슈베르트 피아노 소나타에 나타난 전조방법 : 소나타형식의 발전부를 중심으로

김자경 한국음악교육공학회 2014 음악교육공학 Vol.- No.18

This thesis closely looked into modulation methods shown in Development of 1st Movement in Schubert’s Piano Sonata. Development of 1st Movement in Schubert’s Piano Sonata shows a variety of modulation methods used in the Common Practice Period. Thus, the objective of this thesis is to reclassify the modulation methods that Schubert used so that reclassified modulation methods can be used for analysis of Tonal Music. In general, modulation methods can be classified as diatonic modulation, chromatic modulation, and enharmonic modulation. To be more specific, diatonic modulation can be seen in the closely related key while enharmonic modulation can be seen in the remote key. On the other hand, chromatic pivot chord modulation which uses mixture chord in chromatic modulation is shown in the remote key. However, chromatic pivot chord modulation through neapolitan chord and augmented 6th chords can be shown both in the closely related key and the remote key. Based on this fact, this thesis reclassified modulations into modulation into the closely related key, modulation into the remote key, and modulation into both the closely related key and the remote key. 본 논문은 슈베르트 피아노 소나타 제1 악장의 발전부에서 나타나는 전조방법들을 연구한 논문이다. 슈베르트 피아노 소나타 제1 악장의 발전부에서 공통관습 시대의 다양한 전조방법이 나타나므로 슈베르트 전조방법의 재분류를 통하여 조성음악의 분석 수단이 되게 하는데 그 목적이 있다. 일반적으로 구분하는 온음계적 전조와 반음계적 전조, 이명동음적 전조 중 온음계적 전조는 근친조에서 나타나고 이명동음적 전조는 원격조에서 나타난다. 반면, 반음계적 전조 중 장단조혼용 축화음 전조는 원격조에서 나타지만 나폴리 화음과 증6화음을 통한 반음계적 축화음 전조는 근친조와 원격조에서 모두 나타나는 것을 근거로 근친조로의 전조, 원격조로의 전조, 근친조 및 원격조로의 전조로 재분류하였다.

여성 흉부 CT 검사 시 ASIR의 적용과 Bismuth Breast Shield 사용으로 인한 선량감소효과 및 화질평가

박소연(So Yung Park),방성호(Sung Ho Bang),남윤철(Yoon Chul Nam),김문찬(Moon Chan Kim),한동균(Dong Kyoon Han) 대한CT영상기술학회 2011 대한CT영상기술학회지 Vol.13 No.2

