• Journal of the Korean Geophysical Society
• /
• v.2 no.2
• /
• pp.135-142
• /
• 1999

Interpretations of 3-component magnetic logging data obtained for a reinforced bar as a model of the line of the magnetic dipoles are conducted using a least squared inversion technique. The length of the bar is 1.12 m, sampling interval is 0.05 m, the distance between the bar and the borehole is 0.3 m, and the top of the bar is fixed at 0 m of depth. The bar is set to be approximately vertical. Magnetic anomalies smoothed with FFT are used as input data for the inversion. For the interpretation of magnetic logging data the depth to the top, the length, the magnetic moment per unit length, the direction of the magnetization (declination and inclination), and the bearing and plunge of the line of magnetic dipoles are left as unknown parameters. The comparison of the results obtained from the individual inversion of the horizontal component or the vertical component of the magnetic anomalies, and those from the simultaneous inversion of horizontal and vertical component of the magnetic anomalies shows that there exist some disagreements between each inversion result. The depth to the bottom of the bar, which is actually 1.12 m, is estimated as 1.18 m, and the inclination of the magnetization is estimated as -76°by simultaneous inversion. The negative value of the inclination indicates that the strength of the remnant magnetization is much greater than that of the induced magnetization, so that the direction of the resultant magnetization points to the top of the bar.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.2
• /
• pp.30-39
• /
• 2009

Extraction of glomeruli region plays a very important role for diagnosing nephritis automatically. However, it is not easy to extract glomeruli region correctly because the difference between glomeruli region and other region is not obvious, simultaneously unevennesses that is brought in the sampling process and in the imaging process. In this study, a new method for extracting renal glomeruli region using genetic algorithm is proposed. The first, low and high resolution images are obtained by using Laplacian-Gaussian filter with ${\sigma}=2.1$ and ${\sigma}=1.8$, then, binary images by setting the threshold value to zero are obtained. And then border edge is detected from low resolution images, the border of glomeruli is expressed by a closed B-splines' curve line. The parameters that decide the closed curve line with this low resolution image prevent the noises and the border lines from breaking off in the middle by searching using genetic algorithm. Next, in order to obtain more precise border edges of glomeruli, the number of node points is increased and corrected in order from eight to sixteen and thirty two from high resolution images. Finally, the validity of this proposed method is shown to be effective by applying to the real images.

• Journal of Environmental Health Sciences
• /
• v.43 no.5
• /
• pp.370-381
• /
• 2017

Objectives: The rate at which the nationwide highway is outsourcing the duties of toll gate cashiers to the public is increasing. The aim of this study is to conduct research on job stress for the rate at which the fares are collected by national highway toll gate cashiers. Methods: The population selected was a statistically significant group making up 10% of the total number of people surveyed in 2015, with a population of approximately 5,495 persons. The sample size is intended to cover the maximum sample size of 550 samples and the maximum number of samples that should be obtained. After allocating the number of samples by quota allocation, the qualitative function of Quality Function Deployment (QFD) was applied by random sampling. Results: Job stress ranked at $46.6{\pm}11.5$ points was found to be under the stress of 50% reported in other occupations. Job stress items showed higher for "job instability" compared to other types of tasks. Also, it appeared lower in "conflict in relationships." This is a result of the work characteristics of highway service operators. Conclusions: Time was found to have the highest influence on the workload (${\beta}=0.80$, p. 0.001), which calls for a reduction in time and workload. est influence on the workload (${\beta}=0.80$, p. 0.001), which requires a reduction in time and workload.

