Effective Separation Method for Single-Channel Time-Frequency Overlapped Signals Based on Improved Empirical Wavelet Transform

( Zhipeng Liu ),( Lichun Li ),( Huiqi Li ),( Chang Liu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.5

To improve the separation performance of time-frequency overlapped radar and communication signals from a single channel, this paper proposes an effective separation method based on an improved empirical wavelet transform (EWT) that introduces a fast boundary detection mechanism. The fast boundary detection mechanism can be regarded as a process of searching, difference optimization, and continuity detection of the important local minima in the Fourier spectrum that enables determination of the sub-band boundary and thus allows multiple signal components to be distinguished. An orthogonal empirical wavelet filter bank that was designed for signal adaptive reconstruction is then used to separate the input time-frequency overlapped signals. The experimental results show that if two source components are completely overlapped within the time domain and the spectrum overlap ratio is less than 60%, the average separation performance is improved by approximately 32.3% when compared with the classic EWT; the proposed method also improves the suitability for multiple frequency shift keying (MFSK) and reduces the algorithm complexity.

광흡수 신호가 완전 중첩된 조건에서 내재 흡수 면적 도출을 통한 2종 가스 농도 분석에 관한 연구

유미연(Miyeon Yoo),맹새롬(Saerom Maeng),소성현(Sunghyun So),이창엽(Changyeop Lee) 한국에너지기후변화학회 2016 에너지기후변화학회지 Vol.11 No.1

In a huge combustion system such as powerplant boiler, it is important to measure gas concentrations and internal temperatures precisely. The gas concentrations and temperatures is are the indispensable physical to operate and maintain the combustion system efficiently and to design a new combustion system. And the concentration of a combustion gas like CO₂ and CO can be a most important factor to indicate the energy efficiency of a large combustion system. TDLAS (Tunable Diode Laser Absorption Spectroscopy) method can be used to measure the gas concentration, temperature or speed of a gas with a diode laser. Absorption spectroscopy measurement measuring system with DFB(Distributed feed-back) diode laser can realize non-contacting and real-time measurement and semipermanent longevity. In this study, a TDLAS-based gas concentration measurement method was suggested to analyze the concentration of two gas species, CO₂ and CO, with a non-independent absorption signal.

표준규격 교통신호제어기에서 교통류별 전용신호구현방안 연구

한원섭,이호원,현철승,주두환,이철기 한국ITS학회 2009 한국ITS학회논문지 Vol.8 No.5

교통여건의 변화로 좌·우회전, 중앙버스 및 자전거 전용신호에 대한 요구가 증대되고 있다. 그러나 현재 운영되고 있는 표준규격 교통신호제어기는 4색등화기를 기반으로 하고 있어, 3색등화기의 방향별 차종별 전용신호를 운영하는 데 제약이 있다. 따라서 본 연구는 기존 표준 교통신호제어기에서 좌·우회전 및 중앙버스의 전용신호를 제어할 수 있는 물리적 소프트웨어적인 방안을 제시하였다. 물리적으로 보행 적, 보행 녹, 적, 황, 화살표 및 녹색등화의 6개 출력단자로 설계된 4색등화기의 신호등구동장치(LSU)를 적, 황, 녹색의 3개 씩 2단 배열로 그룹화 하여, 3색등화기의 전용신호로 사용하는 방안을 제시하였다. 소프트웨어적으로 신호 맵 데이터의 코드값을 3색등화기의 적1·황1·녹1·적2·황2·녹색2의 LSU 출력에 맞게 설정하여, 링별(A/B링) LSU별로 전용신호를 스텝별로 구동하는 방안을 제안하였다. 전용신호 도입 시의 운영효과를 중앙버스전용차로가 운영되고, 좌회전이 허용되는 서울시 망우역교차로를 대상으로 분석한 결과 버스전용차로가 운영되고 있는 주도로(동-서)에서 지체가 크게 개선되어 교차로 전체의 지체시간이 70초/대 이상 개선되는 것으로 분석되었다. According to the change of the traffic conditions, the requirement of controlling the separated left(or right) turn, the median bus lane and bicycle signal is increasing. However, the traffic signal controller standard based on the four-set lights restricts to control the three-set lights which control the separated direction and kind of traffics. This study suggests the method to control the three-set lights signal by improving the hardware and software for the traffic signal controller which is operated currently in the traffic scene. The 6 output ports of Load Signal Unit(LSU) which is consisted of Pedestrian Red, Pedestrian Green, Red, Yellow, Arrow and Green signal reconstitute 2 rows of the Red, Yellow, Green for three-set lights while the Signal Map data's code values which control the signal step of an individual Ring and LSU are established to adjust the LSU's output ports(R1·Y1·G1·R2·Y2·G2) of the three-set lights. The effect of using the separated through/left turn and the median lane bus signal of three-set lights is analyzed from a Mangwoo intersection in Seoul. The results of analysis show that the delay time of the east-west direction where the median bus lane is operated is especially improved with over 70 sec/veh.

