• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.393-408
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• 2004

There exists a clear need to monitor the performance of civil structures over their operational lives. Current commercial monitoring systems suffer from various technological and economic limitations that prevent their widespread adoption. The wires used to route measurements from system sensors to the centralized data server represent one of the greatest limitations since they are physically vulnerable and expensive from an installation and maintenance standpoint. In lieu of cables, the introduction of low-cost wireless communications is proposed. The result is the design of a prototype wireless sensing unit that can serve as the fundamental building block of wireless modular monitoring systems (WiMMS). An additional feature of the wireless sensing unit is the incorporation of computational power in the form of state-of-art microcontrollers. The prototype unit is validated with a series of laboratory and field tests. The Alamosa Canyon Bridge is employed to serve as a full-scale benchmark structure to validate the performance of the wireless sensing unit in the field. A traditional cable-based monitoring system is installed in parallel with the wireless sensing units for performance comparison.

• Safety and Health at Work
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• v.4 no.1
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• pp.52-62
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• 2013

Objectives: To investigate the association between psychological distress and obesity among law enforcement officers (LEOs) in the United States. Methods: Self-reported data on psychological distress based on six key questions were obtained from LEOs who participated in the National Health Interview Survey (2004-2010). We used Prochaska's cut-point of a Kessler 6 score ${\geq}5$ for moderate/high mental distress in our analysis. Mean levels of body mass index (BMI) were compared across three levels of psychological distress. Results: The average age of LEOs (n = 929) was 39.3 years; 25% were female. Overall, 8.1% of LEOs had moderate or high psychological distress; 37.5% were obese (BMI ${\geq}30$). Mean BMI increased with increasing psychological distress (no distress, BMI = $27.2kg/m^2$; mild distress, $27.6kg/m^2$; and moderate/high distress, $33.1kg/m^2$; p = 0.016) after adjustment for age, race, income, and education level among female officers only. Physical activity modified the association between psychological distress and BMI but only among male LEOs (interaction p = 0.002). Among male LEOs reporting low physical activity, psychological distress was positively associated with BMI ($30.3kg/m^2$ for no distress, 30.7 for mild distress, 31.8 for moderate/high distress; p = 0.179) after adjustment, but not significantly. This association was not significant among males reporting high physical activity. Conclusion: Mean BMI significantly increased as psychological distress increased among female LEOs. A longitudinal study design may reveal the directionality of this association as well as the potential role that physical activity might play in this association.

• Journal of The Korean Association For Science Education
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• v.25 no.4
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• pp.533-540
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• 2005

This study investigated the effects of drawing and writing as methods to assist students in connecting and integrating multiple external representations provided in learning the particulate nature of matter. Seventh graders (N=224) at a coed middle school were assigned to a control group, a drawing group, and a writing group. The students were taught about "Boyle's Law" and "Charles's Law" for two class periods. Students observed macroscopic phenomena through experiments. After this observation, students in the control group learned the topic with both external visual and verbal representations simultaneously. Students in the drawing group drew their mental model from the external verbal representation provided, and then compared their drawing with external visual representation. Students in the writing group wrote their mental model from the external visual representation provided, and then compared their writing to the external verbal representation. The two-way ANCOVA results revealed that the scores of a conception test for the writing group were significantly higher than those for the control group. While the drawing group performed better than the control group, the difference is relatively smaller. There were no significant interactions between the instruction and spatial visualization ability in the scores of the conception test. Most students perceived the writing or drawing activities helpful in understanding the concepts, and a few students responded that the writing or drawing activity was interesting. Educational implications were discussed.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.367-375
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• 2006

This study investigated the effects of varying visuals in drawing and writing as methods to assist students in connecting and integrating multiple external representations provided in learning the particulate nature of matter. Seventh graders (N=233) at a coed middle school were assigned to control, static drawing (SO), dynamic drawing (DD), static writing (SW), and dynamic writing (DW) groups. The students were taught about "Boyle's Law" and "Charles's Law" for two class periods. Two-way ANCOVA results revealed that the scores of a conception test for the two drawing (SD, DD) groups and the two writing (SW, DW) groups were significantly higher than those for the control group. Within the writing groups, students of lower spatial visualization ability in the DW group scored significantly higher than those in the SW group. However, no significant differences were found in the scores of the conception test for the two drawing (SD, DD) groups regardless of students' visualization ability. Researchers also found that most students in both DD and DW groups had respectively positive perceptions of dynamic visuals in drawing or writing.

• Journal of The Korean Association For Science Education
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• v.26 no.2
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• pp.191-199
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• 2006

This study investigated the influence of time to draw students' mental models and students' field dependence-independence on learning the particulate nature of matter with multiple representations. Seventh graders (N=295) at two middle schools were assigned to control, after-drawing, and before-drawing groups. The students learned "Boyle's Law" and "Charles's Law" for two class periods. Results revealed that the scores of a test on conceptual understanding for the two drawing groups were significantly higher than those for the control group. However, there was no significant interaction between the instruction and students' field dependence-independence in the scores of the test on conceptual understanding. In 'novelty' on a situational interest test, field independent students in the two drawing groups scored significantly higher than those in the control group. The scores for field independent students in each group were similar, while field dependent students in the before-drawing group scored lower than those in the control and after-drawing groups in 'attention demand' on the situational interest test. It was found that most students positively perceived after-drawing or before-drawing, but field independent students in the before-drawing group were more apprehensive about the activities than those in the after-drawing group.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.156-167
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• 2009

