• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.26-38
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• 1994

We demonstrate a repeatless transmission of 2.5 Gbps digital signal over 98 km opticla filbers using optical transmitter and optcial receiver which are designed and implemented using commercially available devices. The optical transmitter is realized by using a distributed feedback(DFB) laser. Temperature of the laser is thermoelectrically stabilized and the output optical power is also stabilized by using negative feedback. The output power of the transmitter is 0 dBm. The optical receiver consists of an InGaAs avalanche photodiode, a preamplifier. an automatic gain control amplifier, and a clock/data regenerator. We find an optimum decision threshold that gives the best receiver sensitivity form the measured V curve. The best sensitivity is -35.5dBm( BER-1*10S010T, PRBS=2S023T -1 ) and the overload power is -9 dBm. Finally, we achieve error free optical transmission with 98 km optical fibers. The exinction ration penalty of 2 dB. the chromatic dispersion penalty of 1 dB, and the total power penalty of 3.0 dB are measured. These results satisfy CCITT recommendation.

• Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.23-28
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• 2004

Olive flounder (Paralichthys olivaceus) was exposed to waterborne iron (0.1, 0.5, 1, 5 and 10 mg/L) for 50 days. The effects of iron on blood iron status and iron binding capacity were studied. The serum iron concentration was significantly higher than in the group exposed to iron (1, 5 and 10 mg/L) in comparison to the control after 30 days of exposure to iron. A significant decrease in unsaturated iron binding capacity was found between the control and the group exposed to iron (5 and 10 mg/L, respectively) at 40 and 50 days, respectively. The total iron binding capacity of serum in the fish exposed to iron concentrations (5 and 10 mg/L) showed a significant decrease compared to that of the control at 40 days after iron exposure. Serum iron saturation values increased in the flounder exposed to iron concentration (5 and 10 mg/L) at 50 days. Our data suggest that sub-lethal exposure of waterborne iron alters the blood iron concentration and iron binding capacity, and these parameters seems to be valuable factors for screening and diagnosis of iron overload syndromes in fish.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.2
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• pp.181-191
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• 2016

This study aimed to investigate current nutrition education and effective plans for nutrition teachers in schools. Data were collected by a face-to-face questionnaire. Surveyed schools were elementary, middle, and high schools at percentages of 32.4%, 35.1%, and 32.4%, respectively. Percentage of nutrition education was above 90%, whereas off-line education was very uncommon in middle (8.3%) and high schools (27.3%) compared with elementary schools (63.6%), (p<0.05). Satisfaction of nutrition education was also very low in middle (7.7%) and high schools (8.3%) when compared with elementary schools (41.7%), (p<0.05). The main reason for this was due to 'work overload of mealing service (44.4%)' and 'insufficient time of students (25.9%)'. Effective education plans were as follows: beginning of education and education scale were 'elementary school (67.6%)' and 'below 20 people (81.1%)', and the most preferred counterplan was 'development of diverse education programs (4.81 score)' > 'systematic education process (4.76 score)' > 'professional nutrition education (4.51 score)'. Most important duty was 'nutrition education and consultation (51.4%)', although it achieved the lowest satisfaction at a score of 2.46. Overall analysis, demand and awareness of nutrition teachers for nutrition education were very high. Therefore, an institutional strategy and environmental improvements are required by setting up curriculum subjects and developing diverse education programs for systematic nutrition education.

• Structural Engineering and Mechanics
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• v.5 no.6
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• pp.803-815
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• 1997

It is well understood that concentrated forces applied in the plane of a beam or panel (such as a wall or slab) lead to splitting forces developing within a disturbed region forming beyond the bearing zone. In a linearly elastic material the length of the disturbed region is approximately equal to the depth of the member. In concrete structures, however, the length of the disturbed region is a function of the orthotropic properties of the concrete-steel composite. In the detailing of steel reinforcement within the disturbed regions two limit states must be satisfied; strength and serviceability (in this case the serviceability requirement being acceptable crack widths). If the design requires large redistribution of stresses, the member may perform poorly at service and/or overload. In this paper the results of a plane stress finite element investigation of concentrated loads on reinforced concrete panels are presented. Two cases are examined (i) panels loaded concentrically, and (ii) panels loaded eccentrically. The numerical investigation suggests that the bursting force distribution is substantially different from that calculated using elastic design methods currently used in some codes of practice. The optimum solution for a uniformly reinforced bursting region was found to be with the reinforcement distributed from approximately 0.2 times the effective depth of the member ($0.2D_e$) to between $1.2D_e$ and $1.6D_e$. Strut and tie models based on the finite element analyses are proposed herein.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.78-84
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• 2010

