• Journal of Korean Society of Transportation
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• v.10 no.1
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• pp.41-54
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• 1992

The purpose of this thesis is to construct a model to estimate the delay that vehicles arriving randomly will be experienced at an isolated singalized intersection. To do this the following objectives are set in this study: (i) An what distance a random arrival pattern occurs after a platoon of vehicles are dis-charged from the stop line; (ii) A model which estimates the average delay per through-vehicle with respect to the de-gree of saturation; and (iii) The relation between the stepped delay and average approach delay per vehicle. The following are the findings of this study: (i) A random arrival pattern on the first second and third lanes occur 300,400 and 300m downstream from stop line rdspectively. A random arrival pattern on lane group occurs 500m downstream from the stop line ; (ii) A model for the estimation of approach delay has been developed in such a way that up to x=0.7 the delay increases linearly and beyond 0.7 the delay increases rapidly in a form of second order polynomial due to high degree of saturation : and (iii) Approach delay equals approximately 1.21 times of stopped delay.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.1-7
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• 2000

This paper studies the delay-characteristics using the singular values and vectors of Hankel operators for input delay systems. First, the computational method of Hankel singular values and their corresponding singular vectors are introduced, and then it is analytically provea that all the Hankel singular vlues have a monotone increasing properties as the length of delay time increases. Furthermore, through a simple numerical example, it is shown that the Hankel singular values are dependent only on the ratio of the time constant of a lumped parameter system to the length of delay , and in case that the time constant is relatively larger than the delay time, the lumped parameter characteristic has a great influence on the input delay systems.

• Journal of Preventive Medicine and Public Health
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• v.53 no.3
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• pp.164-167
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• 2020

Objectives: As of March 3, 2020, the Shincheonji religious group accounted for the majority of Korean cases of coronavirus disease 2019 (COVID-19). Nonetheless, the most likely cause of the broad spread of COVID-19 among members of the Shincheonji religious group remains largely unknown. Methods: We obtained data of laboratory-confirmed cases related to the Shincheonji religious group from press releases by Korean public health authorities and news reports. We measured the period from the date of illness onset to the date of COVID-19 confirmation. Results: We analysed data from 59 cases (median age, 30 years). The estimated median period between the date of symptom onset and the date of COVID-19 confirmation was 4 days (95% confidence interval, 1-12). Conclusions: There was a delay in COVID-19 confirmation from the date of illness onset among the cases linked to the Shincheonji religious group. This delay likely contributed to the occurrence of many cases of COVID-19 in the group.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.310-316
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• 2014

The location template matching(LTM) method is a technique of identifying an impact location on a structure, and requires a certain measure of similarity between two time signals. In general, the correlation coefficient is widely used as the measure of similarity, while the group delay based method is recently proposed to improve the accuracy of the impact localization. Another possible measure is the frequency response assurance criterion(FRAC), though this has not been applied yet. In this paper, these three different measures of similarity are examined comparatively by using experimental data in order to understand the properties of these measures of similarity. The comparative study shows that the correlation coefficient and the FRAC give almost the same information while the group delay based method gives the shape oriented information that is best suitable for the location template matching method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.506-511
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• 2014

The location template matching (LTM) method is a technique of identifying an impact location on a structure, and requires a certain measure of similarity between two time signals. In general, the correlation coefficient is widely used as the measure of similarity, while the group delay based method is recently proposed to improve the accuracy of the impact localization. Another possible measure is the frequency response assurance criterion (FRAC), though this has not been applied yet. In this paper, these three different measures of similarity are examined comparatively by using experimental data in order to understand the properties of these measures of similarity. The comparative study shows that the correlation coefficient and the FRAC give almost the same information while the group delay based method gives the shape oriented information that is best suitable for the location template matching method.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.51-51
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• 2002

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.11
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• pp.924-927
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• 2017

