• 항공우주시스템공학회지
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• 제9권1호
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• pp.12-18
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• 2015

The inter-conversion between different control laws in flight has a lot of risk. The SWM(Switching Mechanism) including logic and stand-by mode is designed to analyze the transient response of aircraft during inter-conversion between different control laws, based on the in-house software for non-real-time and real-time simulation. The SWM applies the fader logic of TFS(Transient Free Switch) to minimize the transient response of an aircraft during the inter-conversion, and applies the reset '0' type of the stand-by mode to prevent surface saturation due to integrator effect in the disengaged flight control law. The transition time is also important to minimize the objectionable transient response in the inter-conversion, as well as the transition control law design. This paper addresses the results of non-real-time simulation for the characteristics of transient response to different transition time to select the adequate transient time, and the real-time pilot evaluation, using SSWM(Software Switching Mechanism) and HSWM(Hardware Switching Mechanism), which is met for Level 1 flying qualities and assures safety of flight.

• Journal of electromagnetic engineering and science
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• 제8권2호
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• pp.84-89
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• 2008

In a wireless channel above microwave frequency, rain attenuation is very important. In order to predict rain attenuation, 1-min. rain rate distribution is required. This paper discusses appropriate conversion methods to estimate 1-minute rain rate from that of other integration time. Based on the measurement data filed in ITU-R WP3J including ETRI data for 6 consecutive years, distributions of rain rate with 1-, 5-, 10-, 20-, 30-minute integration time were analyzed, both on the global and regional basis, and the parametric relationship between the statistical characteristics of 1-minute and other measurement data were investigated to deduce the conversion methods. It is shown that the global model works good with good accuracy for 5-, 10-, 20-min integration time, and the global model is also applicable globally with good accuracy for 5-, 10-, 20-min integration time. The global conversion model was adopted last year as an ITU-R document for new recommendation. The regional conversion model would also be very useful for locations of similar climatic zone.

• Journal of Gastric Cancer
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• 제14권4호
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• pp.266-270
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• 2014

Purpose: Palliative gastrectomy and chemotherapy are important options for peritoneal seeding of gastric cancer. The treatment stage IV gastric cancer patient who respond to induction chemotherapy, is converted to gastrectomy (conversion therapy or conversion surgery). This study explored the clinical outcomes of gastric cancer patients with peritoneal seeding who had undergone conversion therapy. Materials and Methods: Between 2003 and 2012, gastric cancer patients with peritoneal seeding, as determined by preoperative or intraoperative diagnosis were reviewed retrospectively. Clinicopathologic characteristics and clinical outcomes of patients with peritoneal seeding were analyzed. Results: Forty-three patients were enrolled. Eighteen patients had undergone conversion surgery and 25 patients continued conventional chemotherapy. Among the 18 conversion patients, 10 received clinically curative resection. The median follow-up period was 28.5 months (range 8 to 60 months) and the total 3-year survival rate was 16.3%. The median survival time of the patients who received clinically curative conversion therapy was 37 months, and the 3-year survival rate was 50%. The median follow-up for non-curative gastrectomy patients was 18 months. No patient treated using chemotherapy survived to 3 years; the median survival time was 8 months. The differences in survival time between the groups was statistically significant (P<0.001). Conclusions: In terms of survival benefits for gastric cancer patients with peritoneal seeding, clinically curative conversion therapy resulted in better clinical outcomes.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.679-682
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• 2008

Probability precipitation is one of the most important factor for designing the hydrology structures. Probability precipitation is calculated based on the frequency analysis on each durations of annual maximum rainfall data. For frequency analysis we need a conversion factor between the rain data per random-time interval and fixed-time-interval. In this study, the minutely precipitation data on observatory of the Meteorological Administration are used for 37 stations. Therefore, we should conversion factors between the rain data per minute and fixed-time-interval.

