• International Journal of Concrete Structures and Materials
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• v.2 no.2
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• pp.123-136
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• 2008

A new plastic-damage constitutive model applicable to lightweight concrete (LWC) and normal weight concrete (NWC) is proposed in this paper based on both continuum damage mechanics and plasticity theories. Two damage variables are used to represent tensile and compressive damage independently. The effective stress is computed in the Drucker-Prager multi-surface plasticity framework. The stress is then computed by multiplication of the damaged part and the effective part. The proposed model is coded as a user material subroutine and incorporated in a finite element analysis software. The constitutive integration algorithm is implemented by adopting the operator split involving elastic predictor, plastic corrector and damage corrector. The numerical study shows that the algorithm is efficient and robust in the finite element analysis. Experimental investigation is conducted to verify the proposed model involving both static and dynamic tests. The very good agreement between the numerical results and experimental results demonstrates the capability of the proposed model to capture the behaviors of LWC and NWC structures for static and impact loading.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.1-10
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• 1997

It is well-known that rectangular bulk-Si sensors prepared by etch or epi etch-stop micromachining technology are already in practical use today, but the conventional bulk-Si sensor shows some drawbacks such as large chip size and limited applications as silicon sensor device is to be miniaturized. We consider a circular-shape SOI(Silicon-On-Insulator) micro-cavity technology to facilitate multiple sensors on very small chip, to make device easier to package than conventional sensor like pressure sensor and to provide very high over-pressure capability. This paper demonstrates the cross-functional results for stress analyses(targeting $5{\mu}m$ deflection and 100MPa stress as maximum at various applicable pressure ranges), for finding permissible diaphragm dimension by output sensitivity, and piezoresistive sensor theory from two-type SOI structures where the double SOI structure shows the most feasible deflection and small stress at various ambient pressures. Those results can be compared with the ones of circular-shape bulk-Si based sensor$^{[17]}. The SOI micro-cavity formed the sensors is promising to integrate with calibration, gain stage and controller unit plus high current/high voltage CMOS drivers onto monolithic chip.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1426-1437
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• 2002

Using the Lagrangian explicit time-integration finite element code NET3D which can treat three-dimensional high-velocity impact problems, oblique penetration processes of long rod projectile with yaw against thin plate are simulated. Through the comparison of simulation result with experimental result and other code's computational result, the adaptability and accuracy of NET3D is evaluated under the complex situation in which yaw angle and oblique angle exist simultaneously. Main research contents to be handled in this paper include the followings. First, the accuracy and efficiency estimation of NET3D code result obtained from the oblique penetration simulations of long rod projectile with yaw against thin plate. Second, the effect of increasing impact velocity. Third, the effect of initial yaw for the spaced-plate target. Residual velocities, residual lengths, angular velocities, and final deformed configurations obtained from the NET3D computations are compared with the experimental results and other code's computational results such as Eulerian code MESA and Lagrangian code EPIC. As a result of comparisons, it has been found that NET3D code is superior to EPIC code and MESA code in the prediction capability of residual velocity and residual length of penetrator. The key features obtained from the experiment can be successfully reproduced through NET3D simulations. Throughout the study, the applicability and accuracy of NET3D as a metallic armor system design tool is verified.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3270-3294
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• 2020

Some things come easily to humans, one of them is the ability to navigate around. This capability of navigation suffers significantly in case of partial or complete blindness, restricting life activity. Advances in the technological landscape have given way to new solutions aiding navigation for the visually impaired. In this paper, we analyze the existing works and identify the challenges of path selection, context awareness, obstacle detection/identification and integration of visual and nonvisual information associated with real-time assisted mobility. In the process, we explore machine learning approaches for robotic path planning, multi constrained optimal path computation and sensor based wearable assistive devices for the visually impaired. It is observed that the solution to problem is complex and computationally intensive and significant effort is required towards the development of richer and comfortable paths for safe and smooth navigation of visually impaired people. We cannot overlook to explore more effective strategies of acquiring surrounding information towards autonomous mobility.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.359-370
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• 2017

