• Computers and Concrete
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• v.7 no.2
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• pp.87-102
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• 2010

This paper discusses new capabilities developed for the Virtual Penetration Laboratory (VPL) software package to address the challenges of determining Penetration Resistance (PR) equations for concrete materials. Specifically, the paper introduces a three-invariant concrete constitutive model recently developed by the authors. The Advanced Fundamental Concrete (AFC) model was developed to provide a fast-running predictive model to simulate the behavior of concrete and other high-strength geologic materials. The Continuous Evolutionary Algorithms (CEA) automatic fitting algorithms used to fit the new model are discussed, and then examples are presented to demonstrate the effectiveness of the new AFC model. Finally, the AFC model in conjunction with the VPL software package is used to develop a PR equation for a concrete material.

• Advances in aircraft and spacecraft science
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• v.4 no.1
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• pp.37-52
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• 2017

Gas turbines operating in dusty or sandy environment polluted with micron-sized solid particles are highly prone to blade surface erosion damage in compressor stages and molten sand attack in the hot-sections of turbine stages. Commercial/Military fixed-wing aircraft engines and helicopter engines often have to operate over sandy terrains in the middle eastern countries or in volcanic zones; on the other hand gas turbines in marine applications are subjected to salt spray, while the coal-burning industrial power generation turbines are subjected to fly-ash. The presence of solid particles in the working fluid medium has an adverse effect on the durability of these engines as well as performance. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The focus of this research work is to simulate particle-surface kinetic interaction on typical turbomachinery material targets using non-linear dynamic impact analysis. The objective of this research is to understand the interfacial kinetic behaviors that can provide insights into the physics of particle interactions and to enable leap ahead technologies in material choices and to develop sand-phobic thermal barrier coatings for turbine blades. This paper outlines the research efforts at the U.S Army Research Laboratory to come up with novel turbine blade multifunctional protective coatings that are sand-phobic, sand impact wear resistant, as well as have very low thermal conductivity for improved performance of future gas turbine engines. The research scope includes development of protective coatings for both nickel-based super alloys and ceramic matrix composites.

• KOREAN ASSOCIATION OF OCCUPATIONAL HEALTH NURSES
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• v.19 no.3
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• pp.50-54
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• 2012

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.897-903
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• 2011

In this paper, we consider a future u-Army network with VoIPv6 and evaluate the performance based on the large-scale simulation. The target model chosen in our paper is extended to an division network from several unit networks in which the scope of the performance simulation was limited with the small experiment network[l]. The simulation model is based on several practical scenarios and the actual condition of the division network with some assumption. The evaluated performance results will help to predict whether a future u-Army network meet the real-time service or not, and to design the network suitable for military condition and requirements.

• Computers and Concrete
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• v.7 no.2
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• pp.191-202
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• 2010

A laboratory investigation was conducted to characterize the constitutive property behavior of Cor-Tuf, an ultra-high-performance composite concrete. Mechanical property tests (hydrostatic compression, unconfined compression (UC), triaxial compression (TXC), unconfined direct pull (DP), uniaxial strain, and uniaxial-strain-load/constant-volumetric-strain tests) were performed on specimens prepared from concrete mixtures with and without steel fibers. From the UC and TXC test results, compression failure surfaces were developed for both sets of specimens. Both failure surfaces exhibited a continuous increase in maximum principal stress difference with increasing confining stress. The DP tests results determined the unconfined tensile strengths of the two mixtures. The tensile strength of each mixture was less than the generally assumed tensile strength for conventional strength concrete, which is 10 percent of the unconfined compressive strength. Both concretes behaved similarly, but Cor-Tuf with steel fibers exhibited slightly greater strength with increased confining pressure, and Cor-Tuf without steel fibers displayed slightly greater compressibility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.904-910
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• 2008

In this paper, we consider the military requirement, study the military network services and their related traffic parameters, evaluate the performance the experimental army network and then suggest the design guideline of applying VoIP to the whole military. We evaluate the performance of the delay and loss in the viewpoint of packet and call levels for the several scenarios. First, the performances of separate network service were considered and the satisfaction of the requirement was obtained. Secondly, the delays and losses of the integrated network services were calculated as the amount of the background traffic increases. Finally, based on the simulation results, we presented the design guideline which classified network configurations for applying VoIP equipment and helped estimate the number of VoIP terminals in the existing link.

