• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권5호
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• pp.193-200
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• 2003

This Paper analyses several model-order reduction methods and then proposes an improved n model and a new delay calculation method to be used in analyzing RC-class interconnects, which does not involve moment calculation processes. The proposed delay calculation method has been derived by combining the unproved $\pi$ model, the concept of effective capacitance and Elmore delay. This method has an advantage in that it can be applied in the calculation of end-to-end delay as well as incremental delay.

• 한국군사과학기술학회지
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• 제11권4호
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• pp.116-123
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• 2008

In this paper we study the performance of the measurement time-delay estimation of tightly-coupled GPS/INS(Global positioning system/Inertial Navigation system) system. Generally, the heading error estimation performance of loosely-coupled GPS/INS system using GPS's Navigation Solution is poor. In the case of tightly-coupled GPS/INS system using pseudo-range and pseudo-range rate, the heading error estimation performance is better. However, the time-delay error on the measurement(pseudo-range rate) make the heading error estimation performance degraded. So that, we propose the time-delay model on the measurement and compose the time-delay estimator. And we confirm that the heading error estimation performance in the case of measurement time-delay existence is similar with the case of no-delay by Monte-Carlo simulation.

• 대한교통학회지
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• 제13권1호
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• pp.125-152
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• 1995

The purposes of this study are twofold ; (1) to investigate the accuracy of estimation power of the individual models. such as those of Highway Capacity Nanual (HCM), Korea Highway Capacity Manual (KHCM), and NationalCooperative Highway Research Program(NCHRP) Report339 ; and (2) to develop an adjusted delay model which can be applied to the signal control system in urban areas. The study is mainly focused on four subjects related to the research purposes, which are as follows ; (1) characteristecs of exsisting delay models ; (2) inherent problems in exsisting delay models : (3) validation of the proposed model by the comparison of observed delay with estimated delay :and (4) a method which can be applied to develop an appropriate delay model for actrual signal control systems by the adjusted fact of the proposed model.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.43-51
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• 2023

Slotted ALOHA (S-ALOHA) is a classical medium access control protocol widely used in multiple access communication networks, supporting distributed random access without the need for a central controller. Although stability and delay have been extensively studied in existing works, most of these studies have assumed ideal channel conditions or independent fading, and the impact of time-correlated wireless channels has been less addressed. In this paper, we investigate the queueing delay performance in S-ALOHA networks under time-correlated channel conditions by utilizing a Gilbert-Elliott model. Through simulation studies, we demonstrate how temporal correlation in the wireless channel affects the queueing delay performance. We find that stronger temporal correlation leads to increased variability in queue length, a larger probability of having queue overflows, and higher congestion levels in the S-ALOHA network. Consequently, there is an increase in the average queueing delay, even under a light traffic load. With these findings, we provide valuable insights into the queueing delay performance of S-ALOHA networks, supplementing the existing understanding of delay in S-ALOHA networks.

• 센서학회지
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• 제3권1호
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• pp.40-45
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• 1994

SAW 가스센서의 기판으로 $112^{\circ}$ rot. x-cut $LiTaO_{3}$ 기판을 사용하였고, 사진식각법으로 reference delay line과 sensing delay line으로 구성된 dual delay line SAW소자를 제작하였다. 각각의 IDT는 전극의 폭이 $10{\mu}m$이고, 10 개의 전극쌍을 갖는다. 각각 두개의 delay line 중에서 reference delay line은 감지막을 증착시키지 않고, sensing delay line은 유기물 반도체의 일종인 Pb-프탈로시아닌을 shadow mask로써 $10^{-5}$torr의 진공하에서 선택적으로 증착시켰다. 제작된 SAW소자로 rf amp.와 AGC(Auto Gain Control)를 사용하여 dual delay line oscillator를 만들었다. 이때 발진주파수는 $87{\sim}$89 MHz였다. 온도와 $NO_{2}$ 가스농도의 변화에 따른 발진주파수의 변화를 조사하였다.

• 한국정보통신학회논문지
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• 제21권7호
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• pp.1261-1266
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• 2017

지연 시간 전압 분산 변환기 (DVVC) 및 평균 회로 (AC)가 있는 지터 억제 지연 고정 루프 (DLL) 기반 클록 발생기를 제안하였다. 제안한 클록 발생기는 지연고정루프에서 무작위로 발생하는 지터와 회로의 구조에 의해 발생하는 지터를 억제하도록 하였다. 지연 시간 전압 분산 변환기는 각 지연단의 지연 차이를 감지하고 출력 전압을 생성한다. 평균회로는 두개의 연속되는 지연 시간 전압 분산 변환기의 출력 전압을 평균화 한다. 지연 시간 전압 분산 변환기 및 평균 회로는 연속적인 지연단의 지연 시간을 평균화하고 모든 지연단의 지연 시간을 동일하게 만든다. 또한 루프필터 출력 전압의 변동을 줄이기 위해 부궤환 기능으로 효과적인 작동을 하는 스위치가 있는 커패시터가 도입되었다. One-poly six-metal $0.18{\mu}m$ CMOS 공정으로 제작 된 DLL 기반 클록 발생기의 측정 결과는 13.4 ps rms 지터특성을 보여준다.

