• 한국안전학회지
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• 제11권4호
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• pp.34-41
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• 1996

The purpose of this study is to obtain an effective enclosing method for noise reduction of press machine operating in a manufacturing company located in Taegu region. Noise level of the machine is about 95～120 ㏈ which is higher than legal standards by industrial safety and health law. In this study, two experiments were conducted to achieve the above purpose. In the first experiment in which the effects of three independent variables-type and depth of sound-absorbing materials, and depth of air space-on noise level was investigated, it was found that depth of sound-absorbing materials and air space was significant at $\alpha$ = -0.01. In the second experiment studying relationship between depth of sound-absorbing materials and air space and noise level, it was shown that noise level lowered as depth of sound-absorbing materials and air space became thick. Based on these results, two alternatives of enclosing method adequate for the selected company's noise characteristics were suggested.

• 한국과학교육학회지
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• 제26권7호
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• pp.790-797
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• 2006

본 연구에서는 제 7차 교육과정에서 제시한 심화 보충형 수준별 수업과 심화형 또는 보충형 획일적 수업의 효과를 비교해보고자 하였다. 연구 대상은 중학교 1학년 남녀학생 200명으로 심화 보충집단, 심화집단, 보충집단의 세 집단으로 구성하였다. 기본과정 이수 후에 치른 형성평가 점수에 따라 각 집단의 학생들을 심화수준과 보충수준으로 나누었다. 한 학기동안 심화 보충집단은 학생들의 수준에 해당하는 수준별 실험활동을 하였고, 심화집단은 모두 심화 실험활동을, 보충집단은 모두 보충 실험활동을 하였다. 수업처치에 따른 효과를 알아보기 위해 과학 학업성취도와 과학 탐구능력에 대해 사전 사후 검사를 실시하였고, 심화 보충형 수준별 수업에 대한 학생들의 의견을 조사하였다. 그 결과 과학 탐구능력 검사에서는 각 집단별로 유의미한 차이가 없는 것으로 나타났으나, 과학 학업성취도 검사에서는 유의미한 차이가 있는 것으로 나타났다. 사후비교 결과 이러한 차이는 심화 보충집단과 보충집단의 차이에 기인한 것을 알 수 있었다. 학생들의 의견 조사 결과 심화 보충집단의 심화수준 학생들은 심화활동에 대해 만족하는 학생들이 많았으며, 보충수준 학생들도 부정적인 반응을 보이는 학생들은 적었다. 그러므로 본 연구 결과에 의하면 중학교 과학 수업에서 심화 보충형 수준별 수업이 보충형 획일적 수업보다는 더 효과적이라고 할 수 있다.

• Journal of Periodontal and Implant Science
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• 제28권3호
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• pp.523-531
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• 1998

The purpose of this investigation was to examine the pattern of progression of periodontitis and the change in the extent and severity of the periodontal condition in young adults. Fourteen subjects with periodontitis, 11 males and 3 females in the age range 22-26, participated in the study. Following a baseline examination, the subjects were monitored for gingival index, probing pocket depth, gingival recession, probing attachment level and radiogrphic crestal bone height for 24 months without therapy. Re-examination were performed after 12 and 24 months. Gingival index, probing pocket depth, gingival recession and probing attachment level were assesed at 6 locations per tooth, and crestal bone height was assessed by subtraction radiography. The results from the follow-up examination revealed that the subjects underwent minor changes with respect to a series of different clinical parameters. The mean values of gingival index was improved, however, the mean values of probing pocket depth, gingival recession, probing attchment level and crestal bone height showed no significant change between baseline and the re-examination after 1 and 2 years.

