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Behaviors of the High-profile Arch Soil-steel Structure During Construction (높은 아치형 지중강판 구조물의 시공 중 거동 분석)

  • 이종구;조성민;김경석;김명모
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.71-84
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    • 2003
  • The metallic shell of soil-steel structures are so weak in bending moment that it should sustain the applied load by the interaction of the backfill soil around the structures. The shell can be subjected to excessive bending moment during side backfilling or under live-load when the soil cover is less than the minimum value. The current design code specifies the allowable deformation and Duncan(1979) and McGrath et al.(2001) suggested the strength analysis methods to limit the moments by the plastic capacity of the shell. However, the allowable deformation is an empirically determined value and the strength analysis methods are based on the results of FE analysis, hence the experimental verification is necessary. In this study, the full-scale tests were conducted on the high-profile arch to investigate its behaviors during backfilling and under static live-loads. Based on the measurements, the allowable deformation of the tested structure could be estimated to be 1.45% of rise, which is smaller than the specified allowable deformation. The comparison between the measurements and the results of two strength analyses indicate that Duncan underestimates the earth-load moment and overestimates the live-load moment, while McGrath et al. predicts both values close to the actual values. However, as the predicted factors of safeties using two methods coincide with the actual factor of safety, it can be concluded that both methods can predict the structural stability under live-loads adequately when the cover is less than the minimum.

Bond Characteristics and Splitting Bond Stress on Steel Fiber Reinforced Reactive Powder Concrete (강섬유로 보강된 반응성 분체 콘크리트의 부착특성과 쪼갬인장강도)

  • Choi, Hyun-Ki;Bae, Baek-Il;Choi, Chang-Sik
    • Journal of the Korea Concrete Institute
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    • v.26 no.5
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    • pp.651-660
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    • 2014
  • Structural members using ultra high strength concrete which usually used with steel fiber is designed with guidelines based on several investigation of SF-RPC(steel fiber reinforced reactive powder concrete). However, there are not clear design method yet. Especially, SF-RPC member should be casted with steam(90 degree delicious) and members with SF-RPC usually used with precast members. Although the most important design parameter is development method between SF-RPC and steel reinforcement(rebar), there are no clear design method in the SF-RPC member design guidelines. There are many controversial problems on safety and economy. Therefore, in order to make design more optimum safe design, in this study, we investigated bond stress between steel rebar and SF-RPC according to test. Test results were compared with previously suggested analysis method. Test was carried out with direct pull out test using variables of compressive strength of concrete, concrete cover and inclusion ratio of steel fiber. According to test results, bond stress between steel rebar and SF-RPC increased with increase of compressive strength of concrete and concrete cover. Increasing rate of bond stress were decrease with increase of compressive strength of SF-RPC and concrete cover significantly. 1% volume fraction inclusion of steel fiber increase the bond stress between steel rebar and SF-RPC with two times but 2% volume fraction cannot affect the bond stress significantly. There are no exact or empirical equations for evaluation of SF-RPC bond stress. In order to make safe bond design of SF-RPC precast members, previously suggested analysis method for bond stress by Tepfers were evaluated. This method have shown good agreement with test results, especially for steel fiber reinforced RPC.

THE COMPARISON OF CITRIC ACID AND TETRACYCLINE HCL ON TREATED ROOT SURFACES ON THE PROLIFERATION AND SPREADING OF PERIODONTAL LIGAMENT CELLS (치근면 탈회제인 테트라시이클린과 구연산이 치주인대세포 증식과 전개에 미치는 영향에 대한 비교)