• 한국도로학회논문집
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• 제16권5호
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• pp.109-119
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• 2014

PURPOSES : The control delay in seconds per vehicle is the most important traffic operational index to evaluate the level of service of signalized intersections. Thus, it is very critical to calculate accurate control delay because it is used as a basic quantitative evidence for decision makings regarding to investments on traffic facilities. The control delay consists of time-in-queue delay, acceleration delay, and deceleration delay so that it is technically difficult to directly measure it from fields. Thus, diverse analysis tools, including CORSIM, SYNCHRO, T7F, VISTRO, etc. have been utilized so far. However, each analysis tool may use a unique methodology in calculating control delays. Therefore, the estimated values of control delays may be different by the selection of an analysis tool, which has provided difficulties to traffic engineers in making solid judgments. METHODS : This study was initiated to verify the feasibility of diverse analysis tools, including HCM methodology, CORSIM, SYNCHRO, T7F, VISTRO, in calculating control delays by comparing estimated control delays with that measured from a field. RESULTS : As a result, the selected tools produced quite different values of control delay. In addition, the control delay value estimated using a calibrated CORSIM model was closest to that measured from the field. CONCLUSIONS : First, through the in-depth experiment, it was explicitly verified that the estimated values of control delay may depend on the selection of an analysis tool. Second, among the diverse tools, the value of control delay estimated using the calibrated microscopic traffic simulation model was most close to that measured from the field. Conclusively, analysts should take into account the variability of control delay values according to the selection of a tool in the case of signalized intersection analysis.

• 한국멀티미디어학회논문지
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• 제15권3호
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• pp.356-363
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• 2012

이동 ad hoc 네트워크 (MANET)에서의 전력인지 라우팅 프로토콜은 각 노드의 전력소비를 최소화 하여 네트워크의 수명을 연장할 수 있도록 하였다. 하지만 프로토콜의 특성상 전송지연을 증가시키는 경향이 있어 전송지연이 중요한 멀티미디어 전송에는 적용하기 어려웠다. 따라서 본 논문에서는 ad hoc 네트워크에 적용할 수 있는 전송지연-전력인지 라우팅 프로토콜을 제안하였다. 제안된 프로토콜은 전송지연과 전력소비 두 가지의 상충된 지표를 동시에 고려하는데 전송지연을 일정한 수준으로 유지하면서 소비전력을 최소화 하는 방식을 사용한다. 시뮬레이션 결과 기존의 전송지연을 고려하지 않은 방식에 비하여 전송지연은 30% 정도로 크게 감소한 반면 전력소비는 10% 미만의 증가에 그쳤다.

• 화약ㆍ발파
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• 제41권4호
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• pp.41-50
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• 2023

본 연구에서는 굴착 물량 증대와 발파공해 저감을 위해서 전자뇌관을 이용한 수직방향 더블 데크 공법을 적용하였다. 더블 데크 공법은 상부 데크 발파 후 자유면이 완전히 형성되지 않은 상태에서 하부 데크 발파가 진행되면 발파 효율이 감소할 가능성이 있다. 이와 같은 이유로 더블 데크 공법은 데크 단차에 따라서 발파 효율이 달라진다. 따라서 본 연구에서는 홀 단차의 1~5배를 적용한 4가지 데크 단차를 제안하였고, 발파 후 파쇄도 분석을 통해 발파 효율을 평가하였다. 파쇄도 평가 결과 패턴 4(데크 단차=홀 단차×5)의 파쇄도가 가장 좋았으며, 패턴 3(데크 단차=홀 단차×3) 이상에서 파쇄효율이 큰 폭으로 증가하는 것을 확인할 수 있었다. 이에 따라 수직방향 더블 데크 발파 시 데크 단차는 최소 홀 단차의 3배 이상이 되어야 효율적인 발파 효과를 얻을 수 있다고 분석되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup3호
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• pp.167-174
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• 2016

One of the major causes of morbidity and mortality in breast cancer patients is delay in seeking help. Leventhal's self-regulation model provides an appropriate framework to assess delay in seeking help. The aim of this study was to investigate the relationship between "illness perception" and "help seeking delay" in breast cancer patients based on Leventhal's self-regulation model. In this correlational descriptive study with convenience sampling conducted in 2013, participants were 120 women with breast cancer who were diagnosed in the last year and referred to chemotherapy and radiotherapy centers in Rasht, Iran. Data collection scales included demographic data, Revised Illness Perception Questionnaire (IPQ-R)and a researcher made questionnaire to measure the delay in seeking help. Pre-hospital delay (help seeking delay) was evaluated in 3 phases (assessment, disease, behavior). The data were analyzed using SPSS-19. The mean (SD) age calculated for the patients was $47.3{\pm}10.2$. Some 43% of the patients had a high school or higher education level and 82% were married. The "pre-hospital delay" was reported ${\geq}3months$. Logistic regression analysis showed that none of the illness perception components were correlated with appraisal and behavioral delay phases. In the illness delay phase, "time line" (p-value =0.04) and "risk factors"(p-value=0.03) had significant effects on reducing and "psychological attributions" had significant effects on increasing the delay (p-value =0.01). "Illness coherence" was correlated with decreased pre-hospital patient delay (p-value<0.01). Women's perceptions of breast cancer influences delay in seeking help. In addition to verifying the validity of Leventhal's self-regulation model in explaining delay in seeking help, the results signify the importance of the "illness delay phase" (decision to seek help) and educational interventions-counseling for women in the community.