• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.530-537
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• 2011

The purpose of this study is to examine material performance of fiber reinforced cement composite for mass production. It is necessary to manufacture SHCC(Strain Hardening Cement Composite) by batch plant for field application and mass production. For the study, a mock-up test of SHCC manufactured in the batch plant was conducted, and the performance was compared with SHCC manufactured in the laboratory. Assessment items were freshness and hardening properties. Specifically, direct tensile test machine was used for performance verification of SHCC. As a result, there was a tendency of less satisfactory fiber dispersion and performance of strain hardening compared with the performance of SHCC manufactured in the laboratory. To address this, dry mixing and mortar mixing time should be increased compared to laboratory mixing, and injection time of an agent such as a water reducing agent should be properly controlled according to mixing combination, or the capacity to secure dispersion and homogeneity of material.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.380-389
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• 2012

In this study, Systematic review and meta-analysis using the correlation coefficients was carried out to integrate precedent studies on factors affecting domestic occupational therapists' job stress. It aims at providing basic information resources of preventing and reducing stress of occupational therapists and effective counter-measurement to improve quality of occupational therapy and to establish efficient human resource management policy. Systematic review and meta-analysis were performed on eight thesis proven relevant to selection criteria in order to figure out correlation coefficients value by total, and factors correlation coefficients value. Also homogeneity test and publication bias test was performed too. The total correlation coefficients value of occupational therapists was .30 which was statistically significant. As to job stress factors, the organization related factor showed the highest correlation of coefficiency, followed by factors other than the organization related, physical environment, job related factor and personal factor. This research result can be used as a reference to prevent and reduce job stress of occupational therapists and to develop an effective measurement scheme.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.257-264
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• 2009

The purpose of this study was to examine the effects of the game application learning 8th graders' scientific attitude, which was utilized as a strategy to improve the teaching skills and methods in the lesson of 'the history of the earth and diastrophism'. The subjects of this study were 120 students of 8th grade at a middle school located in a metropolitan city in Korea. To start off with homogeneity of a group, this study recruited participants by the results of a diagnostic test taken early in the year and a mid-term examination taken at the end of April. As a result, a total of 4 male classes that showed similar results on the two tests were selected and divided into two groups: one in experimental and the other in control. In addition, the top 20% students and the low 20% students were chosen for comparison of their scientific attitudes based on the results of the mid-term examination. The traditional teachings were offered to the control groups while the experimental lessons with the game activities performed at the stages of application and summary in teaching were offered to the experimental groups over 10 periods. Results of the pre- and post-test on the students' scientific attitude demonstrated that there was a statistical significance between the two groups, which suggested that the experimental group showed a meaningful improvement in the scientific attitude after experimental intervention lesson activities with game applications. Also, the more meaningful improvement in the scientific attitude was found in the lower group than in the higher group. It implies that lessons with the game activities motivated the students to voluntarily participate in school science learning by enhancing their interests. Therefore, it is suggested that game application learning be a new teaching-learning material that helps to encourage learners to actively participate in middle school science learning.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.504-514
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• 2013

Purpose: This study was to identify the educational effects of self directed learning applying basic nursing practice contents of e-learning on nursing students' knowledge, self-confidence, and learning satisfaction. Method: This study applied a quasi-experimental pre-test and post-test control group design with 63 freshman nursing students (31 experimental group, 32 control group) of G. university in Incheon, Korea as subjects. The e-learning content was about the application of topical medications, central line care, and blood transfusion. All were available at the web site in school. Self-directed e-learning was more than 120 min.(3 times a week, 2 weeks)during Sep-Nov in 2011. In both groups, there were no significant difference in general characteristics, self-directed learning readiness, knowledge, and self-confidence for the pre-homogeneity. Results: The experimental group showed a higher level of improvement in knowledge and learning satisfaction but not significantly. However, the self-confidence was significantly improved in the experimental group. Conclusion: When self-directed learning using e-learning contents added to the conventional practical class, it may be beneficial for the nursing students to learn skills effectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1063-1069
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• 2012

