OFDMA 하향링크 시스템에서의 PAPR 저감을 위한 다단계 및 가변길이 첨두 윈도윙 기법들

이성은,민현기,방극준,홍대식,Lee, Sung-Eun,Min, Hyun-Kee,Bang, Keuk-Joon,Hong, Dae-Sik 대한전자공학회 2008 電子工學會論文誌-TC (Telecommunications) Vol.45 No.2

본 논문에서는 OFDMA 하향링크 시스템에서 PAPR를 저감할 수 있는 두 가지 새로운 첨두 윈도윙(peak windowing) 기법을 제안한다. 제안한 첨두 윈도윙 기법들은 기존의 첨두 윈도윙 기법에서 매우 인접한 여러 개의 첨두들 또는 주변 신호에 비해 상대적으로 큰 첨두에 의해 발생하는 과도한 신호 왜곡 효과를 완화시킨다. 여러 단계의 임계치를 이용한 다단계 첨두 윈도윙(multi-stage peak windowing) 기법은 인접 신호에 비해 상대적으로 매우 큰 첨두들을 우선적으로 제거함으로써, 윈도우가 과도하게 인접 신호를 억제할 수 있는 경우를 방지한다. 다음으로 가변적인 윈도우 길이를 이용하는 가변길이 첨두치 윈도윙(variable-length peak windowing) 기법은 연속적인 첨두가 매우 인접하여 발생하였을 경우 여러 첨두에 적용되는 윈도우들이 중첩되지 않도록 윈도우 길이를 줄여서 과도하게 인접 신호가 억제되는 경우를 줄이게 된다. 제안한 첨두 윈도윙 기법들은 인접하여 발생하는 연속적인 첨두치나 상대적으로 큰 첨두에 의한 과도한 신호 억제를 미연에 방지함으로써 기존의 첨두 윈도윙 기법에 비해서 우수한 성능을 나타낸다. 기존의 첨두 윈도윙 기법 및 제안한 첨두 윈도윙 기법의 수신비트 오율(BER), 스펙트럼 특성은 OFDMA를 적용한 WiBro 하향링크 모의 실험 환경을 통해서 평가되며, 이를 통해 제안한 첨두 윈도윙 기법이 월등한 성능을 나타냄을 검증한다. This paper proposes two peak-windowing algorithms for peak-to-average power reduction(PAPR) of orthogonal frequency division multiple access(OFDMA) downlink systems. The Proposed algorithms mitigate the effect of excessive suppression due to successive peaks or relatively high peaks of the signal. First, multi-stage peak windowing algorithm is proposed, which exploits multiple threshold of target PAPR in order to step down the peaks gradually. Secondary, variable-length peak windowing algorithm is proposed, which adapts the window length with respect to the existence of successive peaks within a half of window length. Therefore, the proposed method reduces the distortion of signal amplitude caused by window overlapping. The proposed algorithms outperform the conventional peak windowing with the aid of window-length adaptation or sequential peak power reduction. Simulation results show the efficiency of the proposed algorithms over OFDMA downlink systems, especially WiBro systems.

확장 칼만필터를 이용한 수중 표적의 불안정 주파수선 추출 기법

이성은,황수복,남기곤,김재창,Lee, Sung-Eun,Hwang, Soo-Bok,Nam, Ki-Gon,Kim, Jae-Chang 한국음향학회 1996 韓國音響學會誌 Vol.15 No.6

수동 소나 시스템에서는 표적을 탐지, 추적 및 식별을 위하여 표적의 방사 소음으로부터 발생되는 주파수선을 주요 특징 인자로 활용한다. 이 연구에서는 수중 표적의 방사 소음으로부터 시간 영역의 표본화된 데이타를 이용한 불안정 주파수선의 추출 기법에 대하여 연구하였다. 불안정 주파수선은 시간에 따라 주파수선이 변화되어 나타나므로 불안정 주파수선 추출을 위하여 비선형 시스템에 유용한 확장 칼만 필터 알고리듬을 적용하였다. 모의 실험 및 표적 신호에 적용하여 제시한 방식이 불안정 주파수선을 추출할 수 있음을 보인다. In passive sonar system, frequency lines generated by underwater target are very important for detection, tracking and classification. In this paper, the extraction method of unstable frequency line from the time samples of the radiated noise of underwater target is studied. As unstable frequency line is time varying, an extended Kalman filter algorithm which is desirable for nonlinear system is applied to extract unstable frequency line. The proposed method shows good extraction of unstable frequency line by application of simulated signal and real target.

군용항공기 연구개발 사업 사례분석

이성은,권용수,Lee, Sung Eun,Kwon, Yong Soo 한국시스템엔지니어링학회 2009 시스템엔지니어링학술지 Vol.5 No.1

This paper describes a case study on the R&D programs of fighter and attacker aircraft such as F-22A, F/A-18E/F, and T/A-50. F-22A and F/A-18E/F were developed in same age. The performance of each program was, however extremely different. F-22A program results in a lot of cost overrun and schedule delay. On the other hand F/A-18E/F program met the cost, schedule, and performance goals. In the T/A-50 program with a super-sonic advanced trainer, T-50 was also developed successfully on planned cost and time by Korea Air-force and KAI. This paper derives key elements for the success of the military aircraft R&D program through lessons learned from th e case study. Each program is analyzed in terms of its background, planning and management.

