• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.4
• /
• pp.61-71
• /
• 2010

Five half-scale beam-to-column connections in a precast concrete frame were tested with cyclic loading that simulated earthquake-type motions. Five half -scale interior beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including one monolithic specimen and four precast specimens. Variables included the detailing used at the joint to achieve a structural continuity of the beam reinforcement, and the type of special reinforcement in the connection (whether ECC or transverse reinforcement). The specimen design followed the strong-column-weak-beam concept. The beam reinforcement was purposely designed and detailed to develop plastic hinges at the beam and to impose large inelastic shear force demands into the joint. The joint performance was evaluated on the basis of connection strength, stiffness, energy dissipation, and drift capacity. From the test results, the plastic hinges at the beam controlled the specimen failure. In general, the performance of the beam-to-column connections was satisfactory. The joint strength was 1.15 times of that expected for monolithic reinforced concrete construction. The specimen behavior was ductile due to tensile deformability by ECC and the yielding steel plate, while the strength was nearly constant up to a drift of 3.5 percent.

• Atmosphere
• /
• v.21 no.1
• /
• pp.35-44
• /
• 2011

We investigated characteristics of new particle formation and growth events observed at Gosan climate observatory using Scanning Mobility Particle Sizer (SMPS) measurements of particle number size distribution with 54 size ranges from 10 to 487 nm in October 2009. Four days (17~20 October) and five days (22~26 October) were classified into strong new particle formation and growth event ($N_S$) and weak particle formation and growth event ($N_W$), respectively. $N_S$ and $N_W$ divided by increase of aerosol number concentration in nucleation mode and continuity of growth from nucleation to Aitken mode. Particle growth rates of $N_S$ (5.34~$9.19nm\;h^{-1}$) were greater than that of $N_W$ (2.15~$3.53nm\;h^{-1}$). $N_S$ and $N_W$ were analyzed with synoptic pattern over East Asia, meteorological elements, and sulfur dioxide ($SO_2$) measured at Gosan. We found that $N_S$ was characterized by a fast and northwesterly wind accompanied cold and dry airmass, but $N_W$ was affected airmass originated from South China and come through the Korea Peninsula. The events ($N_S$ and $N_W$) occurred at conditions of high solar flux ($&gt;700W\;m^{-2}$) and low relative humidity (< 60%). The $SO_2$ concentration on $N_S$ and $N_W$ was higher than that on case of non observed new particle formation.

• Spatial Information Research
• /
• v.9 no.2
• /
• pp.291-307
• /
• 2001

In today's environmental engineering practice, many technologies such as GIS have been adopted to analyze chemical and biological process in water bodies and pollutants movements on the land surface. However, the linkage between spatially represented land surface pollutants and the in-stream processes has been relatively weak. This lack of continuity needs to develop a method in order to link the spatially-based pollutant source characterization with the water quality modeling. The objective of this thesis was to develop a two-way(forward and backward) link between ArcView GIS software and the USEPA water quality model, WASP5. This thesis includes a literature review, the determination of the point source and non-point source loadings from WASP5 modeling, and the linkage of a GIS with WASP5 model. The GIS and model linkage includes pre-processing of the input data within a GIS to provide necessary information for running a model in the forms of external input files. The model results has been post-processed and stored in the GIS database to be reviewed in a user defined form such as a chart, or a table. The interface developed from this study would provide efficient environment to support the easier decision making form water quality management.

• Geophysics and Geophysical Exploration
• /
• v.18 no.4
• /
• pp.181-196
• /
• 2015

A 3.5 kHz or chirp sub-bottom profiling survey is widely used in the marine geological and engineering purpose exploration. However, swells in the sea degrade the quality of the survey data. The horizontal continuity of profiler data can be enhanced and the quality can be improved by correcting the influence of the swell. Accurate detection of sea bottom location is important in correcting the swell effect. In this study, we tried to pick sea bottom locations by finding the position of crossing a threshold of the maximum value for the raw data and transformed data of envelope or energy ratio. However, in case of the low-quality data where the sea bottom signals are not clear due to sea wave noise, automatic sea bottom detection at the individual traces was not successful. We corrected the mispicks for the low quality data and obtained satisfactory results by picking a sea bottom within a range considering the previous average of sea bottom, and excluding unreliable big-difference picks. In case of trace by trace picking, fewest mispicks were found when using energy ratio data. In case of picking considering the previous average, the correction result was relatively satisfactory when using raw data.

