• Child Health Nursing Research
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• v.12 no.2
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• pp.196-203
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• 2006

Objectives: This study was conducted to test whether stretching helps high school students recover from their fatigue and improve concentration. Method: The method of this study adopted a nonequivalent control group with pre-test and post-test designs. The period of data collection was from November to December in 2004. The 135 subjects were randomly selected from two high schools in Ulsan : one school as control group(n=66) and the other school as an experimental group(n=69). The experimental group had stretching for 10 minutes before the start of their fifth period class, five times a week(once a day) 4weeks of period, but the control group did not do. Result: After stretching, the students' level of fatigue in the experiment group was immensely reduced (t=4.75, p<.001). After the stretching, the concentration level of the experimental group increased vastly compared to the control group (t=3.35, p≤.005). Conclusion: Stretching is useful to reduce fatigue and improve concentration of high school students. This study recommended that stretching, which is not limited by high physical techniques, or specific time or spaces would help high school students' health, since they do not exercise regularly and are tired physically and mentally.

• Journal of Nutrition and Health
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• v.19 no.5
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• pp.333-341
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• 1986

Several aspects including physical development, reflex acquistion, neuromotor development and learning behavior at Y water maze were compared at the progeny of rats fed low 91.2mg/kg diet) or adequate leves(22mg/kg diet 0 of pyridoxine during growth, gestation, lactation, and adult period. Physical development and development of reflexes (righting reflex, cliff avoidance, negative geotaxis, palmar grasp, and startle reflex to sound) appeared different between control and deficient groups but not significantly. At the 2nd week, rats spent more time in supported standing during 6 minute period was longer in the control then the deficient groups. In the Y-water maze position reversal test, learning ability as judged by the number of errors was not different among three groups, but the rats in supplemented group(DC) reached the escape platform in significantly shorter time than the other two groups, which may suggest their emotional instability. In the visual discrimination test, the performance of rats from the supplemented group had the lower errors than the other groups on the early test days. but as the testing period progressed, the performance of rats in the supplemented group became inferior to those of the control and deficient groups. The performance of control group became superior to that of the deficient group.

• The Korean Journal of Food And Nutrition
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• v.34 no.2
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• pp.207-216
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• 2021

This study analyzed the quality characteristics of Soksungjang combined with sorghum koji, according to the amount of sorghum added and the length of the fermentation period. The moisture content of Soksungjang was the lowest in the control group when there was no sorghum koji added, but gradually increased as the amount of added sorghum koji increased. The reduction in the sugar content of sorghum Soksungjang did not change according to the fermentation period of the control group, but increased alongside the fermentation period when sorghum koji was added to Soksungjang. The amino nitrogen content increased from 67.20-80.73 mg% from the beginning of the fermentation period to 173.13-383.60 mg% at the end of the fermentation period, and the total polyphenol content increased from 260.25-351.28 mg% from the beginning of the fermentation period to 567.28 mg%-674.93 mg% to the end of the fermentation period. DPPH radical scavenging activity also increased as the fermentation period elapsed, and ABTS radical scavenging activity increased and then decreased slightly over the fermentation period. The antioxidant activity was the highest in the Soksungjang mixture with a 10% concentration of sorghum koji.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.3
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• pp.19-27
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• 2011

Due to the growth of optical fiber network technologies, most networks recently support several tens of Gb/s bandwidth. UDT(UDP-based Data Transfer protocol) is an optimized protocol for bulk data transmission on the network, which has the high bandwidth and long delay time. It periodically controls the sending rate on the fixed sync-interval, 0.01 sec. Here, if the network traffic status varies quickly, available network bandwidth is not able to be properly utilized in-between the sync-intervals. In this paper, we propose an adaptive rate control method with considering the network traffic status in-between the sync-interval periods. The network traffic status is determined based on the RTT variances. With dividing the network status into four classes, the proposed method performs a new rate control by adjusting the inter-packet sending period for a corresponding class. As a simulation result, the proposed method improves the message delivery throughput as well as stability than that of the existing UDT Protocol.

• Journal of Korean Academy of Nursing
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• v.22 no.1
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• pp.29-41
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• 1992

The purpose of this research was to study the effects of antenatal breast care on decreases in breast discomfort and increases in the breast feeding rate during the postpartum period. A nonequivalent control group posttest research design was used. The experimental group consisted of fifty -one pregnant women(primigravida) who were receiving antenatal care in the OBGYN clinics of four hospitals between March 5 and May 30, 1991. The control group was made up of seventy - five postpartum women who delivered at two hospitals OBGYN clinic and one midwife clinic between May 4 and June 15, and between September 5 and October 15, 1991. Data were collected via telephone interviews on the seventh postpartum day and at the end of the second month. Data analysis methods used frequencies and the x$^2$- test. The results were as follows : 1. The rate of breast feeding practice at two months was higher in the experimental group(70.6%) than in the control group(25.3%) (p＜.01). 2. Nipple soreness in the early breast feeding period was lower in the experimental group(14.6%) than in the control group(25.3)(p＜.01). 3. Severe breast discomfort in the early breast feeding period was lower in the experimental group (12.5%) than in the control group(39.2%)(P＜.01). 4. There was a significant relationship between the breast feeding practice and the planned feeding method(p＜.05), and between breast feeding practice and nipple soreness(p＜.01) in the experimental group, and the presence of a job(p＜.01), the sex of the infant(p＜.05), and the first feeding time(p＜.05) in the control group. 5. The reasons for unsuccessful breast feeding were a deficiency of breast milk (66.7% in the experimental group, 30.4% in the control group), poor sucking on the part of the baby(13.3% in the experimental group, 21.4% in the control group).