목적 여성의 흉부 CT 검사에서 dose modulation, bismuth 재질의 유방 차폐재, ASIR 기술 적용을 통한 유방, 갑상선, 폐의 선량 감소효과와 화질평가를 위함이다. 대상 및 방법 CT장비는 GE VCT XTe(GE Medical System, USA)를 사용하였고, 선량 측정을 위해서 Rando anthropomorphic woman phantom(model RAN-110, Churchin associate LTD, USA)과 형광유리선량계(GD-352M, 12mm, FGD-1000 reader, Asahi Techno Glass Cooperation, shizuoka, Japan)를 사용하였으며, 유방의 차폐를 위해 bismuth로 코팅된 라텍스(F&L Medical Products Co., 0.060 mmPb equivalent, USA)를 사용하였다. 화질평가를 위해서는 ACR phantom(model #438, Gamex RMI, USA)을 사용하였다. 선량측정은 유방과 갑상선, 폐에 각각 형광유리선량소자를 2개씩 삽입하여 본원 흉부CT 검사인 2.5mm slice thickness, 40 mm beam bollimation, 0.6 sec rotation time, 1.375:1 pitch, 120 kVp로 고정하고, bismuth 유방 차폐재 유무에 따른 non dose modulation, dose modulation, dose modulation과 ASIR를 함께 적용한 여섯 가지 방법에서 측정하여 선량감소 효과를 평가하였다. 화질평가는 Rando 팬텀과 ACR 팬텀에서 각각의 방법에 따라 스캔한 후 노이즈와 균일도, 직선성을 평가하였다. 결과 Dose modulation을 적용하면 유방, 갑상선, 폐의 organ dose는 각각 36.5%, 50.7%, 37.2% 감소되었으며, dose modulation과 bismuth를 함께 적용 시 각각 47.2%, 58.0%, 47.6% 감소되었다. 또한, dose modulation과 bismuth, ASIR를 모두 적용하면 각각 69.8%, 66.9%, 65.0% 감소되었다. ACR 팬텀을 통한 노이즈 측정 결과는 선량감소 방법을 적용하지 않은 검사 방법이 31.2로 가장 낮게 측정되었으며, dose modulation과 bismuth를 적용한 경우 64로 가장 높게 측정되었다. Dose modulation과 ASIR를 함께 적용하였을 때에는 dose modulation만 적용했을 때보다 낮았다. 중앙, 3시, 6시, 9시, 12시 방향에서 측정한 균일도는 bismuth를 사용하지 않은 스캔방법에서는 ACR의 권고기준에 포함되었으나 bismuth를 사용한 서까지 스캔방법에서는 중앙부 값이 상승하여 ACR에서 권고하는 허용범위에 속하진 않았으나 중앙과 가장자리의 CT number 값의 차이는 차폐재와 인접한 12시의 경우만 제외하고 5HU 이내로 허용범위 내에 속하였다. 직선성 평가는 bismuth를 사용하지 않은 스캔방법에서는 물의 CT number 값을 제외하고는 ACR의 권고 치에 포함되었다. 그러나 bismuth를 사용한 세 가지 스캔방법에서는 뼈의 CT number 값은 허용범위에 안에 들어왔으나 공기, 아크릴, 폴리에틸렌은 기준치에 근소한 차이로 벗어났으며 물의 CT number 값은 가장 크게 증가하였다. 결론 여성의 흉부 CT 검사 시 dose modulation, bismuth 유방 차폐재 사용 및 ASIR의 적절한 적용은 영상의 질은 유지하면서 환자의 선량을 감소시킬 수 있는 방안으로 이를 적극적으로 활용할 것을 권고한다. I. Purpose The purpose of this study was to assess radiation dose savings when using bismuth breast shield in the female chest CT- non dose modulation, dose modulation, adaptive statistical iterative reconstruction(ASIR)-in various combinations and to evaluate the effect on image quality. II. Meterial and Methods The glass dosimetry elements were put on the left and right breast, thyroid and lung of rando phantom. The phantom were scanned with same protocol, 2.5 mm slice thickness, 40 nun beam collimation, 0.6 sec rotation time, 1.375:1 pitch, 120 kVp and with each of following methods without and with bismuth breast shield, respectively. 1. In application of non dose modulation, 275 mA 2. In application of dose modulation, noise index at 15.86(100-275 mA) 3. In application of dose modulation and 40% ASIR, noise index at 20.14 (100-275 mA) All examinations were performed with a 64 slice MDCT scanner(GE LightSpeed VCT XTe, Waukesha, Wisconsin, USA), Rando anthropomorphic woman phantom(model RAN-110, Churchin associate LTD, USA) and glass dosimetry system(GD-352M, 12 mm, FGD-1000 reader, Japan) in the measurement of organ dose. Protection device of breast was constructed from the bismuth-coated latex sheets(F&L Medical Products Co., USA). ACR phantom(model #438, Gamex RMI, USA) was used same methods for assessment of the image quality. III. Result When the dose modulation was applied, the organ doses of breast, thyroid, lung have decreased to 36.5%, 50.7%, 37.2% and in case of dose modulation with bismuth breast shield, those of breast, thyroid, lung have decreased to 47.2%, 58.0%, 47.6%, respectively. Then when the combinations of using ASIR with dose modulation and bismuth breast shield was applied, the organ doses of breast, thyroid and lung have decreased to 69.8%, 66.9%, 65.0%, respectively. Also, radiation dose of superficial radiosensitive organ, thyroid decreased 15.5%, 14.9%, 2.4% by bismuth breast shield during the application of non dose modulation, dose modulation, ASIR with dose modulation, respectively. The measurement of noise with ACR phantom bas shown that method reducing the radiation dose was not adopted, the noise reached the lowest value. The result of applying ASIR with dose modulation was lower than in that case of applying dose modulation only. The combinations of using ASIR with dose modulation and bismuth breast shield reduced 8% of noise as well as 31.5% of the CTDIvol as compared with using dose modulation with bismuth breast shields. IV. Conclusions The application of ASIR technology brings not only the decrease of noise but also low radiation dose. The bismuth breast shield reduced radiation dose in adjacent radiosensitive organ, thyroid as well as directly shielded breast. Further study is required to diminish the radiation dose of the patients while maintaining adequate image quality through the combinations of the various dose reduction methods.