  • Park, Jae-Wan;Lee, Jae-Mok;Suh, Jo-Young
    • Journal of Periodontal and Implant Science
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    • v.25 no.3
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    • pp.587-602
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    • 1995
  • The purpose of this study was to compare the effects of citric acid and tetracycline HCI application to the root surfaces of periodontally diseased teeth on the proliferation and spreading of human periodontal ligament cells. The roots were prepared so that the comparison could be made among root planed, citric acid treated and tetracycline HCI treated surfaces. In the cell proliferation experiment, human periodontal ligament cells at a concentration of $1{\times}10^5$ cells/ml were seeded in each culture well with specimens and incubated for 6 hours. Then, the specimens were transferred to a fresh culture well and incubated for 24, 48, 72 hours respectively. The cell counting was done after trypsinization. In the cell spreading experiment, $1{\times}10^4$ cells/ml were seeded in each culture well and incubated for 30min, 6 hours and 24 hours at 37.5$^{\circ}C$ in a $CO_2$ incubator. Then, all specimens were fixed with phosphate buffered glutaraldehydes, postfixed with phosphate buffered osmium tetraoxide, stained with phosphate buffered tannic acid, dehydrated in ethanol, dried at a critical point, coated with gold and examined under a scanning electron microscope. The results were as follows:In the cell proliferation experiments, the number of attached cells increased more in the tetracycline treated group than in the other groups. In the initial attachment, the appearance of the tetracycline treated the groups was slightly more spread out than in the other groups. After 6 hours of incubation, it was observed in most of the cells that cell morphologic alteration went from ovoid shapes sto spindle shapes. After 24 hours of incubation, the cells of all groups had a fusiform appearance and were connected to each other by numerous cytoplasmic processes. The tetracycline and citric acid treated groups had a similar spreading appearance of periodontal ligament cells, but the tetracycline treated group was more effective in the cell proliferation than the citric acid group.

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The effect of silane treatment timing and saliva contamination on shear bond strength of resin cement to porcelain (Silane의 처리시기와 타액오염이 도재-레진 시멘트의 전단 결합강도에 미치는 영향)

  • Ro, Young-Seon;Ryu, Jae-Jun;Suh, Kyu-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.1
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    • pp.61-69
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    • 2009
  • Statement of problem: Porcelain veneers have become a popular treatment modality for aesthetic anterior prosthesis. Fitting porcelain veneers in the mouth usually involve a try-in appointment, which frequently results in salivary contamination of fitting surfaces. Purpose: An in vitro study was carried out to investigate the effect of silane treatment timing and saliva contamination on the resin bond strength to porcelain veneer surface. Material and methods: Cylindrical test specimens (n=360) and rectangular test specimens (n=5) were prepared for shear bond test and contact angle analysis. Whole cylindrical specimens divided into 20 groups, each of which received a different surface treatment and/or storage condition. The composite resin cement stubs were light-polymerized onto porcelain adherends. The shear bond strengths of cemented stubs were measured after dry storage and thermocycling (3,000 cycles) between 5 and $55^{\circ}C$. The silane and their reactions were chemically monitored by using Fourier Transform Infrared Spectroscopy analysis (FTIR) and contact angle analysis. One-way analysis of variance (ANOVA) and Dunnett's multiple comparison were used to analyze the data. Results: FT-IR analysis showed that salivary contamination and silane treatment timing did not affect the surface interactions of silane. Observed water contact angles were lower on the saliva contaminated porcelain surface and the addition of 37% phosphoric acid for 20 seconds on saliva contaminated porcelain increased the degree of contact angle. Silane applied to the porcelain, a few days before cementation, resulted in increasing the bond strength after thermocycling. Conclusion: Within the limitation of this study, it can be concluded that it would be better to protect porcelain prosthesis before saliva contamination with silane treatment and to clean the contaminated surface by use of phosphoric acid.

Quality Characteristics and Antioxidant Properties of Saccharified Banana Gruels (바나나 첨가량을 달리한 당화 바나나죽의 품질특성 및 항산화효과)

  • Kim, Jin Sook;Kim, Ja Young;Kim, Gi Chang;Kim, Kyung Mi;Kang, Myung Hwa
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.7
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    • pp.1071-1078
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    • 2013
  • We conducted this study in order to investigate the quality and antioxidant properties of saccharifed banana gruel containing different levels (0, 15, 30, and 45%) of banana puree. Saccharified banana gruel with different ratios of banana was prepared and proximate composition, sweetness ($^{\circ}brix%$), pH, total acidity, Hunter's color value, viscosity, free sugar, sensory evaluation, and physiological activities of the sample were measured. With increasing banana content, proximate composition, sweetness, and acidity of banana gruel increased, and pH showed a significant decrease (P<0.05). Saccharified banana gruel prepared with 15~45% banana showed significantly lower viscosity. As the level of banana increased, L-value decreased, whereas the a-value, b-value increased. Free sugar content of fructose, glucose, maltose, and sucrose showed a significant increase (P<0.05). Saccharified banana gruel with 30% added banana was the most preferred for color, flavor, taste, mouth-feeling, texture, and overall acceptability. The total phenolic compound contents of saccharified banana gruel with banana puree ranged from 1.73 to 5.75 mg/g. DPPH and ABTS radical scavenging activities of saccharified banana gruel with banana puree were 8.67~31.26% and 6.02~55.16%, respectively. With increasing banana content, total polyphenol contents, DPPH and ABTS radical scavenging activity of banana gruel showed a significant increase (P<0.05). From these results, we found that addition of 30% banana was the best method for preparation of gruel with high sensory quality.