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.47.2-47
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• 2001

This paper is concerned with the limiting zeros, as the sampling period tends to zero, of a multivariable discrete-time system composed of an approximate fractional-order hold (AFROH), a continuous-time plant and a sampler in cascade. An approximate fractional-order hold is proposed to implement fractional-order hold (FROH) and is applied to instead of the zero-order hold (ZOH). The implementing problem of the fractional-order hold is overcome. The properties of the limiting zeros are studied and the location problem of them is solved. In addition, a stability condition of the zeros for sufficiently small sampling period is derived ...

• Journal of Korean Academy of Nursing
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• v.14 no.2
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• pp.38-46
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• 1984

The purpose of this study was to test the effect of the structured preoperative teaching on post-operative recovery and to observe the effects of an structured preoperative teaching on the adult surgical patient's ventilatory function ability, the length of hospital stay, the number of analgesics within a 72 hour postoperative period, the length of early ambulation. The research question investigated in this study was: What would be the effects of a structured preoperative teaching upon the adult surgical patients postoperative recovery? This study was based on a sample of 40 patients who were scheduled for abdominal surgery. They were asssigned alternately to experimental and control group. Among 40 subjects, 20 were placed in the experimental group and 20 in the control group. Preoperative ventilation function testing of control and experimental subjects was done the evening before surgery and before the patient received the structured preoperative teaching. A structured preoperative teaching was given to the subjects in the exporimental group only by writer. Postoperative testing was done the 5th postoperative day. The data were collected over a period of two months, from Aug. 8 to Oct. 31, 1983. For the analysis of the data and test for the hypotheses, the t-test with mean difference was used. The results of this study regarding the four-hypotheses were as follows: 1. Experimental group which received structured preoperative eaching will have more increase to-cough and deep breathe as measured byhis forced vital capacity(FVC), forced expiratory volume 1 (FEV1), maximal voluntary volume 15 (MVV 15) than control group without structured preoperative teaching. The ventilation function ability was more increase in experimental group than in control group, the mean difference was statistically significant at 0.01 level. Hypotheses 1 was supported. 2. Experimental group with structured preoperative teaching will have more reduced the length of hospital stay than control group without structured preoperative teaching. The length of hospital stay of the experimental group and control group were 11.90 days and 16.05 days respectively. However, the difference was. not statistically significant at .05 level. Therefore the hypothese 2 was not supported. 3. Experimental group with structured preoperative teaching will have more reduce the number of analgesics within a 72 hour postoperative period than control group. The number of analgesics within a 72 hour' postoperative period of experimental group and control group were 1.65 times and 2.4 times. The difference was not statically significant at .05 level. Therefore, the hypotheses 3 was not supported. 4. Experimental group with structured preoperative. teaching will have more reduce the length of early ambulation than control group without structured preoperative teaching. The length of early ambulation of experimental group and control group were 2.2 days and 3.5 days respectively The difference was statistically signficant at 0.05 level. Thus the hypothess 4 was supported.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1993.10a
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• pp.107-110
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• 1993

This paper presents the technical requirements and configuration of power demand control system in office building Generally, the peak power demand is occurred in cooling period. For power demand control in existing building, the most effective control points are the motors for air handling units.

• 전기의세계
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• v.26 no.2
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• pp.84-88
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• 1977

In this paper we apply the maximum principle to design of time optimal nonlinear sampled-data control systems. We introduce the general design procedures and the mathematical formalas for time optimal processes and trajectories. Then we show the application of the technique to determine the optimal control signal, control sequence, switching time and sampling period to the given 4th order process.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.29-36
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• 2008

An optical rotary encoder is easy to implement for automation system applications. In particular, the output of the encoder has a digital form pulse, which is also easy to be connected to a popular digital controller. By using an incremental encoder and a counting device, it is easy to measure angular displacement, as the number of the output pulses is proportional to the rotational displacement. This method can only detect the angular placement once a pulse signal comes out of the encoder. The angular displacement detection period is strongly subject to the change of the angular displacement in case of ultimate low velocity range. They have ultimate long detection period or cannot even detect angular displacement at near zero velocity. This paper proposes an algorithm for detecting angular displacement by using a dual encoder system with two encoders of normal resolution. The angular displacement detecting algorithm is able to keep detection period moderately at near zero velocity and even detect constant angular displacement within nominal period. It is useful for motion control applications in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the angular displacement detection algorithm.