정진폭 다중부호 트랜스직교변조

홍대기(Hong, Dae-Ki) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.1

기존의 직교변조 (Orthogonal Modulation)는 그 효용성에 비해 대역폭 효율이 지나치게 떨어져 이를 개선하 기 위한 다중부호 트랜스직교변조 (MCTO: Multi-Code Trans-Orthogonal Modulation)가 제안되었다. 그러나 MCTO 변 조는 송신신호의 진폭이 일정하게 유지되지 않아 RF (Radio Frequency) 단에 포함되어 있는 전력 증폭기 (Power Amplifier)의 부담이 커지게 되는 문제점이 있다. 따라서 본 논문에서는 다중부호 신호를 정진폭으로 부호화하는 방식 을 이용한 정진폭 다중부호 트랜스직교변조 (CAMCTO: Constant-Amplitude Multi-Code Trans-Orthogonal Modulation) 를 제안한다. 또한 제안된 CAMCTO 변조의 성능을 실험을 통해 제시하고 기존의 직교변조 및 MCTO 변조와 비교한 다. 실험 결과에 의하면 제안된 CAMCTO 변조는 기존의 직교변조에 비해 대역폭 효율은 매우 증가하며 MCTO 변조 에 비해 RF의 부담을 매우 경감시킬 수 있음을 알 수 있다. To improve the bandwidth efficiency of conventional orthogonal modulation, the MCTO(Multi-Code Trans-Orthogonal) modulation, which is modified orthogonal modulation, was proposed. However, the RF(Radio Frequency) power amplifier for the MCTO modulation is too complex to reject the amplitude distortion due to the non-constant amplitude property of the MCTO. Therefore, in this paper, CAMCTO(constant-amplitude multi-code trans-orthogonal) modulation is proposed by using the constant-amplitude encoding algorithm for multi-code signal. Additionally, the performance of the proposed CAMCTO modulation is compared with those of the orthogonal modulation and the MCTO modulation by using the computer simulation. The computer simulations show that the bandwidth efficiency of the proposed CAMCTO modulation is better than that of the conventional orthogonal modulation.

