• Title, Summary, Keyword: decay curve

Search Result 103, Processing Time 0.042 seconds

Empirical Fitting Curve for Luminous Transmittance in Tinted Lenses Using Superposition of Exponential Decay Curves (지수감소곡선의 중첩을 이용한 착색렌즈 시감투과율의 실험적 맞춤곡선)

  • Choi, Eun Jung;Lee, Sin Ui;Lee, Eun Jin;Yoon, Moon Joo;Jeong, Ji-Hyeon;Kim, Chang-Jin;Yang, Gye Tak;Jeong, Ju-Hyun;Kim, Hyun Jung
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.16 no.3
    • /
    • pp.283-291
    • /
    • 2011
  • Purpose: To find an empirical fitting curve to represent the relationship between the luminous transmittance and tinted time in tinted lenses using exponential decay curves. Methods: Total ninety tinted lenses were prepared with CR-39 lenses and six different colored dyes. Single, double and triple exponential decay curves were used as trial curves in order to find the empirical fitting curve. Result: The results showed that the best empirical fitting curve was triple exponential decay curves. Conclusions: We propose triple exponential decay curves as proper empirical fitting curves to represent the tinted-time dependence of the luminous transmittance in tinted lenses.

Design of a Wavelet Filter for Experimental Error Improvement on Acoustic Decay Measurements (음 감쇠 측정에서 측정 오차 개선을 위한 웨이블렛 필터 설계)

  • 이민성;이상권;김봉기
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • 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.

  • PDF

Simulation of chlorine decay by waterhammer in water distribution system based on hypothetical water demand curve (가상의 물 수요곡선에 따른 수충격에 의한 염소농도변동 모의연구)

  • Baek, Dawon;Kim, Hyunjun;Kim, Sanghyun
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.32 no.2
    • /
    • pp.107-113
    • /
    • 2018
  • Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

Comparison of IIR Filter and Wavelet Filter on Acoustic Decay Measurements (음 감쇠 측정에서의 IIR 필터와 웨이블렛 필터의 영향에 대한 수치 계산, 비교)

  • 이상권;이민성;김봉기
    • The Journal of the Acoustical Society of Korea
    • /
    • v.20 no.5
    • /
    • pp.5-13
    • /
    • 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 investigated in detail. To minimize the influence of the filter, the product of the filter bandwidth B (3dB bandwidth) and the reverberation time T/sub 60/ of the room under test should be 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 a result, the influence of filter is reduced and then the value of BT/sub 60/ required for obtaining an acceptable decay curve becomes 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.

  • PDF

Estimation of Reverberant Time Using Wavelet Transform (웨이브렛 변환을 이용한 잔향시간의 측정)

  • Lee, Sang-Kwon;Kim, Bong-Gi
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.1762-1766
    • /
    • 2000
  • Estimation of reverberant time is one of important factor for the calculation of absorption ration of absorption material. In general the digital filter bank has been used for the, estimation of decay curve of the sound pressure in a reverberant room. However at low frequency, it is not easy to get a good linear decay curve for the estimation of reverberant time. Now, wavelet transform is applied to this difficult task, a good result has been obtained at low frequency. The decay curve using wavelet filter bank is better than that using digital filter bank at low frequency. At higher frequency, both curves are similar.

  • PDF

Application of the Projection Operator Technique to the Study of NMR Line Shape and Free Induction Decay Curve (NMR 吸收線 모양과 誘導磁氣自由減衰曲線 硏究에의 投影演算子法의 應用)

  • Lee Jo W.;Sung Nak Jun
    • Journal of the Korean Chemical Society
    • /
    • v.21 no.5
    • /
    • pp.362-371
    • /
    • 1977
  • In this paper application of the projection operator technique to the study of NMR absorption line shape and free induction decay curve is explored. It is found that the projection operator technique can provide a convenient means for deriving a set of hierarchy equations which may serve as a good starting point for theoretical calculation of the absorption line and free induction decay function by successive approximation or by an appropriate decoupling approximation. A brief review of linear response theory of NMR line shape and the relation between the absorption line shape and free induction decay function are also described.

  • PDF

A Study on the to Shorten of Early Decay Time in the Reverberation Curve Using MINT (MINT법을 이용한 실내 잔향곡선의 초기감쇠시간 단축에 관한 연구)

  • 차경환
    • The Journal of the Acoustical Society of Korea
    • /
    • v.21 no.1
    • /
    • pp.37-41
    • /
    • 2002
  • In this paper, we made shorter EDT(early decay time) of room reverberation curve using multiple-channel. The speech signal was processed inverse filtering with full-band and sub-band in the basis MINT, and then the multiple-channel adaptive filters were used LMS (Least Mean Square) and NLMS (Normalized Least Mean Square) algorithm. Experimental results, we could get 1/3 of time reduction at 20dB level in the reverberation curve using full-band NLMS when two microphones were used. Also, it is shown that the speech articulation was improved 80% from the test listeners with the speech, which was to shorten EDT by MINT in the subjective assessments using real room impulse response.

A Novel Approach for Blind Estimation of Reverberation Time using Gamma Distribution Model

  • Hamza, Amad;Jan, Tariqullah;Jehangir, Asiya;Shah, Waqar;Zafar, Haseeb;Asif, M.
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.2
    • /
    • pp.529-536
    • /
    • 2016
  • In this paper we proposed an unsupervised algorithm to estimate the reverberation time (RT) directly from the reverberant speech signal. For estimation process we use maximum likelihood estimation (MLE) which is a very well-known and state of the art method for estimation in the field of signal processing. All existing RT estimation methods are based on the decay rate distribution. The decay rate can be obtained either from the energy envelop decay curve analysis of noise source when it is switch off or from decay curve of impulse response of an enclosure. The analysis of a pre-existing method of reverberation time estimation is the foundation of the proposed method. In one of the state of the art method, the reverberation decay is modeled as a Laplacian distribution. In this paper, the proposed method models the reverberation decay as a Gamma distribution along with the unification of an effective technique for spotting free decay in reverberant speech. Maximum likelihood estimation technique is then used to estimate the RT from the free decays. The method was motivated by our observation that the RT of a reverberant signal when falls in specific range, then the decay rate of the signal follows Gamma distribution. Experiments are carried out on different reverberant speech signal to measure the accuracy of the suggested method. The experimental results reveal that the proposed method performs better and the accuracy is high in comparison to the state of the art method.