This paper describes the safety assessment of power cable splices connecting different sized 6/10[kV] class power cables. To assess the safety, AC withstand voltage tests, partial discharge tests and impulse tests were carried out to the cable splice specimens and thermal rise due to overload and cross section of joint were examined as well. As a result, a breakdown due to the $4.5[U_0](27[kV_{ac}])$ application could not found for 5 minutes. Under $1.73[U_0](10.4[kV_{ac}])$ application, partial discharges of 4~8[pC] were detected. In impulse tests, all the specimens withstood to the standard waveforms of $75[kV_{peak}](1.2{\times}50[{\mu}s])$ without any breakdowns. In addition, the temperature on the splice rose by $3[^{\circ}C]$ when the 200[A] flew through the splice for 20minutes, however the thermal rise of $3[^{\circ}C]$ was considered due to the atmospheric temperature. After all the electrical tests, the cross section of the splice was visually examined. The conditions of the conductors of both $185[mm^2]$ and $240[mm^2]$ were good.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.190-205
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• 2011

The purpose of this study was to investigate the effects of the MICE industrial employee's job stressors on intent to leave and test of the mediating role of job satisfaction and job commitment. For the study, job stressors were defined 3 groups with 7 sub-factors, such as role stressors of role ambiguity, role conflict and role overload, task stressors of job routineness and job heteronomy, organizational stressors of job insecurity and distributive injustice. Data were collected from 303 MICE industrial employees in metropolitan area by structured questionnaires. Collected data were analyzed by AMOS 18.0 and findings are as follows. Firstly, on aspect of total effectiveness, the seven job stressors had harmful effect on intent to leave, especially organizational stressors had more serious effect on intent to leave than role stressors. Secondly, not only job satisfaction and job commitment had meditators role but also influenced on intent to leave directly. Thirdly, role ambiguity had effect on intent to leave indirectly through the job satisfaction, while role conflict and role overload had effect on intent to leave directly, and also indirect effectiveness on it through the job commitment. Fourthly, job routineness and job heteronomy had effected on intent to leave only through the meditators. Not only job insecurity and distributive injustice had influenced on intent to leave directly but also effectiveness on it indirectly through the meditators.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.4
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• pp.177-184
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• 2015

The purpose of this study was to investigate the effect that the job stress of employees would have on the organization effectiveness. In this study, 222 employees in Seoul and Gyeonggi province were surveyed from March to May, 2015 through empirical research with the structured questionnaires, and the collected data were statistically computerized under a statistical package of SPSS 18.0 and analyzed based on the correlation analysis, frequency analysis, and multiple regression analysis. The Following results were derived. First, the job stress of employees according to demographic characteristics had a significance difference. The technical employees had the lower role ambiguity of job stress compare to other group and the higher the income years and educational background, the higher the role overload of job stress. Second, the job stress of employees had a negative effect on the job satisfaction and Organization effectiveness but a positive effect on the turnover intention and the hypothesis was adopted. Thus, it turned out that the job stress of employees had a significant effect on the organization effectiveness and there was a significance at the statistical level. Based on this research finding, it is considered necessary to seek the specific measures that can help reduce the turnover rate of employees and improve their job satisfaction and organization commitment in a more effective methods.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.1026-1032
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• 2004