중앙버스전용차로 버스전용신호 도입시 신호 최적화에 관한 연구

김보겸,김영찬,김승일,김진태 대한교통학회 2006 대한교통학회지 Vol.24 No.5

Seoul and many large cities in Korea have implemented Median Exclusive Bus Lane(MEB). But exclusive bus lane in the middle of the road caused new contradictions between left turn movement and through bus movement and several signal operation techniques like ‘left turn protected’ and ‘overlap phase’ couldn't be applied in intersections on MEB. We suggest ‘Bus-only Signal for median lane’ technique as solution of these problems.This study presents optimum signal time design process and detailed algorithms for intersections where bus-only signals are installed. As a test field, we took Yang-Je intersection where Median Exclusive Bus Lane go through, and have large gap in volume of left turn in main direction. And we verified that revised optimum signal time including overlap phase can reduce average delay time of vehicle through before and after simulation. 서울시를 포함한 수도권 각 도시는 중앙버스전용차로의 적극적인 도입으로 버스속도 및 정시성 향상을 통해 대중교통우선 처리 전략을 적극 추진 중에 있다. 그러나 이로 인해 중앙부 1~2개 차로를 버스전용차로가 차지함으로써 기존 신호운영체계에 큰 변화를 가져오게 되었다. 좌회전 차량과 중앙버스전용차로를 이용해 직진하는 버스 간에 새로운 상충이 발생하게 되어 동시신호 기법 등 교차로 신호운영대안이 줄어들게 된 것이다. 이 해결방안으로서 버스전용신호를 도입하여 중첩현시 및 동시신호 등 Dual-Ring방식의 다양한 신호 운영을 가능케 하는 방안이 모색되고 있다. 본 연구에서는 이러한 버스전용신호 도입 시 교차로 정체를 최소화할 수 있는 신호설계방법을 제시하였고, 중앙버스전용차로가 운영 중인 양재역사거리에 동 기법을 이용한 최적신호 설계를 적용, 시뮬레이션을 통해 그 효과를 검증하였다.

Measurement of Elastic Constants by Simultaneously SensingLongitudinal and Shear Waves as an Overlapped Signal

서호건,송동기,장경영 한국비파괴검사학회 2016 한국비파괴검사학회지 Vol.36 No.2

Measurement of elastic constants is crucial for engineering aspects of predicting the behavior of materials under load as well as structural health monitoring of material degradation. Ultrasonic velocity measurement for material properties has been broadly used as a nondestructive evaluation method for material characterization. In particular, pulse-echo method has been extensively utilized as it is not only simple but also effective when only one side of the inspected objects is accessible. However, the conventional technique in this approach measures longitudinal and shear waves individually to obtain their velocities. This produces a set of two data for each measurement. This paper proposes a simultaneous sensing system of longitudinal waves and shear waves for elastic constant measurement. The proposed system senses both these waves simultaneously as a single overlapped signal, which is then analyzed to calculate both the ultrasonic velocities for obtaining elastic constants. Therefore, this system requires just half the number of data to obtain elastic constants compared to the conventional individual measurement. The results of the proposed simultaneous measurement had smaller standard deviations than those in the individual measurement. These results validate that the proposed approach improves the efficiency and reliability of ultrasonic elastic constant measurement by reducing the complexity of the measurement system, its operating procedures, and the number of data

