• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.3 s.309
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• pp.20-29
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• 2006

The Java language has been established as one of the most widely used language due to its object-oriented programming, safety and flexibility and the garbage collection of the virtual machine has relieved programmers of many difficulties related to the memory management. In the embedded environment, Java is also prevalent, the virtual machine and garbage collector that takes into account the embedded environment is required. In this paper we manage the heap memory area by dividing into young generation and old generation, and we propose a garbage collector in which appropriate techniques are applied to each generation to utilize the different characteristics of each generation. Also, we propose the write barrier technique and double filtering technique for efficient garbage recognition, and double check method for determining and reclaiming the garbage with cyclic structure. The proposed method satisfies the embedded environment's requirements of fast object allocation, real time property, recollection of all the garbage, elimination of fragmentations and high locality.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.1
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• pp.67-73
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• 2020

In this paper, we used FEM technique to perform warpage and von Mises stress analysis on PCB according to the cavity structures of embedded PCB for FCCSP and the types of prepreg material. One-half substrate model and static analysis are applied to the FEM. According to the analysis results of the warpage, as the gap between the cavity and the chip increased, warpage increased and warpage increased when prepreg material with higher modularity and thermal expansion coefficient was applied. The analysis results of the von Mises stress show that the effect of the gap between the cavity and the chip varies depending on prepreg material. In other words, when material whose coefficient of thermal expansion is significantly higher than that of core material, the stress increased as the gap between the cavity and the chip increased. When the prepreg with the coefficient of thermal expansion lower than the core material is applied, the result of stress is opposite. These results indicate that from a reliability perspective, there is a correlation between the structure of the cavity where embedded chips are loaded and prepreg material.

• Journal of the Korean Geotechnical Society
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• v.31 no.2
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• pp.27-37
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• 2015

The micropile is small diameter pile foundation of which diameter is below 300 mm. This system has been applied to reinforce the foundation structure. In the present study, the effects of embedded conditions of group micropiles were investigated from a series of uplift load tests. For the study, uplift load tests were performed using group micropiles in various pile spacing and installation angle. The increase of uplift resistance and the reduction of uplift displacement were investigated in the tests. As the result, the resistances were principally changed by embedded pile angle, the resistance increase were 33%, 59% and 5% for $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of embedded pile angle. The uplift displacement reduction increases with lower pile spacing condition and the reduction ratios of uplift displacements in the same spacing condition were 50%, 53%, -45% for $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of embedded pile angle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.45-45
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• 2007

Capacitors among the embedded passive components are most widely studied because they are the major components in terms of size and number and hard to embed compared with resistors and inductors due to the more complicated structure. To fabricate a capacitor-embedded PCB for in-line process, it is essential to adopt a low temperature process (<$200^{\circ}C$). However, high dielectric materials such as ferroelectrics show a low permittivity and a high dielectric loss when they are processed at low temperatures. To solve these contradicting problems, we studied BMN materials as a candidate for dielectric capacitors. processed at PCB-compatible temperatures. The morphologies of BMN thin films were investigated by AFM and SEM equipment. The electric properties (C-F, I-V) of Pt/BMN/Cu/polymer were evaluated using an impedance analysis (HP 4194A) and semiconductor parameter analyzer (HP4156A). $Bi_2Mg_{2/3}Nb_{4/3}O_7$(BMN) thin films deposited on copper clad laminate substrates by sputtering system as a function of Ar/$O_2$ flow rate at room temperature showed smooth surface morphologies having root mean square roughness of approximately 5.0 nm. 200-nm-thick films deposited at RT exhibit a dielectric constant of 40, a capacitance density of approximately $150\;nF/cm^2$, and breakdown voltage above 6 V. The crystallinity of the BMN thin films was studied by TEM and XRD. BMN thin film capacitors are expected to be promising candidates as embedded capacitors for printed circuit board (PCB).

• Journal of Korea Multimedia Society
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• v.16 no.1
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• pp.75-86
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• 2013

This paper presents a technique to implement embedded systems using interrupts of the one-chip microcontroller with many peripherals based on a multiple finite state machines model. The multiple finite state machine model utilizes the structure of FSMD used for hardware design and the features of flow control by interrupts. The main finite state machine corresponds to the main program and the sub-state machines corresponds to the interrupt subroutines. Therefore, interrupts from the peripherals can be processed immediately in the sub-state machines. The request and reply variables are used to interface between the finite state machines. Additional operating system is not necessary for the context switching between the main state machine and the sub-state machine, because the flow-control caused by interrupt can be replaced with the switching. An embedded system modeled on multiple finite state machine with ASM charts can be easily implemented by the conversion of ASM charts into C-language programs. This implementation technique can be easily adopted to the hardware oriented embedded systems because of the detail description of the model and the fast response to the interrupt events in the sub-state machine.

• Journal of the Korean GEO-environmental Society
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• v.19 no.10
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• pp.35-41
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• 2018

Dynamic interaction of the ground-foundation-structure must be considered for safety of earthquake resistant design for piles supported structures. The p-y curve, which is proposed in the static load and cyclic load cases, is used for the earthquake resistant design of piles. The p-y curve does not consider dynamic interaction of the ground-foundation-structure on dynamic load cases such as earthquake. Therefore, it is difficult to apply the p-y curve to earthquake resistant design. The dynamic p-y curve by considering dynamic interaction of the ground-foundation-structure has been studied, and researches had same conditions that pile caps were on the ground surface and superstructures were added on pile caps for the simple weight. However, group piles are normally embedded into the ground except for marine structures, so it seems that the embedding the pile cap influences on the dynamic p-y curve of group piles. In this study, the shaking table model test was conducted to confirm dynamic behavior of group piles by the embedded pile cap in the ground. The result showed that dynamic behavior was different between two cases by embedding the pile cap or not.

• Proceedings of the Korean Society for Language and Information Conference
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• 2002.02a
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• pp.237-248
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• 2002

This paper investigates the internal structure of finite small clauses (FSC). I will propose that a FSC is base-generated at Spec-CP and a null operator is involved to check the formal features of the embedded T and turn a sentence into a predicate.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.289-296
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• 2000

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.132-137
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• 2001

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1684-1689
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• 2003

This paper concerns the analytical modeling and dynamic analysis of advanced cantilevered blade structure implemented by a dual approach based on structural tailoring and viscoelastic materials technology. Whereas structural tailoring uses the directionality properties of advanced composite materials, the passive materials technology exploits the damping capabilities of viscoelastic material(VEM) embedded into the host structure. The structure is modeled as a composite thin-walled beam incorporating a number of nonclassical features such as transverse shear, secondary warping, anisotropy of constituent materials, and rotary inertias. The case of VEM spreaded over the entire span of the structure is considered. The displayed numerical results provide a comprehensive picture of the synergisitic implications of the application of both techniques, namely, the tailoring and damping technology on vibration response of thin-walled beam structure exposed to external time-dependent excitations.