption in chest compression, reduce the hands-off time, the American Heart Association has recommended the ratio of chest compression to ventilation ratio to 30:2 from 2005 CPR guideline to 2010 CPR guideline. However, current studies have shown that the hands-off time was > 10 seconds with that method. For this reason, we devised new CPR method that a ventilation to chest compression ratio of 2:30 to reduce pt assessment time and skipped the assessment step of carotid artery pulse would be a more effective way to reduce the hands-off time & the time to set the CPR. According to the more detailed purpose are listed below. 1) We would like to confirm efficiency of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 to reduce the hands-off time & the time to set the CPR. 2) We would like to evaluate possibility of increasing for chest compression accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 3) We would like to evaluate possibility of increasing for ventilation accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 Methods: According to 2005 American Heart Association Guidelines, 60 paramedic students(20 students X freshmen, sophomore, junior) performed 5 cycles of 3~ chest compressions : 2 ventilations after A, B, C evaluation with Laerdal Resusci R Anne SkillReporters. After 5 minutes rest, the 60 students performed 5 cycles of 2 ventilations : 30 chest compressions after A, B evaluation with the manikins between 13 and 17 September 2010. The short reports including speed & accuracy of chest compression, respiratory, CPR cycle were gained from the manikins. Hands-off times were measured by assistants. Results: Recently, the importance of high quality CPR was emphasized in order to perform the CPR faster and more accurate. To find out improving the conventional CPR method, we switch the procedure of the compression and the ventilation. By switching the procedure back and forth, we are able to compare the effectiveness of CPR between two type of CPR method which are 2:30 and 30:2 methods. 2:30 is that the breaths is delivered twice, first and perform 30 compressions while 30:2 perform 30 compressions first and give 2 breaths followed by the ABC method. Also, we verify the effectiveness of the hands off time, compression accuracy of the compression through the comparison of the two procedure as mentioned earlier. Consequently research verified that 2:30 is the efficient by providing faster set up delivering more accurate chest compression. Conclusion: 2:30 can minimize a time delay from cardiac standstill until starting the chest compression. In addition, hands-off time which is an interruption in chest compression can be shortened by 2:30 method, which result to effective oxygenation of coronary artery & maintenance of the bloodstream. Once again, performing the 2:30 method provide lessen hands off time and increase the accuracy of the chest compression.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1253-1258
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• 2006

In the mobile vector map service environments, there are problems like as terminal resource shortage and transmission delay for the characteristics of large spatial data. For the normal mobile vector map services, some techniques are required to overcome the problems. Spatial data compression approach is one of the techniques to reduce the bandwidth and the waiting time at clients. However it also must be considered that the effect on total efficiency caused by the overhead of compression and restoration time. This thesis proposes two spatial data compression techniques. First approach is to get relative coordinates to first coordinate of each object. The other approach is to compute client coordinates before transmission. Through the implementation and experiments, proposed techniques are evaluated the compression effects and efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.94-103
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• 2022

As a large amount of data generated by sensors or devices at the manufacturing site is transmitted to the server or client, problems arise in network processing time delay and storage resource cost increase. To solve this problem, considering the manufacturing site, where real-time responsiveness and non-disruptive processes are essential, QRC (Quotient Remainder Compression) and BL_beta compression algorithms that enable real-time and lossless compression were applied to actual manufacturing site sensor data for the first time. As a result of the experiment, BL_beta had a higher compression rate than QRC. As a result of experimenting with the same data by slightly adjusting the data size of QRC, the compression rate of the QRC algorithm with the adjusted data size was 35.48% and 20.3% higher than the existing QRC and BL_beta compression algorithms.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.2
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• pp.41-47
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• 1983

The analysis shows that the variation of maximum pressure of the cycle, rate of hear release, rate of mass burned, and combustion delay are influenced by the inlet air humidity in the spark-ignition engine. The quantitative combustion delay can be obtained from the rate of mass burned. Also, the variation of time loss and effective compression ratio with the change of inlet air humidity are dominated by the development of rate of heat release.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.147-158
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• 2001

In general, two methods have been used to predict settlement of soft ground. One method is Terzaghi's one dimensional consolidation theory which gives time-settlement relationship using the standard consolidation test results. The other is forecasting method of ground settlement to be occured in the future using in-situ monitoring data. The above both methods have some defects in application manner or in itself especially in very deep and soft clayey ground. In view of the lessons and experiences of soft ground improvement projects, several techniques were proposed for more accurate theorectical calculation of consolidation settlement as follows ; ① Subdivision of soft ground, ② Consideration of secondary compression, ③ Using the modified compression index, etc. And also, revised hyperbolic fitting method was suggested to minimize the error of predicted future settlement. In addition, revised De-Beer equation of immediate settlement of loose sandy soil was proposed to overcome the tendency to show too small settlement calculation results by original De-Deer equation. And also, considering the various effects of settlement delay in the improved ground by vertical drains, time-settlement caculation equation(Onoue method) was revised to match the tendency of settlement delay by using the characteristics of discharge capacity decreases of vertical drain with time elapse by the pattern of hyperbolic equation.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.543-552
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• 2002

Wireless Session Protocol(WSP) which was updated and supplemented based on HyperText Transfer Protocol(HTTP) was designed by Wireless Application Protocol(WAP) forum regarding the characteristics of wireless environment. WSP improved the performance in wireless network, and introduced various facilities considering wireless environment. In this paper, we more improve the performance of WSP adding protocol message compression capability; we cail improved WSP protocol as WSP+. And, we analysis the performance of each protocol with WSP and WSP+ implementation. As a result of experiment, the capability which proposed in this paper reduced a response traffic about 45%. In $10^{-4}$ bit error rate, we also found the packet loss rate and time delay per transaction of WSP+ was improved over 40%. Finally, we found that the protocol message compression capability reduces message retransmission count in transaction layer and shorten the delay time per transaction by reducing a message size.