• 한국통신학회논문지
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• 제22권2호
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• pp.306-317
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• 1997

This ppaer presents a bit-rate conversion system for efficient communications between 3 channel CVSD systems with different bit-rates. The proposed conversion system is implemented in the digital domain and specially, the conversion problem between 32 Kbps and 16 Kbps CVSD systems is studied. The conventional conversion system implemented in the analog domain allows signals to be easily degraded by external noises. To overcome this problem, a digital CVSD bit-rate conversion system robust to external noises is developed. the new systemdecodes CVSD bit sequences and converts sampling rates of decoded signals, then encodes signals at target bit-rates. Since linear phase property does not matter in this application, instead of FIR filters a IIR filter is employed to reduce the system complexity. Therefore, a 3 channel digital CVSD bit-rate conversion system was successfully real-time implemented using a general purpose DSP. In addition, conversion problems with unkown time constants were experimented and good experimental results were obtained.

• 한국표면공학회지
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• 제49권5호
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• pp.395-400
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• 2016

This article reports improved corrosion resistance and adhesion of electro-paint (E-paint) with fluoride conversion coating (FCC) on AZ31 Mg alloy for the first time. These improvements were observed in comparison to chemically polished samples with no chemical conversion coating and samples with cerium conversion coatings (CeCC). FCCs were prepared in a hydrofluoric acid (HF) solution for four different times; 10, 30, 60, and 120 s. The colour of the samples changed from light gold to brown with increasing immersion time, indicating the formation of thicker FCC coatings with increasing immersion time. The adhesion of the E-paint on FCC-coated AZ31 Mg alloy was tested after 500 h of immersion in deionized (DI) water. Salt spray test (SST) results revealed delamination of E-paint on the chemically polished sample, severe blistering on the samples with CeCC, but no delamination and no blistering on the samples with FCC.

• 센서학회지
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• 제24권6호
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• pp.359-363
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• 2015

This paper proposes an algorithm that reduces the conversion time of a single-slope A/D converter (SSADC) that has n-bit resolution, which typically is limited by conversion time taking up to $2^n$ clock cycles for an operation. To improve this situation, we have researched a novel hybrid-type A/D converter that consists of a pseudo-pipeline A/D converter and a conventional SSADC. The pseudo-pipeline A/D converter, using a single-stage of analog components, determines the most significant bits (MSBs) or upper bits and the conventional SSADC determines the remaining bits. Therefore, the modified SSADC, similar to the hybrid-type A/D converter, is able to significantly reduce the conversion time because the pseudo-pipeline A/D converter, which determines the MSBs (or upper bits), does not rely on a clock. The proposed A/D converter was designed using a $0.35-{\mu}m$ 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) technology process; additionally, its characteristics were simulated.

• 한국컴퓨터정보학회논문지
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• 제14권1호
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• pp.135-143
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• 2009

최근 모바일 장치에서 고해상도 영상의 인코딩 및 디코딩에 대한 요구가 늘어남에 따라 효율적인 영상 코덱 개발의 필요성이 증대되고 있다. 본 논문은 JPEG 디코딩 과정에서 IDCT 변환과 컬러변환 배열간의 선형성을 바탕으로 이들 연산순서를 재배열함으로써 컬러변환 과정에서 요구되는 계산 횟수를 줄이고 재배열된 부동소수점 연산에 정수 맵핑을 적용하여 시간 복잡도를 줄임으로써 실행시간을 크게 단축하는 컬러변환 기법을 제안한다. 또한, 제안된 기법은 연산 재배열 및 정수 맵핑의 양자화오류로 인한 화질 저하를 다중 모드 채도 재구성 기법을 적용하여 보상하도록 한다. 임베디드 시스템 개발 플랫폼에서의 성능평가를 통해 제안 된 기법이 기존의 컬러변환 기법들과 비교하여 복원 영상의 화질 저하를 최소화하면서 실행시간을 크게 단축함을 알 수 있었다.