• Journal of Periodontal and Implant Science
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• 제34권3호
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• pp.509-522
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• 2004

This study was performed to compare the clinical effectiveness of two regenerative techniques for class II furcation involvements in human: a combination of bone grafts with PRP vs. GTR with bone grafts. The e-PTFE group was treated with non-absorbable membrane and bone grafts, the PRP group was treated with PRP and bone grafts Pocket depth, clinical attachment level, and gingival recession were measured at baseline and postoperative 6 months. Vertical and horizontal furcation depth were measured by re-entry surgeries at 6 months post-treatment Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was decreased significantly at 6 months than at baseline. (p<0.05) 2. The change of gingival recession in both groups was increased significantly at 6 months than at baseline. (p<0.05) 3. The change of alveolar crest absorption in both groups was increased at 6 months than at baseline but there were no statistically significant differences. 4. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was increased significantly at 6 months, but there were no statistically or clinically significant differences with both groups. 5. The change of gingival recession and alveolar crest absorption in both groups was increased at 6 months, but there were no statistically or clinically significant differences with both groups. In conclusion, the use of bone graft with PRP or GTR technique improved clinical index of the soft and hard tissue in mandibular class II furcation involvement but there were no statistically or clinically significant differences between bone graft with PRP and GTR technique.

• 대한치과의사협회지
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• 제55권1호
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• pp.22-29
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• 2017

Purpose : Preservation of the periodontal health of the treated patient requires supportive periodontal therapy for the elimination of periodontal disease. After Phase I therapy is completed, patients are placed on a schedule of periodic recall visits for maintenance care to prevent recurrence of the disease. The amount of tooth loss would be the most relevant criterion in an evaluation of the effect of periodontal treatment, but this would require studies with extremely long follow-up periods. Thus the most commonly used outcome criteria in clinical research have been clinical attachment level change, reduction of pocket depth and bleeding frequency. The purpose of this case study is to identify the effect of supportive periodontal therapy after periodontal flap surgery. Materials & Methods : Following routine hygienic phase of treatment, patients with chronic periodontitis received surgical periodontal treatment. Bleeding on probing, pocket depth and clinical attachment level were measured at baseline, pre-operation and 1 year follow up. All procedures were performed by one operator. Results : One year a total of 28 patients (58sites) to recheck remained, when conducted maintenance program after periodontal flap surgery was observed reduction of bleeding frequency, pocket depth and improvement of clinical attachment level. Conclusion : The results from this study indicate that supportive periodontal therapy after periodontal flap surgery is effective for reduction of bleeding frequency, pocket depth and gain of clinical attachment level.

• 한국멀티미디어학회논문지
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• 제20권9호
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• pp.1491-1501
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• 2017

In this paper, we propose a method to measure respiration rate by dividing the respiration related region in depth image using level set method. In the conventional method, the respiration related region was separated using the pre-defined region designated by the user. We separate the respiration related region using level set method combining shape prior knowledge. Median filter and clipping are performed as a preprocessing method for noise reduction in the depth image. As a feasibility test, respiration activity was recorded using depth camera in various environments with arm movements or body movements during breathing. Respiration activity was also measured simultaneously using a chest belt to verify the accuracy of calculated respiration rate. Experimental results show that our proposed method shows good performance for respiration rate estimation in various situation compared with the conventional method.

• 산업기술연구
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• 제32권A호
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• pp.47-55
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• 2012

Currently, we only estimate the average flood water level by the cross-sections of the river using one-dimensional numerical analysis when establishing the basic plans. However, the reliability decreases when it comes to the river bend. In river bend, the difference of water-level between the inside and the outside of the river arises by centrifugal force. And it is estimated less than what it could be estimated when establishing the plan with average estimate of flood level. It is apprehended that the exterior of the river will be under-constructed when establishing the scour depth only with the mean depth. In the case of local scour of the abutment, it is difficult to estimate its depth precisely, and it tends to be over-estimated in the case of the empirical formulas. Therefore, the modification considering the deviation of the water depth of the exterior of the river bend is needed. In observing the deviation of each formula in river bend, it is found: Andru's formula for 58%, followed by the Laursen's for 26%, and the C.S.U's for 17% in pier, while it is 44% for Froehlich's formula in abutment. Under the 500CMS of the flood discharge, the deviation of the scour depth between pier and abutment was about 10 %. However, in further flood discharge, it shows 24~58% the biggest in deviation of piers. It is concluded that the scour depth estimate should be done with 2-dimensional numerical analysis.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.477-488
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• 2001

