• Journal of the Earthquake Engineering Society of Korea
• /
• v.15 no.4
• /
• pp.33-43
• /
• 2011

This paper addresses a fundamental study that is necessary to complement and improve the current domestic design specifications for the strong motion duration criterion and the envelope function of artificial accelerograms that can be applied to the earthquake-proof design of nuclear structures. The criteria for the design response spectra and strong motion duration suggested by USNRC and ASCE Standard 4-98 are commonly being used in the profession, and they are first compared with each other and reviewed. By applying 209 real strong earthquake records that are greater than 5 in magnitude at rock sites to the strong motion duration criterion in ASCE 4-98, an empirical regression model that predicts the strong motion duration as a function of the earthquake magnitude was then developed. Using synthetically generated earthquake time histories for the 10 cases whose strong motion durations varied from 6 to 20 seconds, extensive seismic analyses were finally conducted to identify the effects of the strong motion durations on the seismic responses of the nuclear power plant containment structures.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.5
• /
• pp.151-156
• /
• 2013

The experiment was done on cars travelling at the speeds of 20km/h, 60km/h and 100km/h using the performance testing mode for chassis dynamometer. In this experiment, the relativity between the secondary waveform coming from ignition coil and exhaust emissions were measured in case of cars with failures, in oxygen sensor, spark plugs. The following results obtained by analysis of the relativity between the secondary waveform and exhaust emissions. 1) When the oxygen sensor is failure, the average value of CO emission measured was 6.8 times higher than the standard CO emission value and the average value of HC emission measured was 2.3 times higher than the standard emission level. 2) When engine parts are in failure, more fuel enters the cylinder due to longer opening duration of injector, and it tended to make CO and HC emission values increase. 3) Combustion duration, the shape of flame propagation during spark line, and the size of the discharge-induced energy were the three main elements that directly cause variations in CO and HC emission values.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.2
• /
• pp.70-75
• /
• 2009

In this experiment, we did sampling 6 kinds of photovoltaic modules and analyzed the discrepancy of measurement results between l laboratory and 4 PV makers to have performance repeatability at Standard Test Condition(STC) condition. From the KIER's results, Korea's standard test laboratory, other laboratory showed -10% measurement variation. The causes came from correction of reference cell, test condition and the state of skill. Form the comparison test, we analyzed the problems. But three PV maker reduced measurement variation, other one PV maker and one test laboratory didn't improve the problems of correction of reference cell, test condition and the state of skill. Also, High Efficiency Module had a big discrepancy of -10.0$\sim$-6.2% among 3 laboratories which have a less than 10msec light pulse duration time. This made low spectrum response speed so the Fill Factor decreased maximum output power under 10msec light pulse duration time

• MALSORI
• /
• no.25_26
• /
• pp.52-64
• /
• 1993

This paper aims to explore the rhythmic phenomena of standard Korean by an experimental phonetic method. A total of 16 informants taking part in this experiment were divided into four groups : old males(OM) and old females(OF) in their fifties and young males(YM) and young females(YF) in their twenties. The informants were asked to read speech data consisting of two rhythmic units, each of which began with a stressed syllable with a long wowel. Starting with the frame / 'ma:1 'ma:nta /, the first rhythmic unit was expanded up to five syllables in all while keeping the second rhythmic unit constant with a view to investigate the pattern of increase in the interstress time interval. The results of this study are as follows: 1. There is a considerable difference between yen and old generations with respect to the duration of interstress interval . The young generation tends to speak faster than the old generation. This observation is supported by difference in the interstress intervals as exhibited by OM(389.66), OF(473), YM(275.55), YF(285.83) in the test frame '말 많다' ['ma:1 'ma:nta]. 2. Young and old generations showed a different tendency in the increase rate of duration between mono-syllables and polysyllables. In other words, the rhythm of young generation shows the tendency of syllable-timed language whereas that of old generation clearly leans towards the stressed-timed language.

• Korean Journal of Acupuncture
• /
• v.22 no.3
• /
• pp.17-26
• /
• 2005

Objectives : The aim of this study is to investigate the effect of Shinmun-acupuncture stimulation on the relationship of change in electrocardiopgraphy (ECG). Methods : For this purpose, 11 healthy volunteers were acupunctured at Shinmun acupoint using the reinforcing or reducing by inserting the needle in the same direction as the channel runs or in the opposite direction (迎隨補瀉). Then, we measured and observed the change of standard leads I, II and III in ECG. Results : In lead I , acupuncture treated groups were increased the activity of PR interval and PR segment compared to the control group. In lead II, during the acupuncture treated group by inserting the needle in the opposite direction as the channel runs was increased the activity of T wave duration, and after the acupuncture group by inserting the needle in the same direction as the channel runs was increased the activity of PR interval. In lead III, acupuncture treated groups were increased the activity of ST duration, PR interval and QT interval. Conclusions : These results suggested that Shinmun acupuncture stimulation plays an important role on the activities of ECG.

