• Geomechanics and Engineering
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• v.20 no.5
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• pp.461-474
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• 2020

Analysing the incompatible deformation and damage evolution around the tunnels in mixed strata is significant for evaluating the tunnel stability, as well as the interaction between the support system and the surrounding rock mass. To investigate this issue, confined compression tests were conducted on upper-soft and lower-hard strata specimens containing a circular hole using a rock testing system, the physical mechanical properties were then investigated. Then, the incompatible deformation and failure modes of the specimens were analysed based on the digital speckle correlation method (DSCM) and Acoustic Emission (AE) data. Finally, numerical simulations were conducted to explore the damage evolution of the mixed strata. The results indicate that at low inclination angles, the deformation and v-shaped notches inside the hole are controlled by the structure plane. Progressive spalling failure occurs at the sidewalls along the structure plane in soft rock. But the transmission of the loading force between the soft rock and hard rock are different in local. At high inclination angles, v-shaped notches are approximately perpendicular to the structure plane, and the soft and hard rock bear common loads. Incompatible deformation between the soft rock and hard rock controls the failure process. At inclination angles of 0°, 30° and 90°, incompatible deformations are closely related to rock damage. At 60°, incompatible deformations and rock damage are discordant due that the soft rock and hard rock alternately bears the major loads during the failure process. The failure trend and modes of the numerical results agree very well with those observed in the experimental results. As the inclination angles increase, the proportion of the shear or tensile damage exhibits a nonlinear increase or decrease, suggesting that the inclination angle of mixed strata may promote shear damage and restrain tensile damage.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10683-10690
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• 2015

The big gap between efficacy of population level prevention and expectations due to heterogeneity and complexity of cancer etiologic factors calls for selective yet personalized interventions based on effective risk assessment. This paper documents our research protocol aimed at refining and validating a two-stage and web-based cancer risk assessment tool, from a tentative one in use by an ongoing project, capable of identifying individuals at elevated risk for one or more types of the 80% leading cancers in rural China with adequate sensitivity and specificity and featuring low cost, easy application and cultural and technical sensitivity for farmers and village doctors. The protocol adopted a modified population-based case control design using 72, 000 non-patients as controls, 2, 200 cancer patients as cases, and another 600 patients as cases for external validation. Factors taken into account comprised 8 domains including diet and nutrition, risk behaviors, family history, precancerous diseases, related medical procedures, exposure to environment hazards, mood and feelings, physical activities and anthropologic and biologic factors. Modeling stresses explored various methodologies like empirical analysis, logistic regression, neuro-network analysis, decision theory and both internal and external validation using concordance statistics, predictive values, etc..

• The Journal of Internal Korean Medicine
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• v.23 no.1
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• pp.25-31
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• 2002

Objectives : To prevent stroke, it is very important to reduce risk factors which might cause stroke. However, previous studies that having investigated coffee consumption associated with stroke reported various results. In addition, there were only a few studies based on the Korean population. Therefore, we studied the association of coffee consumption and the possibility of getting stroke among Koreans. Methods : A case-control study was carried out on 207 cases(stroke patients) and 207 controls(non-stroke patients) in a hospital. Information on characteristics, health habits, dietary habits and coffee consumption were obtained through direct interview by using an organized questionnaire; WHR(Waist-Hip Ratio) was determined through physical examination. The coffee consumption was classified by the average frequency of intake, such as less than 1 cup/day, 2-3 cups/day, more than 5 cups/day). Possible confounding effects of age, sex, smoking and alcohol drinking were controlled by multiple logistically regressive analysis. Results : After adjusting age and sex, coffee consumption significantly increased risk factors of stroke(${\leq}$1 cup/day OR=1.018, 95% CI=0.631-1.644; 2-3 cup/day OR=1.782, 95%CI=1.032-3.079;${\geq}$5 cup/day OR=1.210, 95% CI=0.588-2.490). When other factors were controlled, the risk factors of stroke were associated with alcohol drinking, whereas no significant association was observed with coffee consumption. Conclusion : Coffee consumption is not a major risk factor of causing stroke in this study. Prospective and cohort study on the association between coffee consumption and the possibility of getting strokes among the Korean population will be needed in the future.

