• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.33-39
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• 2007

LonWorks over IP (LonWorks/IP) virtual device network (VDN) is an integrated form of LonWorks device network and IP data network. LonWorks/IP VDN can offer ubiquitous access to the information on the factory floor and make it possible for the predictive and preventive maintenance on the factory floor. Timely response is inevitable for predictive and preventive maintenance on the factory floor under the real-time distributed control. The network induced uncertain time delay deteriorates the performance and stability of the real-time distributed control system on LonWorks/IP virtual device network. Therefore, in order to guarantee the stability and to improve the performance of the networked distributed control system the time-varying uncertain time delay needs to be compensated for. In this paper, under the real-time distributed control on LonWorks/IP VDN with uncertain time delay, a control scheme based on disturbance observer and ZPETC(Zero Phase Error Tracking Controller) phase lag compensator is proposed and tested through computer simulation. The result of the proposed control is compared with that of internal model controller (IMC) based on Smith predictor and disturbance observer. It is shown that the proposed control scheme is disturbance and noise tolerant and can significantly improve the stability and the tracking performance of the periodic reference. Therefore, the proposed control scheme is well suited for the distributed servo control for predictive maintenance on LonWorks/IP-based virtual device network with time-varying delay.

• Journal of Ecology and Environment
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• v.41 no.6
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• pp.152-164
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• 2017

Background: Natural regeneration of seedlings as well as saplings of Korean fir has been significantly impacted by the browsing from the early stages of their development, potentially, by roe deer for the last two to three decades at the study site since late 1980s. This study was carried out to investigate current status of the disturbance in the seedling development of Korean fir (Abies koreana) on Mt. Hallasan, Jeju Island, Korea. Methods: Field survey was carried out during June and August in 2016 to measure the characteristics of study site and understory vegetation by applying systematic sampling to 125 plots of $5m{\times}5m$ quadrat located on eastern slope of the mountain. Correlation and regression analyses were applied to the variables quantified from the data sets using the SAS software. Results: No saplings with their diameters at breast heights smaller than 5.0 cm were found at the study site indicating the serious disturbance in the natural regeneration of Korean fir at the study site. No seedlings with their heights taller than 36.0 cm were found at the study site indicating even more serious disturbance during earlier stage of the natural regeneration of Korean fir at the study site. A total of 616 individuals of the seedlings of Korean fir were found at 54 out of 125 sampling plots. One hundred thirty-eight seedlings (22.4%) out of 616 individual seedlings have the vestiges for being grazed, potentially, by roe deer. Conclusions: Due considerations should be given to the effects of browsing of the seedlings by roe deer to promote the natural regeneration of Korean fir, ultimately to restore Korean fir. It is needed for the managers of the forest to install fences around the forest area. Exclosure experiments as well as enclosure experiments of different densities of browsing should be carried out. In addition, treatment with different densities of Jeju dwarf bamboo should also be included in the experiment on Mt. Hallasan National Park, Jeju Island, Korea.

• 한국노년학
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• v.31 no.3
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• pp.607-621
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• 2011

Purpose The purpose of this study was to examine the relationship between physical activities, sleep disturbance, and health related quality of life (HRQOL) in patients with chronic obstructive pulmonary disease (COPD). Methods A descriptive survey design used pretest dataset of COPD symptom management intervention study (N=245). Measures included the international physical activity questionnaire, the COPD and asthma sleep impact scale, and the St. George's respiratory questionnaire of HRQOL. The data were analyzed using descriptive analysis, t-test, ANOVA, Pearson correlation coefficients, and simultaneous multiple regression by the SPSS WIN 18.0 program. Results The mean scores (SD) of HRQOL and sleep disturbance were 36.04 (19.43) and 14.33 (6.20), respectively. About 32% of participants were physically inactive. The multivariate approach showed the patients who have more sleep disturbance (β=.27), lower levels of FEV1 % predicted (β=-.23), lower physical activities (β=-.19), lower household income (β=-.16), and diagnosed longer than 5 years (β=.14) reported lower HRQOL (R²=.34). Conclusion The findings of this study suggest that improving the quality of sleep and physical activities can be efficient strategies for HRQOL in patients with COPD. Future research in enhancing HRQOL through improving sleep quality and physical activities is needed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.10 no.1
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• pp.45-56
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• 2002

