• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.681-686
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• 1999

In this study, the gain characteristics of the strained structures for SOA were calculated numerically and the optimized strained quantum well for the polarization-insensitive SOA was obtained. The structures used in this calculation were consisted of one, two, and three GaAs Delta layers respectively in the GaInAs(160 $\AA$) well. Moreover the third one was calculated by changing from one mono-layer to three mono-layers in the thichless of GaAs delta layers. This structure enhances the TM mode gain coefficient with good efficiency because the light-hole band is lifted up whereas the heavy-hole band is lowered down. Additionally, The structure of the 3 GaAs delta layers(1 mono layer thickness) shows 3dB gain bandwidth of 85nm in 1.55um wavelength system. This study is expected to be used in making a wide band and polarization-independent semiconductor optical amplifier practically.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1885-1890
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• 2013

In this paper, the electrical properties of nanoscale junctionless p-channel MuGFET at cryogenic temperature have been analyzed experimentally. The experiment was performed using a cryogenic probe station which uses the liquid Helium. It has been observed that the drain current oscillation at low drain voltage and cryogenic temperature was more pronounced in junctionless transistor than in accumulation mode transistor. The reason for more marked oscillation is due to the smaller electrical cross section area of the inversion channel which is formed at the center of silicon film in junctionless transistor. It was also observed that the drain current and maximum transconductance were increased as the measurement temperature increased. This is resulted from the increase of hole mobility and the decrease of the threshold voltage as the measurement temperature increases. The drain current oscillation due to the quantum effects can be occurred up to the room temperature when the device size scales down to the nanometer level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1445-1450
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• 2020

Recently, a hologram-like system to provide a realistic experience has been serviced in performances, exhibitions, education. The constructing method for the hologram-like system can be configured in various forms such as a pyramid-typed, a semi-transparent large screen form. However, in various types of hologram-like systems, it is difficult to provide adjustment by changing and revising the content according to the configured hardware characteristics. In this paper, we propose a novel technique that can automatically visualize virtual contents running on heterogeneous hologram-like systems. To change the content to a given hardware configuration, we receive pre-built simple text-based configuration data, and correcting process was performed. According to the results of this paper, we found automatically and easily corrected visualization with the given configuration of the hologram-like system. Also, the problem of reducing the time by manual control in various types of heterogeneous hologram systems was solved.

• Journal of the Korea Convergence Society
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• v.12 no.12
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• pp.1-18
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• 2021

ICT is the main driving force of Korea's economic growth. Korea has the world's best ICT competitiveness, and several policies are being implemented to maintain it. However, for successful policy implementation, it is crucial to understand ICT trends accurately. Therefore, this study analyzes the trends of 18 core technologies in the ICT field. In particular, the degree of scientific development and commercialization by technology are investigated through research paper analysis and patent analysis, respectively. Then, the trends shown by document type are compared based on the two analysis results. As a result, artificial intelligence and virtual reality are at the stage where commercialization is actively taking place after scientific development, and at the same time, since research is being conducted, it is expected to develop continuously. On the other hand, quantum computer and implantable device are in the basic research stage. It is necessary to understand the current research status and determine the direction of future support. The results of the ICT trend analysis conducted in this study can be used as a criterion for determining the future direction of Korean policy.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.226-226
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• 2013

Si is a dominant solar material, which is the second most abundant element in the earth giving a benefit in the aspect in cost with low toxicity. However, the inherent limit of Si has an indirect band gap of 1.1 eV resulting in the limited optical absorption. Therefore, a critical issue has been raised to increase the utilization of the incident light into the Si absorber. The enhancement of light absorption is a crucial to improve the performances and thus relieves the cost burden of Si photovoltaics. For the optical aspect, an efficient design of a front surface, where the incident light comes in, has been intensively investigated to improve the performance of photon absorption. Lambertian light trapping can be attained when the light active surface is ideally rough to increase the optical length by about 50 compared to a planar substrate. This suggests that an efficient design may reduce thickness of the Si absorber from the conventional 100~300 ${\mu}m$ to less than 3 ${\mu}m$. Theoretically, a hole-array structure satisfies an equivalent efficiency of c-Si with only one-twelfth mass and one-sixth thickness. Various approaches have been applied to improve the incident light utilization in a Si absorber using textured structures, periodic gratings, photonic crystals, and nanorod arrays. We have designed hole and pillar structured Si absorbers. Four-different Si absorbers have been simultaneously fabricated on an identical Si wafer with hole arrays or pillar arrays at a fixed depth of 2 ${\mu}m$. We have found that the significant enhanced solar cell performances both for the hole arrayed and pillar arrayed Si absorbers compared to that of a planar Si wafer resulting from the effective improvement in the quantum efficiencies.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.939-946
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• 2018