In this study, we assess the recent changes in the amount of excretion by the livestock industry, and discuss the effects of increasing the ratio of cultivated land on the reduction of surplus nitrogen from a cost-performance perspective. Nitrogen has contributed to acidification of ecosystems and nitrate concentrations in groundwater, especially in Europe. Therefore, we assessed the level of nitrogen waste from the domestic Japanese livestock industry, including cattle, swine and poultry during the period 1987-2001. This assessment assumed that 40% of the nitrogen from the domestic livestock industry was emitted as gas into the air and that 60% of the nitrogen was contained in manure used on domestic cultivated land. Nitrogen excreted from livestock, excluding gas emission, decreased by 11% from 0.504 million tons to 0.447 million tons during 1993-2001. Thus, the peak period of nitrogen excretion from livestock is already past in Japan. However, the area of cultivated land under management also decreased during 1990-2000. In addition, the area of paddy and upland fields left unplanted for a year increased during 1990-2000. Therefore, if all manure from the domestic livestock industry had been utilized on the fields as organic fertilizer, but not on arable land left uncultivated for the past year, the nitrogen per net area of cultivated land would have increased by 5%, from 125 to 131 N kg/ha, during 1990-2000. To reduce the nitrogen ratio on cultivated land through the planting of feed grain to utilize the nitrogen, a comparison of the cost performance of feed grains indicated that barley would be more suitable than wheat, rice or soybean. Had barley been planted in 100% of the land left fallow for the past year in 2000, 4% (20,000 tons) of the nitrogen from livestock waste would have been used in the harvest, and the nitrogen per land unit would have not increased but decreased from 125 to 121 N kg/ha during the same decade. Furthermore, when converted into Total Digestible Nutrients, 7% of imported feed corn could have been replaced with the harvested barley in 2000. Planting barley on this fallow land had three benefits; reducing the risk of manure overload on the land, slowing down the decrease in cultivated land, and raising the feed self-sufficiency ratio. Thus, it would be beneficial to plant feed grain such as barley in land left fallow for the past year through utilization of manure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.301-310
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• 2016

This study was to conducted to examine the associations between job stress and musculoskeletal symptoms of child care teachers. Questionnaires were administered to 132 child care teachers and the responses were analyzed using the SPSS/WIN 18.0 program. The average total job stress was 2.80. Based on NOISH criteria, musculoskeletal symptoms were prevalent in 46.2% of the participants. The musculoskeletal symptoms by body part appeared mostly on the shoulder (25.8%), followed by the lower back (18.9%), hands/wrist/fingers (17.4%), neck (11.4%), legs/feet (9.1%), and arms/elbows (7.6%). The positive symptom group showed higher levels of total job stress, work overload, and relationship with school parents stress scores than then the symptom free group. Musculoskeletal symptoms were significantly associated with job stress, work overload, and relationship with school parents stress. Overall, the results of this study indicate that it is necessary to develop strategies for reducing job stress to prevent musculoskeletal symptoms.

• Korean Journal of Social Welfare
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• v.56 no.4
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• pp.5-34
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• 2004

This study aims to find out the determinants of burnout in order to better understand the burnout process among social workers. For this purpose, a hypothetical model which explains the relationships among 8 job-related stressors (role ambiguity, role overload, difficulties in solving problems of clients, conflict with the clients, lack of support from the supervisor, closed communication pattern, bureaucracy, and lack of accountability), 4 mediators (job-stress, professional role performance, abiding by the agency policy and partiality in service delivery), and 4 dimensions of burnout (physical exhaustion, psychological exhaustion, depersonalization and personal accomplishment) was developed. Using the data collected from 207 social workers, the hypothetical model was tested. For data analysis, a path analysis was used, and the best-fitting model was found(df=66, $x^2$=63.250, GFI=0.962, CFI=1.00). As a result of this study, the following results were found. Burnout among social workers was increased by the 6 job-related stressors(role ambiguity, role overload, difficulties in solving problems of clients, conflict with the clients, lack of support from the supervisor, closed communication pattern). Job-stress, the mediating variable of the emotional path to burnout, increased professional role performance and the abiding by agency policy, and finally increased burnout. On the other hand, professional self-efficacy (which consists of professional role performance, abiding by agency policy and partiality in service delivery), the mediationg variable of the cognitive path to burnout, reduced burnout when the professional role performance was high, and abiding by agency policy and partiality in service delivery were low.