• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.305-312
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• 2017

To evaluate the reliability of fly ash quality supplied to ready-mixed concrete plant using mass cylinder and hydrometer, in this research, the correlationship between the fly ash properties provided from certification and density measurement with suspension was evaluated. As a result, the reliability of the certification, except fineness and loss on ignition, all properties had a discord. Additionally, in the case of density, fineness, and L.O.I, the relation with the density measured using hydrometer showed high correlation, especially fineness was strongly related with the density measured using hydrometer. Furthermore, according to the comparative analysis with previous research, the fly ash used in this research was similar measurement with raw powder without any refining process, it is considered that the constant error of blaine test or using raw ash sample as a fly ash. In current standard regarding fly ash, the fineness range of class 2 can be changed from $3,000-4,500cm^2/g$ to $3,500-4,500cm^2/g$ for improved quality of fly ash in fineness aspect.

• Journal of Broadcast Engineering
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• v.21 no.6
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• pp.929-943
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• 2016

This paper proposes the rate control algorithm based on the S-JND (Saliency-Just Noticeable Difference) model for considering perceptual visual quality. The proposed rate control algorithm employs the S-JND model to simultaneously reflect human visual sensitivity and human visual attention for considering characteristics of human visual system. During allocating bits for CTU (Coding Tree Unit) level in a rate control, the bit allocation model calculates the S-JND threshold of each CTU in a picture. The threshold of each CTU is used for adaptively allocating a proper number of bits; thus, the proposed bit allocation model can improve perceptual visual quality. For performance evaluation of the proposed algorithm, the proposed algorithm was implemented on HM 16.9 and tested for sequences in Class B and Class C under the CTC (Common Test Condition) RA (Random Access), Low-delay B and Low-delay P case. Experimental results show that the proposed method reduces the bit-rate of 2.3%, and improves BD-PSNR of 0.07dB and bit-rate accuracy of 0.06% on average. We achieved MOS improvement of 0.03 with the proposed method, compared with the conventional method based on DSCQS (Double Stimulus Continuous Quality Scale).

• Journal of the Korean Society of School Health
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• v.15 no.2
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• pp.205-218
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• 2002

Objectives : Because elementary school children are sensitive and prevalent to dental caries, oral health care program for the elementary school children (ESOHCP) should be met the first priority for the national oral health care program. This study was performed to proposed the guidelines for executing the efficient ESOHCP through the evaluation of present oral health care and education status based on the attitudes and opinions of health teachers. Methods : Subjects were 181 health teachers those are a part of the total 273 elementary school health teachers in Busan. From April to June 2001, questionnaire survey on the teacher's attitude and opinion, present status of oral health care and education in their own school was done. Data was analyzed by $\chi^2$-test, t-test, ANOVA using SAS (ver 6.21) program. Results : Mean age of the teachers was 40 years (24~58 years) and mean scale of the subject school was 32 classes (5~58 classes). Above 90% of them agreed with the necessity and importance of ESOHCP, but actual level of concerning was lower. They gained the informations about oral health mainly from media (33%), PC net (26%), academic society (25%), and more used internet (p=0.012) in younger generation. Though most of them (96%) had a specified school dentist, only 58% had the experience of periodic oral health examinations in their own school. The major experienced ESOHCP was fluoride brushing and contest to choose the best healthy teeth. Oral health education given by the teachers was not professional but their own. About half (42%) of the teachers had never taken education during last one year. Major education materials were VTR tape (79%), teeth model (64%), CD (55%), booklet (50%), etc., and the teachers' preference was also VTR tape (43%) and CD (41%). When they need education materials, they frequently request to dentist's association (36%), academic society (35%), but rarely to dental clinics or dentists (6%). They prefer that two times (46%) of annual oral health education, with the contents of regular brushing (53%), but lower regular visit to clinics (13%). The interest to oral health care (p=0.016) increased with teacher's age. And, they agreed regular students education in case of higher interest(p=0.044). Intention about join in the model school program was decreased with scale of school (p=0.002). Conclusions : This result showed that the present status of ESOHCP is still insufficient. It considered that the health teachers' interest and role is most important for the maintenance and success of ESOHCP. The professional and efficient education program would be focused on the health teachers to induce drive on ESOHCP.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.120-125
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• 2002

