• 건축역사연구
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• 제25권6호
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• pp.7-16
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• 2016

The purpose of this study is to find framework schema of early J usimpo-style Buddhist halls (Geungnakjeon Hall of Bongjeongsa Temple, Muryangsujeon Hall of Buseoksa Temple, and Daeungjeon Hall of Sudeoksa Temple). Though the halls are known as built in the late Goryeo Period, they show the influence of the architectural style of the early Unified Silla Period. To find the adopted modules and proportions of these halls, this study conceived a schematic diagram based on the whole frame structure taking reference from the Cai-Fen system in Yingzao Fashi. In these three halls, the heights of each cross-beam (Dori) are made up by the layers of member and member units. This study computes the values of Cai, Zhi, and Fen which can apply to both the section and the plan. The vertical section structure is determined by combining the standard member heights (Cai) and the standard unit heights (CaiZhi). The bays of columns are made by multiples of the standard member width (Fen).

• 대한전자공학회논문지TC
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• 제45권4호
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• pp.38-42
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• 2008

본 논문에서는 다중 안테나 시스템에서 다수의 에너지 검출기를 이용하여 신뢰성 향상을 도모한 새로운 스펙트럼 검출 방법을 제안하였다. 스즈키 채널 상황 하에서 시뮬레이션을 통하여 기존의 에너지 검출기와 스펙트럼 검출 성능 비교하였다. 시뮬레이션 결과 10%로 고정된 오보확률에서 제안하는 구조의 성능을 SNR (Signal to Noise Ratio)에 따른 미 검출 확률로 구하고 또한 ROC(Receive Operation Characteristics) 커브로 나타내어 그 우수함을 보인다.

• Journal of Communications and Networks
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• 제13권4호
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• pp.327-338
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• 2011

With the incitation to reduce power consumption and the aggressive reuse of spectral resources, there is an inevitable trend towards the deployment of small-cell networks by decomposing a traditional single-tier network into a multi-tier network with very high throughput per network area. However, this cell size reduction increases the complexity of network operation and the severity of cross-tier interference. In this paper, we consider a downlink two-tier network comprising of a multiple-antenna macrocell base station and a single femtocell access point, each serving multiples users with a single antenna. In this scenario, we treat the following beamforming optimization problems: i) Total transmit power minimization problem; ii) mean-square error balancing problem; and iii) interference power minimization problem. In the presence of perfect channel state information (CSI), we formulate the optimization algorithms in a centralized manner and determine the optimal beamformers using standard convex optimization techniques. In addition, we propose semi-decentralized algorithms to overcome the drawback of centralized design by introducing the signal-to-leakage plus noise ratio criteria. Taking into account imperfect CSI for both centralized and semi-decentralized approaches, we also propose robust algorithms tailored by the worst-case design to mitigate the effect of channel uncertainty. Finally, numerical results are presented to validate our proposed algorithms.

• World Technopolis Review
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• 제3권1호
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• pp.17-29
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• 2014

The importance of science and technology as the root of exceptional regional economic development has been extolled since the time of Schumpeter. Today emerging technologies are signaling the start of a new economic cycle where regions that are effective in technology translation will gain advantage. The will of policymakers to translate technology into regional job and wealth creation seems to be at an all-time high. Yet an improved process for translating technical development into regional prosperity has proved elusive. If there are no processes other than applying techniques that have worked in the past for other regions to a new region then there is cause for concern. Here the authors seek to add to this field of knowledge by applying elements of the varied cluster theories to provide a basis for policy for regional economic development by turning science and technology into commercial innovation. We provide a review of current cluster theories and discuss the positive and negative issues associated with each. We propose a model that allows interested professionals to utilize aspects of each cluster perspective geared to the realities of their specific area.

• 전력전자학회논문지
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• 제10권6호
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• pp.527-533
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• 2005

선형 하이브리드 스테핑 전동기는 간단한 구조와 저가의 구동 방식으로 위치 제어를 요구하는 일부 반도체 공정 및 사무실 자동화 기기 등에서 최근 각광을 받고 있다. 그러나, 구조가 간단한 반면 이로 인한 릴럭턴스 및 코깅 추력에 의한 리플 때문에 아직까지 고부가가치의 정밀 공정에는 적용이 제한되어 왔다. 본 논문에서는 선형 하이브리드 스테핑 전동기의 추력 리플 발생 원인을 분석하고 이를 통하여 리플 추력을 상쇄하는 고성능 폐루프 제어 방식을 제안한다. 실험실에서 제작된 선형 하이브리드 스테핑 전동기에 대한 다양한 실험 결과를 통하여 해석 및 제안된 방법의 타당성을 검증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1096-1098
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• 2003

In this paper, the control algorithm and control methods for a combined system of shunt passive filter and series active filter in 3-phase 4-wire system are discussed. Moreover, the 3-phase 4-wire system is widely employed in distributing electric energy to several office building and manufacturing plants. In such systems, the third harmonic and odd multiples of $3^{rd}$($9^{th}$, $15^{th}$, etc.) are termed as triple and zero sequence components that do not cancel each other in the system neutral. As a result, the triple harmonics add together creating a primary source of excessive neutral current. Regarding this concern, this paper presents a new control scheme for a series hybrid active system. This series active power filter acts not only as a harmonic compensator but also as a harmonic isolator. Hence the required rating of the series active filter is much smaller than that of a conventional shunt active filter. However, the performance of the combined system is greatly influenced by the filtering algorithm employed in the active power filter. This paper proposes a series active power filter scheme based on performance function. Some experiments was executed and experimental results from a prototype active power filter confirm the suitability of the proposed approach.

