• 전자공학회논문지
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• 제52권4호
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• pp.3-8
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• 2015

이 논문에서는 신호점 매칭 오차(constellation-matched error: CME)와 비 신호점 매칭 오차(non-constellation-matched error: non-CME)를 선형 결합한 오차 신호 기반의 블라인드 등화 알고리즘을 제안한다. 새로운 오차 신호는 초기 수렴을 달성하기 위한 non-CME 항과 출력 신호의 심볼간 간섭(intersymbol interference: ISI) 성능을 개선하기 위한 CME 항을 포함하도록 설계되었고, 결합 인자를 통해 두 오차 항을 제어한다. 오차 항을 제어하여 등화 단계에 적합한 오차 신호를 발생함으로써 기존 알고리즘에 비해 수렴 속도와 심볼간 간섭 제거 성능을 개선하였다. 다중경로 채널에 잡음을 부가한 조건하에서 이루어진 64-QAM과 256-QAM 신호에 대한 모의실험에서 제안 방법이 CMA와 CMA+DD 동시 등화에 비해 우수한 것으로 나타났다.

• 한국컴퓨터정보학회논문지
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• 제23권1호
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• pp.67-74
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• 2018

In this paper, we propose an efficient scene based non-uniformity correction algorithm which performs the offset correction using the uniform obtained from input scenes for Infrared camera. In general, pixel outputs of a infrared detector can not be uniform. Therefore, the non-uniformity correction procedure need to be performed to make the image outputs uniform. A typical non-uniformity correction method uses a black body at the laboratory to obtain the output of the infrared detector's pixels for two temperatures, HOT and COLD, and calculates the non-uniformity correction parameters. However, output characteristics of the Infrared detector changes while the Infrared camera is operated, the fixed pattern noise of the Infrared detector and dead pixels are generated. To remove the noise, the offset correction is generally performed. The offset correction procedure usually need the additional device such as a thermo-electric cooler, shutter, or non-uniformity correction lens. Therefore, we introduce a general scene based non-uniformity correction technique without additional equipment, and then we propose an improved non-uniformity correction algorithm based on image to solve the problem of the existing technique.

• 비교문화연구
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• 제32권
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• pp.109-132
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• 2013

This paper compares sequential and non-sequential verbal conjunctions in Korean, English, and Japanese by looking at how sequential verbal conjunction is treated in each language. It frist reviews verbal conjunctions in Korean, where sequential conjunction is treated as subordination and non-sequential conjunction is treated as coordination, and looks at verbal conjunctions in English and Japanese to see whether or not sequential conjunction in those languages is subordination. According to Oh (2010), sequential and non-sequential conjunctions in Korean behave quite differently with respect to the tense and negation in the final conjunct. Also, Cho (1995, 2005) and Kwon (2004) show that syntactic operations such as extraction and scrambling clearly distinguish sequential conjunction from non-sequential conjunction. The purpose of this paper is to see how sequential and non-sequential conjunctions are analyzed in English and Japanese and to compare those languages with Korean, especially focusing on whether or not sequential conjunctions in English and Japanese are treated as subordination. For this purpose, I first investigate how tense and negation, which provided crucial evidence for concluding that Korean sequential conjunction is subordination, is interpreted in sequential and non-sequential verbal conjunctions in English and Japanese. Also, I investigate the syntactic properties of sequential and non-sequential conjunctions with respect to syntactic operations such as extraction and scrambling in those languages. The results of the investigation show that in Japanese, which is considered typologically similar to Korean, the sequential conjunction is a case of subordination, while in English, which is considered typologically different from Korean, both sequential and non-sequential conjunctions are treated as coordination.

• 대한조선학회논문집
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• 제55권6호
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• pp.466-473
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• 2018

Most frequency domain-based approaches assume that structural response should be a Gaussian random process. But a lot of non-Gaussian processes caused by multi-excitation and non-linearity in structural responses or load itself are observed in many real engineering problems. In this study, the effect of non-Normality on fatigue damages are discussed through case study. The accuracy of four frequency domain methods for non-Gaussian processes are compared in the case study. Power-law and Hermite models which are derived for non-Gaussian narrow-banded process tend to estimate fatigue damages less accurate than time domain results in small kurtosis and in case of large kurtosis they give conservative results. Weibull model seems to give conservative results in all environmental conditions considered. Among the four methods, Benascuitti-Tovo model for non-Gaussian process gives the best results in case study. This study could serve as background material for understanding the effect of non-normality on fatigue damages.

• Earthquakes and Structures
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• 제17권2호
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• pp.191-204
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• 2019

Near-field earthquake records including long-period high-amplitude velocity pulses can cause large isolation system displacements leading to buckling or rupture of isolators. In such cases, providing supplemental damping in the isolation system has been proposed as a solution. However, it is known that linear viscous dampers can reduce base displacements in case of near-field earthquakes but at the potential expense of increased superstructure response in case of far-field earthquakes. But can non-linear dampers with different levels of non-linearity offer a superior seismic performance? In order to answer this question, the effectiveness of non-linear viscous dampers in reducing isolator displacements and its effects on the superstructure response are investigated. A comparison with linear viscous dampers via time history analysis is done using a base-isolated benchmark building model under historical near-field and far-field earthquake records for a wide range of different levels of non-linearity and supplemental damping. The results show that the non-linearity level and the amount of supplemental damping play important roles in reducing base displacements effectively. Although use of non-linear supplemental dampers may cause superstructure response amplification in case of far-field earthquakes, this negative effect may be avoided or even reduced by using appropriate combinations of non-linearity level and supplemental damping.

