• 한국주조공학회지
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• 제41권4호
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• pp.331-341
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• 2021

3.6wt%C-2.5wt%Si 구상흑연주철을 오스템퍼링 열처리하는 동안 프로세싱 윈도우에 미치는 오스템퍼링 온도, 오스테나이트화 처리 온도와 시간, 구리 첨거량 그리고 사전 열처리의 영향을 연구하였다. 350℃의 오스템퍼링 처리 온도에서 최대 프로세싱 윈도우를 얻었다. 프로세싱 윈도우는 오스테나이트화 처리 온도가 850에서 900℃로 증가함에 따라 증가하였으나 950℃로 증가하면 오히려 감소하였다. 프로세싱 윈도우는 오스테나이트화 처리 시간이 30분에서 2시간까지 증가함에 따라 증가하였다가 4시간일 때 감소하였다. 최적 오스템퍼링 처리 조건은 900℃에서 2시간인 것으로 나타났다. 프로세싱 윈도우는 구리 첨가량이 0.0~0.8wt% 범위에서 증가함에 따라 증가하였다. 프로세싱 윈도우는 주방 상태의 구상흑연주철에 비하여 사전 노르말라이징 처리로 증가하였으며 사정 어닐링 처리로 감소하였다.

• Investigative Magnetic Resonance Imaging
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• 제19권4호
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• pp.212-217
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• 2015

Purpose: For a single time-point hyperpolarized $^{13}C$ magnetic resonance spectroscopy imaging (MRSI) of animal models, scan-time window after injecting substrates is critical in terms of signal-to-noise ratio (SNR) of downstream metabolites. Pre-scans of time-resolved magnetic resonance spectroscopy (MRS) can be performed to determine the scan-time window. In this study, based on two-site exchange model, protocol-specific simulation approaches were developed for $^{13}C$ MRSI and the optimal scan-time window was determined to maximize the SNR of downstream metabolites. Materials and Methods: The arterial input function and conversion rate constant from injected substrates (pyruvate) to downstream metabolite (lactate) were precalibrated, based on pre-scans of time-resolved MRS. MRSI was simulated using two-site exchange model with considerations of scan parameters of MRSI. Optimal scan-time window for mapping lactate was chosen from simulated lactate intensity maps. The performance was validated by multiple in vivo experiments of BALB/C nude mice with MDA-MB-231 breast tumor cells. As a comparison, MRSI were performed with other scan-time windows simply chosen from the lactate signal intensities of pre-scan time-resolved MRS. Results: The optimal scan timing for our animal models was determined by simulation, and was found to be 15 s after injection of the pyruvate. Compared to the simple approach, we observed that the lactate peak signal to noise ratio (PSNR) was increased by 230%. Conclusion: Optimal scan timing to measure downstream metabolites using hyperpolarized $^{13}C$ MRSI can be determined by the proposed protocol-specific simulation approaches.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.403-404
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• 2008

In this paper, a new 4-way search window is developed for H.264 Motion Estimation(ME) to improve the memory bandwidth. The proposed 4-way(up, down, left, right) search window could improve the reuse of overlapped window data to reduce the redundancy access factor by 1.4, though the 1/3-way search window requires $7.7{\sim}11$ times of data retrieval redundantly. In experiments, the new implementation of 4-way search window on Altera Stratix-III could deal with CIF ($352{\times}288$) video of 3 reference frame, $48{\times}48$ search area and $16{\times}16$ macroblock by 30fps real time at 55.2MHz.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.211-215
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• 2009

As entering in the time of high oil price, seriousness of an energy is on the rise and the importance of energy is growing. Especially, building energy occupying 24% of total demand of energy is expected to be possible to reduce energy demand more than other section. To reduce the building energy consumption, this study analyzes function and thermal performance of Super window by heat experimental apparatus. Super window is a 2-track low-e glazing window for high insulation efficiency. By applying the results of this experiment to building energy efficiency rating tool, this study compares energy efficiency rates depending on a region.-Jeju, South, Central. And it shows how much does Super window reduce Building energy consumption.

• 교육시설 논문지
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• 제25권4호
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• pp.19-30
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• 2018

The school classroom is a common living place where students spend 7 to 14 hours a day to prepare for their careers. Therefore, if the ventilation of the classroom is not properly performed, it may lead to the deterioration of learning ability due to the unclear air. The concentration of carbon dioxide in the classroom is reported to be high, and the increase in carbon dioxide concentration has a negative effect on the learner's academic performance. In this context, the purpose of this study is to propose a methodology for intelligent and responsive window opening-closing operation process that can reduce the concentration of $CO_2$ in the classroom in order to build a support space that can create an effective teaching-learning environment for adolescents. The specific objectives are as follows. First of all, we define the concept of window opening-closing operation. Secondly, twe develop the operation process of window opening-closing. Thirdly, we develop an algorithm for real-time window opening and closing (process) (Window Opening-Closing Operation Process). Finally, we verify the intelligent responsive window opening-closing operation process through developing examples of window opening-closing operation process using the parametric design program. This study is a preliminary study to develop algorithms necessary for window opening-closing operation. Based on the first-order algorithm, We simulated window opening-closing operations according to a hypothetical scenario. As a result, This study can show that the window is open and close depending on the $CO_2$ concentration, but the $CO_2$ concentration in the room is higher than outdoors. Consequentially, we suggest that it is necessary to develop an algorithm to supplement these results because window is often not working when the temperature difference between indoor and outdoor in winter is large.