• Journal of Preventive Medicine and Public Health
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• v.28 no.1 s.49
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• pp.1-12
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• 1995

Diatomaceous earth, quarried from the remains of aquatic plants deposited millions of years ago, continues to be a very important raw material with many industrial uses. In its natural state, diatomaceous earth is an amorphous silica with no crystalline pattern. For many uses, however, it is calcinated and calcination converts a portion of the amorphous silica to a crystalline form, cristobalite which is far more fibrogenic. In a factory which produces calcinated diatomaceous earth, seven workers were proved as pneumoconiosis on 1991 and 1992. Authors reviewed medical chart and current status of them. Authors also examined thirty one subjects from the factory with questionnaire, physical examination, spirometry and chest radiography on August 13th 1993. The radiographs were independently interpreted by two radiologists and their findings were classified by International Classification of Radiography of Pneumoconiosis(ILO, 1980). Total and respirable dust of diatomaceous earth were measured on October 1993. The results were as follows; 1. Of 31 workers, 6 (19.4%) were diagnosed as diatomaceous earth pneumoconiosis. There was an increasing tendency in prevalence of pneumoconiosis as the duration of dust exposure gets longer. 2. There were no significant differences in age, smoking rate, alcohol drinking rate, and pulmonary function test results between cases and non-cases. 3. The means of total dust exposures at flour manufacturing, fire brick grinding and packaging, ceramic raws packaging processes exceeded Korean and ACGIH standards, $10mg/m^3$. Above results suggest that engineering controls, periodic environmental and medical surveillance are important for preventing pneumoconiosis in the diatomite factory.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.323-329
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• 2017

Purpose: Biocompatible capsules have recently been highlighted as a novel platform for delivering various components, such as drug, food, and agriculture pesticides, to overcome the current limitations of living systems, such as those in agriculture, biology, the environment, and foods. However, few active targeting systems using biocompatible capsules and physical forces simultaneously have been developed in the agricultural engineering field. Methods: Here, we developed an active targeting delivery platform that uses biocompatible alginate capsules and controls movements by magnetic forces for agricultural and biological engineering applications. We designed and fabricated large-scale biocompatible capsules, using custom-made nozzles ejecting alginate solutions for encapsulation. Results: To develop the active target delivery platforms, we incorporated iron oxide nanoparticles in the large-scale alginate capsules. The sizes of alginate capsules were controlled by regulating the working conditions, such as concentrations of alginate solutions and iron oxide nanoparticles. Conclusions: We confirmed that the iron oxide particle-incorporated large-scale alginate capsules moved actively in response to magnetic fields, which will be a good strategy for active targeted delivery platforms for agriculture and biological engineering applications, such as for the controlled delivery of agriculture pesticides and biocontrol agents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.575-583
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• 2004

In this paper, we extend the multiple time scale control framework to the window-based congestion control, in particular, such as the TCP. This is performed by interfacing the TCP with a large time scale control module which adjusts the aggressiveness of the bandwidth consumption behavior exhibited by the TCP as a function of large time scale Self-Similar network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by the RTT. How to effectively utilize such an information-due to its probabilistic nature, dispersion over the multiple time scales, and affection on the top of the existing window-based congestion controls-is a non-trivial problem. The evaluation performance of the multiple time scale TCP is facilitated by a simulation of the bench-mark environment which is based on the physical modeling of a self-similar traffic. We explicate our methodology for discerning and evaluating the impact of changes in transport protocols in the protocol stack under the self-similar traffic conditions. We discuss issues arising in the comparative performance evaluation under heavy-tailed workloads.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.145-149
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• 2017

One of the challenges facing precision manufacturers is the increasing feature complexity of tight tolerance parts. All engineering drawings must account for the size, form, orientation, and location of all features to ensure manufacturability, measurability, and design intent. Geometric controls per ASME Y14.5 are typically applied to specify dimensional tolerances on engineering drawings and define size, form, orientation, and location of features. Many engineering drawings lack the necessary geometric dimensioning and tolerancing to allow for timely and accurate inspection and verification. Plus-minus tolerancing is typically ambiguous and requires extra time by engineering, programming, machining, and inspection functions to debate and agree on a single conclusion. Complex geometry can result in long inspection and verification times and put even the most sophisticated measurement equipment and processes to the test. In addition, design, manufacturing and quality engineers are often frustrated by communication errors over these features. However, an approach called profile tolerancing offers optimal definition of design intent by explicitly defining uniform boundaries around the physical geometry. It is an efficient and effective method for measurement and quality control. There are several advantages for product designers who use position and profile tolerancing instead of linear dimensioning. When design intent is conveyed unambiguously, manufacturers don't have to field multiple question from suppliers as they design and build a process for manufacturing and inspection. Profile tolerancing, when it is applied correctly, provides manufacturing and inspection functions with unambiguously defined tolerancing. Those data are manufacturable and measurable. Customers can see cost and lead time reductions with parts that consistently meet the design intent. Components can function properly-eliminating costly rework, redesign, and missed market opportunities. However a supplier that is poised to embrace profile tolerancing will no doubt run into resistance from those who would prefer the way things have always been done. It is not just internal naysayers, but also suppliers that might fight the change. In addition, the investment for suppliers can be steep in terms of training, equipment, and software.