Development of an Aerodynamic Simulation for Studying Microclimate of Plant Canopy in Greenhouse - (2) Development of CFD Model to Study the Effect of Tomato Plants on Internal Climate of Greenhouse - (공기유동해석을 통한 온실내 식물군 미기상 분석기술 개발 - (2)온실내 대기환경에 미치는 작물의 영향 분석을 위한 CFD 모델개발 -)

  • Lee In-Bok;Yun Nam-Kyu;Boulard Thierry;Roy Jean Claude;Lee Sung-Hyoun;Kim Gyoeng-Won;Hong Se-Woon;Sung Si-Heung
    • Journal of Bio-Environment Control
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    • v.15 no.4
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    • pp.296-305
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    • 2006
  • The heterogeneity of crop transpiration is important to clearly understand the microclimate mechanisms and to efficiently handle the water resource in greenhouses. A computational fluid dynamic program (Fluent CFD version 6.2) was developed to study the internal climate and crop transpiration distributions of greenhouses. Additionally, the global solar radiation model and a crop heat exchange model were programmed together. Those models programmed using $C^{++}$ software were connected to the CFD main module using the user define function (UDF) technology. For the developed CFD validity, a field experiment was conducted at a $17{\times}6 m^2$ plastic-covered mechanically ventilated single-span greenhouse located at Pusan in Korea. The CFD internal distributions of air temperature, relative humidity, and air velocity at 1m height were validated against the experimental results. The CFD computed results were in close agreement with the measured distributions of the air temperature, relative humidity, and air velocity along the greenhouse. The averaged errors of their CFD computed results were 2.2%,2.1%, and 7.7%, respectively.

Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation (보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법)

  • Kwon, Oh-Byung
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

Reactivities of Di-iso-butylnitrosoamine by Anodic Film Formed on Metals (산화피막전극을 이용한 디이소부틸니트로소아민의 전극반응)

  • Hwang Kum-Sho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.14 no.2
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    • pp.94-102
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    • 1981
  • To investigate the characteristics of anodic film formed on metals and the reactivities of organic inhibitor Di-iso-butylnitrosoamine (DBNA) in sea water. the cathodic reactions of anodic film formed on metals were carried out by using the potential drop method and galvanostatic method at $25^{\circ}C$. The investigated results are as follows: The anodic films formed on aluminum and zinc in 60mM $DBNA+9\%_{\circ}$ sea water did not show-changes of potential drop. However, those formed on lead and copper were reasonable electrodes. It was concluded that cathodic reactivities of proton through the anodic film in aqueous solution were constant without regard to the kinds of metals used with anodic film electrode at operated current density ranges, because the values of transition time obtained in 0.5M sodium chloride solution and $9\%_{\circ}$ sea water nearly coincided. The values of transition time of the first step by the galvanostatic method were obtained from 0.22 to 1.40 sec ranges far less than one minute. Therefore, it suggested that cathodic reactions of proton through the anodic film were mainly controlled by diffusion/adsorption process. The differences of between $\tau_{1}/4$ in $9\%_{\circ}$ sea water and $\tau_{1}/4$ in 60mM $DBNA+9\%_{\circ}$ sea water, and between $E_{1}/4$ in sea water and $E_{1}/4$ in 60mM $DBNA+9\%_{\circ}$ sea water at the constant current density with $1.9\times10^{-4}\sim5.0{\times}10^{-6}\;amp/cm^2$ were 0.06 sec and 0.53 v. respectively and cathodic reactions of DBNA on the anodic film electrodes were chiefly controlled by adsorption/diffusion process. The reason that adsorption quantities of proton on anodic film formed on aluminum and zinc in aqueous solutions were much more than those on lead and copper, seems to lie due mostly to the number of porosity produced on anodic film used.