Decision Feedback 신호의 자기 상관 기반 SNR 추정 방법을 적용한 적응 변조 시스템

김선애(Seon-Ae Kim),유흥균(Heung-Gyoon Ryu) 한국전자파학회 2011 한국전자파학회논문지 Vol.22 No.3

적응 변조(Adaptive Modulation: AM) 방식은 시간적으로 공간적으로 바뀌는 채널의 상태에 적합한 변조 방식을 적응적으로 할당함으로써, 시스템의 효율을 높이는 중요한 통신 방식이다. 고정 변조 방식은 시간에 따라 신호 대 잡음비(SNR: Signal-to-Noise Ratio)가 변하는 채널에서 BER(Bit Error Rate) 성능이 변한다. 하지만 적응변조 방식은 모든 채널 상태의 SNR에 대하여 일정한 평균 BER 성능을 유지하므로 채널의 상태가 수시로 변하는 통신 환경에서 시스템의 성능을 확보한다. 이를 위해서 무엇보다도 정확하고, 빠르게 신호 대 잡음비를 추정할 수 있는 간단한 SNR 추정 방법이 요구된다. 본 논문에서는 효과적인 적응 변조를 위하여 SNR 추정 성능이 적응 변조 시스템에 미치는 영향을 평균 BER과 평균 데이터 처리율(throughput)을 통하여 분석한다. 또한, 본 논문에서는 decision feedback 신호의 자기 상관 기반의 SNR 추정 방법 및 기존의 SNR 추정 방법들을 적응 변조 시스템에 적용하여 각 변조 레벨 변환 점에서 SNR 추정 성능에 따라 결정되는 적응 변조 시스템의 성능 변화를 확인한다. Decision feedback 신호의 자기 상관 기반 SNR 추정 방법은 M-QAM(Quadrature Amplitude Modulation)신호에서도 비교적 안정적인 추정 성능을 보이기 때문에 적응 변조 시스템에서 다른 SNR 추정 방법들에 비해 변조 레벨 변환 점에서 성능 열화를 줄인다. Adaptive modulation(AM) is an important technique to increase the system efficiency, in which transmitter selects the most suitable modulation mode adaptively according to channel state in the temporary and spatially varying communication environment. Fixed modulation on channels with varying signal-to-noise ratio(SNR) is that the bit-errorrate(BER) probability performance is changing with the channel quality. An adaptive modulation scheme can be designed to have a BER which is constant for all channel SNRs. The correct as well as fast and simple SNR estimation is required essentially for this adaptive modulation. In order to operate adaptive modulation system effectively, in this paper, we analyze the effect of SNR estimation performance to it through the average BER and data throughput. Applying SNR estimation based on auto-correlation of decision feedback signal and others to adaptive modulation system, we also confirm performance degradation or improvement of its which is decided by SNR estimation error at each transition point of modulation level. Since SNR estimation based on auto-correlation of decision feedback signal shows stable estimation performance for various quadrature amplitude modulation(QAM) comparatively, this can be reduced degradation than others at each transition point of modulation level.

EXPERIMENTAL INVESTIGATION OF CHARACTERISTICS OF PRESSURE MODULATION IN A FUEL INJECTION SYSTEM

D. HUANG,M.-C. LAI 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.1

A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future. A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future.

Analysis of Scout images for Dose modulation

정진욱(Jin Wook Jung),김동주(Dong Jwo Kim),정다희(Da Hyi Jeong),신광철(Kwang Chul Shin),안종진(Jong Jin Ahn),유상재(Sang Jae Yoo),김동성(Dong Sung Kim) 대한CT영상기술학회 2013 대한CT영상기술학회지 Vol.15 No.1

