• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.258-263
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• 1999

In this study, the numerical and experimental investigations were conducted to understand ultrasonic wave propagation and to evaluate the degree of fiber waviness in thick composites nondestructively. The path, energy and traveling time of insonified wave were predicted by adopting the ray and plane wave theories. In the analysis, the composites were assumed to have continuous fiber with sinusoidal waviness in a matrix and were modeled as stacks of infinitesimally short length off-axis elements with varying fiber orientation along the length direction. From the experiments on the specially fabricated thick composite specimens with various degrees of uniform fiber waviness, the energy distributions of received wave were obtain for the various positions of transmitter. It was observed that the energy of wave was converged to the adjacent peaks of fiber waviness. The location where maximum energy of wave was detected from the experiments showed good agreement with the location obtained from theoretical predictions. Finally, the test procedure was Proposed to evaluate fiber waviness in thick composites by considering the energy of wave and relative distance between transmitter and receiver.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.495-501
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• 2001

In this paper, a new technique which models the joints characteristics through reduction of DOFs of structures with joints using component mode synthesis (CMS) method is proposed. Bolt joints are modeled by mass-spring systems. Also generalized mass and stiffness matrices for this models are introduced. Because bolt joints have influence on eigenvalues of structures, exact eigenvalues from modal test are used. The results show that the behaviors of structures with bolt joints depend to a large extent on the translational DOFs and not on rotational DOFs of mass and stiffness matrices of bolts. Furthermore it is confirmed that lumped mass-spring systems as models of bolt joints are effective models considering the facts that joint characteristics converged to constant values in some iterations and eignevalues from proposed method are in good agreement with ones from modal test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.861-862
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• 2008

One of trend of portable devices is convergence with other devices, especially with navigation system. This converged system is generally called PND (Personal Navigation Device). This detachable device is developed for personal entertainment in everyday life and navigation system when deriving, so it should meet the specification of vehicle thermal environment, anti-vibration as well as the anti-shock by sudden drop. In this paper, the way to design the hard disk drive damper with CAE, is introduced to get a reliable system from the beginning of the design step.

• The Journal of the Acoustical Society of Korea
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• v.23 no.3E
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• pp.79-84
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• 2004

In this paper, the AEC(acoustic echo canceller) is designed and implemented using VHDL(VHSIC hardware description language). The designed Echo Canceller employs the pipeline and the master-slave structure, and is realized with FPGA. As an adaptive algorithm, the Normalized LMS algorithm is used. For the coefficient adjustment, the Stochastic Iteration Algorithm(SIA) which uses only current residual values is used and the number of registers are evidently reduced and convergence speed is also much improved comparing to existing methods by using EAB of FPGA for FIR filter structure of transceiver. The designed Echo Canceller is verified with the test board implemented for this paper. From the timing simulation echo signals at about 1500 sampling data are converged and ERLE is improved by about 42-dB.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.29-36
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• 2020

We aim to reinterpret Bong Joon-ho's Snowpiercer through theory of posthumanism. Posthuman is a compound word of 'post' and 'human', which means transcendent-man. However, we would like to extend the meaning of posthuman or cyborgs as not only to "new human figure, or transcendent-man" but as to "human living in a digital age of converged technology". Through the extension of the meaning of posthuman, we would be able to not only find posthuman in Science Fiction movies but also apply it to our real world. Also, through the extended meaning, we will reinterpret all the elements from the film as cyberspace and as posthuman or cyborgs. Moreover, through examination of these "cyborg figures" in Bong Joon-ho's Snowpiercer (2013), we argue that the film is criticizing posthumanism in the reality that these days, people are losing the humanity due to the combination with the machine. It seems that he claims of the collapse of the current system, suggesting new human generation as the solution.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1149-1152
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• 1999

In this paper we analyzed each region of specific points and ｅ-Δｅphase plane in order to make fuzzy rule base. After we composed the fuzzy control rules which can decrease rise time, delay time, maximum overshoot than basic fuzzy control rules. The composed method are converged more rapidly than single rule base in convergence region. Proposed method is alternately use at specific points of ｅ-Δｅphase plane with two fuzzy control rules, that is one control rule occruing the steady state error used in transient region and another fuzzy control rule use to decrease the steady state error and rapidly converge at the convergence region. Two fuzzy control rules in the ｅ-Δｅ phase plane decide the change time according to response characteristics of plants. As the results of simulation through the second order plant and the delay time plan, Proposed dual fuzzy control rules get the good response compare with the basic fuzzy control rule.

• Computational Structural Engineering
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• v.1 no.2
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• pp.83-90
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• 1988

The present work is concerned with the improvement of finite element for the analysis of plate bending structures. The element formulation is based upon Mindlin plate concept. The displacement field of this element is formed by adding nonconforming modes to two rotational displacement components of a 'heterosis plate element. The element has the requisite numbers of zero eigenvalues associated with rigid body modes to avoid the spurious zero energy mode. It is shown that the results obtained by the element converged to the exact solutions very rapidly as the mesh is refined and exhibited reliable solutions through numerical studies for standard benchmark problems. This element is shown to overcome the shear locking problem completely in very thin plate situation even for irregular meshes.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.20-27
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• 2002

An analysis model for an elliptical fluid film bearing is described. The principles of hydrodynamic lubrication are outlined together with an expanded version of the governing pressure field equation as related to elliptical journal bearing. Finite element method approximations are given for the pressure field equation and a temperature model, both related to the fluid film thickness. The thermal effects in the lubricant viscosity, lubricant film thickness, variation of the journal rotating speed and influence of turbulence are investigated in this paper A finite element model and an iterative computational process are described, whereby full simultaneously converged field solutions for fluid film thickness, temperature, viscosity, pressure, stiffness and damping coefficient are obtained.

• Journal of Korean Society of Transportation
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• v.5 no.1
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• pp.3-23
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• 1987

Traffic signal control problems in urban street networks are formulated in two ways. In the formulations network flows are assumed to satisfy the user route choice criterion. the first formulation which is called implicit substiuation incorporates user route behavior implicitly in the objective function by recognizing the dependence of the link flows on the signal variables. On the other hands, the second one which is called 'penalty formulation' consists in expressing the route choice conditions in the form of a single nonlinear constraint. Approximate solution algorithm for each of the formulations was investigated in detail and computer codes were written to examine key aspects of each algorithm. A test was done on a network which is small in size but sufficiently complex in representing real-world traffic conditions and the test result shows that both algorithms produce converged solutions. It is recommended, however, that further studies should be done in order to compare the performance of each algorithm more in depth.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.115-118
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• 2008

Traditionally, Geographical Information System can only process static spatial data, which include geometries and attributes. Recently, According to Special attention is paid to ubiquitous computing environment, we require a u-GIS convergence middleware to efficiently process ubiquitous data and improves the existing GIS engine in order to enable converged processing of spatial and sensor data. So, in this study, we propose a design of u-GIS Convergence Middleware, which are based on the integration between GIS and USN technologies