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A Study of Correlation among the Knowledge of the Disease, Health Promoting Behaviors and the Quality of Life in the Female Patients with Osteoporosis (여성 골다공증환자의 골다공증에 대한 지식, 건강증진행위 및 삶의 질과의 관계 연구)

  • Lee, Hye-Young
    • Journal of muscle and joint health
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    • v.8 no.1
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    • pp.65-85
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    • 2001
  • Osteoporosis is the disease that is the most controversial issue with the aging tendency in 1990. It is an important issue in dealing with the health management for women in middle life. This study is designed to determine the relationships among the level of the knowledge of osteoporosis, the health promoting behaviors and the quality of life. The test has conducted a questionnaire survey of women with osteoporosis. This is a study that focused an interrelation of above issues and its purpose is to gain a foundation of a nursing intervention that can help to improve the qualify of life of an osteoporosis patients. The method of collecting data is collecting a questionnaire survey, individual interviews and records and the collected 123 questionnaire surveys are utilized for an data analysis. Questionnaire surveys are conducted in K and S Universities infirmaries and K general hospital in Seoul and C and J general hospital in near Seoul area from Sep. 27th to Nov. 4th, 2000. The instruments of this study were as follows: Yoon's used the revised and supplemented instrument to test the level of the knowledge of osteoporosis and she referred to the substance of Cassells & Knotz. Lee's revised and supplemented the instrument called Health Promoting Life style Profile that were invented by Walker, Sechrist & Pender and she used it to test the health promoting behaviors with the questionnaires added by this researcher. They are not related to the quality of life but relevant to the patients. Ro's tested the quality of life with the instrument that was invented by herself. The results of this study were as follows. 1. The general characteristics of this study subjects showed that the age of the patients was concentrated from 50 to 59. The periods after menopause was mainly from 6 to 10 years. Subjective symptoms that patients usually complain were musculoskelectal symptoms. 2. The results of measuring the level of the knowledge of osteoporosis, the health promoting behaviors and the quality of life were following. The level of the knowledge was the score 19.83 and it was above middle score out of the score 27 as full marks. In the result of the health promoting behaviors test, the score average was 2.58 with 4 point rating scale and it was about middle score. The quality of life test showed that average score was 2.92 with 5 point rating scale and it indicated that the quality was also around middle score. 3. The statistical test in the activities for promoting health according to the general characteristics of the patients showed that only monthly income has statistically significant difference(F-4.761, p=.004). The same test for the qualify of life indicated that the quality of life was higher from 1 to 5 years after menopause but it was not meaningful statistically. 4. In the correlation among the level of knowledge of osteoporosis, the health promoting behaviors and the qualify of life of the patients, showed a relationship between the health promoting behaviors and the qualify of life. The higher the health promoting behaviors, it was also higher the quality of life. But it was statistically significant with significant positive correlation.

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Effects of Mud Flat Bacteria Origin Protease Supplementation on Egg Quality, Nutrient Digestibility and Total Protein Concentration of Serum in Laying Hens (산란계에 갯벌 미생물 유래 단백질 분해 효소제의 급여가 계란 품질, 영양소 소화율 및 혈청내 총 단백질 함량에 미치는 영향)

  • Kim, H.J.;Cho, J.H.;Chen, Y.J.;Yoo, J.S.;Min, B.J.;Park, B.C.;Kim, I.H.
    • Korean Journal of Poultry Science
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    • v.33 no.4
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    • pp.303-308
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    • 2006
  • This study was conducted to investigate the effects of mud flat bacteria origin pretense supplementation on e99 qualify, nutrient digestibility and total protein concentration of serum in laying hens. A total of two hundred fifty two laying hens were randomly allocated into three treatments with seven replications for eight weeks. Dietary treatments included 1) CON (basal diet), 2) PRO1 (basal diet + 0.05% pretense) and 3) PRO2 (basal diet + 0.1% pretense). During the entire experimental peripd, hen-day egg production was not affected by treatments (P>0.05). Difference of yolk height was increased in PRO1 treatment compared with CON treatment (P<0.05). Difference of egg weight was increased in PRO2 treatment compared with CON and PRO1 treatments (P<0.05). Shell quality, yolk color unit, haugh unit and egg yolk index were not affected by treatments (P>0.05). DM digestibility was improved in CON and PRO2 treatments compared with PRO1 treatment (P<0.05). N digestibility was improved in PRO2 treatment compared with CON treatment (P<0.05). Total protein concentration in serum were not affected by treatments (P>0.05). In conclusion, mud flat bacteria origin pretense was effective for improving egg weight, yolk height and nutrient digestibility in laying hens.