• Journal of Korean Academy of Nursing Administration
• /
• v.9 no.3
• /
• pp.429-445
• /
• 2003

Purpose : The present study attempted to consider the degree of consciousness of economic ethics in nursing students and the factors affecting these perceptions. Method : A survey was conducted to a total of 874 nursing students from the freshmen and seniors of 11 depts of nursing science nationwide selected by convenience sampling (one for each province, and as for Gangwon-do, two schools were selected from Yeongdong area and Yeongseo area ; 13 male students were excluded). A structured questionnaire was used to collect data on their demographic characteristics and economic ethical perceptions. Collected data were analyzed using the SAS V8.1 statistical package. Result : (1) The score for the economic ethical consciousness of the subjects was $36.76{\pm}10.20$. As for each sub-categories, the score for industry was $7.67{\pm}2.77$; thrift, $7.42{\pm}2.37$; cooperation, $7.41{\pm}2.21$; occupational consciousness, $7.18{\pm}2.20$; and, for consumption, $7.02{\pm}1.90$. The score for the consciousness of consumption was the lowest. (2) Among the demographic characteristics of the subjects, age was found to have a statistically significant positive relation to the consciousness of economic ethics(r=.13, p<.001). The next significant factor was grade: seniors seemed to have a higher economic consciousness in all the sub-categories than freshmen(t=-4.32, p<.001). The number of in-home family has a statistically significant negative correlation with economic attitudes(r=-.15, p<.001). In addition, their economic ethical perceptions were significantly higher with no religion (t=2.14, p<.05); have an unemployed father (t=2.78, p<.05); have credit cards under their own names (t=3.04, p<.05); have ever had overdue card bills (t=4.25, p<.001); have ever had part time job(t=1.74, p<.1) and when they don't live with their parents (t=-2.01, p<.05). 3) A multiple regression analysis was conducted to examine the influential power of the factors affecting the consciousness of economic ethics of the subjects. The factors had more influence on the economic attitudes of the seniors than those of freshmen; in those who having credit cards under their own names than under others; and, in those who have ever experienced credit default than those haven't. Though these factors raised average 3.0 points of economic consciousness, their expository power for the consciousness were low. Conclusion : The nursing students had medium-high consciousness of economic ethics and they seemed to have low consciousness of the proper consumption practices. Their actual life experiences had an influence on their economic attitudes. Therefore, practical programs on economic knowledge should be developed and taught to students systematically at school so that they could have sound consciousness of economic ethics and appropriate knowledge closely related with their real life.

• Journal of Korean Society of Forest Science
• /
• v.104 no.1
• /
• pp.14-25
• /
• 2015

This study was carried out to classify forest communities and to aggregate forest cover types for the complex and diversified natural forest areas of Guryongsan, Sobaeksan, Baekhwasan, Sokrisan, and Baekhaksan in the middle part of Baekdudaegan. The vegetation data were collected by point-centered quarter sampling method. One thousand one hundred fourteen sample points were subjected to cluster analysis to classify 27 forest communities, which were aggregated into 7 representative forest cover types on the basis of community similarity from composition of canopy species. They were Quercus mongolica forest cover type, mixed mesophytic forest cover type, Q. variabilis forest cover type, Pinus densiflora forest cover type, the others deciduous forest cover type, Q. serrata forest cover type, and subalpine forest cover type. The Q. mongolica forest cover type was most widely distributed in the study areas. It was assumed that abundance of Q. mongolica might be negatively associated with species diversity. Mixed mesophytic forest cover type and the others deciduous forest cover type were commonly distributed in the areas of valley, on the other hand, Q. mongolica cover type and P. densiflora cover type tended to be distributed in the areas of ridge.

• Composites Research
• /
• v.29 no.1
• /
• pp.1-6
• /
• 2016

Low-speed impact was localized on a stiffened composite structure, using 4 FBG sensors with 100 kHz-sampling rate interrogator and devised localization algorithm. The composite specimen consists of a main spar and several stringers, and the overall size of the specimen's surface is about $0.8{\times}1.2m$. Pre-stored reference data for 247 grid locations and 36 stiffener locations are gathered and used as comparison target for a random impact signal. The proposed algorithm uses the normalized cross-correlation method to compare the similarities of the two signals; the correlation results for each sensor's signal are multiplied by others, enabling mutual compensation. 20 verification points were successfully localized with a maximum error of 43.4 mm and an average error of 17.0 mm. For the same experimental setup, the performance of the proposed method is evaluated by reducing the number of sensors. It is revealed that the mutual compensation between the sensors is most effective in the case of a two sensor combination. For the sensor combination of FBG #1 and #2, the maximum localization error was 42.5 mm, with average error of 17.4 mm.

