• 전기전자학회논문지
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• 제28권3호
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• pp.271-278
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• 2024

본 논문은 위상천이 간섭계 원리를 기반으로 계조도 영상의 위상 변환 매핑을 이용한 암호화와 복호화 방법을 제안한다. 제안한 암호화 시스템에서 대칭형 보안키로 암호화한 암호 영상은 복소 디지털 홀로그램 함수의 형태로 구성된다. 한편 암호화하는 계조도영상은 위상 매핑 변환되고 무작위로 발생한 이진 보안 암호화키의 위상과 합쳐져 입력 위상 합수로 사용된다. 위상 정보의 복호화는 복소 디지털 홀로그램 함수와 보안 암호화키를 사용하여 수행되고 위상 역변환을 통하여 원래의 계조도 영상을 복원한다. 제안한 방법은 암호화 과정에서 CCD의 양자화 수준을 8-bits(2⁸=256 levels)로 하였을 때 복원된 영상의 상관 계수가 0.995로 원래의 256-계조도 영상이 잘 복원되었다.

• Ocean and Polar Research
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• 제30권4호
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• pp.373-378
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• 2008

Long-term tide-gauge data from around the Korean Peninsula were reanalyzed. Both the coastal water and the open sea surrounding the Korean Peninsula appeared to have been influenced by global warming. The long-term change in relative sea levels obtained from tidal stations showed a general rising trend, especially near Jeju Island. It is proposed that global warming may have caused shifting of the path of the Kuroshio branch (Tsushima Warm Current) toward Jeju Island, causing a persistent increase in the water levels along the coast of the island over the last few decades.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.293-296
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• 2001

This paper describes an implementation of 4$^{th}$ order single-loop Butterworth noise shaper for a 16-bit $\Delta$$\Sigma$ DAC with the viewpoint of minimum hardware overhead. we adopt simple bit-shifting scheme and ROM selection technique for the multiplication, and propose a new buffer-and-routing method for the ROM circuits. The behavioral level and timing simulations reveal that our proposal is valid for the target specificationrget specificationn

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1610-1620
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• 2015

A major problem in conventional multilevel inverter is that an increase in power semiconductor switches causes an increase in cost and switching losses of the inverter. The multicarrier strategy adopted for the multilevel inverters has become more popular due to reduced cost, lower harmonic distortion, and higher voltage capability than the conventional switching strategy applied to inverters. Various topologies and modulation strategies have been reported for utility and drive applications. Level shifted based pulse width modulation techniques are proposed to investigate the performance of the multilevel inverter. The proposed work focuses on reducing the utilized switches so that the cost and the switching losses of the inverter do not go up and the consistent efficiency could be achieved. This paper presents the detailed analysis of these topologies. The analysis is based on the number of switches, DC sources, output level, maximum voltage, and the efficiency. As an illustration, single phase cascaded multilevel inverter topologies are simulated using MATLAB/SIMULINK and the experimental results demonstrate the viability of these inverters.

• 전력전자학회논문지
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• 제25권6호
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• pp.484-489
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• 2020

This study proposes a new soft-switching three-level flying capacitor converter with low filter inductance. The proposed converter can achieve zero voltage switching (ZVS) turn-on of all switches by using auxiliary components La and Ca. It can also reduce filter inductance because the applied voltage of the filter inductor is decreased by using the flying capacitor. Furthermore, filter inductance can be reduced because the operating frequency of the filter inductor is doubled by the phase shifting between switches S3 and S4. The operation principle, design of passive components for ZVS turn-on, interleaving effects, and comparison of different topologies are presented. The experimental waveforms of a 1 kW two-phase interleaved converter prototype are provided to verify the validity of the proposed converter.