• Journal of the Ergonomics Society of Korea
• /
• v.19 no.3
• /
• pp.93-107
• /
• 2000

The excessive exposure to powered hand tools can cause damage to nerves, impair blood circulation, and musculoskeletal damage. The symptoms associated with hand-arm vibration syndrome (HAVS) include numbness, tingling, pain and subsequent reduced dexterity of the hands. This study was performed to report the prevalence of the HAVS and evaluate its related factors among the workers using powered hand tools. Total 282 workers in 11 plants of Kyungki and Inchon areas were examined. A standard symptom questionnaire was developed and administered to collect information on personal characteristics, work history, operating conditions, tool characteristics, and subjective symptoms of HAVS. Mean values (standard deviations) of the age, the duration of powered hand tools used, and the daily hours using powered hand tools were 38.3(8.9) years, 79.3(62.2) months and 6.0(2.6) hours, respectively. 132 workers(46.8%) showed vibration-induced white finger symptoms according to the Taylor-Pelmear classification, and 30 workers(10.6%) were interfered with the work. The results of a multiple logistic regression analysis controlling for age and daily working hours showed that smoking, work duration, weight of tools, and continuous work over 2 hours were significantly associated with the symptom of HAVS.

• Journal of Korean Society on Water Environment
• /
• v.28 no.2
• /
• pp.224-231
• /
• 2012

It is necessary to develop flow duration curve (FDC) on each unit watershed in order to analyze flow conditions in the stream for the management of Total Maximum Daily Loads (TMDLs). This study investigated a simple method to develop FDC for the general use of the curve. A simple equation for daily flow estimation was derived from the regression analysis between the 8-day interval flow data of a unit watershed and the daily flow monitoring data of an adjacent upstream region. FDC can be prepared with the calculation of daily flow by the equation for each unit watershed. An annual and a full-period FDC were drawn for each unit watershed in Guem river basin. Standard flow such as low and ordinary flow can be obtained from the annual FDC. Major percentile of flow such as 10, 25, 50, 75 or 90% can be obtained from the full-period FDC. It is considered that this simple method of developing FDC can be utilized more widely for the calculation of standard flow and the assessment of water quality in the process of TMDLs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.48 no.1
• /
• pp.21-32
• /
• 2022

Objectives: Inferior alveolar nerve block (IANB) is commonly used for mandibular dentoalveolar surgery. The objective of this study was to evaluate and compare the effectiveness of coadministration of dexamethasone (4 mg/mL) or adrenaline (0.01 mg/mL) as an adjuvant with lignocaine 2% in IANB during third molar surgery (TMS). Patients and Methods: This double-blind, randomized controlled trial was conducted between March and August 2020. The investigators screened patients needing elective TMS under local anesthesia. Based on strict inclusion and exclusion criteria, patients were enrolled in this study. These patients were assigned randomly into two study groups: dexamethasone group (DXN) or adrenaline group (ADN). Outcome variables were postoperative edema, trismus, visual analogue scale (VAS), perioperative analgesia, onset time, and duration of IANB. Results: Eighty-three patients were enrolled in this study, of whom 23 (27.7%) were eliminated or excluded during follow-up. This study thus included data from 60 samples. Mean age was 32.28±11.74 years, including 28 females (46.7%) in the ADN (16 patients, 57.1%) and DXN (12 patients, 42.9%) groups. The duration of action for DXN (mean±standard deviation [SD], 4:02:07±0:34:01 hours; standard error [SE], 0:06:00 hours; log-rank P=0.001) and for ADN (mean±SD, 1:58:34±0:24:52 hours; SE, 0:04:42 hours; log-rank P=0.001) were found. Similarly, time at which 1st analgesic consume and total number of nonsteroidal antiinflammatory drugs need to rescue postoperative analgesia was found statistically significant between study groups (t (58)=-11.95; confidence interval, -2:25:41 to -1:43:53; P=0.001). Early-hours VAS was also significantly different between the study groups. Conclusion: A single injection of dexamethasone prolongs the duration of action of lignocaine 2% IANB. Additionally, it can be used in cases where adrenaline is contraindicated.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.5
• /
• pp.41-47
• /
• 2010

For the enhancement of structural safety of thermally damaged reinforced concrete structure, rapid evaluation of damage in the structure is very important. This study addresses a simplified method which is equivalent to the standard fire curve (ISO 834) for the residual bond strength evaluation. In the proposed method, a exposure duration as well as the maximum temperature can be considered. For the comparisons with conventional methods, concrete properties obtained from the report of Daegu subway fire accident were referred and the results support the applicability of the proposed method in this study.

• Journal of Korean Society on Water Environment
• /
• v.26 no.6
• /
• pp.903-909
• /
• 2010

The purpose of this study was evaluated on the applicability of Load Duration Curve Method (LDC Method) using HSPF watershed model and sampling data for efficient TMDLs in Korea. The LDC Method was used for assessment pollutant characteristics in watershed and water quality variation in each water flow level. Load Duration Curve is applied for judge the level of impaired water-body and can be estimated the impaired level by pollutant, such as BOD, T-N, and T-P in this study depending on variation of stream flow. As a result, BOD, T-P was usually exceed the standard value at low flow and dry hydrologic period. Improvement of effluent concentration from WWTP and riparian buffer protection zone are effective to improve the water quality. T-N showed the worst condition at mid-range hydrologic period and moist hydrologic period. Therefore, soil erosion control program and BMPs for non-point source pollution control is effective for recovery the water quality, which can be useful method for management of water quality in the plan of recovery water quality spontaneously. Applicability of LDC Method was evaluated in the Nakbon A watershed. However, we need to consider more detailed and accumulated data set such as accurate GIS data and detail pollution data, and WWTP discharge water quality data for accurate evaluation of watershed. Overall, The LDC Method is adequate for evaluation of watersheds characteristics, and its application is recommended for watershed management and TMDL Implementation.