• 화약ㆍ발파
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• 제32권3호
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• pp.10-17
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• 2014

본 연구에서는 2자유면을 가진 암반의 장공발파 시 천공간격과 뇌관의 기폭시차에 따라 발생되는 내부주변형률의 변화를 확인하기 위하여 Visual FEA 유한요소 프로그램으로 해석 암반의 단면을 모델링하여 인접공균열권 내의 주요 절점에서 최대주변형률을 분석하였다. 결과적으로, 장공발파 시 천공간격이 좁고 기폭시차가 길수록 인접공 균열권 내에 미치는 최대주변형률 값이 크게 나타났고, 장약장 내 폭약의 기폭 위치에 따라 최대 주변형률의 차이를 보였다.

• 한국응급구조학회지
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• 제16권1호
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• pp.81-90
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• 2012

Objectives: This study is to research delay time comparison for later defibrillation after hands off according to the changes in defibrillation electrodes. Study purpose: In defibrillation treatment that is the only way for cardiac arrest by arrhythmia, it is to find defibrillator device which can minimize late defibrillation delay time after important affect of hands off. Study object and method: After hands off according to the defibrillator device, we collected total 40 people for emergency medicine doctor, internal medicine doctor, general surgeon, nurse, emergency medical technician who are working at 2 CN, CS University hospitals in Gwangju Jeollanamdo district to find out hand off shock interval(HOSI). We then researched their general properties like occupation sector, experiences in clinic, gender, completion of AHA ACLS-P training and more. Then 40 participants continued ventricular fibrillation cardiac arrest simulation training (using human-model mannequin) designed by researcher and performed their roles as defibrillation operator. Each of participant used manual paddle and performed 4 times of defibrillation (150J) during 8 minutes of CPR and in 8day, the defibrillator devices were replaced from manual paddle to self-adhesive electrodes pads and 4 times of defibrillation (150J) under same simulation condition as manual paddle were performed. Study result: In comparison for delay time of later defibrillation after hands off of manual paddle and self adhesive electrodes pad, the self adhesive electrodes pad ($7.0{\pm}0.5sec$) seemed to reduce delay time of later defibrillation significantly (p<0.05) compared to manual paddle ($10.0{\pm}0.9sec$). The self adhesive electrodes pad, according to the general properties of participants, had no particular change in delay time after later defibrillation for the statistics (p>0.05) but the manual paddle had statistically significant differences for the occupation sector, experiences in clinic and gender (p<0.05). Conclusion: In defibrillation, the self adhesive electrodes pad($7.0{\pm}0.5sec$) showed short HOSI compared to manual paddle ($10.0{\pm}0.9sec$) significantly (p<0.05) and it applied identically for both existence and non-existence of ACLS-P training completion, experiences in clinic, gender and occupation sector. The manual paddle had also significant difference in experiences in clinic and occupation sector (p<0.05). which means the effect on HOSI according to the job mastery. Therefore, if the clinic experience is short or in case for the occupations without frequent defibrillation treatment has a danger of lowering success rate for the defibrillation using manual paddle. Therefore, it is true that using self adhesive electrodes pad for defibrillation electrodes when performing manual defibrillation in pre-hospital as well as in-hospital steps can generally minimize delay time of later defibrillation after hands off.

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.12-20
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• 2002

As numerous sensors and actuators are used in many automated systems, various industrial networks are adopted for real-time distributed control. In order to take advantages of the networking, however, the network implementation should be carefully designed to satisfy real-time requirements considering network induced delays. This paper presents an implementation scheme of a networked control system via Profibus-DP network fur real-time distributed control. More specifically, the effect of the network induced delay on the control performance is evaluated on a Profibus-DP testbed. Also, two conventional PID gain tuning methods are slightly modified fur fouling controllers fur the networked control system. With appropriate choices for gains, it is shown that the networked control system can perform almost as well as the traditional control system.

• 한국정밀공학회지
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• 제18권5호
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• pp.120-129
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• 2001

As many sensors and actuators are used in many automated systems, various industrial networks are adopted for real-time distributed control. In order to take advantages of the networking, however, the network implementation should be carefully designed to satisfy real-time requirements considering network delays. This paper presents the implementation of a remote feedback control system via Profibus-DP net work for real-time distributed control More specifically, the effect of the network delay on the control performance evaluated on Profibus-DP testbed. Also, the traditional PID gain tuning methods are used to demonstrate the feasibility of the remote feedback control.

• International Journal of Control, Automation, and Systems
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• 제4권3호
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• pp.293-301
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• 2006

A new discretization method for calculating a sampled-data representation of a nonlinear continuous-time system is proposed. The proposed method is based on the well-known Taylor series expansion and zero-order hold (ZOH) assumption. The mathematical structure of the new discretization method is analyzed. On the basis of this structure, a sampled-data representation of a nonlinear system with a time-delayed input is derived. This method is applied to obtain a sampled-data representation of a non-affine nonlinear system, with a constant input time delay. In particular, the effect of the time discretization method on key properties of nonlinear control systems, such as equilibrium properties and asymptotic stability, is examined. 'Hybrid' discretization schemes that result from a combination of the 'scaling and squaring' technique with the Taylor method are also proposed, especially under conditions of very low sampling rates. Practical issues associated with the selection of the method parameters to meet CPU time and accuracy requirements are examined as well. The performance of the proposed method is evaluated using a nonlinear system with a time-delayed non-affine input.