• Journal of Periodontal and Implant Science
• /
• v.35 no.3
• /
• pp.563-575
• /
• 2005

The aim of present study is to evaluate the influence of adjacent tooth to the microbiology of clinically healthy implant. Control group included patients who had clinically healthy implant and tooth with healthy $periodontium(PD{\leq}3mm)$, test group was composed of patients who had clinically healthy implant and tooth with periodontal pocket(PD>3mm). The criteria of clinically health implant are no pain or discomfort, the restorative suprastructure provide satisfactory fit and function, and the tissue around the fixtures were firm and probing with standard periodontal probe with a rounded tip 0.5mm in diameter resulted in penetration of no more than 5mm when using a force of 0.5N at any location. 38 patients, partially edentulous subjects with endosseous root-form implants were selected. All subjects were medically healthy and had not taken systemic antibiotics and professional plaque control 3 months before sampling. Number of control group is 25(mean age $52{\pm}13$, 26 teeth, 34 implants) and test group is 13(mean age $60{\pm}13$, 13 teeth, 17 implants). All teeth and implants of each patient were examined probing depth(PD), bleeding on probing(BOP), and plaque index(PI), and samples of subgingival plaque were obtained at each site with sterile curet or fine paper points, then the plaque transferred to PBS. Obtained samples were examined for the presence of P. gingivalis, T. forsythensis, and T. denticola by the polymerase chain reaction(PCR). The relationship among clinical parameters and the colonizations by the 3 bacterial species from natural teeth and implants region were analyzed by student t-test. The results of this study were as follows: 1. PD was different in teeth between 2 groups(p<0.05), but the other parameters were not. 2. Statistically significant difference was not found in clinical parameters of implants between 2 groups. 3. All bacterial prevalences of teeth were higher in test group than in control group, and prevalence of T. forsythensis had statistically significant difference between 2 groups(p<0.05). 4. Prevalences of P. gingivalis and T. forsythensis are higher in test group than control group, and that of T. denticola is higher in control group than in test group. But there were no statistically significant differences between 2 groups. In conclusion, there is no statistically significant difference in prevalence of implant microbiology between 2 groups. But if the number of samples increased, it will be possible to find out statistical significance in prevalence of P. gingivalis. It seems that pocket of adjacent tooth influences prevalence of P. gingivalis. These results mean that improvement of the periodontal condition before implantation is very important.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.4
• /
• pp.187-192
• /
• 2007

Impact on cylindrical surface caused by plunging breaking waves is investigated experimentally. The breaking waves are generated in a wave flume by decreasing the wave maker frequencies linearly and focusing the generated wave components at one specific location. The breaking wave packets are based on constant wave steepness spectrum. Three inclination angles of cylinder are applied to examine the effect of contact angle between cylinder and front surface of breaking waves. Also, the effect of cylinder diameter on pressure distribution and its peak value is investigated by adopting three cylinders with different diameters. The longitudinal location of cylinder is slightly moved in eight different points to find out a probable maximum value of impact pressure. The pressures and total force on cylinder surface are measured by piezo-electric pressure sensors and 3-components load cell with 30kHz sampling rate. The variation of peak impact pressures and forces is analyzed in terms of cylinder diameter, inclination angle and location. Also, the pressure distribution on cylindrical surface is examined. The cylinder location and surface position are more important parameters that govern the magnitude and shape of peak pressures, while the cylinder diameter and inclined angle are relatively insignificant. In a certain conditions, the impact phenomenon becomes very unstable which results in a large variation of measured valves in repeated runs.