In present paper, we used magnesium alloy having a lower density and higher electrical conductivity for bipolar plate to reduce the weight of PEM fuel cell. The silver was coated to prevent corrosion and form passivation film on the metal surface with sputtering. In acid proof evaluation for setting optimal coating conditions, the homogeneity of coating thickness was improved by coating with the thickness of 3 ${\mu}m$ which not indicated any micro cracks and the temperature $180^{\circ}C$. The performance test and evaluation based on the clamping pressure and channel depth to determine the configuration of bipolar plate for assembling single cell was implemented. And then we assembled single cell with this bipolar plate and implemented the performance test to ensure and compare the current-voltage performance followed as several factors such as coating or non-coating, the change of clamping pressure, the change of channel depth, etc. As these results, the maximum power density of single cell with the coated bipolar plate was 192 $mW/cm^2$ and it was confirmed that the power density per unit mass was better than existing metal bipolar plate.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.2
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• pp.145-156
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• 2015

Purpose : The purpose of this study is to evaluate the efficiency of Split VMAT planning(Contouring rectum divided into an upper and a lower for reduce rectum dose) compare to Conventional VMAT planning(Contouring whole rectum) for prostate cancer radiotherapy involving pelvic lymph nodes. Materials and Methods : A total of 9 cases were enrolled. Each case received radiotherapy with Split VMAT planning to the prostate involving pelvic lymph nodes. Treatment was delivered using TrueBeam STX(Varian Medical Systems, USA) and planned on Eclipse(Ver. 10.0.42, Varian, USA), PRO3(Progressive Resolution Optimizer 10.0.28), AAA(Anisotropic Analytic Algorithm Ver. 10.0.28). Lower rectum contour was defined as starting 1cm superior and ending 1cm inferior to the prostate PTV, upper rectum is a part, except lower rectum from the whole rectum. Split VMAT plan parameters consisted of 10MV coplanar $360^{\circ}$ arcs. Each arc had $30^{\circ}$ and $30^{\circ}$ collimator angle, respectively. An SIB(Simultaneous Integrated Boost) treatment prescription was employed delivering 50.4Gy to pelvic lymph nodes and 63~70Gy to the prostate in 28 fractions. $D_{mean}$ of whole rectum on Split VMAT plan was applied for DVC(Dose Volume Constraint) of the whole rectum for Conventional VMAT plan. In addition, all parameters were set to be the same of existing treatment plans. To minimize the dose difference that shows up randomly on optimizing, all plans were optimized and calculated twice respectively using a 0.2cm grid. All plans were normalized to the prostate $PTV_{100%}$ = 90% or 95%. A comparison of $D_{mean}$ of whole rectum, upperr ectum, lower rectum, and bladder, $V_{50%}$ of upper rectum, total MU and H.I.(Homogeneity Index) and C.I.(Conformity Index) of the PTV was used for technique evaluation. All Split VMAT plans were verified by gamma test with portal dosimetry using EPID. Results : Using DVH analysis, a difference between the Conventional and the Split VMAT plans was demonstrated. The Split VMAT plan demonstrated better in the $D_{mean}$ of whole rectum, Up to 134.4 cGy, at least 43.5 cGy, the average difference was 75.6 cGy and in the $D_{mean}$ of upper rectum, Up to 1113.5 cGy, at least 87.2 cGy, the average difference was 550.5 cGy and in the $D_{mean}$ of lower rectum, Up to 100.5 cGy, at least -34.6 cGy, the average difference was 34.3 cGy and in the $D_{mean}$ of bladder, Up to 271 cGy, at least -55.5 cGy, the average difference was 117.8 cGy and in $V_{50%}$ of upper rectum, Up to 63.4%, at least 3.2%, the average difference was 23.2%. There was no significant difference on H.I., and C.I. of the PTV among two plans. The Split VMAT plan is average 77 MU more than another. All IMRT verification gamma test results for the Split VMAT plan passed over 90.0% at 2 mm / 2%. Conclusion : As a result, the Split VMAT plan appeared to be more favorable in most cases than the Conventional VMAT plan for prostate cancer radiotherapy involving pelvic lymph nodes. By using the split VMAT planning technique it was possible to reduce the upper rectum dose, thus reducing whole rectal dose when compared to conventional VMAT planning. Also using the split VMAT planning technique increase the treatment efficiency.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.129-138
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• 2018