• 한국정밀공학회지
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• 제17권11호
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• pp.75-80
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• 2000

Recently, there are a great many research for magnetic levitation system. In case electromagnet is operated as the actuator of control system, first of all, we must analysis about an electromagnet. Important parameters of this system are inductance(L) and resistance(R) which are induced from the coil of electromagnet. And attractive force equation is also important. If the load of this system is large, phase delay is caused by self-inductance effect. Because this delay effect cause stability of whole magnetic evitation system to grow worse, a measures to diminish time constant must have been taken. And the linearized attractive force equation which is used at small range of the operating point is compensated to use at larger range, thus the experiment of magnetic levitation system will get a better result.

• 한국항행학회논문지
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• 제23권5호
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• pp.386-391
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• 2019

본 논문은 정밀한 전파항법시스템 구현을 위해 안테나의 방향별 군지연 차이가 시스템에 미치는 영향을 분석하였다. 분석은 안테나 시뮬레이션과 시험을 통해서 수행 하였고, 시험은 무반향 챔버에서 진행 하였다. 안테나의 방향별 군지연은 위상(phase)을 기반으로 분석 하였으며, 측정 분석 결과 안테나의 방향별로 최대 약 7.7 ns까지 군지연 차이가 발생했다. 분석된 군지연 차이를 거리로 환산하면 약 2.31 m이며, 이를 실제 TOA (time of arrival)기반의 전파항법시스템에서 시험 하였다. 시험 결과 2.1 m의 거리 변화를 확인 하였으며, 이는 시뮬레이션과 챔버 시험 분석 값과 유사한 수치이다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3723-3730
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• 2012

Delay in help-seeking behaviour which is potentially preventable has a major effect on the prognosis and survival of patients with breast cancer. The objective of this study was to explore reasons for delay in seeking help among patients with breast cancer from the East Coast of peninsular Malaysia. A qualitative study using face-to-face in-depth interview was carried out involving 12 breast cancer patients who had been histo-pathologically confirmed and were symptomatic on presentation. Respondents were selected purposely based on their history of delayed consultation, diagnosis or treatment. All were of Malay ethnicity and the age range was 26-67 years. Three were in stage ll, seven in stage lll and two in stage lV. At the time of interview, all except one respondent had accepted treatment. The range of consultation time was 0.2-72.2 months with a median of 1.7 months, diagnosis time was 1.4-95.8 months( median 5.4 months )and treatment time was 0-33.3 months (median 1.2 months). The themes derived from the study were poor knowledge or awareness of breast cancer, fear of cancer consequences, beliefs in complementary alternative medicine, sanction by others, other priorities, denial of disease, attitude of wait and see and health care system weakness. Help-seeking behaviour was influenced by a complex interaction of cognitive, environmental, beliefs, culture and psycho-social factors. Breast cancer awareness and psychological counselling are recommended for all patients with breast symptoms to prevent delay in seeking clinical help.

• 한국통신학회논문지
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• 제39B권10호
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• pp.715-721
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• 2014

두 개 센서에 도래하는 신호 간의 시간 지연을 추정 방법에는 여러 가지가 존재한다. 그 중에서 채널 추정 기법을 기반으로 한 방법의 경우는 두 센서에 입력되는 서로 다른 신호간의 상대적인 지연을 채널의 임펄스 응답처럼 추정하도록 되어 있다. 이 경우에는 해당 채널의 특성이 희박 채널의 특성을 가지고 있다. 기존의 방법들은 채널의 희박성을 이용하지 못하고 있는 방법이 대부분이다. 본 논문에서는 채널의 희박성을 이용하기 위하여 희박신호 최적화 방법의 하나인 LASSO 최적화를 사용한 시간 지연 추정 방법을 제안한다. 제안한 방법을 기존의 방법과 비교하여, 백색 가우시안 신호원에서는 약 10dB 이상의 성능 개선 결과를 보이고, 유색 신호원에서도 갑자기 추정성능이 열하되는 현상이 없음을 보인다.

• 한국전자파학회논문지
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• 제28권6호
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• pp.444-451
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• 2017

본 논문에서는 고속 데이터 송수신을 위해 2차원 iDFT(inverse Discrete Fourier Transform) 및 DFT(Discrete Fourier Transform) 연산을 이용하여 Delay-Doppler 스프레딩 영향을 고속 수신 처리하는 OTFS(Orthogonal Time Frequency Space) 변조 시스템과 OTFS-MIMO(Multiple Input Multiple Output) 시스템을 평가하고 분석한다. 특히 OTFS 변조를 사용하는 MIMO 시스템은 높은 Doppler 효과가 존재하는 채널에서도 시스템의 용량 저하가 거의 없이 모든 데이터 스트림을 전송할 수 있다. 시뮬레이션 결과, $1{\times}1$ OTFS 변조 시스템의 전송률은 $2{\times}2$ OTFS-MIMO 시스템에서 한 스트림의 전송률과 유사함을 확인할 수 있다. 즉, $2{\times}2$ OTFS-MIMO 시스템은 높은 Delay-Doppler 영향이 존재하는 환경에서도 $1{\times}1$ OTFS 변조 시스템과 비교하여 거의 2배의 전송률을 확보할 수 있음을 확인할 수 있다.