This study is performed to analyze the turbulence effect by the analysis of the parameters related with flight data of FDR(Flight Data Recorder). In the analysis, the SSFDR(Solid State Flight Data Recorder) flight data of B747-400 and B767-300 model aircraft was selected. Through this study, we verified that turbulence interfere with flight safety because it is modifiable to flight situation and condition of aircraft.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.639-646
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• 2000

It is important to estimate the mechanical properties of clay since it is directly related to the design and the construction of geotechnical structures. Site exploration, which is composed of boring, sampling, in-situ, or laboratory tests, is preformed to estimate the mechanical properties. However, mechanical properties of clay measured from laboratory test may be different from in-situ properties due to disturbances occurred during sampling, transportation, storage, and trimming. In this study, the degree of disturbance according to sampling method was estimated with the test results of CK/sub o/U triaxial compression test on Yangsan clay. The soil samples were obtained by three types of sampling method, j.e., 76mm-tube sampler, 76mm-piston sampler, and block sampler. In order to evaluate the quality of samples, volumetric strain, undrained shear strength, secant Young's modulus, and pore pressure coefficient at peak measured from each sample were compared with one another. From the test results, it was observed that mechanical properties of the block and piston samples were more reliable than those of tube samples. But it was observed that the water content of piston was similar to that of tube samples at given depths while the water content of block samples was 14.3∼15.8% smaller than that of piston and tube samples. In addition to the evaluation of the quality of samples, relationship between c/sub u// σ/sub vc/'and OCR was established from the results of the CK/sub o/U triaxial compression tests, which were carried out using SHANSEP method. And also undrained shear strength was analyzed using the in-situ test data such as Cone Penetration Test(CPT), Dilatometer Test(DMT), and Field Vane Test(FVT) and was compared with that evaluated from CK/sub o/U triaxial compression test.

• The Journal of Internal Korean Medicine
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• v.28 no.4
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• pp.733-740
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• 2007

Objective : This study investigated the relationship between warning signs and Sasang constitution (SC) in acute stroke patients. Methods : From October in 2005 to March in 2007, 629 acute stroke patients were studied. Patients were hospitalized within 14 days after the onset ofstroke at one of 3 oriental medical hospitals in Seoul and Kyong-gi province. We assessed the type of SC of acute stroke patients by Questionnaire for Sasang Constitution Classification II (QSCC II). We investigated warning signs (motor weakness, blindness, dysarthria, sensory disturbance, finger dullness, facial & eyelid spasm, neck stiffness), general characteristics, etc. Results : This study showed a higher proportion of Tae-eum & So-eum experience upper extremity sensory disturbance but So-yangexperience lower extremity sensory disturbance. Smoker So-eumexperience 1st & 2nd finger dullness more than non-smoker So-eum. So-eum women experience motor weakness more than So-eum men. Conclusion : Besides these results, we could observe almost no relationship between warning signs and Sasang constitution (SC) in acute stroke patients. More data from prospective cohort studies will help people better understand the relationship between warning signs and Sasang constitution (SC) in acute stroke patients.

• Journal of the Korean Society for information Management
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• v.37 no.1
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• pp.107-126
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• 2020

With the rapid increase in information and the development of information technologies, the importance of information management is increasing for individuals. The study aimed to examine how the motivations or disturbance factors of personal information management affect college students. First, the motivation and disturbance factors of personal information management were derived through the analysis of previous studies, and the effects of these factors on information organization and information management activities were analyzed. For this purpose, an online questionnaire was conducted for college students at a university in Seoul and a total of 593 valid responses were analyzed. The study found that the motivations or disturbance factors of personal information management influenced personal information management behavior. The study extends the literature of personal information management by analyzing the information management behavior of individuals and identifying the factors influencing such behavior. Furthermore, the finding of the study suggests the practical implications that it is essential to provide personal information management education so that college students can manage personal information efficiently.

