• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.35.2-35.2
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• 2011

나노와이어를 제작하는 많은 방법들 중에서 실리콘 기판을 무전해식각하여 실리콘 나노와이어를 제작하는 방법은 쉽고 간단하기 때문에 최근 많은 연구가 진행되고 있다. 무전해식각법을 이용한 실리콘 나노와이어 합성은 단결정 실리콘 나노와이어를 합성할 수 있고, p 또는 n형의 도핑 정도에 따라 원하는 전기적 특성의 기판을 선택하여 제작할 수 있다는 장점을 가지고 있다. 하지만 n형으로 도핑된 기판으로 나노와이어를 제작하였을 경우 식각으로 인한 나노와이어 표면의 거칠기로 인하여, 실제로는 n형 반도체 특성을 나타내지 않는 문제점을 가지고 있다. 따라서 본 연구에서는 무전해식각법으로 합성한 n형 나노와이어의 거칠기를 조절하고 filed-effect transistor (FET) 소자를 제작하여 나노와이어의 전기적 특성변화를 확인하였다. n형 나노와이어의 거칠기를 조절하기 위하여 열처리를 통해 표면을 산화시켰고, 열처리 시간에 따른 나노와이어 FET 소자를 제작하여 I-V 특성을 관찰하였다. 이때 절연막과 나노와이어 계면 사이의 결함을 최소화 하기 위하여 나노와이어를 poly-4-vinylphenol (PVP) 고분자 절연막에 부분 삽입시켰다. 나노와이어 표면의 거칠기는 high-resolution transmission electron microscopy (HRTEM)을 통하여 확인하였으며, 전기적 특성은 Ion/Ioff ratio, 이동도, subthreshold swing, threshold voltage 값 등을 평가하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.7-8
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• 2010

The temperature development of a structural element is dependent on section factor, which is estimated as a ratio of the fire-exposed perimeter to the cross-section area. Hence, with the higher section factor, the faster temperature development of the section os observed. Composite beam member, partially embedded asymmetry H beam, has a good fire resistance to the cross-section. The study was intended to conduct with change with section factor. The experimental result of section type which the Slim Beam Floor is bottom flange reinforced method.

• The Journal of the Acoustical Society of Korea
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• v.18 no.8
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• pp.75-83
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• 1999

This paper proposes a new F0 contour model for intonation control in speech synthesis. We assume that the F0 contour of an utterance can be described using a sequence of time-overlapping events, which determine the fluctuation of a given F0 contour, described by asymmetric Gaussian functions. In addition, We propose a parameter estimation algorithm for the proposed model. The proposed model is not developed with a particular phonological theory in mind, and can be used in both F0 contour analysis and synthesis. For testing our F0 model, we collected 500 sentences from various genres and built a corresponding speech corpus uttered by a professional female announcer. As n result of F0 resynthesis experiment using the proposed model, the RMSE was 7.87Hz for given speech corpus.

• Journal of the Korean Chemical Society
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• v.53 no.2
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• pp.159-165
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• 2009

The synthesis of 2-amino-5-substituted-1,3,4-oxadiazoles 4 were carried out from the electrooxidation of semicarbazone 3 at the platinum electrode under controlled potential electrolysis in an undivided cell. This is an environmentally benign method in the field of synthetic organic chemistry. The non-aqueous solvents acetic acid and acetonitrile and a supporting electrolyte lithium perchlorate were used for the electrolysis in the electrooxidation. The products were structurally charecterised by IR, $^1H$-NMR, $^{13}C$-NMR and elemental analysis.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.1-11
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• 1998

A line profile synthesis method is presented that minimizes the nearest-neighbor crosstalk peak level for high-speed pulse transmission in multi-coupled microstrip signal buses. We adopted the optimization technique for the reflected wave control on bus lines resulting in increasing the average spacing between strip conductors, since in a parallel-conductor bus the crosstalk energy is concentrated at the nearest neighbors of the driven line. The generalized S-matrix technique is applied for the input and output waveform prediction, and crosstalk characteristics of various nonuniform lines synthesized for increasing the average spacing are analyzed by comparing each other. Simulation results demonstrate that the Chebyshev taper with dips is adequate to significantly minimize the crosstalk peak level under the satisfactory waveform integrity since the profile is oriented to evenly reflect significant pulse spectra within the frequency range of pulse.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.511-521
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• 2007