목적: 본 연구의 목적은 Scout 영상이 Dose modulation에 미치는 영향을 분석하여 효과적인 Scout영상의 획득방법을 제시 하고자 한다. 대상 및 방법: Anthropomorphic phantom을 서로 다른 4가지 장비(1.GE; Discovery HD750, 2.Philips; Ingenuity, 3.SIEMENS; Definition, 4.Toshiba; Aquillion) 를 이용하여 다양한 노출 조건(80~140kvp, 10~50mA)을 설정하여 Scout 영상을 얻어 각각의 dose modulation의 특징을 분석하였다. 또한 임상에서 Scout 영상을 획득할 때 나타날 수 있는 여러 가지 상황(Tube position, Table위치, 환자 위치, foreign body, Scan direction, Scout lack)을 고려하여 시나리오를 구성하고 이에 따른 변화를 분석하였다. 결과: G사의 경우 Scout 영상의 80kVp와 10mA를 사용시 불안정 하여 선량이 증가 되었고120kVp와 30mA에서 안정적인 Dose modulation을 나타냈다. P, S, T사의 경우 kVp와 mA변화에 따른 영향이 없었고 120kVp에서 안정적인 Dose modulation을 나타냈다. 또한 4가지 장비 모두 Scout kVp와 Scan kVp와의 연관성은 없었다. Scout scenario는 G사의 경우 Bismuth포함, Table up-down, Tube position에서 차이를 보였고 P사의 경우 Tube position, Scout lack 6.6cm, 환자 중심이동에서 차이를 보였다. S사의 경우 Table 4cm updown, Tube position, Scan direction에서 차이가 나타났고 T사의 경우 Bismuth포함, Table 4cm up-down, Tube position(bottom, Lat), 환자 중심이동을 제외한 이외의 항목에서는 큰 변화는 없었다. 결론: CT scout 촬영의 검사 조건에 따라 dose modulation은 다양한 변화가 있으며 각 장비 회사 별로 특징을 파악하고 검사 목적에 따라 세부적인 Scout protocol 관리가 필요하다. Purpose: The purpose of this study is to analyze scout images for dose modulation by using anthropomorphic chest phantom and plan to establish an effective guideline for CT scout images. Materials and methods: Four different MDCT: GE(Discovery), Philips(Ingenuity), Siemens(Definition), Toshiba(Aquillion) were used for this study. Anthropomorphic chest phantom was scanned at various kVp, mA (80~140kVp and 10~50mA) with dose modulation for scout images. Also various scenarios (Tube position, table level, patient position, scan direction, scout lack, and foreign body) were planned considering clinical circumstance and obtained analyzed dose modulation data. Results: Despite a no significant difference in dose modulation by using variety of scout energy ranging from 80kvp~140kVp to 10mA~50mA excepting GE (80kvp and 10mA), we can find 120kVp scout is much better stable than the others during phantom experiments. The results of scenarios, GE: bismuth, table up-down, tube position showed significantly different dose modulation others were not. Philips: scout lack and patient position showed differences. Siemens: table up- down, tube position, scan direction showed differences. In Toshiba bismuth table up- down, tube position (bottom, Lat), patient position showed differences Conclusion: According to CT Scout scan conditions, Dose modulation show wide variation. Therefore we recommend research characteristics of each machines and scout protocol management is required.