• Computers and Concrete
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• v.9 no.4
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• pp.293-310
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• 2012

This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

• Computers and Concrete
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• v.7 no.2
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• pp.169-190
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• 2010

The focus of this research effort was characterization of the flexural and tensile properties of a specific ultra-high-strength, fiber-reinforced concrete material. The material exhibited a mean unconfined compressive strength of approximately 140 MPa and was reinforced with short, randomly distributed alkali resistant glass fibers. As a part of the study, coupled experimental, analytical and numerical investigations were performed. Flexural and direct tension tests were first conducted to experimentally characterize material behavior. Following experimentation, a micromechanically-based analytical model was utilized to calculate the material's tensile failure response, which was compared to the experimental results. Lastly, to investigate the relationship between the tensile failure and flexural response, a numerical analysis of the flexural experiments was performed utilizing the experimentally developed tensile failure function. Results of the experimental, analytical and numerical investigations are presented herein.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.1031-1033
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• 2014

Aim: To investigate the effect of hyperglycemia and hyperinsulinemia on prostate cancer risk. Materials and Methods: This hospital based study was carried out using data retrieved from the register maintained in the Department of Biochemistry of a tertiary care hospital of Kathmandu, Nepal between $31^{st}$ December, 2011 and $31^{st}$ October, 2013. The variables collected were age, serum cholesterol, serum calcium, PSA, fasting blood glucose, serum insulin. Analysis was performed by descriptive statistics and testing of hypothesis using Excel 2003, R 2.8.0, Statistical Package for the Social Sciences (SPSS) for Windows Version 16.0 (SPSS Inc; Chicago, IL, USA) and the EPI Info 3.5.1 Windows Version. Results: Of the total 125 subjects enrolled in our present study, 25 cases were of PCa and 100 were healthy controls. The mean value of fasting plasma glucose was 95.5 mg/dl in cases of prostatic carcinoma and the mean value of fasting plasma insulin was $5.78{\mu}U/ml$ (p value: 0.0001*). The fasting insulin levels ${\mu}U/ml$ were categorized into the different ranges starting from ${\leq}2.75$, >2.75 to ${\leq}4.10$, >4.10 to ${\leq}6.10$, > $6.10{\mu}U/ml$. The maximum number of cases of prostatic carcinoma of fasting insulin levels falls in range of > $6.10{\mu}U/ml$. The highest insulin levels (> $6.10{\mu}U/ml$) were seen to be associated with an 2.55 fold risk of prostatic carcinoma when compared with fasting insulin levels of (< $2.75{\mu}U/ml$). Conclusions: Elevated fasting levels of serum insulin appear to be associated with a higher risk of prostate cancer.

• Journal of Information Technology Services
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• v.20 no.1
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• pp.55-65
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• 2021

For smart defense innovation, the key is to apply state-of-the-art technologies of the Fourth Industrial Revolution to national defense. In order to apply state-of-the-art technology to the defense sector, we need to apply and develop technologies to analyze and respond to uncertain future operational environments. To this end, our military is investing a lot of time and effort. To understand future operational environment analysis and to apply and develop our military, we explored the perspectives of operational environment analysis in major countries and studied specific cases of U.S. troops with systematic analysis functions. The U.S. Army has established a cooperative system to analyze future operational environment under the leadership of the Education Command and operates the organization organically. It also utilizes the collective intelligence of expert groups in various fields by utilizing the MSC, and it is time for the Korean military to take the lead in keeping with the era of transformation. To that end, the organization of the U.S. Education Command should be benchmarked and the Korean Future Operation Environment Analysis Organization should be established and operated. Through this study, we have developed an understanding of the future operational environment analysis system of the U.S. Army and presented a plan to apply the ROK MND.