• 방송공학회논문지
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• 제16권1호
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• pp.73-84
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• 2011

2000년대 들어 본격적인 디지털 HDTV는 영상에 있어 색온도와 조도에 민감하여 조명기법에 많은 변화를 주었으며, 차세대 UHDTV는 기존의 고화질 TV보다 최고 16배까지 해상도가 향상되어 조명에 의한 시각적 효과는 시청자에게 더 크게 작용 할 것으로 예상된다. 따라서 기존 방송제작에서 조명의 색온도 변환 필터를 사용 시, 조도가 떨어지고 휘도신호가 낮게 표현되는 현상이 발생하여 인물의 얼굴색에 왜곡을 줄 수 있으므로 색온도에 따른 조도, 휘도신호를 분석함으로서 고품질의 영상을 구현하고자 한다.

• 대한기계학회논문집B
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• 제26권4호
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• pp.561-569
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• 2002

This paper presents an investigation on $C_2$, CH, OH radicals and NOx emissions in partially premixed flames with acoustic excitation. The radicals are visualized by the digital image technique with optical filters and ICCD camera while NOx emissions are determined by a chemiluminescent detection(NOx analyser). The measurements are made in flames with an overall equivalence ratio (${\phi}_o$) 0.5 and a center tube equivalence ratio(${\phi}_c$) varing from 1.1 to 5.0 for a constant fuel flow rate. In the case of excitation, the visual shape of the flame is changed from laminar to turbulent-like flames. Images of $C_2$, CH, and OH radicals resemble those of the flame appearances as the excitation phase is varied, and the radicals generated at the upstream are convected toward the downstream. It is inferred that the flame characteristics is affected by the flow characteristics of air-fuel mixture. In the case of acoustic excitation, OH radicals are much increased relative to unexcitation. From the radicals and flame visualization under acoustic excitation, the reduction of flame length affects the shorter residence time of center tube mixture, and significantly influences the NOx reduction.

• 한국컴퓨터정보학회논문지
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• 제22권12호
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• pp.101-108
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• 2017

The study proposed a system that filters the data that is entered when analyzing big data such as SNS and BLOG. Personal information includes impersonal personal information, but there is also personal information that distinguishes it from personal information, such as religious institution, personal feelings, thoughts, or beliefs. Define these personally identifiable information as sensitive information. In order to prevent this, Article 23 of the Privacy Act has clauses on the collection and utilization of the information. The proposed system structure is divided into two stages, including Big Data Processing Processes and Sensitive Information Filtering Processes, and Big Data processing is analyzed and applied in Big Data collection in four stages. Big Data Processing Processes include data collection and storage, vocabulary analysis and parsing and semantics. Sensitive Information Filtering Processes includes sensitive information questionnaires, establishing sensitive information DB, qualifying information, filtering sensitive information, and reliability analysis. As a result, the number of Big Data performed in the experiment was carried out at 84.13%, until 7553 of 8978 was produced to create the Ontology Generation. There is considerable significan ce to the point that Performing a sensitive information cut phase was carried out by 98%.

• ETRI Journal
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• 제34권5호
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• pp.649-654
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• 2012

This paper presents a novel 16-quadrature-amplitude-modulation (QAM) E-band communication system. The system can deliver 10 Gbps through eight channels with a bandwidth of 5 GHz (71-76 GHz/81-86 GHz). Each channel occupies 390 MHz and delivers 1.25 Gbps using a 16-QAM. Thus, this system can achieve a bandwidth efficiency of 3.2 bit/s/Hz. To implement the system, a driver amplifier and an RF up-/down-conversion mixer are implemented using a $0.1{\mu}m$ gallium arsenide pseudomorphic high-electron-mobility transistor (GaAs pHEMT) process. A single-IF architecture is chosen for the RF receiver. In the digital modem, 24 square root raised cosine filters and four (255, 239) Reed-Solomon forward error correction codecs are used in parallel. The modem can compensate for a carrier-frequency offset of up to 50 ppm and a symbol rate offset of up to 1 ppm. Experiment results show that the system can achieve a bit error rate of $10^{-5}$ at a signal-to-noise ratio of about 21.5 dB.

• 센서학회지
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• 제20권3호
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• pp.199-206
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• 2011

Sell call radio buoy is mostly used for searching for the location of fishing nets. Sell call radio buoy for the detection of the code uses the band pass filter(BPF). All BPF is used by imported from Japanese companies. But, Japanese companies stopped selling buoys for searching for the location of fishing nets, and domestic manufacturing companies could not sell buoys any more. Therefore, In this paper, a new method to replace the conventional buoy code detector is proposed. The proposed methods are constructed with an analog filter division composed of BPFs and notch filters as well as a microprocessor with analog digital converters. The advantage of proposed methods is able to combine various codes, can enhance receiver sensitivity. The experimental results confirm the usefulness of the proposed method.

