• Journal of Korean Society for Quality Management
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• v.9 no.2
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• pp.26-30
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• 1981

A typical industrial data - monitoring scheme often requires trend detection Trend detection can be accomplished in many ways. Common statistical methods are the sign test, the run test, and the trend test. Graphical methods include various smoothing schemes and the cusum. The cusum has established itself as an efficient method of detecting changes in the mean level of a process being monitored. The cusum requires a "target value" with which the raw data are compared. At production start - up it is often difficult to designate the target value. This paper offers a means of initiating the cusum technique without a target value.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.656-665
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• 2010

Shear modulus has been recognized as one of the important soil properties in dynamic analysis of ground and can be calculated from in situ measurement of shear wave velocity. Field seismic tests are the most accurate but expensive methods to investigate dynamic ground characteristics. Due to that reason, empirical equations for estimating the shear wave velocity are widely used rather than conducting in-situ tests. The most common equations are based on the N value obtained in conjuctions with a standard penetration test. In this paper, the field datas of standard penetration test and suspension PS logging measured in 126 sites of Korea were summarized and the correlation equations between N value and shear wave velocity are suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.97-101
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• 1996

In this paper, We have studied internal quality incluiding chemical compositions, microscopic structrue and nonmetalic inclusion of test materials. We have analyzed dynamic characteristics of cutting resistence including tensile strength value, hardeness value, impact value etcs. We have compared chip treatments of test materials. In analyzing internal quality, all of test materials have typical ferrite+pearlite structure. But, nonmetallic inclusion have oxide and sulfide inclusion in medium carbon steels, mainly sulfide inclusion is existed in S-free cutting steels. In Ca+S-free cutting steels, calcium aluminate and sulfide complex inclusion, had low-melting points, as deformation of sulfide and oxide inclusion is existed. machining characteristics, cutting resistence is maximum in Ca+S-free cutting steels, minimum in medium carbon steels. Chip treatements are excellent in S-free cutting steels, similar to the Ca+S free cutting steels and medium carbon steels.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.331-338
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• 2001

Seismic performances of the base isolated model of Five Story Stone Pagoda were studied through shaking table tests. Friction pendulum system (FPS), Pure-friction system with laminated rubber bearing (LRB) and Ball with rubber bearing were selected fur the comparison of performances. Performances of specially designed isolation systems were tested dynamically using shaking table. The test results of isolated model are compared with those of fixed base model. Compared with fixed base model, the isolated model showed that it could withstand much higer intensity of earthquake motion. The Effective Peak Ground Acceleration (EPGA) value of isolated model when the top component tipped over was above twice of that value in case of fixed base model. According to the additional test results, the lower value of coefficient of friction than that of common frictional base isolation systems is more effective to protect the piled multi-block system of Pagoda against moderate intesity of ground motion.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.15-18
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• 1997

The plane strain stretch test (PSST) developed by POSCO as an activity of customer service was applied to the establishment of the formability criteria and the prediction of failure during the stamping processes. The PSST was applied to the actual parts such as oil pan and shock mount and the criteria of PSST value for each forming parts were established. These value can provide the possibility of prediction of failure before the stamping process. These results show that the PSST can precisely predict the stamping formability of steel sheets.

• Journal of environmental and Sanitary engineering
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• v.9 no.2
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• pp.101-109
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• 1994

Acute toxicity of heavy metals( mercury, cadmium lead, chromium and copper ), organophosphours insecticides( EPN, 2, 4- D, and parathion ), and other chemicals( arsenic, cyanide, and phenol ) to Daphnia magna was analyzed. Acute toxicity of heavy metals, organophosphours insecticides and other chemicals on Daphnia magna, LC$_{50}$ was showed 0.07-0.73mg/1, 0.22-1.94mg/t and 1.73-39.92mg/1 respectively. Daphnia magna to most of toxic chemicals was sensitive and then it seems to be useful except phenol in toxic test of water. Toxic chemicals were classified as Group 1 which had a high LC$_{50}$ value and the low increase rate of toxicity according to the increase of concentration, Group 2 which had a high LC$_{50}$ value and the high increase rate of toxicity, Group 3 which had a low LC$_{50}$ value and the low increase rate of toxicity. To Daphnia magna, lead, chromium, EPN, and parathion were included in Group 1; Mercury and copper in Group 2; Arsenic and cadmium in Group 3; Cyanide 2,4- D, and phenol in Group 4.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.19-24
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• 1999

Understanding of wear mode and prediction of wear rate of parts in sliding contact are very important in field of meterial design relating with wear resistant. This paper has been undertaken to analyze the possibility of elucidation of wear mode and prediction of wear rate for annealed steel in sliding contact using the X-ray diffraction. The sliding wear test with various velocities using pin-on-disc machine and the X-ray diffraction test on the worn surface have been carried out. The results have been shown that the magnitude of residual stress and half-value breadth on the worn surface have a good correlation with wear mode. The difference between before and after test of half-value breadth on worn surface has been shown to be exponential relation with wear rate in the same wear mode.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1157-1166
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• 2021

In this study, a numerical sensitivity analysis was performed to determine the fire suppression time for a large number of water mist nozzles in a large fire compartment. Fire simulations were performed using FDS (Fire dynamics simulator) 6.5.2 under the same condition as the test scenario 5 of the International Maritime Organization (IMO) 1165 test protocol. The sensitivities of input parameters including cell size, extinguishing coefficient (EC), droplets per second (DPS), and peak heat release rate (HRR) of fuel were investigated in terms of the normalized HRR and temperature distribution in the compartment. A new method of determining the fire suppression time using FDS simulation was developed, based on the concept of the cut-off time by cut-off value (COV) of the heat release rate per unit volume (HRRPUV) and the cooling time by the HRR cooling time criteria value (CTCV). In addition, a method was developed to determine the average EC value for the simulation input, using the cooling time and cut-off time.

• 한국가스학회:학술대회논문집
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• 2005.05a
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• pp.225-225
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• 2005

• The Journal of Korean Academic Society of Nursing Education
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• v.6 no.2
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• pp.199-217
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• 2000

This descriptive longitudinal study was done to identify the ethical value of nursing students and to compare the differences of results with one year interval. The data were collected twice in 1999 and in 2000, from the 82 first year and 64 second year nursing students who have been attending at C college in Chonnam province. The analysis of data was done by frequency, mean, paired t-test, t-test, and ANOVA. The results of data were summarized as follows: 1. The total ethical value score of the first year students was 3.48 (maximum : 5) and, one year later, the score was lowered to 3.26. Especially, the degree of their ethical value was significantly decreased in the sub-areas of human-life and nurse-nursing task. 2. The total ethical value score of the second year students was 3.24 and, one year later, the score was increased to 3.39. The degree of their ethical value was significantly increased in the subarea of nurse- client relationship. 3. In the subarea of human-life, the mean score of ethical value was 3.25 and, one year later, the score was 2.95. The degree of ethical value was significantly lowered among the first year students with an utilitarian position. 4. In the subarea of nurse-client relationship, the mean score of ethical value was 3.39 and, one year later, the score was 3.67. The degree of ethical value was significantly increased among the second year students with a deontological position. 5. In the subarea of nurse-nursing task relationship, the mean score of ethical value was 3.38 and, one year later, the mean score was 3.08. The degree of ethical value was significantly decreased among the first year students. 6. In the subarea of nurse-collaboration relationship, the mean score of ethical value was 3.96 and, one year later, the mean score was 4.08 in second year students. There was no statistically significant difference. 7. The ethical values of nursing students were significantly different depending on their religion, length of study, attitude toward nursing and the experience of dying during their clinical practice.