The present study evaluated of regeneration effect of platelet rich plasma on the treatment of grade II furcation involvement, with coralline calcium phosphate bone in humans. 30 teeth with grade II furcation defect were selected and 15 teeth(control) were treated with coralline calcium phosphate bone, the others(test) were treated with coralline calcium phosphate bone and platelet rich plasma. Pocket depth, clinical attachment level, width of keratinized gingiva width were measured at baseline, postoperative 3, 6months. from cementoenamel junction to alveolar crest and fundus were measured at baseline, 6months(re-entry). Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program(5% significance level). The results were as follows: 1. Pocket depth, clinical attachment level, keratinized gingva width, cementoenamel junction - alveolar crest, cementoenamel junction - fundus were not differ significantly in both groups at baseline 2. The change of pocket depth, clinical attachment level, keratinized gingva width, cementoenamel junction - alveolar crest, cementoenamel junction - fundus in both groups were decreased significantly at 3, 6months(p<0.05). 3. The change of pocket depth, clinical attachment level in test group decreased significantly than control at 3, 6months(p<0.05). 4. The change of keratinized gingiva width, cementoenamel junctional - alveolar crest, cementoenamel junction - fundus were not differ significantly in both groups at 3, 6months. 5. The pocket depth, clinical attachment level, keratinized gingiva width exhibited marked changes at 3 months in both groups. In conclusion, the results of this study suggest that platelet rich plasma have adjunctive clinical treatment effect to periodontal regeneration in grade II furcation defects.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.427-434
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• 2006

The form of furcation influence both the pathogenesis of periodontal destruction and therapeutic results. The present study was performed to evaluate the effect of root trunk length on clinical outcomes of guided tissue regeneration. Total 30 mandibular first molars were evaluated in this study. Probing pocket depth, clinical attachment level, vertical defect depth and horizontal defect depth were measured at baseline and 6 month after GTR. Correlation coefficients between root trunk length and other clinical measurement were analyzed. The results of this study were as follows 1. The mean root trunk length in lower 1st molar was 2.15 mm. 2. Probing pocket depth, clinical attachment level, vertical defect depth and horizontal defect depth were significantly reduced at 6 month postoperatively compared to values of baseline 3. Correlation coefficient between root trunk length and vertical defect depth at baseline was 0.406 showing the positive correlation 4. Correlation coefficient between root trunk length and horizontal defect depth at baseline was -0.463 showing the negative correlation. 5. Correlation coefficient between root trunk length and decrease of horizontal defect depth after GTR was 0.654 showing the positive correlation. In conclusion, the root trunk length maybe effector for clinical outcome after guided tissue regeneration.

• 한국농공학회논문집
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• 제57권6호
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• pp.163-171
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• 2015

This study aimed to establish a field observation system for monitoring tempo-spatially precise changes of groundwater level and to analyze the impact of rainfall and irrigation practices on groundwater changes in paddy regions. The monitoring system comprising of all nine groundwater observation wells and four ponding depth sensors was installed in a part of paddy regions benefited from Gosam reservoir, Ansung-si. The result of grundwater level change during the irrigation period in 2002 was averagely 0.51 m higher than that during the non-irrigation period. In particular between March before puddling and June after transplanting, there was maximum 1.23 m rise in groundwater level. On the other hand, concerning the change in ponding depth, groundwater level changed similarly, and hourly rainfall was revealed to have better correlation with 24-hour delayed hourly groundwater level than with the corresponding groundwater level. Eventually, this study could be referenced for further studies to set up a more comprehensive and sustainable monitoring system of groundwater conditions.