• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.1
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• pp.35-41
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• 2003

In this paper statistics on the radiation field waveforms produced by stepped leaders just prior to lightning return strokes were described. As a parameter of stepped leader pulse characteristics, the time interval between the final leader pulse and return stroke peak, the pause time between stepped leaders, the ratio of the final leader peak to the return stroke peak and the stepped leader pulse width at half maximum were examined. The average time intervals between the final leader pulse and return stroke peak were about 16.2 and 14.8$mutextrm{s}$ for the positive and negative polarities, respectively. When the stepped leader approaches closely to ground, the time interval between leader steps was decreased and the mean value was about 17$mutextrm{s}$, and the present results were in reasonable agreement with the data observed in Florida and Japan. The large fraction of the ratios of the final stepped leader pulse to the lightning return stroke peak were distributed over the range from 5 to 35% and in average the ratio of the final leader pulse to the return stroke peak was 17.4$\pm$11.9% for the positive and 18.5$\pm$9.4% for the negative electric field waveforms. In addition, the mean pulse widths at half maximum of the stepped leaders are 1.4Us with a standard deviation of 0.9 for the positive Polarity and 2.2us with a standard deviation of 1.2 for the negative polarity, respectively.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.120-126
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• 2001

For the past five years, Inha University has been observing the electric fields produced by cloud-to-ground return strokes. This paper presents the summary of most recent results. Statistics on the zero-to-peak rise time, the zero-to-zero crossing time and the amplitude ratio of the second peak in the opposite polarity to the first peak were examined. The radiation electric fields produced by distant cloud-to-ground return strokes were substantially same pattern. The first return stroke field starts with a slowly increasing front and rises abruptly to peak. The rising portions of the electric fields produced by cloud-to-ground return strokes last 1 $mutextrm{s}$ to a few $mutextrm{s}$. The mean values of the zero-to-peak rise times of electric fields were 5.72 $mutextrm{s}$ and 4.12 $mutextrm{s}$ for the positive and the negative cloud-to-ground return strokes, respectively. The mean of the zero-to-zero crossing time for the positive return strokes was 29.48 $mutextrm{s}$ compared with 38.54 $mutextrm{s}$ for the negative return strokes. The depths of the dip after the peak of return stroke electric fields also have the dependence on the polarity of cloud-to-ground return stroke, and the mean values for the positive and negative cloud-to-ground return strokes were 33.55 and 28.19%, respectively.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.824-831
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• 2013

Lightning electromagnetic fields are important issues for the evaluation of lightning induced overvoltage on power lines and for setting the appropriate protection level for power networks. Such electromagnetic fields are strongly dependent on lightning return stroke currents at different heights along the lightning channel. On the other hand, the ground reflection factor due to the difference between the return stroke channel impedance and the equivalent ground impedance at channel base can have an effect on the shape of the return stroke currents by entering additional reflected currents into the channel. In this paper, the effect of the ground reflection factor on the return stroke currents at different heights along a channel and the electromagnetic fields associated with the lightning channel at close distances are considered. Moreover, the behavior of the electromagnetic fields versus the reflection factor changes and the radial distance changes are considered and the results are discussed accordingly. The results illustrate that the reflection factor has a direct relationship with the values of the electromagnetic fields while this is usually ignored in earlier studies.

• Physical Therapy Korea
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• v.31 no.1
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• pp.48-54
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• 2024

Background: Promoting patients' safe return home at discharge and reducing length of stay in hospital is key for Restorative Rehabilitation Institution (RMI). Objects: This study was designed to identify the factors influencing the return to home and length of stay among various factors. Methods: A total of 120 stroke patients (76 males and 44 females) who were hospitalized in an adult inpatient unit of a RMI for more than 2 months were retrospectively analyzed for this study (multivariate logistic regression analyses, p < 0.001). As predictor variables for assessing the return to home and length of stay, demographic data (sex, age, duration between onset and admission, length of stay, caregiver after discharge, occupation after discharge, reason for discharge, and household type after discharge) were collected. Additionally, following measurements were selectively collected from patient's medical records: scores of Mini-Mental State Examination Korean version (K-MMSE), modified Barthel Index Korean version (K-MBI), Berg Balance Scale and Functional Ambulation Category were obtained at admission and discharge. Results: The K-MMSE at admission and K-MBI at discharge were found to be the predictors of return to home. Additionally, K-MBI at admission influenced the length of stay. Conclusion: This study suggests cognitive functioning at admission and the level of activities of daily living at discharge predicted the return to home and length of stay.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.542-548
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• 1995

The goal of this study is to develop an effective control system for cardiac output regulation based upon the preload and afterload conditions without any transducers and compliance chambers in the moving actuator type total artificial heart. Motor current waveforms during the actuator movement are used as an input to the automatic control algorithm. While the current waveform analysis is performed, the stroke length and velocity of the actuator are gradually increased up to the maximum pump output level. If the diastolic filling rate of either right or left pump begins to exceed the venous return, atrial collapse will occur. Since the diastolic suction acts as a load to the motor, this critical condition can be detected by analyzing the motor current waveforms. Every time this detection criterion is met, the control algorithm decreases the stroke velocity and length of the actuator step by step just below the critical detection level. Then, they start to increase. In this way the maximum pump output under given venous return can be achieved. Additionally the control algorithm provides some degree of afterload sensitivity. If the aortic pressure is detected to exceed 120 mmHg, the stroke length and velocity decrease in the same way as the response to the preload. Left-right pump output balance is maintained by proper adjustment of the asymmetry of the stroke angle. In the mock circulatory test, this control system worked well and there was a considerable range of stroke volume difference with adjustment of the asymmetry value. Two ovine experiments were performed. It was confirmed that the required cardiac output regulation according to the venous return could be achieved with adequate detection of diastolic function, at least in the in vivo short-term survival cases[2-3 days . We conclude that this control algorithm is a promising method to regulate cardiac output in the moving actuator type total artificial heart.