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.66-70
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• 2018

Preliminary investigation and analysis of the effectiveness of controlling the number of ecosystem disturbance fishes residing in Togyo reservoir using the native carnivorous fish species were performed. The data were collected from August 2011 to November 2016. The release of native carnivorous fish species was carried out from the end of May, 2012 to the end of July, 2016, considering fishing ban period of Siniperca scherzeri. The comparative abundance of Lepomis macrochirus was found to be 12.8% in the first year and increased a little bit after releasing the native carnivorous fish. However, it decreased to 3.9% in the last year showing a value of less than 5%. On the other hand, the Micropterus salmoides populations tended to increase after the release of native carnivorous fish species. This seems to be the result of the segregation of habitat by interspecific competition with S. scherzeri. The M. salmoides moved from inside of the lake to edges, and to influent tributaries. Stable isotope analysis showed that Channa argus had the highest levels of nutrition, S. scherzeri and M. salmoides were in competition, and L. macrochirus was used as a feed source for released species. Changes of the fish community in the Togyo reservoir was represented by the rank abundance curves based on the results of the fish fauna. As a result, the fish group in incoming tributaries are somewhat disturbed after the release of the native carnivorous species. Similarly, the fish group in the reservoir were disturbed as well but it's gradually stabilizing afterwards. Therefore, the control of the ecosystem disturbance species using the native carnivorous fish of Korea is effective and helps to stabilize the fish community in the lake.

• Journal of Environmental Health Sciences
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• v.38 no.1
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• pp.66-72
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• 2012

Objectives: The AHERA method by the US EPA, ASTM E2356-04, and HSG264 by the UK HSE, all of which are hazard/risk assessment methods for asbestos-containing building materials, were reviewed and compared based on 231 homogeneous areas. In addition, the current Act on Asbestos Safety Management (enforcement: April 29, 2012) was reviewed and analyzed. This trial provided fundamental data for improving the current asbestos hazard/risk assessment method. Methods: For the hazard/risk assessment of 77 asbestos-containing public buildings including schools, 231 homogeneous areas were selected, each of which was assessed using AHERA, ASTM E2356-04, and HSG264. Results: The matching rate of the hazard/risk assessment stood at 20.4 percent between AHERA and ASTM, at 71.4 percent between AHERA and HSG264 and at 17.8 percent between ASTM and HSG264. The AHERA method includes a seven-category rating scale. There were three categories, two of which have three subcategories. ASTM provides two decision-making charts consisting of ten rating scales for current condition estimation and for potential for disturbance estimation. In addition, the HSG264 method has a total of 20 scores with four items, and then provides four grades. This HSG264 method cannot clearly separate current condition and potential for disturbance. Conclusions: In the Korean Act on Asbestos Safety Management, the hazard/risk assessment method for asbestos-containing building materials should consider balance between current condition estimation and the potential for disturbance estimation.

• Journal of Korean society of Dental Hygiene
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• v.8 no.3
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• pp.115-126
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• 2008

Purpose : The research which sees width for a wide gain and loss is about brush qualitative management of the child about dental hygiene of the child is investigated the brush qualitative actual condition. Methods : The data which is collected used SPSS(Statistical Package for the Social Science) WIN 11.5 programs and analyzed, a frequency and a percentage with analytical technique, in order to grasp the general quality of the investigation object person produced to examine is about the brush quality control actual condition of the children opinion t-test (verification) frequency analyses and $x^2$(Chi-square) verifications, executed. Result : The followings are the findings of this research. First, the children about the reason which wipes this 83.4% the thing protection dental caries answer back, followed in grade and considers the difference which was visible(p<0.001). Second, wipes whether to experience is educated answer back 83.0% was educated, followed in sex and considers the difference which was visible(p<0.05). Third, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.01). Fourth, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.01). Fifth, when 1 time is brush quality of the children doing, in grade and the time when becomes disturbance was, most between 2~3 minutes followed considers the difference which was visible(p<0.05, p<.001). Sixth, Use duration of the toothbrush the child of most was 3~6 months, according to grade and sex was visible the difference which considers. Conclusion : Are oral healthily of the children is the knowledge which relates with a brush quality and practical degree important. Therefore this there must be dental health education program development will be able to improve, means must reflect the dental health education at the time of.