• 한국정밀공학회지
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• 제30권12호
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• pp.1321-1325
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• 2013

In this paper, we proposed an air bearing stage with active magnetic preloads in vertical directions compensating motion errors and attenuating vibrations to improve dynamic characteristics. This preloaded design gives simpler configuration of the stage, and active control of preload can be used for compensating motion errors by feedforward method. To improve dynamic characteristics, vibration of the table is monitored by an accelerometer, and controlled by a DSP based digital controller with integrator and band pass filters for suppressing roll and pitch vibration modes. The modes were evaluated by measuring frequency response functions, and compared with compensated responses. This showed effective results for suppressing poorly damped regenerative vibration of air bearings.

• 천문학회보
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• 제35권1호
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• pp.92-92
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• 2010

A short-period comet, 17P/Holmes, is one of the most outstanding comets because of the outburs in 2007. It orbits the sun at the distance between 2.1AU and 5.2 AU with the orbital period of 6.9 year. On 2007 October 23, its brightness was suddenly increased by about a million times from 17 mag to 2.5 mag. We made observations of 17P/Holmes soon after the outburst on October 25, 27 and 28, using a 105cm telescope at the Ishigakijima Astronomical observatory, Japan. We took the images with V, R and I-band filters simultaneously. Total exposure times are 15 (October 25), 69 (October 27), and 37 (October 28) minute in each filter. The composite images provide good signal to noise ratio and help us to recognize faint structures embedded in the dust cloud. We examined a sequence of images using a digital filter that enhances the small-scale structures. As the result of the data analysis, we confirm (1) the radial expanded structure coming out from the nucleus of comet, and (2) dozens of blobs that moved radially away from the nucleus. In this presentation, we introduce the observations and the data reductions, and consider the origins of these fine structure.

• 대한전자공학회논문지
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• 제26권2호
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• pp.1-9
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• 1989

本 硏究에서는 多相回路와 高速 DCT를 利用한 12채널의 TDM/FDM 相互變煥 시스템의 單純化 方法 및 變煥時間을 短縮시키는 方法 다루었다. 多相回路의 原試型필터는 補間 FIR 필터의 設計技法을 適用하여 設計되었다. 그리고 DCT의 高速알고리듬과 補間 FIR 필터의 線型 位相特性 때문에 나타나는 係數間의 對稱性을 活用한 結果, 變煥時間의 大部分을 차지하는 곱셈回數가 $0.1640{\times}10^6$Multiplications/sec.channel로서 기존의 연구 結果보다 約 25% 以上 감소되는 效果를 얻었다. 복조시스템을 포함하는 全體 시스템의 컴퓨터 시뮬레이션을 통해 理論的인 結果의 타당성을 確認하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제17권4호
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• pp.38-42
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• 2015

In terms of food safety,mixture of contaminants in food is a serious problem for not only consumers but also manufacturers. In general, the target size of the metallic contaminant to be removed is 0.5 mm. However, it is a difficult task for manufacturers to achieve this target, because of lower system sensitivity. Therefore, we developed a food contaminant detection system based on high-Tc RF superconducting quantum interference devices (SQUIDs), which are highly sensitive magnetic sensors. This study aims to improve the signal to noise ratio (SNR) of the system and detect a 0.5 mm diameter steel ball. Using a real time digital signal processing technique along with analog band-pass filters, we improved the SNR of the system. Owing to the improved SNR, a steel ball with a diameter as small as 0.3 mm, with stand-off distance of 117 mm was successfully detected. These results suggest that the proposed system is a promising candidate for the detection of metallic contaminants in food products.

• Journal of Power Electronics
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• 제12권2호
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• pp.344-356
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• 2012

In recent years, multilevel technology has become an effective and practical solution in the field of moderate and high voltage applications. This paper discusses an APF with a three-level NPC inverter. Obviously, the application of such converter to APFs is hindered by the problem of the voltage unbalance of DC capacitors, which leads to system instability. This paper comprehensively analyzes the theoretical limitations of the neutral-point voltage balancing problem for tracking different harmonic currents utilizing current switching functions from the space vector PWM (SVPWM) point of view. The fluctuation of the neutral point caused by the load currents of certain order harmonic frequency is reported and quantified. Furthermore, this paper presents a close-loop digital control algorithm of the DC voltage for this APF. A PI controller regulates the DC voltage in the outer-loop controller. In the current-loop controller, this paper proposes a simple neutral-point voltage control method. The neutral-point voltage imbalance is restrained by selecting small vectors that will move the neutral-point voltage in the direction opposite the direction of the unbalance. The experiment results illustrate that the performance of the proposed approach is satisfactory.