This paper presents a 6~18 GHz 8-bit true time delay (TTD) circuit. The unit delay circuit is based on m-derived filter with relatively constant group delay. The designed 8-bit TTD is implemented with two single-pole double-throw (SPDT) switches and seven double- pole double-throw (DPDT) switches. The reflection characteristics are improved by using inductors. The designed 8-bit TTD was fabricated using $0.18{\mu}m$ CMOS. The measured delay control range was 250 ps with 1 ps of delay resolution. The measured RMS group delay error was less than 11 ps at 6~18 GHz. The measured input/output return losses are better than 10 dB. The chip consumes zero power at 1.8 V supply. The chip size is $2.36{\times}1.04mm^2$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3B
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• pp.179-187
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• 2002

This paper proposes and analyzes the iterative groupwise equal-delay interference cancellation(IGEIC) algorithm for coherent detection of an asynchronous wideband DS-CDMA system in a single cell over multipath fading channels. The IGEIC algorithm divide users in a system into several groups, and subtract out interference signal from the received signal as many as the number of users within a user group, iteratively. The IGEIC algorithm is also classified into the iterative groupwise equal-delay serial interference cancellation(IGESIC) algorithm and the iterative groupwise equal-delay parallel interference cancellation(IGEPIC) algorithm. In the case of perfect correlation for spreading codes, it shows that the performance of IGESIC and IGEPIC algorithm is the same after interference cancellation of as many as the number of users within a user group, but the performance of IGEPIC algorithm is superior to the IGESIC algorithm just before fecal cancellation within a user group. The results show that (he performance of the two proposed algorithms are also superior to the SIC algorithm by 3dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.236-244
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• 2010

In this paper, a planar structure negative group delay circuit(NGDC) is proposed to overcome the limited availability of the component values required for the prototype lumped element(LE) NGDC design. From the prototype LE circuit analysis, general design equations and the conditions to obtain the NGD are derived and illustrated. Then the LE circuit is converted into the planar structure by applying the transmission line resonator(TLR) theory. As a design example, the LE NGDC and the proposed planar structure NGDC are designed and compared. To estimate the commercial applicability, 2-stage reflection type planar NGDC with -5.6 ns of total group delay, -0.2 dB of insertion loss, and 30 MHz of bandwidth together with 0.1 dB and 0.5 ns of the magnitude and group delay flatness, respectively, for Wideband Code Division Multiple Access(WCDMA) downlink band is fabricated and demonstrated. Also, to show the applicability of the proposed NGDC, we have configured a simple signal cancellation loop and obtained good loop suppression performance.

• Journal of Korean Foot and Ankle Society
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• v.21 no.4
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• pp.151-155
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• 2017

Purpose: Reducing tenderness or pain on the ankle joint and improving the range of motion are thought to be possible using hyaluronate-based anti-adhesive agents. On the other hand, there are more aspects to be studied regarding the incidence of complications, such as resting pain, tenderness, and stiffness, after surgery. Therefore, the aim of this study was to prove the effectiveness of the agents after ankle fracture surgery. Materials and Methods: Patients, who underwent open reduction and internal fixation surgery due to ankle joint fractures from June 2015 to May 2016, were studied prospectively. Thirty patients of them received a $Guardix^{(R)}$ injection during their surgeries and were included in the injection group. The other 30 patients were included in the control group. Postoperatively, tenderness on the scar, a delay in wound healing, and the active range of motion were evaluated at 2, 6, and 12 weeks after surgery. Results: A significant difference in tenderness on the scar was observed 2 weeks after surgery. On the other hand, there was no significant difference at 6 and 12 weeks after the surgery. The agent-using group showed a 6.7% delay in wound healing and a 93.3% nondelaying. In the non-using group, the delay was 63.3%, while non-delay was 36.7% (p<0.001). The group that underwent $Guardix^{(R)}$ usage showed an effective result in the visual analogue scale, which was statistically significant (p<0.001). The result at 6 and 12 weeks after surgery showed a significant difference. Conclusion: Improvement was observed in the patients who underwent a $Guardix^{(R)}$ injection, regarding the range of motion, visual analog scale, and healing of the wound postoperatively.