• Journal of Magnetics
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• 제14권2호
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• pp.66-70
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• 2009

The dynamic magneto-mechanical behaviors in a type of iron-nickel-based ferromagnetic alloy with constant elasticity were investigated as a function of both the DC bias magnetic field ($H_{dc}$) and the frequency. The rectangular plate-like samples were excited to vibrate at a half-wavelength, longitudinal resonance by an AC magnetic field superimposed with various $H_{dc}$. The experimental results found that the strain coefficient at resonance reached 819.34 nm/A and the effective mechanical quality factor ($Q_m$) was greater than 2000. The ratio of the maximum variation of the Young's modulus over $H_{dc}$ to the value of the Young's modulus at a zero bias field was only ${\sim}0.83%o$ because of the so-called constant elasticity. The resonant strain coefficients and $Q_m$ are strongly dependent on $H_{dc}$, which indicates a promising potential for use in DC and quasistatic magnetic field sensing.

• 대한안전경영과학회지
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• 제16권4호
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• pp.123-131
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• 2014

Modern weapon systems are getting more complex in terms of the functionality and also the conditions on the environment and range in which they are deployed and used. Therefore, many development programs can easily be exposed to a variety of risks, resulting in delayed schedules and cost overrun. As such, effective means are necessary to keep the defence budget at an affordable level while competitive edges on technological aspects are retained. As one way to meet those need, modeling and simulation (M&S) methods have widely been used, particularly in the test and evaluation (T&E) process for weapon systems development. The result of M&S-based systems development should be evaluated by the verification, validation & accreditation (VV&A) process to assure keeping reliability at a desired level. On the other hand, due to the explosiveness, the weapons systems development naturally requires to consider safety issues in both the T&E and operational periods. The purpose of this paper is to improve the VV&A process by reflecting the safety requirements therein. To do so, the VV&A process has been analyzed and graphically modeled first and then safety elements have been incorporated effectively. The use of the improved process in the war ships development has also been discussed. Based on the process proposed and the consequent database constructed, the target system can be expected to benefit from reducing development risks while assuring systems safety.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.791-800
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• 2016

Optimal Power Flow (OPF) is an important operational and planning problem in minimizing the chosen objective functions of the power systems. The recent developments in power electronics have enabled introduction of dc links in the AC power systems with a view of making the operation more flexible, secure and economical. This paper formulates a new OPF to embrace dc link equations and presents a heuristic optimization technique, inspired by the behavior of fireflies, for solving the problem. The solution process involves AC/DC power flow and uses a self adaptive technique so as to avoid landing at the suboptimal solutions. It presents simulation results of IEEE test systems with a view of demonstrating its effectiveness.

• 시스템엔지니어링학술지
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• 제16권1호
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• pp.36-42
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• 2020

Due to the population of the Republic of Korea is getting less, the shortage of available troops has become a big issue. In response to this, the need for Unmanned weapon systems is rising. To operate an Unmanned weapon system near borderlines or low altitude, it is necessary to protect not only the system itself but also operational information communicated between the Unmanned system and control station, so that they should be safe using Cybersecurity measures. Besides, it is critical to protect a few core technologies applied to Unmanned weapon systems throughout the Anti-Tamper measures. As the precedent studies only focus partially, Cybersecurity or Anti-Tamper, it is acknowledged that comprehensive studies are needed to be conducted. This study is to incorporate both concepts into Korea's defense acquisition process. Specifically, we will outline the concepts and needs of Cybersecurity and Anti-Tamper, and briefly present ways to apply them simultaneously.

• 산업경영시스템학회지
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• 제35권2호
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• pp.155-162
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• 2012

This work describes identification of essential considerations when we develop OMS/MP for the shipboard weapon systems. It is compulsory to develop OMS/MP which describes quantity of what mode to have and how often to operate. In this point of view, relationships between OMS/MP and shipboard weapon systems are analyzed. From the analysis, considerations of OMS/MP development for the weapon systems are presented.

• 시스템엔지니어링학술지
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• 제20권spc1호
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• pp.1-11
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• 2024

Today, the importance of test and evaluation of defense systems is increasing day by day. In performing efficient defense systems test works, process improvement based on quantitative management is essential. The purpose of this paper is to present the results of process improvement for the defense systems test works of the test organization based on quantitative management activities. As a methodology to confirm process improvement performance, the 'MPM(Managing Performance and Measurement)' practice area of the CMMI model was applied. The quantitative management model for defense systems test works was developed so that it could be practically applied not only to the entire test organization but also to the organization at the department level that actually performs the test work. Finally, the application cases of the quantitative management model for defense system test works and the results of process improvement were described.

• International Journal of Control, Automation, and Systems
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• 제2권1호
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• pp.68-75
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• 2004

In this paper, an estimator with an appropriate adaptive law for updating parameters is designed and analyzed based on the Lyapunov theory. The adaptive law is designed so that the estimation model follows the parameterized plant model. Using the proposed estimator, the parameters of the T-S fuzzy model can be estimated by observing the behavior of the system and it can be a basis for indirect adaptive fuzzy control.

• 한국정밀공학회지
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• 제31권7호
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• pp.585-590
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• 2014

Recently, monitoring systems, such as POP, take a core role in scheduling or planning of manufacturing facilities for production, maintenance, and so on. Such monitoring systems require functionalities for real-time parameter monitoring and controlling to maximize efficiency of facilities. However, vendors usually do not provide internal communication protocols or interface to access the machine controller. Therefore, the values of parameters related to machine operations and controls cannot be easily accessed from external devices. In this paper, we propose an interface methodology for a real-time monitoring and controlling of injection molding machine parameters such as user input parameters, embedded sensor data and injection molding status information.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권4호
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• pp.207-223
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• 2015

In this paper a method for simultaneous swift non-linear analysis and optimal design/posture of mechanical/biomechanical systems is presented. The method is developed to get advantages of iterations in non-linear analysis and/or generations in genetic algorithm (GA) for the purpose of efficient analysis within the optimal design/posture. The method is applicable for both size and geometry optimizations wherein material and geometry non-linearity are present. In addition to established mechanical systems, the method can solve biomechanical models of human musculoskeletal system. Optimization-based procedures are popular methods for resolving the redundancy at joints wherein the number of unknown muscle forces is far more than the number of equilibrium equations. These procedures involve optimization of a cost function(s) which is assumed to be consistent with the central nervous system's strategy when activating muscles to assure equilibrium. However, because of the complexity of biomechanical problems (i.e., due to non-linear biomaterial, large deformation, redundancy of the problem and so on) efficient analysis are required within optimization procedures as suggested in this paper.

• 산업경영시스템학회지
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• 제19권39호
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• pp.37-46
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• 1996

The purpose of this study is to increase the economical efficiency and the efficiency of MIS user's attitudes. It hypothesized that an attitudes of users are different from an environmental variables and demographic variables of an organization. So, it selected attitude variables as moderating variables. The sample in this study is the management staff of financial industries only, and the data are selected by field study using a questionnaire. The hypotheses adopted were analyzed statistically by t-test and ANOVA etc.