Piperlongumine 유도체 합성과 $Aflatoxin\;B_1$ 생성 억제 효과

이성은,최원식,이현상,이영행,박병수,Lee, Sung-Eun,Choi, Won-Sik,Lee, Hyun-Sang,Lee, Young-Haeng,Park, Byeoung-Soo 한국응용생명화학회 2003 한국농화학회지 Vol.46 No.4

Anti-aflatoxigenic studies on synthetic pyridione alkaloids were conducted. Seven derivatives using piperlongumine as a leading compound were prepared from 3,4,5-trimethoxycinnamic acid (TMCA). These derivatives were analyzed for their structural confrmation and purity by HPLC, GC, GC/MS and $1^H-NMR$. 1-piperidin-1-yl-3-(3,4,5-trimethoxyphenyl)propenone (1) reaction with piperidine; 1-morpholin-4-yl-3-(3,4,5-trimethoypenyl)propenone (2) with morpholine; 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (3) with 3,5-dimethylpiperdine; 1-(2-methylpiperidine-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (4) with 2-methylpiperidine; 1-(3-hydroxypiperidin-1-yl)-3- (3,4,5-trimethoxyphenyl)propenone (5) with 3-hydroxypiperidine hydrochloride; 1-[3- (3,4,5-trimethoxyphenyl)acryloyl]piperidin-2-one (6) with ${\delta}-valerolactam;\; and\;ethyl\;1-[3-(3,4,5-trimethoxyphenyl)acyloyl]piperidine-4-carboxylate$ (7) with ethyl isonipectotate were synthesized respectively. All derivatives showed an inhibitory activity on aflatoxin $B_1$ production. In conclusion, we believe that they might be an agent for the control of mycotoxin in agricultural commodities. 필발 열매로부터 추출 및 분리한 piperlongurnine (1-[3-(3,4,5-trimethoxyphenyl)acryloyl]-5,6-dihydro-1H-pyridin-2-one)이 aflatoxin $B_1\;(AFB_1)$ 생성억제에 있어서 탁월한 효과가 입증되어 3,4,5-trimethoxycinnamic acid (TMCA)를 모체로 하여 1-piperidin-1-yl-3-(3,4,5-trimethoxyphenyl)propenone (1), 1-morpholin-4-yl-3-(3,4,5-trimetholfrphenyl)propenone (2), 1- (3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (3), 1-(2-methylperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (4), 1- (3-hydroxypiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)propenone (5), 1-[3-(3,4,5-trimethoxy-phenyl)acryloyl]piperidin-2-one (6) 및 ethyl 1-[3-(3,4,5-trimethoxyphenyl)acryloyl]piperidin-4-carboxylate (7)의 유도체를 합성하여 구조를 확인하고, 이 화합물들을 이용하여 $AFB_1$ 생성저해 효과를 측정하였다. Aspergillus flavus NRRL 2061로부터 생성되는 $AFB_1$ 생성저해에 대한 실험한 결과 모든 유도체 화합물에서 활성을 나타내었으며, 특히 화합물 (3)이 1000, 500, 250, 100및 $50\;{\mu}g/ml$에서 100, 95, 90, 53 및 10%의 생성저해를 나타냈다. 이러한 연구 결과 유도체 화합물 (3)은 항진균 독소제 개발을 위한 선도화합물로 이용하여 새로운 농약으로 개발이 가능할 것이라고 판단된다.

자동 연상 기억장치 신경망을 이용한 음향 표적의 신호 주파수선 탐지

이성은,황수복,남기곤,김재창,Lee, Sung-Eun,Hwang, Soo-Bok,Nam, Ki-Gon,Kim, Jae-Chang 한국음향학회 1996 韓國音響學會誌 Vol.15 No.5

수동 소나 시스템에서 표적을 탐지, 식별하는데 가장 중요한 인자는 표적소음에서 나타나는 신호 주파수선 성분이다. 수중의 주변잡음과 표적소음이 복합된 환경에서 표적의 신호 주파수선 성분을 정확히 추출하는데는 신호 탐지 문턱값 설정이나 주변잡음의 변화 때문에 어려움이 따른다. 이 연구에서는 자동 연상 기억장치 신경망을 이용하여 신호 탐지 문턱값 설정이나 주변잡음의 변화에 강인한 음향 표적의 신호 주파수선 탐지 방식을 제안한다. 모의 실험 및 실제 표적 신호에 적용하여 제안한 방식이 우수한 신호 주파수선 탐지성능을 나타냄을 보인다. Signal frequency lines generated from the acoustic targets are of particular importance for target detection and classification in passive sonar systems. The underwater noise consists of a mixture of ambient noise and radiated noise of targets. Detction of exact signal frequency lines depends on signal detection threshold and variation of ambient noise. In this paper, a detection method of signal frequency lines for acoustic targets using autoassociative memory (ASM) neural network, which is not sensitive to variation of signal detection threshold and ambient noise, is proposed. It is confirmed by simulation and application of real acoustic targets that the proposed method shows good performance for detection of signal frequency lines.