In this work, we present simple schematics for a three-terminal graphene-based nanoelectromechanical switch with the vertical electrode, and we investigated their operational dynamics via classical molecular dynamics simulations. The main structure is both the vertical pin electrode grown in the center of the square hole and the graphene covering on the hole. The potential difference between the bottom gate of the hole and the graphene of the top cover is applied to deflect the graphene. By performing classical molecular dynamic simulations, we investigate the nanoelectromechanical properties of a three-terminal graphene-based nanoelectromechanical switch with vertical pin electrode, which can be switched by the externally applied force. The elastostatic energy of the deflected graphene is also very important factor to analyze the three-terminal graphene-based nanoelectromechanical switch. This simulation work explicitly demonstrated that such devices are applicable to nanoscale sensors and quantum computing, as well as ultra-fast-response switching devices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.677-682
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• 2015

In this paper, we investigated the effect of light on the performance of the receiver system noise and external noise added from the ever-present influence in general optical system. And calculated the reception sensitivity of the receiver at the time of off-keying transmission - from the optical transmission system in consideration of the case that the photo detector has a quantum yield of less than one-one. Not less than 50 it was confirmed that it is possible to configure the low power system is calculated and compared with the case where less than 300 the receiver sensitivity of the optical system to maintain the standard error probability. However, even if these values were considered, and the preamplifier in the receiver, considering a case of using a low-output light source, so that a heavy burden in the value less than the actual system installation, using the light source having less than the output, as shown in Figure 3, the results that were obtained also may be used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.479-485
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• 2006

The double gate(DG) MOSFET is a promising candidate to further extend the CMOS scaling and provide better control of short channel effect(SCE). DGMOSFETs, having ultra thin undoped Si channel for SCEs control, ale being validated for sub-20nm scaling. A novel analytical transport model for the subthreshold mode of DGMOSFETs is proposed in this paper. The model enables analysis of short channel effect such as the subthreshold swing(SS), the threshold voltage roil-off$({\Delta}V_{th})$ and the drain induced barrier lowering(DIBL). The proposed model includes the effects of thermionic emission and quantum tunneling of carriers through the source-drain barrier. An approximative solution of the 2D Poisson equation is used for the distribution of electric potential, and Wentzel-Kramers-Brillouin approximation is used for the tunneling probability. The new model is used to investigate the subthreshold characteristics of a double gate MOSFET having the gate length in the nanometer range $(5-20{\sim}nm)$ with ultra thin gate oxide and channel thickness. The model is verified by comparing the subthreshold swing and the threshold voltage roll-off with 2D numerical simulations. The proposed model is used to design contours for gate length, channel thickness, and gate oxide thickness.

• Journal of Korean Philosophical Society
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• no.93
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• pp.231-260
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• 2011

Simondon's theory of individuation and methodology of transduction presents a possibility of contemporary natural philosophy and a new perspective about the relation between philosophy and sciences. According to Simondon's anti-substantial viewpoint, being, as a metastable system charged with potential energy, complicates itself with quantum leaps transversing successive equilibriums. Individuation is the becoming of phases of being which transits from preindividual state to individuated states. Physical individuation as a paradigmatic model of individuation in general demonstrates not only insufficiency of form-oriented hylomorphism, but also spontaneous formational capacity of matter and reality of energetic relational operation immanent in matter. Genesis of a individual (structure or form) occurs as a resolution of the disparation between orders of magnitude, that is, the difference of potentials immanent in nature through the internal resonance, communication by information, transductive relation between the opposites. I'm trying to show that Simondon revives 'physis' of ancient natural philosophy by his own transductive applications of contemporary physics' conceptions, and therefore suggest a new non-reductive materialism. Especially Simondon's 'transduction' which is neither induction, deduction, nor dialectic, but an original ontological process and a peculiar method of thinking, I think, is worthy of note in order to construct network of knowledge and inter-relation between various sciences.

• Journal of Sensor Science and Technology
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• v.27 no.5
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• pp.317-327
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• 2018

Terahertz (THz) time-domain spectroscopy(TDS), imaging techniques, and related systems have become mature technologies, widely used in many universities and research laboratories. However, the development of creative technologies still requires improved THz application systems. A few key points are discussed, including the innovative advances of mode-locking energy-emitting semiconductor lasers and better photoconductive semiconductor quantum structures. To realize a compact, low cost, and high performance THz system, it is essential that THz spectroscopy and imaging technologies are better characterized by semiconductor and nano-devices, both static and time-resolved. We introduce the THz spectroscopy and imaging systems, the OSCAT(Optical Sampling by laser CAvity Tuning) system and the ASOPS(ASynchronous Optical Sampling) system, are constructed by our research team. We report on the THz images obtained from their use.