• 한국콘텐츠학회논문지
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• 제15권12호
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• pp.8-17
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• 2015

본 논문은 공감각의 한 부분인 색청(colored-hearing) 공감각을 이용한 사운드-컬러 신호 변환에 관한 연구로서, 인간이 인지 할 수 있는 오감 중 공감각적 변환이 가장 많이 일어나는 청각과 시각을 이용한 실시간 변환 시스템의 구축을 목표로 한다. 본 논문에서 제안하는 음-색 실시간 변환 방법으로서, 입력으로 사용하는 MIDI(Musical Instrument Digital Interface) 신호에서 음계(scale), 옥타브(octave) 및 음의 세기(velocity)를 추출한 후 HSI 컬러모델의 기본 요소인 색상(hue), 명도(intensity) 및 채도(saturation)에 각각 대응하여 변환하는 방법으로 단순하지만 직관적인 방법을 사용한다. 변환된 HSI 컬러 모델은 모니터 출력을 위해 RGB 컬러 모델로 최종 변환하여 출력한다. 실험에서, MIDI 입력신호 전송 H/W 시스템과 VC++ 기반 해당 사운드-컬러 변환 입 출력 S/W 모니터링 시스템을 구축하여 사운드에서 컬러로의 출력이 제안한 방식에 따라 값이 출력됨을 확인하였다.

• Restorative Dentistry and Endodontics
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• 제25권1호
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• pp.17-40
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• 2000

Resin cements are used for cementing indirect esthetic restorations such as resin or porcelain inlays. Because of its limitations in curing of purely light cured resin cements due to attenuation of the curing light by intervening materials, dual cured resin cements are recommended for cementing restorations. The physical properties of resin cements are greatly influenced by the extent to which a resin cures and the degree of cure is an important factor in the success of the inlay. The purpose of this study was to evaluate the influence of porcelain thickness and exposure time on the polymerization of resin cements by measuring the microhardness and the degree of conversion, to investigate the nature of the correlation between two methods mentioned above, and to determine the exposure time needed to harden resin cements through various thickness of porcelain. The degree of resin cure was evaluated by the measurements of microhardness [Vickers Hardness Number(VHN)] and degree of conversion(DC), as determined by Fourier Transform Infrared Spectroscopy(FTIR) on one light cured composite resin [Z-100(Z)] and three dual cured resin cements [Duo cement(D), 3M Resin cement(R), and Dual cement(DA)] which were cured under porcelain discs thickness of 0mm, 1mm, 2mm, 3mm with light exposure time of 40sec, 80sec, 120sec, and regression analysis was performed to determine the correlation between VHN and DC. In addition, to determine the exposure time needed to harden resin cements under various thickness of porcelain discs, the changes of the intensity of light attenuated by 1mm, 2mm, and 3mm thickness of porcelain discs were measured using the curing radiometer. The results were obtained as follows ; 1. The values of microhardness and the degree of conversion of resin cements without intervening porcelain discs were 31~109VHN and 51~63%, respectively. In the microhardness Z was the highest, followed by R, D, DA. In the degree of conversion, D and DA was significantly greater than Z and R(p<0.05). 2. The microhardness and the degree of conversion of the resin cements decreased with increasing thickness of porcelain discs, and increased with increasing exposure time, D and R showed great variation with inlay thickness and exposure time, whereas, DA showed a little variation. 3. The intensity of light through 1mm, 2mm, and 3mm porcelain inlays decreased by 0.43, 0.25, and 0.14 times compared to direct illumination, and the respective needed exposure times are 53 sec, 70 sec, and 93 sec. In D and R, 40 sec of light irradiation through 2mm porcelain disc and 80 sec of light irradiation through 3mm porcelain disc were not enough to complete curing. 4. The microhardness and the degree of conversion of the resin cements showed a positive correlationship(R=0.791~0.965) in the order of R, D, Z, DA. As the thickness of porcelain discs increased, the decreasing pattern of microhardness was different from that of the degree of conversion, however.