Purpose : An aim of this study was to compare the effect of multi leaf collimator(MLC) types for high dimension radiotherapy in treatment sites used clinically. Material and Method : 70 patients with lung cancer, spine cancer, prostate cancer, whole pelvis, head and neck, breast cancer were included in this study. High definition(HD) MLC of TrueBeam STx (Varian Medical system, Palo Alto, CA) and millenium(M) MLC of VitalBeam (Varian Medical system, Palo Alto, CA) were used. Radiotherapy plans were performed for each patient under same treatment goals with Eclipse (Version 13.7, Varian Palo Alto USA, CA). To compare the indicators of the radiotherapy plans, planning target volume(PTV) coverage, conformity index(CI), homogeneity index(HI), and clinical indicators for each treatment sites in normal tissues were evaluated. To evaluate low dose distribution, $V_{30%}$ values were compared according to MLC types. Additionally, length and volume of targets for each treatment sites were investigated. Result : In stereotatictic body radiotherapy(SBRT) plan for lung, the average value of PTV coverage was reduced by 0.52 % with HD MLC. With SBRT plan using HD MLC for spine, the average value of PTV coverage decreased by 0.63 % and maximum dose decreased by 1.13 %. In the test of CI and HI, the values in SBRT plan with HD MLC for spine were 1.144, 1.079 and the values using M MLC were 1.160, 1.092 in SBRT plan for lung, The dose evaluation of critical organ was reduced by 1.48 % in the ipsilateral lung mean dose with HD MLC. In prostate cancer volumetric modulated arc therapy(VMAT) with HD MLC, the mean dose and the $V_{30}$ of bladder and the mean dose and the $V_{25}$ of rectum were reduced by 0.53 %, 1.42 %, 0.97 %, and 0.69 %, respectively (p<0.05). The average value of heart mean dose was reduced by 0.83 % in breast cancer VMAT with M MLC. Other assessment indices for treatment sites showed no significant difference between treatment plans with two types of MLC. Conclusion : Using HD MLC had a positive impact on the PTV coverage and normal tissue sparing in usually short or small targets such as lung and spine SBRT and prostate VMAT. But, there was no significant difference in targets with long and large such as lung, head and neck, and whole pelvis for VMAT.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.89-97
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• 2021

Purpose: The purpose of this study is to compare and evaluate the dose change according to the gas volume variations in the rectum, which was not included in the treatment plan during radiation therapy for cervical cancer. Materials and methods: Static Intensity Modulated Radiation Therapy (S-IMRT) using a 9-field and Volumetric Modulated Arc Therapy (VMAT) using 2 full-arcs were established with treatment planning system on Computed Tomography images of a human phantom. Random gas parameters were included in the Planning Target Volume(PTV) with a maximum change of 2.0 cm in increments of 0.5 cm. Then, the Conformity Index (CI), Homogeneity Index (HI) and PTV D_max for the target volume were calculated, and the minimum dose (D_min), mean dose (D_mean) and Maximum Dose (D_max) were calculated and compared for OAR(organs at risk). For statistical analysis, T-test was performed to obtain a p-value, where the significance level was set to 0.05. Result: The HI coefficients of determination(R²) of S-IMRT and VMAT were 0.9423 and 0.8223, respectively, indicating a relatively clear correlation, and PTV D_max was found to increase up to 2.8% as the volume of a given gas parameter increased. In case of OAR evaluation, the dose in the bladder did not change with gas volume while a significant dose difference of more than D_mean 700 cGy was confirmed in rectum using both treatment plans at gas volumes of 1.0 cm or more. In all values except for D_mean of bladder, p-value was less than 0.05, confirming a statistically significant difference. Conclusion: In the case of gas generation not considered in the reference treatment plan, as the amount of gas increased, the dose difference at PTV and the dose delivered to the rectum increased. Therefore, during radiation therapy, it is necessary to make efforts to minimize the dose transmission error caused by a large amount of gas volumes in the rectum. Further studies will be necessary to evaluate dose transmission by not only varying the gas volume but also where the gas was located in the treatment field.