In the preceding tests using the KSR-III Sub.(I) engines, it was observed that the heat resistant capability of the engines was not enough for the mission. So Sub.(I) Mod. engines were designed and tested. The Sub.(I) Mod. engines have three major design parameters - the arrangement of main injectors, the impinging angle of main injectors and thermal barrier coating. More than twenty experiments were carried on to evaluate engine performance and heat resistance capability with respect to design parameters. In this study, the test results are introduced. Analysing the result of Sub.(I) engine tests, it is found that decreasing the impinging angle, adopting the H-type arrangement(rather than radial type arrangement) and adopting the thermal barrier coating can increase heat resistance capacity substantially. Also, engine performance evaluation is conducted using specific impulse and characteristic velocity parameter. The results show that the performance variation is small(about 5%) and the performance is better in the case of radial arrangement. It is suspected that these phenomena are caused by the change of flame structure atomization mixing characteristic of sprays and the distortion of recirculation zone. Also from the low frequency instability point of view, it is observed that reducing the impinging angle and adopting the H type arrangement can increase the instability characteristics.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.325-331
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• 2009

Three beneficial bacterial agents, Lactobacillus strain KLF01, Lactococcus strain KLC02 and Paenibacillus strain KPB3 were showed clear zone against plated Pectobacterium carotovorum subsp. carotovorum (Pcc) soft rot pathogen. In greenhouse test, bio-control efficacy was more significantly effective in the treatments by KLC02 and KPB3 as 64%, 50%, 56% and 66%, 57%, 58% according to date of evaluation, respectively. In case of KLF01 control effect was relatively lower than treatments of KLC02 and KPB3 but its efficacy was still significantly observed when compared to control (only water treatment). Furthermore, KLF01, KLC02 and KPB3 showed 55%, 60% and 62% bio-control efficacy, respectively in field test from early March to late July of 2009. Thus, we suggest that these strains can be useful as bio-control agents against soft rot caused by Pcc.

• Journal of the Korean Dietetic Association
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• v.13 no.2
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• pp.183-193
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• 2007

School foodservice employees are involved with every aspect of ensuring that high quality meals are prepared and they influence student satisfaction. The objective of this study was to identify whether job satisfaction of cooks is affected by their relationships with management. Survey forms that were developed for foodservice dietitians and employees were interviewed. Questionnaires to measure job satisfaction were distributed to 30 schools in the Gyeonggi province and completed by 30 dietitians and 323 cooks. Foodservice cooks' job satisfaction was evaluated by measuring attitudes towards aspects of their job using the modified Smith method(1969). All items in the scales were coded by 4 Likert scale(1: nerver satisfied, 4: very satisfied), then grouped by using factor analyses. Statistical methods used in this study were a $x^2$-test, t-test with SPSS software(version 12.0). The study results were as follows; 1) The demographic data showed that 65.3% of respondents were in their 40s, 96% were married, 68.8% were high school graduates, and 93.5% were contracted employees. Regarding overall experience in their current workplace, 27.9% had been in their position over 5 years and 25.7% said less than 2 years. 2) Most of the school lunches was served in the classroom(73.3%). The cook working was rotated among the employees(90%). Most employees did not use a day's leave of absence per month because they were averse to burdening their coworkers. 3) There were no significant differences in job satisfaction between the cooks' self-evaluation scores(2.92) and those of the dietitians(2.92). Among the factors influencing job satisfaction, dietitians(2.10) perceived that cooks(1.99) were more satisfied with their salaries than was actually the case. The cooks(3.19) rated their level of work satisfaction higher than the dietitians(3.03) perceived it to be. Employees rated their relationship satisfaction as 3.50, but dietitians on the other hand rated it 3.37. Most of the cook respondents want a higher salary and a some kind of employment guarantee. This study provides foodservice managers information useful for design positions that will increase productivity. Future study is needed to determine the factors that will improve job satisfaction and satisfy the employees' needs, which in turn will improve school food service quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.641-645
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• 2004