슈만의 가곡에서 나타나는 조성의 순환관계: 《시인의 사랑》Op.48의 전조과정을 중심으로

김자경 연세대학교 음악연구소 2015 음악이론포럼 Vol.22 No.1

본 논문에서는 슈만의 연가곡 《시인의 사랑》Op.48에서 나타나는 조성의 순환을 전조의 관 점에서 살펴보았다. 연가곡의 조건인 단일조성이나 주제적 동기의 반복에 의한 음악적인 순환 및 일관성 있는 시적 내용이 있어야 한다는 두 가지 조건에서 볼 때, 슈만의 연가곡 《시인의 사랑》은 일관적인 시적 내용이 부족하지만 조성적 순환과 악곡간의 유기적 관계가 잘 나타나고 있다. 그리하여 본 논문에서는 첫 번째, 악곡과 악곡을 연결해주는 방법과 개별 악곡 내에서 나타나 는 다양한 전조방법을 통하여 음악적 문맥을 더욱 명확하게 하였다. 두 번째, 연가곡 전체의 조성구 조와 개별 악곡의 조성구조의 유기적 관계를 살펴보았다. 슈만의 연가곡 《시인의 사랑》의 개별 악곡은 단일 조성구조와 장단조 혼용 조성구조로 구분할 수 있었다. 악곡 간의 연결에서는 으뜸화음으로 시작하고 으뜸화음으로 끝나는 유형(T-T/T-T″)인 닫힌 형식 악곡과의 연결 및 으뜸화음으로 시작하지 않고 으뜸화음으로 끝나는 유형(X-T/X-T′), 으뜸화 음으로 시작하지 않고 으뜸화음으로 끊나지 않는 유형(X-Y)인 열린 형식 악곡과의 연결로 구분하여 전조방법을 살펴보았다. 악곡 간의 전조는 5도권조(버금 딸림조와 딸림조)와 3도권조(관계 장단조, 가온조, 버금 가온 조)인 근친조에 국한되어 온음계적 전조 및 반음계적 전조, 이명동음적 전조가 나타났다. 개별 악곡 에서는 근친조 및 원격조의 범위에서 온음계적 축화음 전조, 장단조 혼용화음 및 변화화음, 딸림화 음의 기능을 하는 2차적 화음인 부 딸림화음의 반음계적 축화음 전조와 이명동음적 축화음 전조, 동형진행적 전조 등의 전조방법이 나타났다. 또한, 연가곡 전체와 개별 악곡의 화성구조가 같고 전 조를 통한 조성방법이이 유사하다는 점을 통하여 연가곡《시인의 사랑》에서 나타나는 유기적 관계 를 찾을 수 있었다. This article aims to analyze the tonal organization of Schumann's song cycle, Dichterliebe op.48 with emphasis on its various modulations. As the attributes of a ‘song cycle' include; 1) a single tonality and musical organization by repetition of thematic motive, 2) unifying features such as recurring motive or consistency deriving from a coherent poetic context, the analysis Schumann’s work can be made by its features. One can conclude that though the poetic contents of Schumann's song cycle Dichterliebe op.48 may lack consistency, it is apparent that the closely related keys of its individual songs form a cyclic relationship, and the songs are connected through various modulation techniques. The focus of this article lies on enlightening the musical context of Dichterliebe op.48, by analyzing how connections are made between musical pieces, as well as observing various modulation techniques manifested in each piece. Another focal point that should be recognized in this paper is the organic relation formed in the song cycle by its individual songs. This was elaborated by examining the relations between the tonal organization of each separate song and that of the entire song cycle. This article categorizes the individual songs consisting Dichterliebe op.48 into two structures, one being 'a single tonal structure' and the other referred to as 'a mode mixture tonal structure'. For further scrutiny, the paper has also divided the modulation methods by its form. The three categories are as follows: 1) the T-T(T-T") type: the song begins and ends with a tonic, 2) the X-T(X-T') type: the song begins with a tonic and ends with a parallel key of the tonic, 3) the X-Y type : the song neither starts nor ends with a tonic. The types of modulation revealed in Dichterliebe op.48 also varied. Modulations were progressed within limited boundaries, i.e. the Circle of Fifths (dominant and subdominant keys), the Circle of Thirds (related keys, median key, submedian key), and thus accordingly appeared in the form of diatonic modulation, chromatic modulation or enharmonic modulation. The modulation methods used to connect individual songs feature a limited range of keys-starting from relative keys to remote keys, as well as characterized by the use of diatonic pivot cords, mode mixture chords, Neapolitan chords, Augmented 6th chords, and chromatic pivot chord modulation using secondary dominant and enharmonic pivot chords. In addition, the use of chromatic common tone modulation for 3rd related keys and mode mixture chord for Neopolitan keys are noticeable within individual songs. Through this study, The organic relationship has been derived from thorough analysis of the song cycle, the analysis indicating that the tonal structure of each individual song and that of the song cycle are similar, and the modulation techniques applied are alike. Thus, these similar techniques and structure have resulted in creating a cyclic structure.