This study presents a particle swarm optimization algorithm integrated with weighted particle concept and improved fly-back technique. The rationale behind this integration is to utilize the affirmative properties of these new terms to improve the search capability of the standard particle swarm optimizer. Improved fly-back technique introduced in this study can be a proper alternative for widely used penalty functions to handle existing constraints. This technique emphasizes the role of the weighted particle on escaping from trapping into local optimum(s) by utilizing a recursive procedure. On the other hand, it guaranties the feasibility of the final solution by rejecting infeasible solutions throughout the optimization process. Additionally, in contrast with penalty method, the improved fly-back technique does not contain any adjustable terms, thus it does not inflict any extra ad hoc parameters to the main optimizer algorithm. The improved fly-back approach, as independent unit, can easily be integrated with other optimizers to handle the constraints. Consequently, to evaluate the performance of the proposed method on solving the truss weight minimization problems with discrete variables, several benchmark examples taken from the technical literature are examined using the presented method. The results obtained are comparatively reported through proper graphs and tables. Based on the results acquired in this study, it can be stated that the proposed method (integrated particle swarm optimizer, iPSO) is competitive with other metaheuristic algorithms in solving this class of truss optimization problems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.3
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• pp.97-105
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• 2004

The purpose of this study is to design and implement web-based quality cost management system to measure the performance of quality improvement activities in the business firms. The designed web-based quality cost management system which is also known as WQCMS (Web-based Q-Cost Management System) utilized newly classified objective performance indicator items to measure quality related activities. Well-classified performance measurement Indicator item lists which are played key role in the system was researched and standardized according to size and business categories of enterprise. Its code standards are based from fundamental PAF Model. Developed WQCMS have ability to collect and analyze quality data generated from various different departments in the inside or outside of the enterprise without any limitations, if end-users are able to access wide area network. It provides the capability to integrate quality information from database and to generate various easy analysis reports to management's needs using built-in analysis tool modules with real-time. The proposed system was developed using Microsofi's .Net technology, ASP.NET and MS-SQL Server 2000. By web-enabling Q-cost management system, the effectiveness of the system management and utilization was realized by easiness of information Integration and economical efficiency.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.130-137
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• 2013

This study tries to investigate the relationship between physical perception and creative thinking of dancers by dance imagery training programs. The inner imagery and the external expression of dancers are a divergent expression process of autosuggestion, and substantiate the relationship between physical perception and creative thinking. The key point consists in the active thinking process of problem recognition and problem solving by imagination, and means a new perceptivity and the communication capability. Dance imagery is a perception training based on the integration principle of body and soul, and so dancers should create a new approach of communication through the diversity of wide inner imagination and the active thinking of external expression.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.632-635
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• 2008

In this paper, a diplexer circuit to separate GSM/CDMA band is designed using a LTCC (Low Temperature Cofired Ceramic) multi-layer technology. In order to increase a integration capability of the diplexer, it is designed in 6-layer LTCC sunstrate with a elative dielectric constant of 7.2 using 3-dimensional (3-D) multi-layer inductors and capacitors. The size of the designed diplexer including CB-CPW pads is $3,450{\times}4,000{\times}600{\mu}m^3$. An insertion loss (IL) and return loss of GSM band are less than -0.23dB and -10dB, respectively. In the case of CDMA band, the IL of -0.53dB and RL of below -10dB are archieved.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.625-632
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• 2006

A Datawarehouse, which extracts and saves the massive analysis data from the operating servers, is a decision support tool in which data quality and processing time are very important. Thus, it is necessary to standardize and improve datawarehouse development process in order to stabilize data quality and improve the productivity. We propose a novel improved process for datawarehouse development by applying the configuration management of CMMI (Capability Maturity Model Integration) which has become a major force in software development process improvement. In addition, we specify some matrices for evaluating datawarehouse development process. Through the comparison analysis with other existing processes, we show that our proposal is more efficient in cost and productivity as well as improves data quality and reusability.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.319-325
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• 2004

The major factors that make ZEV affordable are the range and cost. The development of advanced batteries such as Ni-MH battery can solve the problem partly； on the hand the battery management system is an efficient way. Ni-MH battery and battery ECU is a key component influencing ZEV performance, such as range, acceleration and hill-climbing capability. Because most problems related to battery such as short circuit, over-discharge and overcharge occur easily during operation, it is necessary to develop a dedicated battery ECU for HEV. This paper proposes a new SOC algorithm for the HEV based on the terminal voltage and current integration. And battery ECU was designed and analyzed. Also, the validity is confirmed through experiment.