• 전기의세계
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• v.27 no.4
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• pp.3-6
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• 1978

(차례) 1.기체방전형식의 분류 2.기체방전기구 (1)Streamer (Primary와 Secondary) (2)Leader (3)Return Stroke와 Spark 3.문제점

• The Journal of Korean Medicine
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• v.19 no.1
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• pp.385-391
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• 1998

Stroke is badly demaged for patient, family, society and country. To reduce a sequelae and return rapidly to society, treatment at acute stages is very important. In the research on xiafa(下法;diarrhea technique) used at the acute stages of stroke, the results were as follows. On the treatment of stroke, we are to control qi(氣) For it, sweeting technique(汗法), vomitting technigue(吐法) and diarrhea technique(xiafa ;下法) are used. For treatment on biaoshizheng(標實 reyufushi, 熱鬱腑實) at acute stages, tongfuxiexiafa(通腑瀉下法) is in general use. At acute stages, mental state is very important. Therefore, Xiafa(下法) have to conduct by zangfu(臟腑)'s law. At the acute stages, xiafa(下法) improved a whole body problems by treatment on a constipation and dysuria. We think that xiafa(下法) clinically effect on the cerebral edema and increased intracranial pressure. In the future, experimental study is needed.

• The Journal of Korean Medicine
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• v.24 no.1
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• pp.181-189
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• 2003

Background : Patient, family, society and country are badly damaged by stroke (CVA : cerebrovascular accident). To reduce sequelae and return rapidly to society, treatment in the acute stage is very important. In many studies on purgation therapy (下法) used in acute stages of stroke, the changes of blood pressure, pulse and so on before and after purgation therapy were reported. However, the changes in the human body according to the day elapsed after defecation were not reported, so study was needed to confirm such changes. Methods : Seventy-six patients were studied. We observed forty-three patients at acute stroke and thirty-three patients at convalescent stroke. To confirm the importance of regular defecation in stroke patients, we analyzed blood pressure according to the day elapsed after defecation. Results : The following result were obtained. 1. In stroke group, compared with the day after defecation, the mean blood pressure of the third day after defecation increased. It increased the most in the acute stroke group. 2. Especially in stroke and acute stroke groups, compared with the second day after defecation, the mean systolic blood pressure of the third day after defecation increased significantly. 3. In the infarction group, compared with the day after defecation, the mean blood pressure of the third day after defecation increased. It increased the most in the acute infarction group. 4. Especially, in the infarction and acute infarction groups, compared with the second day after defecation, the mean systolic blood pressure of the third day after defecation increased significantly. Conclusion : In stroke patients, regular defecation is important, so we think that purgation therapy (下法) is needed in stroke patients over the third day elapsed after defecation. We think that the bowel movement control in acute stroke patients is more important than in convalescent stroke patients.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1637-1640
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• 2005

This paper presents a technique for electromagnetic field analysis on surge response due to Mid-span back-flashovers effects in lightning protection system of 500 kV EHV single circuit transmission tower by the neural networks method. These analyses are based on modeling lightning return stroke as well as on coupling the electromagnetic fields of the stroke channel to the line. The ground conductivity influences both the electric field as well as the coupling mechanism and hence the magnitude and wave shape of the induced voltage. The technique can be used to analyzed the corona voltage effect, the effective of stroke to the span tower, the surge impedance of transmission lines. The maximum voltage from flashovers effects in the lines. The model is compatible with general electromagnetic transients programs such as the ATP-EMTP. The simulation results show that this study analyses for time-domain with those produced by a cascade multi-section model, the surge impedance of a full-sized tower hit directly by a lightning stroke is discussed.

• Journal of East-West Nursing Research
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• v.20 no.2
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• pp.145-153
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• 2014

Purpose: The purposes of this study were to evaluate the degree of social support, self-esteem, and motivation for rehabilitation in stroke patients and examine correlations between activities of daily living and study variables. Furthermore, this study explored factors that influence on activities of daily living. Methods: The study population was 192 stroke patients admitted in two general hospitals and two rehabilitation hospitals in M city. We collected the data using the structured questionnaires from July 11 to September 30, 2013. Results: The higher degree of social support, self-esteem, motivation for rehabilitation, the higher performance level for activities of daily living. Influencing factors of activities of daily living in the participants were motivation for rehabilitation(${\beta}$=.32, p<.001) and social support(${\beta}$=.31, p<.001). The model explained 45.9% of the variance. Conclusion: This study shows that intrinsic motivation of change in stroke patients themselves, a strong will to return to society and social supports are important factors on activities of daily living. Therefore, it is needed to develop a systemic nursing intervention improving activities of daily living in stroke patients through positive social support from patients' family members and health care providers.