• 경영과정보연구
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• 제34권5호
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• pp.213-231
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• 2015

본 연구에서는 우리나라의 상장기업이 K-IFRS 도입 후 현금흐름표에서 보고되는 영업현금흐름을 상향조정하기 위하여 분류조정을 이용하는 경향이 있는지를 분석하였다. 분류조정의 대용변수로는 계량경제학적으로 산출되는 비정상영업현금흐름, 그리고 이자 및 배당금의 수취와 지급을 영업현금흐름을 최대화하는 방향으로 분류하는지의 여부를 반영하는 더미변수를 사용한다. 조정의 유인으로는 기업의 재무적 부실, 투자적격과 부적격의 경계영역에 해당하는 신용등급, 음(-), 혹은 전년도의 보고영업현금흐름보다 낮은 실적보고의 회피동기 등을 고려한다. 실증분석 결과 분류조정 변수와 조정유인 변수사이에 기회주의 설명과 일치하는 양(+)의 관련성은 관찰되지 않았으며 오히려 일부의 분석에서는 음(-)의 관계가 확인되었다. 이는 K-IFRS에서 허용하고 있는 분류의 재량이 영업현금흐름을 최대화하는 방향으로 행사되는 것이 아니라 오히려 초과 영업현금흐름 실적과 관련되고 있을 가능성을 제시하는 것이며 이는 분류방식을 기간별로 일관되게 채택할 것을 요구하고 있는 K-IFRS의 규정과 무관하지 않은 것으로 해석된다.

• Journal of Power Electronics
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• 제13권5호
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• pp.779-786
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• 2013

A highly efficient sustaining driver is proposed for plasma display panels (PDPs). When the PDP is charged and discharged, the proposed sustaining driver employs an address voltage source used in an addressing period. A voltage source is used for fully charging the panel to the sustaining voltage, and an initial inductor current helps the panel discharge to 0 V. The resonance between the panel and an inductor is made by shifting the voltage and current bias level when charging and discharging the panel. As a result, the proposed circuit can reduce power consumption, switching loss, heat dissipation, and production cost. Experimental results of a 42-inch PDP are provided to verify the operation and features of the proposed circuit.

• 반도체디스플레이기술학회지
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• 제5권3호
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• pp.11-16
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• 2006

A low cost PDP sustain power supply is proposed based on flyback topology. By using Boundary Conduction Method(BCM) to control input current regulation, DCM condition can be met under all load conditions. Another feature of the proposed method is that a excessive voltage stress due to the link voltage increase can be suppressed by removing link capacitor and suggest new 'Level-shifting switch driver'. this new gate driver is improved 66% of efficiency than switching loss of a existed push-pull amplifier. The proposed converter is tested with a 400W(200V-2A output) prototype circuit.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.107-108
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• 2015

It's became essential that Korea construction companies should enter into the overseas construction market for their growth and sustainability. In order to comply with the client's required global standard and to compete with in the international market, the shifting the construction project management system to global level is required. In accordance with the demand, this paper proposes the top-level document of construction project management system as a to-be model that utilized in overseas construction projects. The project management plan ("PMP") suggested in this paper is not only the most appropriate one, which complies with the global standard, to be used when companies bid for international construction projects against foreign competitors but also has the process modeling and hierarchical structure.

• 한국컴퓨터정보학회논문지
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• 제22권10호
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• pp.63-71
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• 2017

In this paper, we develop the system for audio volume equalization of video on demand(VoD) content and propose the solution for it. In recent years, there has been a steady increase in the number of VoD users in addition to linear channels. However, viewers ought to sit in an uncomfortable way, adjusting the volume intermittently while they are broadcasted. Sudden changes of volume occur between the broadcasting channels, the programs from the co-channel, or the linear channels and the VoDs. Especially, upsurged dissatisfaction from the televiewers has been found due to the unequalized volume when shifting between the linear channel and the VoD. In order to solve this problem, multilateral efforts were put forth, such as a system for keeping the volume at a certain level in digital broadcasting program has been legislated domestically. It leads success in equalizing linear channel volume. On contrary, too little notice has been taken for distorted volume problem of video on demand(VoD) content. In this paper, we developed and applied the volume equalization system into VoD content to achieve uniformization, a similar condition with linear channel(-24LKFS). This suggestion helped uneven current of volume which was in the stage -16 ~ -20LKFS to stable condition by lowering into the stage of -24LKFS. It also brought 20% increase in perspective of volume quality satisfaction level.