• Journal of Hospice and Palliative Care
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• v.7 no.2
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• pp.189-199
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• 2004

Purpose: Despite the small incidence, head and neck cancer may cause a wide range of physical transformation by surgical operation, damage to active functions such as eating and speaking. It may provoke hopelessness, change self-esteem and self-concept after its operation, influencing the quality life of head and neck cancer patients. Thus nursing intervention should be developed to provide supportive nursing for head and neck cancer patients and play roles as competent supporters. Methods: This study was a nonequivalent, control group, pretest-posttest, non-synchronized quasi-experimental research designed to determine how supportive nursing intervention effects on hopelessness, self-esteem and self-concept of head and neck cancer patients. Subjects of the study included 40 adult inpatients of K University hospital in Pusan who were diagnosed as having head and neck cancer and operated. They were divided into experimental and comparison groups, each consisting of 20 members. The data were collected during the period from December 1, 1999 to April 11, 2000. Tools of the study included the protocol of supportive nursing intervention which was developed by researcher by means of reference, literal review and expert's advice. The measurement tool of hopelessness was translated by Won was the device of hopelessness self-evaluation from Beck, the tool for self-esteem measurement was developed by Rosenberg and translated by Kim, and the device of self-concept used by Lee et al, modified by Lee were used respectively. Data were analyzed using the SPSS/PC 9.0 program. The homogeneity of the subjects were tested using $x^2-test$ and t-test. 3 hypotheses were tested using t-test. Results: The results of the study can be summarized as follows. 1. The third hypothesis that the experimental group receiving supportive nursing intervention showed a little hopelessness than the control group not receiving supportive nursing intervention was supported (t=4.550, P=.000). 2. The third hypothesis that the experimental group receiving supportive nursing intervention showed more self-esteem than the control group not receiving supportive nursing intervention was supported (t=-6.40, p=.000). 3. The third hypothesis that the experimental group receiving supportive nursing intervention showed more self-concept than the control group not receiving supportive nursing intervention was supported (t=-6.065, P=.000). Conclusion: Supportive nursing intervention was effective nursing intervention strategy for reducing hopelessness and increasing self-esteem and self-concept of head and neck cancer patients. Then the quality of life of head and neck cancer patients can be enhanced by providing supportive nursing intervention in nursing practice.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.218-229
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• 2015

The proficiency testing for the residue laboratories of pesticide registration was conducted in order to improve the reliability and the ability for pesticide residue analysis. On November 2012 the testing was carried out using the soil collected and kept as the moistened state for five years, which was expected to very low residue levels of pesticides. The soil was fortified with azoxystrobin, imidacloprid and methabenzthiazuron in a manner similar to prepare soil samples for indoor soil degradation test, and then sub-samples were prepared for the distribution to participants. Some of them were randomly selected for confirm of homogeneity and to ensure the stability of samples at room temperature. Samples were consisted of two soils treated as different levels, one of which was used to the assessment and another used to confirm. In addition, provided three standard solutions, respectively concentration of 10 mg/L, and untreated soil. Forty eight institutions submitted results. The medians of results were used as the assigned values for pesticide residues. Fitness for purpose standard deviation of proficiency test was calculated by applying 20% RSD as the coefficient of variation allowed in the soil residue test. Z-score was applied for evaluation of individual pesticides, and the average of the absolute value of the Z-score for the overall assessment of pesticides. Laboratories evaluated the absolute value of the Z-score less than 2 to fit the case of azoxystrobin were 48, imidacloprid and methabenzthiazuron 46.