• Journal of Haehwa Medicine
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• v.15 no.2
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• pp.39-52
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• 2006

We came to the conclusion as follows from the research about pulse diagnostic technique (脈診) out of "Nan Jinghoeju jeonjung" (難經滙注箋正). 1. "Nan Jing" is practical medical book for clinician and holds different opinions about three portions and nine takings(三部九候脈法) from Huang Di Nei Jing's Taking the pulse of Bu Jung Chim Chon Kwan Chuk((浮中沈 寸關尺) is a quite creative means which has been a important role to future generation. 2. We pointed the differences between western medical science and traditional medical science. And can explain the pulse in western medicine divided from twelve channels of Oriental Medicine. We can explain special connection between heart and lungs using the theory of systemic & pulmonary circulation in western medicine. And this can be a basement of Lung controls every pulse theory in oriental medicine. 3. We have negative assertion about viewing the human body using theory of Yin and Yang-Five Elements. And have poor opinion of explaining about the matching internal organs to Chon Kwan Chuk using the theory of Yin and Yang-Five Elements. 4. We pointed out the mistake that Porak & Sang hwa act for heart. We took pulses considering heart is a real actual internal organ as others. 5. We denied the theory of Man's Chuk pulse is always weak(男子尺脈恒弱) & Woman's Chuk pulse is always strong(女子尺脈恒盛). The physical form of man and woman is not different from each other considering their inheritances from forefather & same shape of organs. So, we cannot insist on the theory.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.246-254
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• 2016

Objectives: The aim of this investigation was to give insights into the impact of carbohydrate-electrolyte drinks on the likely capacity of enamel surface dissolution and the influence of human saliva exposure as a biological protective factor. Materials and Methods: The pH, titratable acidity (TA) to pH 7.0, and buffer capacity (${\beta}$) of common beverages ingested by patients under physical activity were analyzed. Then, we randomly distributed 50 specimens of human enamel into 5 groups. Processed and natural coconut water served as controls for testing three carbohydrate-electrolyte drinks. In all specimens, we measured surface microhardness (Knoop hardness numbers) and enamel loss (profilometry, ${\mu}m$) for baseline and after simulated intake cycling exposure model. We also prepared areas of specimens to be exposed to human saliva overnight prior to the simulated intake cycling exposure. The cycles were performed by alternated immersions in beverages and artificial saliva. ANOVA two-way and Tukey HDS tests were used. Results: The range of pH, TA, and ${\beta}$ were 2.85 - 4.81, 8.33 - 46.66 mM/L and 3.48 - $10.25mM/L{\times}pH$, respectively. The highest capacity of enamel surface dissolution was found for commercially available sports drinks for all variables. Single time human saliva exposure failed to significantly promote protective effect for the acidic attack of beverages. Conclusions: In this study, carbohydrate-electrolyte drinks usually consumed during endurance training may have a greater capacity of dissolution of enamel surface depending on their physicochemical proprieties associated with pH and titratable acidity.

• Journal of Ginseng Research
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• v.23 no.4
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• pp.247-256
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• 1999

Ginseng has been used in maintaining physical vitality throughout the far-eastern countries and recently its metabolism and actions on neurologic, cardiovascular, and endocrinologic systems are studied. Korean red ginseng (KRG) has been used in various ailments, and to prove its efficacy for erectile dysfunction an international study on Asians other than Korean was performed. Patients with borderline organic and psychogenic erectile dysfunction were included. KRG were given daily, and placebo were given as controls. Treatment lasted a total of 3 months. Surveys including libido, erection, ejaculation, sexual activity, and sexual satisfaction were given. Serum testosterone and erectile function study were taken. Among the 64 patients, 37 patients were followed with KRG. Five had diabetes, 5 hypertension, 5 hypercholesterolemia, 6 low testosterone, 6 psychogenic, and 11 idiopathic. The improvement after KRG administration was $70.2\%$ on objective questionnaire and $75.7\%$ on subjective analysis. When KRG were given, all parameters surveyed have shown improvements compared to the placebo. The effects of KRG in Chinese and Singapores were similar to the Koreans. Serum testosterone levels were nonnalized in 6 patients with KRG, who's serum testosterone levels were reduced from pre-study. Two patient reported constipation, and 2 gastric upsets in the KRG group. In conclusion, KRG has beneficiary action on male erectile capabilities with little side effects. KRG is effective in Koreans and also Asians. The exact action mechanism and the active ingredients in KRG need to be studied.