• The Korean Nurse
• /
• v.33 no.1
• /
• pp.65-79
• /
• 1994

The purpose of this study was to describe the job retainment factors and the level of job satisfaction, and to identify the relationship between job retainment and the level of job satisfaction among the registered nurses working in hospitals. Four hundred eight registered nurses currently employed at 8 hospitals in Seoul were surveyed for the study. The 39 item, 5 point likert scale questionnare was developed by the researcher. The internal consistency of job satisfaction was. 86 and that of job retainment was. 90 in Cronbach's alpha test. The data sas collected from July 15 to July 30, 1993. The SPSS/PC+statistical program was used for data analysis. The descriptive analysis of the characteristics of the subjects, the level of job satisfaction and the job retainment factors was done. The relationship between the job satisfaction level and the job retainment factors was tested with. the Pearson Correlation Coefficient analysis, and thd differences of job retainment scores among the sample was tested with t-test and ANDVA. The results of the study were summarized. 1. The mean age of the subjects was 29.7 years, 41.7% of them were married. 71.1% of them were 3 years course graduates, 71.8% of them were staff nurses, and the mean duration of experience was 6 years. 2. The factors related to professionalism(3.43), society(3.31), and interpersonal relationship(3.29) were significant in job retainment. The maximum score was 5.0 Two other factors, personal(3.05) and organization(2.83) factors, also showed relatively high scores. 3. The factors to the job satisfaction showed similar pattern as job retainment: professionalism (3.47), society (3.33), finance(3.31), interpersonal relationship(3.02), and organization(2.72). 4. Society related factors(r=.7420, p<.00l) and professionalism(r=.7249, p<.00l) had high correlation with job retainment. Personal(r=.6372, p<.001) and organizational(r=.3597, p<.001) factors had moderate relationship to job retainment. Finance(r=.3597, p<.00l) had significant but weak relationship to job retainment. 5. Age, marital status, job position, departmental involvement, experience, and continuity of employment of the sample showed significant differences in job retainment. However, the period of job retainment, number of children, educational level, type of hospital, previous employment experience were not significant. 6. lndiviuals older than 40 years of age, who were married, who held the position of charge or head nurse position, who worked in central supply or nursing administration showed significantly high job retainment score. This research indicates that the professionalism is the most significant factor in job retainment. In order to retain more experienced nurses, it is important to improve the profesionalism among nurses.

• Korean Journal of Social Welfare Studies
• /
• v.45 no.2
• /
• pp.99-122
• /
• 2014

The purpose of this study is to examine how providing care to grandchildren and the continuity of care affects the grandparents' perception on old-age support. Specifically, in this study, providing care is divided into three continuous types: did not provide care, provided care at one point in time and provided care at two points in time. This is done to investigate how the duration of providing care influences the perception on old-age support. The results show that grandparents providing care to their grandchildren prefer to reside with their own children in the future more often than those who do not provide care to their grandchildren. Furthermore, grandparents providing care to their grandchildren during two-time points and grandparents providing care during one-time point prefer to reside with their adult children in the future more than grandparents providing care not once during two-time points. Interestingly, grandparents who provide care to grandchildren during two-time points prefer to reside with their children in the future more frequently than grandparents providing care during just one-time point. These results suggest it is likely that grandparents recognize providing care to their grandchildren as an insurance in care and support for themselves in the future. Additionally, these results suggest that the family plays an efficient and flexible role to meet needs of family members through a reciprocal relationship in Korean society where the public sector is weak. These findings have suggested theoretical implications.

• Geophysics and Geophysical Exploration
• /
• v.8 no.2
• /
• pp.145-155
• /
• 2005

A two-dimensional (2-D) interpretation of MT data has been performed for the purpose of fracture detection for geothermal development. Remote stations have been operated in Kyushu, Japan (480 km apart) as well as in Korea (60 km and 165 km apart in 2002 and 2003 data set, respectively). Apparent resistivity and phase curves calculated by remote processing with the Japan remote data showed enough quality for 2-D inversion for the whole frequency range. Remote reference processing with Korea remote reference data also showed quite good continuity in apparent resistivity and phase curves except some noisy frequency bands; around the power frequency, 60 Hz, and around the dead band $10^{-1}Hz\;Hz\;\~1\;Hz$, where the natural EM signal is known to be very weak. Even though the subsurface showed severe three-dimensional (3-D) characteristics in the survey area so that 2-D inversion by itself could not give enough information for deep geological structures, the 2-D inversion for the 5 survey lines showed several common features. The conductive semi-consolidate mudstone layer is dipping from north to south (about 500 m depth on the south and 200 m on the north most part of the survey area). The boundary between the low (L-2) and high (H-2) resistivity anomalies can be thought as a major fault with strike $N15^{\circ}E$, passing through the sites 206, 112 and 414. The shallow (< 1 km) conductive anomalies (L-4) seem to be fracture zones having strike E-W (at site 105) and $N60^{\circ}W$ (at site 434). And there exists a conductive layer in the western and west-southern part of the survey area in the depth below $2\~3\;km$, for which further investigation is to be needed.

• Economic and Environmental Geology
• /
• v.52 no.2
• /
• pp.169-188
• /
• 2019

This study was carried out unmanned aerial photography and terrestrial laser scanning to establish digital database on original wall of Gyejoksanseong fortress, and measured ground control points for continuity of the monitoring. It also performed precise examination with the naked eye, unmanned aerial photogrammetry, endoscopy, total station and handy measurement to examine the structural stability of the original walls. The ground control points were considered as a point where visual field can be secured, 3 points were selected around each of the south and north walls. For the right side of the south original wall, aerial photogrammetry was conducted using drones and a deviation analysis of 3-dimensional digital models was performed for short-term monitoring. As a result, the two original walls were almost matched in range within 5mm, and no difference indicating displacement of stones was found, except for partial deviation. Regular monitoring of the areas with structural deformation such as bulging, weak and fracture zone by precisely examining with the naked eye and using high-resolution photo data revealed no distinct change. The inner foundation observed through endoscopy found out that filling stones of the original walls were still remained, while most filling soil was lost. As a result of measuring the total station focusing around the points with structural deformation on the original walls, the maximum displacements of the north and south walls were somewhat high with 6.6mm and 3.8mm, respectively, while the final displacements were relatively stable at below 2.9mm and 1.4mm, respectively. Handy measurement also did not reveal clear structural deformation with displacements below 0.82mm at all points. Even though the results of displacement monitoring on the original walls are stable, it is hard to secure structural stability due to the characteristics of ramparts where sudden brittle fracture occurs. Therefore, it is necessary to conduct conservational scientific diagnosis, precise monitoring, and structural analysis based on the 3-dimensional figuration information obtained in this research.