A Study on the Learning Curve and VOC Factors Affecting of Telecommunication Services (통신 상품별 VOC 영향 요인과 학습곡선에 관한 연구)

  • Jung, So-Ki;Cha, Kyoung Cheon
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.39B no.8
    • /
    • pp.518-527
    • /
    • 2014
  • This study is to estimate the learning curve based on the consequences of reduced voice of customer from each telecommunication service products. We used Exponential Decay Model, which is the most popular among the learning curve models. We attempted to add how VOC changes in accordance with seasonal factors, human resource input, application of software, and the investment. The results of the empirical analysis of each service product as follows: First, as learning curve, customer complaints decreased. Second, human resource input, Network fault make increase or decrease customer complaints(VOC). Third, even though increasing the customer's quality of experience, VOC would not decrease due to service paradox.

$Ca^{++}$ Polls in Isolated Rabbit and Turtle Heart (적출된 토끼와 자라심장에서의 $Ca^{++}$ Pool)

  • Kim, In-Kyo;Lee, Joong-Woo;Kang, Doo-Hee
    • The Korean journal of physiology & pharmacology
    • /
    • v.9 no.1
    • /
    • pp.13-22
    • /
    • 1975
  • From the study of movements of $Ca^{++}$ in frog cardiac muscle, Niedergerke (1963) postulated that $Ca^{++}$ necessary for the cardiac contraction is stored in a specific pool. Langer et al (1967) and DeCaro (1967) also found a close relationship between the change of $Ca^{++}$ flux kinetics and the change of contractile force. According to the studies of several investigators, Ca II (Bailey and Dressel 1968) or phase I and II (Langer 1965, Langer et al 1967, 1971) in the $Ca^{++}$ washout curve was associated with cardiac contractility. This investigation was aimed to elucidate the anatomical region of the contractile active $Ca^{++}$ pool. At the same time, it was assumed in this study that $Ca^{++}$ in the sarcoplasmic reticulumn represents one of the major intracellular $Ca^{++}$ pool and cardiac contractility was also dependent on the intracellular $Ca^{++}$ concentration. Consequently, this experiment was performed at different temperatures to activate to activate inhibit the deactivating process of activated $Ca^{++}$ in the intracellular space to see if changes in the contractility decay curve existed at different temperatures. The isolated hearts of rabbits and turtles (Amyda maackii) were attached to the perfusion apparatus according to the method employed by Bailey and Dressel (1968). The isolated hearts were initally perfused with a full Ringer solution containing 2 mg/ml of inulin for 1 hr, and then $Ca^{++}$ and inulin-free Ringer solution was perfused while the isometric tension was recorded and a serial sample of perfusion fluid dripping from the cardiac apex was collected for 10 sec throughout experimental period. The above procedure was performed at $23^{\circ}C$, $30^{\circ}C$ and $38^{\circ}C$ on the rabbit heart and $10{\sim}13^{\circ}C$, $10^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$ on the turtle heart. After determination of $Ca^{++}$ and inulin concentration of the samples, the $Ca^{++}$, inulin washout curve and the contractile tensin decay curve were analysed according to the method of Riggs (1963). The results were summarized as follows; 1. In the rabbit heart, there are 2 inulin compartments, 3 $Ca^{++}$ compartments and sing1e exponential decay of contractile tension. In the turtle heart, there are $1{\sim}2$ inulin compartments, $1{\sim}2$ $Ca^{++}$ compartments and $1{\sim}2$ phases of contractile tension decay. The fact that the inulin space was divided into 3 compartments in the washout curve in these hearts indicates the presence of heterogeneity in cardiac perfusion, i.e., overfused and underperfused area. 2. Ca I a9d Ca II in these hearts were found to have $Ca^{++}$ in the ECF compartments because their half times in the washout curves were far smaller than those of the inulin washout curves in the rabbit heart and similar to those of the inulin washout curves in the turtle heart. Ca III in the rabbit heart may have originated from the intracellular $Ca^{++}$ store. But no Ca III in the turtle heart was found. This may be due to the fact that the iutracellular $Ca^{++}$ pool in the turtle heart was too small to detect using this experimental procedure since sarcoplasmic reticulumn in the turtle heart is poorly developed. 3. In the rabbit heart, there were no chages in the half time of Ca I, Ca II, inulin I and inulin II at different temperatures, but the half time of Ca III was significantly prolonged at lower temperatures, and the half time of the contractile tension decay tended to be prolonged at lower temperatures but this was not significant. In the turtle heart, there were no changes in the half time of Ca I, Ca II, inulin 1, inulin II and phase I of the contractile tension decay at different temperatures, but the half time of phase II of the contractile tension decay was significantly prolonged at lower temperatures. This finding indicates that intracellu!ar $Ca^{++}$ in these hearts was also responsible particulary for maintaining the cardiac contractility at the lower temperatures. 4. The half times of contractile tension decay were shorter than those of Ca II in the $Ca^{++}$ washout curves in both animal hearts. According to the above results it was shown that $Ca^{++}$ in ECF is primarily and $Ca^{++}$ in the intracellular space is partially associated with the cardic contractility.

  • PDF