벌크 다결정 SnS / PEDOT:PSS 박막 이중층에서의 변조 도핑을 통한 열전 역률 강화

이동욱 대한금속·재료학회 2022 대한금속·재료학회지 Vol.60 No.7

Modulation doping occurs in a heterojunction where a charge carrier-rich material transfers charge to a carrier-deficient material. The modulation-doped material is intentionally selected to have higher charge carrier mobility than the modulation dopant material, so that the overall electrical conductivity can be boosted. Although this modulation doping strategy has proven effective in enhancing power factor in thermoelectrics, selection criteria for such semiconductor couples have not been explicitly clarified, resulting in only a few discovered semiconductor couples available for modulation doping-driven thermoelectric systems [1-4]. Here, we (i) report an electronic band structure-based guideline to actualize modulation doping, (ii) reveal that hole-rich PEDOT:PSS can modulation dope otherwise undoped tin monosulfide (SnS) in their bilayered structure, (iii) prove that modulation doping is responsible for thermoelectric power factor enhancement by comparing computational and experimental Seebeck coefficient and electrical conductivity values. The optimized PEDOT:PSS thin film / SnS pellet bilayered structure had a 134.7 fold improvement in electrical conductivity and a 93.6 fold power factor enhancement over those of undoped SnS, with only a ~ 20 % decrease in Seebeck coefficient. The modulation doping effect can result in further power factor improvement when SnS becomes a nanoscale thin film or nanoparticles in the future.

정 진폭 다중 보호 이진 직교 변조

홍대기,강성진,주민철,김용성,서경학,조진웅,Hong Dae ki,Kang Sung jin,Ju Min chul,Kim Young sung,Seo Kyeung hak,Cho Jin woong 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.3C

본 논문에서는 다중 부호 신호 (MC: multi-code signal)를 정 진폭으로 전송하는 정 진폭 이진 직교 다중 부호 변조 방식 (CABM: constant-amplitude biorthogonal multi-code modulation)을 제안한다. 정 진폭을 유지하기 위해 제안된 CABM 방식에서는 잉여 비트를 사용하여 신호를 부호화 하였다. 제안된 CABM 변조 방식은 매우 높은 스펙트럼 효율을 지원할 수 있다. 또한 본 논문에서는 제안된 CABM 신호를 복조하기 위한 다양한 복조 방식들을 제시하고 기존의 정 진폭 직교 변조 방식 (CAOM: Constant-amplitude orthogonal multi-code modulation)과 그 성능을 비교한다. 제안된 CABM 변/복조 방식은 고속 데이터 율을 제공해야 하는 디지털 무선 통신 시스템으로 사용될 수 있다. In this paper, we propose a biorthogonal modulation employing a constant-amplitude transmission of multi-code signals by introducing a simple constant-amplitude coding scheme with redundant bits. The proposed constant-amplitude biorthogonal multi-code (CABM) modulation can provide high spectral efficiency compared with a conventional direct sequence/spread spectrum (DS/SS) modulation. Nevertheless the proposed CABM modulation can keep up a constant-amplitude signal. Additionally, we propose various types of demodulation structures for the CABM modulation. Simulation results show that bit error rate (BER) performance and hardware complexity of the proposed CABM modulation are highly improved in comparison with those of a constant-amplitude orthogonal multi-code (CAOM) modulation.

Effects of amplitude modulation on perception of wind turbine noise

Kiseop Yoon,Doo Young Gwak,Yeolwan Seong,이승훈,홍지영,Soogab Lee 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

Wind turbine noise is considered to be easily detectable and highly annoying at relatively lower sound levels than other noise sources. Many previous studies attributed this characteristic to amplitude modulation. However, it is unclear whether amplitude modulation is the main cause of these properties of wind turbine noise. Therefore, the aim of the current study is to identify the relationship between amplitude modulation and these two properties of wind turbine noise. For this investigation, two experiments were conducted. In the first experiment, 12 participants determined the detection thresholds of six target sounds in the presence of background noise. In the second experiment, 12 participants matched the loudness of modified sounds without amplitude modulation to that of target sounds with amplitude modulation. The results showed that the detection threshold was lowered as the modulation depth increased; additionally, sounds with amplitude modulation had higher subjective loudness than those without amplitude modulation.