우리나라 병원감염관리 활성화를 위한 모형 개발

이성은,Lee, Sung-Eun 한국지역사회간호학회 1997 지역사회간호학회지 Vol.8 No.2

In Korea, the nosocomial infection control program is not well developed. This situation is created by a lack of interest from medical personnel and the medical payment system. This study identifies current problems and develops a model for nosocomial infection control. The studies of Lee & Kim(1995), Lee (1993) and SENIC project model were used to construct this model. 1. The problems of nosocomial infection control were identified as the following: dis approval by hospital authorities, lack of sources for program direction, lack of overall structure and function in the program, inadequate direct action, lack of education and training, and so on. 2. The problems are reorganized according to the 5 elements of system theory. 3. As a result, the new nosocomial infection control model was developed. The inputs of the model were the elements, resources and boundaries of nosocomial infection. With the new model, each hospital can evaluate their current programs and plan a new program for the better control of nosocomial infection.

아토피 피부염에 운용 가능한 경혈(經穴) 탐구 - 상용(常用) 본초(本草)를 중심으로

이성은,윤화정,고우신,Lee, Sung-Eun,Yoon, Hwa-Jung,Ko, Wo-Shin 대한한방안이비인후피부과학회 2018 한방안이비인후피부과학회지 Vol.31 No.2

Objectives : The purpose of this study is to investigate acupoints for atopic dermatitis which have similar impact with frequent herbs. Methods : We collected research materials in "The Journal of Korean Medicine Ophthalmology & Otolaryngology & Dermatology" published from Feburary, 2000 to September, 2017. The search terms are 'atopic Dermatitis', 'antiallergic', 'anti-inflammatory', 'antianaphylaxis', 'dermatitis' and we elected experimental researches about herbal medicine. Among the herbal medicine, we extracted frequent herbs using more than 5 times, and categorized through "Herbal Medicine". By Consulting "Principles of Meridians & Acupoints; A Guidebook for College Students", we matched frequent herbs and acupoints. Results : 1. There are 38 frequent herbs for study except Glycyrrhiza uralensis FISCH. because it was used for balance in herbal medicine. Arrange meridians in order of frequency, the most is 'Lung meridian'. Among the organs, the most related one with skin is 'Lung' and 'Lung meridian' can treat skin diseases. 2. We researched acupoints called 'specific acupoints' under elbow, knee because of clinical usage. Exceptively, SP6 and GV20 are not included in 'specific acupoints' but they can be effective for atopic dermatitis treatment. 3. Researching on MEDLINE about frequent herbs and acupoints, there are many studies that acupuncture is effective for reducing pruritus. Therefore, the acupoints which were mentioned in this study can be choosed for atopic dermatitis. Conclusions : We found several applicable acupoints for Atopic Dermatitis. We hope it will be useful in experiment such as randomized controllized trial on Atopic Dermatitis and acupuncture and futhermore in clinic.

하중흐름을 통한 대형구조실험용 반력시설물의 설계

이성은,고동우,Lee, Sung-Eun,Ko, Dong-Woo 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.2

The purpose of this study is to present a method that can estimate the height of reaction facilities for large structural experiment through load flow as primary design procedure. The characteristic of the load transmission according to the type of experiment was analyzed to obtain tensile and compressive forces occurring on the reaction facilities. Strong walls that are affected by the bending moment is applied the post-tensioning method, and the strong floor under the control of the tension and compression is designed in accordance with the load flow. And the optimum cross-section of the reaction facilities was obtained by comparing the stresses of the tensile stress and crack the concrete. Through validating elastic analysis, the design results were satisfied a given design conditions.

전신소양감을 동반한 심상성 천포창 치험 1례

이성은,윤화정,고우신,Lee, Sung-Eun,Yoon, Hwa-Jung,Ko, Woo-Shin 대한한방안이비인후피부과학회 2016 한방안이비인후피부과학회지 Vol.29 No.2

Objectives : The purpose of this report is to know the effect of Korean medical treatments on pemphigus vulgaris with generalized pruritus. Methods : We treated a 44-years-old woman patient with pemphigus vulgaris on the whole body with Korean medicine. After Korean medical treatment for 17 weeks, we measured the extinction of blisters and decrease of pruritus. We recorded pictures of changes on symptoms. Results & Conclusions : The symptoms of pemphigus vulgaris were significantly improved. The blisters and itching were decreased and skin damages were almost recovered. Thus Korean medical treatments are effective on pemphigus vulgaris.

우리나라 간호교육기관의 현장실습교육 실태 파악 및 개선방향 모색에 관한 연구

이성은(Lee, Sung Eun) 한국간호교육학회 1997 한국간호교육학회지 Vol.3 No.2