• 정보처리학회논문지B
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• 제13B권3호
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• pp.223-230
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• 2006

윈도우 기반의 영상처리는 전체 영상처리 분야에 있어서 기본이 되는 분야이다. 이러한 윈도우 기반의 영상처리는 처리해야 할 데이터와 연산이 매우 많은 편이기 때문에 범용 컴퓨터 구조에서 소프트웨어 프로그램을 사용하여 윈도우 기반 영상처리에서 필요로 하는 모든 연산을 실시간으로 수행하기 힘들다. 본 논문에서는 FPGA(Field Programmable Gate Array)를 사용하여 윈도우 기반 영상처리를 실시간으로 수행할 수 있는 병렬 하드웨어 구조를 제안하고자 한다. 또한 제안한 구조를 통해 VHDL(VHSIC Hardware Description Language)을 이용하여 윈도우 기반의 영상처리 중 하나인 동적 문턱치화(dynamic thresholding) 회로와 국부 히스토그램 평활화(local histogram equalization) 회로를 설계하고 FPGA로 해당 회로를 구현할 것이다. 구현된 회로의 성능 측정도 다루어 진다.

• 한국음향학회지
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• 제37권2호
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• pp.110-117
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• 2018

본 논문에서는 음성/오디오 부호화기를 위한 저지연 윈도우 스위칭 MDCT(Modified Discrete Cosine Transform) 방법을 제안한다. 윈도우 스위칭 알고리즘을 사용하여 신호의 특성이 빨리 변하는 전이 구간에서 음질 저하를 개선하고, 저지연 TDAC(Time Domain Aliasing Cancellation)를 사용하여 알고리즘 지연을 1/2로 줄일 수 있는 MDCT 방법을 제안한다. 제안된 윈도우 스위칭 방법은 기존 윈도우 스위칭 알고리즘이 다른 길이의 중첩합(overlap-add)을 사용하는 것과 달리, 일정한 길이의 중첩합을 사용하여 알고리즘 지연을 1/2로 줄일 수 있었고, 신호의 특성에 따라 윈도우의 종류를 2개로 줄여 프레임 상태를 표현하는 정보 비트를 1 bit 감소시킬 수 있었다. 제안한 알고리즘을 MDCT 기반의 음성/오디오 부호화기인 ITU-T(International Telecommunication Union - Telecommunication) G.729.1 부호화기에 적용하여 성능을 확인하였으며, 알고리즘 지연을 절반으로 감소시키면서 동일한 음질을 유지할 수 있었다.

• 한국수산과학회지
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• 제49권2호
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• pp.214-223
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• 2016

Joint time-frequency images of the broadband acoustic echoes of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The acoustic features were extracted by changing the sliced window widths and dividing the time window by a 0.02-ms interval and the frequency window by a 20-kHz bandwidth. The 22 spectrum amplitudes obtained in the time and frequency domains of the SPWVD images were fed as input parameters into an artificial neural network (ANN) to verify the effectiveness for species-dependent features related to fish species identification. The results showed that the time-frequency approach improves the extraction of species-specific features for species identification from broadband echoes, compare with time-only or frequency-only features. The ANN classifier based on these acoustic feature components was correct in approximately 74.5% of the test cases. In the future, the identification rate will be improved using time-frequency images with reduced dimensions of the broadband acoustic echoes as input for the ANN classifier.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.337-338
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• 2023

As the number of defects in apartments has increased recently, lawsuits and disputes related to defects have also increased. As a result, the loss of time and money is enormous. Therefore, fundamental measures are needed to reduce the occurrence of defects. Therefore, the purpose of this study is to propose a plan to reduce defects, focusing on window construction. To this end, existing studies were reviewed, and data from domestic construction companies were collected and classified to organize the types of defects. Based on the classified data, eight types with a high incidence of window glass were analyzed according to the time of occurrence, and the cause and causal relationship of the defect were schematized. It aims to identify the degree of possibility of recurrence of defects for each of the eight defect types for experts and derive key management elements using the RII method. Therefore, the goal is to select key management elements of window construction that actively reflect the characteristics of the construction stage.

• 한국농공학회논문집
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• 제64권3호
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• pp.9-24
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• 2022

Currently, a vast amount of hydrologic data is accumulated in real-time through automatic water level measuring instruments in agricultural reservoirs. At the same time, false and missing data points are also increasing. The applicability and reliability of quality control of hydrological data must be secured for efficient agricultural water management through calculation of water supply and disaster management. Considering the characteristics of irregularities in hydrological data caused by irrigation water usage and rainfall pattern, the Korea Rural Community Corporation is currently applying the Hampel filter as a water level data quality management method. This method uses window size as a key parameter, and if window size is large, distortion of data may occur and if window size is small, many outliers are not removed which reduces the reliability of the corrected data. Thus, selection of the optimal window size for individual reservoir is required. To ensure reliability, we compared and analyzed the RMSE (Root Mean Square Error) and NSE (Nash-Sutcliffe model efficiency coefficient) of the corrected data and the daily water level of the RIMS (Rural Infrastructure Management System) data, and the automatic outlier detection standards used by the Ministry of Environment. To select the optimal window size, we used the classification performance evaluation index of the error matrix and the rainfall data of the irrigation period, showing the optimal values at 3 h. The efficient reservoir automatic calibration technique can reduce manpower and time required for manual calibration, and is expected to improve the reliability of water level data and the value of water resources.