• 한국정보통신학회논문지
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• 제17권5호
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• pp.1076-1082
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• 2013

자기 공분산 기울기를 이용하여 음성 신호와 배경 잡음 신호를 구분할 때 구분 가능성을 높이기 위해 주파수 영역에서 음성 신호의 자기 공분산 기울기를 최대화하는 주파수 대역을 찾아내었다. 디지털 샘플링 된 음성 신호를 일정한 개수의 신호로 이루어진 블록으로 나눈 후 각 블록에 고속푸리에변환(Fast Fourier Transform, FFT)을 하여 주파수 영역으로 변환한 다음 임의의 주파수 대역에서 각 블록에서의 공분산을 구하고 이 공분산 값들을 연결하는 직선 근사를 한 후에 이 직선의 기울기를 자기 공분산 기울기로 사용하는데 이 값은 음성 신호의 특성 상 주파수 대역별로 차이가 있다. 따라서 어느 주파수 대역에서 자기 공분산 기울기가 크게 나타나는지 200개의 남성 음성 파일을 이용하여 주파수 대역별로 비교 분석하였다.

• 로봇학회논문지
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• 제14권4호
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• pp.285-292
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• 2019

Path planning is an important problem to solve in robotics and there has been many related studies so far. In the previous research, we proposed the Heterogeneous-Ants-Based Path Planner (HAB-PP) for the global path planning of mobile robots. The conventional path planners using grid map had discrete state transitions that constrain the only movement of an agent to multiples of 45 degrees. The HAB-PP provided the smoother path using the heterogeneous ants unlike the conventional path planners based on Ant Colony Optimization (ACO) algorithm. The planner, however, has the problem that the optimization of the path once found is fast but it takes a lot of time to find the first path to the goal point. Also, the HAB-PP often falls into a local optimum solution. To solve these problems, this paper proposes an improved ant-inspired path planner using the Rapidly-exploring Random Tree-star ($RRT^*$). The key ideas are to use $RRT^*$ as the characteristic of another heterogeneous ant and to share the information for the found path through the pheromone field. The comparative simulations with several scenarios verify the performance of the improved HAB-PP.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.29-40
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• 1995

This paper describes the procedure to predict steady and unsteady performances of a contrarotating propeller(CRP) by a mixed formulation of the boundary value problem(BVP) far the flow around a CRP. The blade BVP is treated by a classical vortex lattice method, whereas the hub BVP is solved by a potential-based panel method. Blades and trailing wakes are represented by a vortex and/or source lattice system, and hubs are represented by normal dipole and source distributions. Both forward and aft propellers are solved simultaneously, thus treating the interaction effect without iteration. The unsteady performance is computed directly in time domain. The new numerical procedure requires a large amount of storage and computing time, which is however no longer a limit in a modern computer system. Sample computations show that the steady performance compares very well with the experiments. The predicted unsteady behavior shows that the dominant harmonics of the total forces are multiples of not only the number of blades of the forward and aft propellers but also the product of both blade numbers. The magnitude of the latter harmonics, present also in uniform oncoming flow, may reach abort 50% of the mean torque for the aft propeller, which in turn may cause a serious vibration problem in the complicated contrarotating shafting system.

• 가정∙방문간호학회지
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• 제29권1호
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• pp.105-115
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• 2022

Purpose: This study aims to determine the factors that affect the breastfeeding of late preterm infants (gestation age 34⁺⁰~36⁺⁶) in South Korea. Method: A cross-sectional and questionnaire-based survey was conducted on 178 mothers of 209 late preterm infants discharged from a university hospital. We collected data on participants' demographics, breastfeeding-related characteristics and current status of breastfeeding and analyzed them using SPSS. Results: Breastfeeding duration varied significantly according to the number of babies born (t=3.691, p<.001), birth order (F=6.416, p=.002), type of feeding planned (F=8.691, p<.001), planned breastfeeding period(F=24.779, p<.001), previous baby's breastfeeding type(F= 8.510, p<.001), previous baby's breastfeeding duration(F=10.589, p<.001). The mothers with incomes of 3-5 million won a month were less likely to continue breastfeeding than those with incomes over 5 million won (CI: 0.049-0.086: p=0.035). Conclusion: Our results are meaningful in that we revealed that mother's monthly income influenced breastfeeding continuation, first-time mothers and mothers of multiples were at risk of breastfeeding difficulties. Interventions for helping late preterm infants' mothers establish breastfeeding and maintain an adequate milk supply are vital.