In this paper, we designed and fabricated a Ka-band synthesizer module. In addition, the systematic layout procedure and the test procedure were presented for the construction of compact synthesizer. To implement the Ka-band synthesizer, X-band VCO is employed as VCO and its frequency was multiplied by 3 with frequency tripler. The fabricated frequency synthesizer shows a frequency tuning range of 500 MHz, output power of about 14 dBm, and a phase noise of -96.17 dBc/Hz at the 100 kHz offset frequency.

• Polymer(Korea)
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• v.24 no.3
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• pp.306-313
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• 2000

Polycaprolactone (PCL) macromer containing terminal methacrylate group was synthesized by ring-opening polymerization. The number average molecular weight of PCL macromer was 11600 g/mole and polydispersity index was 1.09. The synthesized PCL macromer was copolymerized with styrene by stable free radical polymerization using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), benzoyl peroxide, and well-defined poly(styrene-g-caprolactone)s were synthesized. The synthesized copolymers was characterized by $^1$H-NMR and gel permeation chromatography equipped with multiangle laser light scattering detector. Thermal properties of graft copolymers were investigated by DSC.

• Polymer(Korea)
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• v.34 no.4
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• pp.381-385
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• 2010

Aiphatic diester monomer, 3-[(benzyloxycarbonylamino)butyl]-1,4-dioxane-2,5-dione (BABD), was synthesized with the N-$\varepsilon$-benzyloxy-carbonyl-L-lysine as starting material. This monomer was synthesized to add the functionality to poly(lactic acid)s. BABD unit was successfully incorporated into the PLLA chain which was confirmed by $^1H$ NMR. The copolymer composition could be controlled by the feed ratios of monomer. The $M_n$ of this resultant polymer is expected to reach high molecular weight after the purification of monomer and optimization of polymerization time, though the polymer showed relatively low degree of polymerization ($M_n$＝3300). The copolymer is expected to possess the enhanced hydrophilicity and the possibility of chemical modification on amino group.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.431-441
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• 2003

This paper presents the design of 32 bit microprocessor for a sequence control using a field programmable gate array(FPGA). The microprocessor was designed by a VHDL with top down method, the program memory was separated from the data memory for high speed execution of sequence instructions. Therefore it was possible that sequence instructions could be operated at the same time during the instruction fetch cycle. In order to reduce the instruction decoding time and the interface time of the data memory interface, an instruction code size was implemented by 32 bits. And the real time debug operation was implemented for easeful debugging the designed processor with a single step run, PC break point run, data memory break point run. Also in this designed microprocessor, pulse instructions, step controllers, master controllers, BM and BCD type arithmetic instructions, barrel shift instructions were implemented for sequence logic control. The FPGA was synthesized under a Xilinx's Foundation 4.2i Project Manager using a V600EHQ240 which contains 600,000 gates. Finally simulation and experiment were successfully performed respectively. For showing good performance, the designed microprocessor for the sequence logic control was compared with the H8S/2148 microprocessor which contained many bit instructions for sequence logic control. The designed processor for the sequence logic showed good performance.

• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.15-26
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• 2010

Social Networks such as 'Facebook' and 'Myspace' are regarded as useful tools for people to share interests and maintain or expand relationships with other people. However, they pose the risk that personal information can be exposed to other people without explicit permission from the information owner. Therefore, we need a solution for this problem. Although existing social network sites allow users to specify the exposing range or users who can access their personal information, this cannot be a practical solution because the information can still be revealed to third parties through the permitted users albeit unintentionally. Usually, people allow the access of unknown person to personal data in online social networks and this implies the possibility of information leakage. We could use an access control method based on trust value, but this has the limitation that it cannot reflect the quantitative risk of information leakage. As a solution to this problem, this paper proposes an access control method based on a synthesized metric from trust and risk factors. Our various experiments show that the risk of information leakage can play an important role in the access control of online social networks.