This study investigated the effects of dynamic visual on students' field independence-dependence on connecting errors and conceptual understanding in learning chemistry concepts with multiple representations. Seventh graders (N=123) at a co-ed middle school were assigned to a static visual (SV) group learning with text and static visual, and a dynamic visual (DV) group learning with text and dynamic visual. The students then learned 'Boyle's Law' and 'Charles's Law' for two class periods. Results revealed that the percentages of the DV group were lower than those of the SV group on connecting errors. However, the percentages of the students' connecting errors were still high regardless of their field independence-dependence. There was a little different tendency in the percentages of connecting errors between the two groups by students' field independence-dependence according to the types of connecting errors. The scores of the DV group were significantly higher than those of the SV group in a test on conceptual understanding. However, there was no significant interaction between the instruction and the students' field independence-dependence. Educational implications of these findings are discussed.

• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.28-36
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• 2007

This study investigated the influences of small group discussion and students' visual learning style in learning chemical concepts with drawing and writing as methods to assist students in connecting and integrating multiple external representations. Seventh graders (N=449) at a coed middle school were assigned to individual drawing (ID), pair drawing (PD), individual writing (IW), and pair writing (PW) groups. All students learned "Boyle's Law" and "Charles's Law" for two class periods. Analyses of the results revealed that the students in the PD group, regardless of students' visual learning style, scored significantly higher than those in the ID group in a conception test. The scores of the students with strong visual learning preference in the PW group were significantly higher than those in the IW group in the conception test, while the scores of the students with weak visual learning preference were not significantly different between the two groups. Although the conception test scores of the PD group were higher than those of the PW group, the difference was relatively small. It was found that most students in both PD and PW groups perceived pair drawing and pair writing positively upon cognitive and motivational aspects.

• Journal of Preventive Medicine and Public Health
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• v.49 no.4
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• pp.249-251
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• 2016

Objectives: Nail salon owners in New York City (NYC) are required to provide their workers with gloves and it is their responsibility to maintain healthy, safe working spaces for their employees. The purpose of this study was to determine the frequency with which nail salon workers wear protective gloves. Methods: A Freedom of Information Law request was submitted to New York Department of State's Division of Licensing Services for a full list of nail salons in Manhattan, NYC. A sample population of 800 nail salons was identified and a simple random sample (without replacement) of 30% (n=240) was selected using a random number generator. Researchers visited each nail salon from October to December of 2015, posing as a potential customer to determine if nail salon workers were wearing gloves. Results: Among the 169 salons in which one or more workers was observed providng services, a total of 562 workers were observed. For 149 salons, in which one or more worker was observed providing services, none of the workers were wearing gloves. In contrast, in six of the salons observed, in which one or more workers was providing services, all of the workers (1 in 2 sites, 2 in 1 site, 3 in 2 sites, and 4 in 1 site) were wearing gloves. Almost three-quarters of the total number of workers observed (n=415, 73.8%) were not wearing gloves. Conclusions: The findings of this study indicate that, despite recent media attention and legislation, the majority of nail salon workers we observed were not wearing protective gloves when providing services.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.107-113
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• 2008

We investigated the electro-optical characteristics of an ICP(Inductively Coupled Plasma) light source depending on driving temperature, and length of discharge tube. An electro-optical stability of a sample at operating was measured to see a steady state of a sample. In this results, we can see that a stability of power loss and luminous flux of a sample at operating of upper 70[min] was 1.45[%1 and 0.36[%]. We measured the optical characteristics of a sample in a thermal chamber operated at a specific temperature divided into 5 steps. While luminance increased with temperature increasing, the decrement of luminance a eared at u or $46.7[^{\circ}C]$. According to Parchen's and Boyle-Charles' law, we can speculate that a pressure was increased and a higher voltage was needed but a ballaster having a rating power can't support a higher voltage corresponding to a pressure change, 0.02[Torr] at $46.7[^{\circ}C]$. Moreover, we measured an a lied power and current of samples depending to a various length of a discharge tube.

• Safety and Health at Work
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• v.8 no.1
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• pp.36-41
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• 2017

Background: Police work is generally sedentary although there may be situations that require physical endurance and strength, such as foot chases and arresting suspects. Factors such as excessive body fat can impede an officer's physical ability to deal with such occurrences. Our objective was to examine associations between officers' body fat percentage (BF%) and performance on a standardized fitness protocol. Methods: Data were obtained from fitness screening among 1,826 male and 115 female officers in a large US police agency. The screening consisted of a 2.4-km run, push-ups, sit-ups, and sit-and-reach test. Sex-specific body fat percentages were estimated from skinfold thickness measured using calipers. Linear regression models were used to examine unadjusted and adjusted mean scores of fitness tests across BF% tertiles. Results: The prevalence of overall fitness was 4.3 times greater in male officers and 3.6 times greater in female officers having the lowest BF% tertile compared with the highest tertile (30.3% vs 7.1% and 46.0% vs 12.8%, respectively). BF% was linearly and positively associated with the time of 2.4-km run (p < 0.001), and linearly and inversely associated with the number of push-ups (p < 0.001), sit-ups (p < 0.001), and the distance of sit-and-reach (p < 0.001) in men. Similar associations were observed in women with the exception of sit-and-reach (p = 0.122). Associations were independent of age, race/ethnicity, rank, and duty station. Conclusion: Overall, BF% was inversely associated with fitness levels in male and female officers. Future longitudinal studies should be initiated to explore the potentially causal relationship between BF% and fitness in law enforcement officers.