Crude chondroitin sulfates extracted from midduck tunics (Styela clava) and munggae tunics (Halocynthia roretzi) were examined in vivo in order to be utilized as a cosmetic material which was followed by an in vitro assay. Examinations, such as acute oral toxicity, skin sensitization, acute eye irritation, and primary skin irritation, were peformed with a variety of laboratory animals. Phototoxic and photosensitization tests were not conducted since all chondroitin sulfates failed to absorb U.V. light at the range of 280 to 420 nm. In acute dermal and eye irritation, both specific clinical signs and dead cases were not demonstrated during the test period, but crude chondroitin sulfates from midduck and munggae tunics, and standard chondroitin sulfate from bovine trachea were showed 2.5, 1 and 1.25 of acute ocular irritation index (A.O.I.), respectively. In the case of skin sensitization, crude chondroitin sulfate from midduck tunics exhibited neither specific clinical signs nor dead cases in the entire course of the examination. While in acute oral toxicity, crude chondroitin sulfates from both midduck and munggae tunics found neither specific clinical signs nor dead cases during the test, and LD50 was suspected to be over 2 g/kg. Based on this study, it was proven that crude chondroitin sulfates from either midduck or munggae tunics can be used safely as a cosmetic material.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.281-289
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• 2018

The Korean environmental impact assessment(EIA) system, and explored ways to improve it as a more efficient and viable institution relevant to the demand of our time and conditions in study. The first problem this study identified is found in the fact that the party to write up the assessment report is itself the business operator or the one who is planning to work out the business plan. This structure translates into placing an order with an agent for EIA report. The reporting job may br subcontracted to the agent at a cost far below the rate specified in the 'Standard for Estimate of Agency Fee for Environmental Impact Assessment.' This practice also causes the vicious circle of producing a report that is written to justify the project or business in question or it leads to rough-and ready and poor documentation to minimize the time required. Second, in order to achieve the goal of the plan or business, which is the target of EIA, the local residents tend to ve regarded as an obstacle. This means elimination of the local people from participating in the EIA or their opinion being frequently ignored. This is the seed of distrust and hostility that sometimes provoke disagreements or fierce conflicts. The first proposal to improve these problem is to improve the factors that cause poor documentation of the assessment report as well as improve the understanding of the EIA system. This study proposes the following measures for improvement. The agency cost for EIA should be paid by the business operator or a third party that can ensure faithful implementation of the payment. A system should be established to verify transparent estimation of the agency cost. In order to enhance the professional quality of EIA agents, there should be implementation of qualification test for industrial engineer of related engineers in addition to the current EIA Qualification Test. The second proposal for improvement is to improve the citizen participation process by instituting a legal framework to make clear the purpose of the briefing session for local residents, which is held as a procedure of EIA, and to ensure more positive publicity during the stage of listening to the opinion of the local community. For a smooth and rational communication process, a moderator and a communicator of opinion, as is the case in a public hearing, could be instituted to clearly get the purpose of the briefing session across to the residents and to help to carry out the explanation and Q & A sessions according to the categories of the opinion of the residents. At present, the notification of the public inspection of the draft of the assessment report and briefing session for the residents is made on the newspaper and internet network. But some people have difficulty with access to this method of announcement. A higher participation rate could be secured if a legal provision is added to specify putting up placards in specific places such as the entrance to the place for the briefing session for residents or the building of administrative agencies of the area concerned.

• Composites Research
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• v.29 no.2
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• pp.45-52
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• 2016

An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.1
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• pp.20-23
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• 2016

Purpose Because of heart movement, PET image of heart is very blur. So, PET scan gated with ECG is necessary to improve a spatial resolution of heart PET image. In this study, we will evaluate a image quality of both gated $^{13}N-ammonia$ PET scan and non-gated one. Materials and Methods Before start a heart PET, we attached a ECG electrode on patients (n = 5, $aged=54{\pm}17$). And we started a list mode PET scan that used by a mCT40 PET/CT (siemens, germany) during 10 minute, injected $^{13}N-ammonia$ ($378{\pm}50MBq$) to a patients at same time. By using this list mode data, we reconstructed both gated PET image and non-gated PET image. Then we analysed a profiles of those images, performed a blind test, and subtracted a gated image on non-gated image. Results FWHM of a gated image is improved about 23% and there is a differency count distribution at a subtracted image from non-gated image to a gated image. But in case of blind test, everybody select the gated image as a better quality among each images. Conclusion As a result, we can find that image quality will improve by using gated PET scan. In additional, we can calculate a EF valve, apply QGS, QPS of PET. Therefore, the gated PET scan help improving an accuracy, applying a more information for a diagnosis.