• 한국전자통신학회논문지
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• 제16권4호
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• pp.611-616
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• 2021

본 논문은 상관 관계 중첩 코딩/non-SIC 비직교 다중 접속의 향상된 outage 확률을 고찰한다. 먼저, 기존의 독립 중첩 코딩/SIC 비직교 다중 접속의 outage 확률을 고찰한다. 다음, 모의실험을 통하여, 상관 관계 중첩 코딩/non-SIC 비직교 다중 접속의 outage 확률이 독립 중첩 코딩/SIC 비직교 다중 접속의 outage 확률에 비하여 크게 향상되는 것을 입증한다. 결론으로, 이러한 향상된 outage 확률로 인하여, 상관 관계 중첩 코딩/non-SIC 비직교 다중 접속 기술은 5G 시스템의 유망한 기술이 될 수도 있다.

• 도시과학
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• 제10권1호
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• pp.21-28
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• 2021

The purpose of this study is to examine the factors affecting the housing satisfaction of elderly households in comparison with non-elderly households, and to present policy implications in terms of housing welfare policies. For this purpose, this study used ordered logit model analysis using '2019 Housing survey data'. As a result of the analysis, in the case of individual/housing characteristics, the analysis results of the non-elderly household model and the elderly household model were similar. However, in the case of regional characteristics, non-elderly households living in the metropolitan area showed higher housing satisfaction than non-elderly households living in the non-metropolitan area, whereas the elderly households living in the metropolitan area had lower housing satisfaction than the elderly households living in the non-metropolitan area. In addition, the satisfaction variable of neighborhood/environmental characteristics that had the greatest impact on the housing satisfaction of non-elderly households was found to be crime prevention status satisfaction, and the satisfaction variable of neighborhood/environmental characteristics that had the greatest impact on the housing satisfaction of elderly households was air pollution satisfaction. The results of the analysis can be used as various reference materials when establishing housing welfare policies for elderly households.

• Wind and Structures
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• 제32권2호
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• pp.89-104
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• 2021

Non-synoptic winds generated by tornadoes, downbursts or gust fronts exhibit significant non-stationarity and can cause significant wind load effect on flexible structures such as long-span bridges. However, conventional assumptions on stationarity used to evaluate the structural wind-induced vibration are inadequate. In this paper, an efficient frequency domain scheme based on fast CQC method, which can predict non-stationary buffeting random responses of long-span bridges, is presented, and then this approach is applied to evaluate the buffeting response of a long-span suspension bridge located in a complex mountainous wind environment as an example. In this study, the data-driven method based on one available measured wind speed sample is firstly presented to establish non-stationary wind models, including time-varying mean wind speed, time-varying intensity envelope function and uniformly modulated fluctuating spectrum. Then, a linear time-variant (LTV) system based on the proposed scheme can be generally applied to calculate the non-stationary buffeting responses. The effectiveness and accuracy of the proposed scheme are verified through Monte Carlo time domain simulation implemented in ANSYS platform. Also, the transient effect nature of the bridge responses is further illustrated by comparison of the non-stationary, quasistationary and steady-state cases. Finally, buffeting response analysis with traditional stationary treatment (10 min constant mean plus stationary wind fluctuation) is performed to illustrate the importance of the non-stationary characteristics embedded in original wind speed samples.

• 청정기술
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• 제26권4호
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• pp.257-262
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• 2020

Two-dimensional (2D) metal organic framework (MOF) nanosheets (NSs) have recently gained considerable interest owing to their structural advantages, such as large surface area and exposed active sites. Two different types of 2D MOF NSs have been reported, including inherently layered MOFs and non-layered ones. Although several studies on inherently layered 2D MOFs have been reported, non-layered 2D MOFs have been rarely studied. This may be because the non-layered MOFs have a strong preference to form three-dimensionality intrinsically. Furthermore, the non-layered MOFs are typically synthesized in the presence of the surfactant or modulator, and thus developing facile and clean synthetic routes is highly pursued. In this study, a facile and clean synthetic methodology to grow non-layered 2D cobalt-based zeolitic imidazolate framework (ZIF-67) NSs is suggested, without using any surfactant and modulator at room temperature. This is achieved by directly converting ultrathin α-Co(OH)2 layered hydroxide salt (LHS) NSs into non-layered 2D ZIF-67 NSs. The comprehensive characterizations were conducted to elucidate the conversion mechanism, structural information, thermal stability, and chemical composition of the non-layered 2D ZIF-67. This facile and clean approach could produce a variety of non-layered 2D MOF NS families to extend potential applications of MOF materials.

• 공학교육연구
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• 제25권2호
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• pp.32-41
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• 2022

The purpose of this study was in a pandemic situation caused by COVID-19 to explore the online distance experiments and interaction of engineering freshmen, and to identify practical difficulties, resulting in to derive implications. Seven freshmen from engineering college participated in the interview, of which data were analyzed based on phenomenological analysis methods. The types of non-face-to-face experiments experienced by students were complete non-face-to-face experiment, mixed face-to-face experiment, and fusion face-to-face experiment. Students were completely isolated in time and space in complete non-face-to-face experiment. In biweekly mixed face-to-face experiment, isolation was halved. In fusion face-to-face experiment, isolation was removed. Non-face-to-face interactions can be characterized by restrictions on simultaneous activities, on rapport formation, and on observation opportunities. Based on these results, three implications were derived: First, it is necessary to allow students to manage time and space constraints on their own in non-face-to-face experiments. Second, support is needed to solve the difficulty of forming rapport, which is a characteristic of non-face-to-face interaction. Third, an opportunity to observe the interaction between other students and professors should be provided.