• 한국해양학회지
• /
• v.7 no.1
• /
• pp.24-45
• /
• 1972

The Han River is an important water source in Seoul and neighbouring districts, for public and industrial supply, and for agriculture and fishery. Nowadays, more than six million inhabitants are supplied withe water from this river. The total length of the river is 470km, and has 17 10$\^$9/㎥ an average annual flow. The hydrographic characteristics at Seoul are 653㎥/sec in an average flow, 4,608㎥/sec in the maximum average flow, and 201㎥/sec in the minimum average flow. These are influenced in some degree by snowmelt in early spring, and greatly by the flood during summer. For the pollution problems, the periods of low flow are critical ones. As a rule they occur around the months November through June. Nowadays, most of the sewage from towns and industries is discharged untreated. Apart from domestic and industrial sewages, there are some discharges of mineral matter by mines in the upriver region. In general, water quality of the Han River is kept very clean and healthy until Kwangnaru of the upper region of Seoul. A large pollution, however, is received in the downstream by the domestic and industrial sewages of Seoul. It can be seen that dissolved oxygen, COD and BOD$\sub$5/ diminish markedly, and the intensity of almost every water parameter of the river continues to increase. Comparison of the figures for 1971 derived from a sampling point 40km downstream of Kwangnaru leads to the conclusion that hardness, Ca and Mg were no changed; alkalinity, Si and soluble- Fe were slightly increased; CO$\sub$2/, acidity, Cl, NO$\sub$2/-N, Cu, Zn and Al were increased in 2 and 3 times; total residue, total ignitious residue, COD, BOD$\sub$5/, NH$\sub$4/-N, PO$\sub$4/-P, Mn, Pb and total-Fe were increased in 4 to 7 times; and SO$\sub$4/, particulate-Fe and Cd were increased in 10 to 11 times. On the other hand, coliforms were increased in 650 times; fecal coliforms in 365 times; enterococci and total plate counts in 30 times, respectively. In view points of water quality standards, the down Han River water is now leveling out in Cd, coliforms and fecal coliforms for the agricultural use; in dissolved oxygen and some trace elements (Cu, Zn, Pb and Cd) for the fishery use; in ammonia, COD, BOD$\sub$5/, and Cd for the drinking use.

• The Journal of Korean Society for School & Community Health Education
• /
• v.18 no.3
• /
• pp.69-82
• /
• 2017

Objectives: This study was conducted to investigate the relationship between general characteristics and oral health behavior, oral health knowledge, and oral health literacy for adult workers. Methods: This study chose some adult workers located D City by convenience sampling method, and accepted those who understood the purpose of the study and agreed with a survey as subjects. The final study subjects were 297 except 24 with unsound questionnaires among a total of 321 questionnaires. The contents of a survey were demographic characteristics, oral health behavior, oral health knowledge, and oral literacy, and the survey was done by a self-administered questionnaire. Results: In the verbal oral health literacy distribution based on REALM standard of the subjects, a scale of 7-8, 45-60 points by score was the highest with 62.0%. In average monthly household income and oral health knowledge level of general characteristics, oral health literacy was statistically significant, and was statistically significant according to oral health literacy, monthly income of house hold, and marital status as well, and was statistically significant in oral health knowledge and oral health literacy level according to oral health behavior and in the oral health knowledge level depending on a regular checkup. And In experience existence and nonexistence of oral health education and understanding and misunderstanding of dentistry and dental health education, and main body of the decision of dental treatment, verbal oral health literacy of oral health knowledge and oral health literacy was significant. It can be seen that based on correlation among general characteristics, oral health knowledge level, verbal oral health literacy, and functional oral health literacy, there is a correlation among gender and education level, age and average monthly income, and age and marital status. Conclusions: This study presented the need for oral health literacy along with the oral health knowledge of oral health behavior affecting adult workers' oral health, and tried to establish the connection among them. Accordingly, it is thought that an improvement plan of oral health literacy for the prevention and promotion of adult workers' dental disease in the future.