• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4141-4149
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• 2013

Background: Mammography is considered the gold standard of breast cancer mass screening and many countries have implemented this as an established breast cancer screening strategy. However, although the incidence of breast cancer and racial characteristics are different between Western and Asian countries, many Asian countries adopted mammography for mass screening. Therefore, the objective of this research was to determine whether mammography mass screening is cost-effective for both Western and Asian countries. Materials and Methods: A systematic review was performed of 17 national mammography cost-effectiveness data sets. Per capita gross domestic product (GDP), breast cancer incidence rate, and the most optimal cost-effectiveness results [cost per life year saved (LYS)] of a mammography screening strategy for each data set were extracted. The CE/per capita GDP ratio is used to compare the cost-effectiveness of mammography by countries. Non-parametric regression was used to find a cut-off point which indicated the breast cancer incidence rate boundary line determining whether mammography screening is cost-effective or not. Results: We found that the cost-effective cut-off point of breast cancer incidence rate was 45.04; it exactly divided countries into Western and Asian countries (p<0.0014). Conclusions: Mammography screening is cost-effective in most of Western countries, but not in Asian countries. The reason for this result may be the issues of incidence rate or racial characteristics, such as dense breast tissue. The results indicate that mammography screening should be adopted prudently in Asian countries and other countries with low incidence rates.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.187-195
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• 2023

Sarcopenia is a phenomenon in which muscle function, including muscle strength, deteriorates as muscle mass decreases in the process of increasing age. The diagnosis of sarcopenia utilizes total muscle mass and limb muscle mass, and limb muscle mass is expressed as height squared, body weight, and BMI. Each divided value is used as an index, mainly less than 7.23 kg/m2 for men and less than 5.67 kg/m2 for women. Grip strength, standing up from a chair, and walking speed were mainly used as physical function factors, and grip strength less than 27 kg for men and less than 16 kg for women were used as indicators. The limb muscle mass showed a decreasing trend after peaking in the mid-20s in men, and maintaining a gradual peak in women from the mid-20s to the mid-40s, showing a more rapid decline in men. The rate of decrease in muscle mass and strength continues to increase after the age of 20, and muscle strength rapidly decreases after the age of 80. In Korean men, total muscle mass and limb muscle mass show a decreasing trend from the mid-30s, and a more markedly rapid decrease from the age of 60. For women, it remains constant from the age of 30 to the age of 50, then gradually decreases after the mid-50s, and shows a rather rapid decrease after the mid-70s, showing a more gradual decrease than that of men. Men show a sharp decrease from the mid-40s when limb muscle mass is divided by height squared, and women show a marked decrease after 70 years old when limb muscle mass is divided by height squared. Exercise for the prevention and treatment of sarcopenia results in an increase in protein assimilation hormone, an increase in antioxidant activity, a decrease in inflammation, an increase in muscle insulin sensitivity, and an increase in protein synthesis. Resistance exercise is basically used, and aerobic exercise and equilibrium A combination of exercises is effective. In addition, for a more efficient effect of sarcopenia through resistance exercise, it is necessary to supplement nutrition including protein.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.637-642
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• 1987

In immobilized cell reactors, effective cell mass is a very important parameter which must be estimated during operation for control and regeneration of biocatalyst. In this report, the effective cell mass in immobilized cell reactor was studied using a sequential estimation method. An immobilized yeast reactor was operated in batch recycle mode. The states of the immobilized cell reactor could be estimated from the process data using an extended Kalman filter.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.297-298
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• 2006

Free-machining agent 'KSX' contains complex calcium oxide is developed. The effect of admix ratio of KSX on mechanical properties and machinability with two different cutting speeds is reported. KSX displays improved machinability without deterioration of mechanical properties up to 0.3mass% addition. It was observed that KSX is effective with a small addition of 0.1mass% at slower cutting speed, and increased of admix ratio is effective at faster cutting speed.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.61-66
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• 2022

The purpose of this study is to derive photon energy fluence and mass energy absorption coefficient for 1 Gy of absorbed dose of water in brachytherapy using an Ir¹⁹² source. From the radiotherapy physics written by Khan, the half-value of lead for the gamma ray beam of the Ir¹⁹² source was obtained. The linear attenuation coefficient and the mass attenuation coefficient were calculated from the obtained half-value layer of lead. By matching the calculated lead mass attenuation coefficient with the NIST mass attenuation coefficient data, the photon energy of the matching mass attenuation coefficient was determined as the effective energy. By matching the determined effective energy with the photon energy of the NIST data on the mass energy absorption coefficient of water, the mass energy absorption coefficient of water was obtained as 0.03273 cm²/g(32.73 cm²/kg). The photon energy fluence was calculated as 0.03055 J/cm² by dividing the obtained mass energy absorption coefficient (32.73 cm²/kg) by the absorbed dose of water 1 Gy.

• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1758-1771
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• 2017

In this study, to determine the most effective alloy for shielding against gamma-rays, the gamma-ray shielding parameters of six types of cerrobend alloys have been investigated. Gamma-ray interaction with the cerrobend alloys has been discussed mainly in terms of total mass attenuation coefficient (${\mu}_t$), half value layer (HVL), tenth value layer (TVL), effective atomic number ($Z_{eff}$), and effective electron density ($N_{eff}$). These parameters have been calculated by theoretical approach using the ParShield program in a photon energy range between 0.1 MeV and 100 GeV. The dependence of these parameters on the incident photon energy and chemical composition of the cerrobend alloys has been studied.

• ALGAE
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• v.19 no.2
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• pp.129-137
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• 2004

Since cultural eutrophication has the detrimental effects on estuarine and coastal ecosystems, recognition of early stage of nutrient over-enrichment is critical for effective managements of the ecosystems. Since released nutrients into coastal ecosystems are diluted and dissipated through tidal action and rapid uptakes by marine plants, monitoring of in situ nutrient concentrations may not be useful for detecting early eutrophication on coastal and estuarine ecosystems. To develop an effective indicator of cultural eutrophication using marine plants, tissue N content and area normalized leaf mass of eelgrass, Zostera marina were examined in Kosung Bay and Koje Bay on the south coast of Korea from June 2001 to April 2003. Eelgrass tissue N content exhibited obvious seasonal variations. Leaf N content was highest during winter and early spring and lowest during summer. Eelgrass tissue N content was higher at Kosung Bay site, which has higher sediment organic content, than at Koje Bay site. Area normalized leaf mass showed reverse trend of leaf N content, and consequently, eelgrass leaf N content and leaf mass exhibited strong negative correlation at both study sites. The results of the present study suggested that the ratio of eelgrass leaf N content to area normalized leaf mass can be applied to assess environmental nitrogen conditions on the coastal and estuarine ecosystems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.730-738
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• 2007

As well known when the linear machine is operated between two points repeatedly under positioning control, there are various positioning error at the moment of zero speed owing to the non-linear disturbance like as unpredictable friction force. To remove this positioning error, a simple least order disturbance observer is introduced and is actually implemented in this study. Due to this simple algorithm the over-all machine system can be modified to simple arbitrary given one-mass load without any disturbance. So, the total construction process for positioning control system is much easier than old one. Moreover, to generate a proper effective position profile with the limited actual machine force, a very powerful on-line mass identification algorithm using the load force estimator is presented. In the proposed mass identification algorithm, the exact load mass can be calculated during only one moving stage under a normally generated position profile. All presented algorithm is verified with experimental result with commercial linear servo machine system.

• Computational Structural Engineering
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• v.10 no.1
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• pp.149-158
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• 1997

This paper presents the illustration of application under attached point mass to the special orthotropic plates with a pair of opposite edges simply supported and the other pair of opposite edges free. Design engineers need to calculate the natural frequencies of such elements but obtaining exact solution to such problems is very much difficult. Pretlove reported a method of analysis of beams with attached masses using the concept of effective mass. This method, however, is useful only for certain simple types of beam. Therefore, considering the method has been developed by D. H. Kim(1974) is simple, accurate, and very effective for the plates with arbitrary boundary conditions and irregular sections, this paper calculates the natural frequencies of composite laminated plate under attached point mass/masses.

• Nuclear Engineering and Technology
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• v.35 no.1
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• pp.1-13
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• 2003

In this study, an effective method to estimate the fundamental frequencies of co-axial cylinders immersed in fluid is proposed. The proposed method makes use of the equivalent mass or density that is derived from the added mass matrix caused by the fluid-structure interaction (FSI) phenomenon. The equivalent mass is defined from the added mass matrix based on a 2-D potential flow theory. The theory on two co-axial cylinders extended to the case of three cylinders. To prove the validity of the proposed method, the eigenvalue analyses upon coaxial cylinders coupled with fluid gaps are peformed using the equivalent mass. The analyses results upon various fluid gap is conditions reveal that the present method could provide accurate frequencies and be suitable for expecting the fundamental frequencies of fluid coupled cylinders in beam mode vibration.