Measurement of Elastic Constants by Simultaneously Sensing Longitudinal and Shear Waves as an Overlapped Signal

Hogeon Seo,Dong-Gi Song,Kyung-Young Jhang 한국비파괴검사학회 2016 한국비파괴검사학회지 Vol.36 No.2

Measurement of elastic constants is crucial for engineering aspects of predicting the behavior of materials under load as well as structural health monitoring of material degradation. Ultrasonic velocity measurement for material properties has been broadly used as a nondestructive evaluation method for material characterization. In particular, pulse-echo method has been extensively utilized as it is not only simple but also effective when only one side of the inspected objects is accessible. However, the conventional technique in this approach measures longitudinal and shear waves individually to obtain their velocities. This produces a set of two data for each measurement. This paper proposes a simultaneous sensing system of longitudinal waves and shear waves for elastic constant measurement. The proposed system senses both these waves simultaneously as a single overlapped signal, which is then analyzed to calculate both the ultrasonic velocities for obtaining elastic constants. Therefore, this system requires just half the number of data to obtain elastic constants compared to the conventional individual measurement. The results of the proposed simultaneous measurement had smaller standard deviations than those in the individual measurement. These results validate that the proposed approach improves the efficiency and reliability of ultrasonic elastic constant measurement by reducing the complexity of the measurement system, its operating procedures, and the number of data.

디지털 위성통신중계기시스템에 적합한 다중채널 신호처리 알고리즘 분석

이정섭(Jung-sub Lee),홍근표(Keun-pyo Hong),진병일(Byoung-il Jin) 한국항공우주학회 2015 韓國航空宇宙學會誌 Vol.43 No.7

본 논문에서 디지털 위성통신중계기시스템에 적합한 다중채널 신호처리 알고리즘을 분석하였다. 위성통신중계기에 적합한 다중채널 신호처리 알고리즘을 찾는데 있어 본 논문에서는 완전복원 성능, 간섭제거시 성능, 알고리즘 별 리소스 사용량 그리고 전력소모예상량 비교 수행하였다. 이 네가지 분석기준에 따른 각 알고리즘별로 분석하여 디지털 위성통신중계기시스템에 적합한 다중채널 신호처리 알고리즘을 선정하고 제안한다. In this paper, Analyzed the multi-channel signal processing algorithms for digital-transponder. To analyze suitable multi-channel signal processing algorithms, compare algorithms about four criteria. Four criteria are as follows, perfect reconstruction, interference rejection, resource usage and power consumption. Analysis for each algorithm in accordance with these four criteria. then propose the multi-channel signal processing algorithms for digital satellite communication system.

Measurement of Elastic Constants by Simultaneously Sensing Longitudinal and Shear Waves as an Overlapped Signal

Seo, Hogeon,Song, Dong-Gi,Jhang, Kyung-Young The Korean Society for Nondestructive Testing 2016 한국비파괴검사학회지 Vol.36 No.2

Measurement of elastic constants is crucial for engineering aspects of predicting the behavior of materials under load as well as structural health monitoring of material degradation. Ultrasonic velocity measurement for material properties has been broadly used as a nondestructive evaluation method for material characterization. In particular, pulse-echo method has been extensively utilized as it is not only simple but also effective when only one side of the inspected objects is accessible. However, the conventional technique in this approach measures longitudinal and shear waves individually to obtain their velocities. This produces a set of two data for each measurement. This paper proposes a simultaneous sensing system of longitudinal waves and shear waves for elastic constant measurement. The proposed system senses both these waves simultaneously as a single overlapped signal, which is then analyzed to calculate both the ultrasonic velocities for obtaining elastic constants. Therefore, this system requires just half the number of data to obtain elastic constants compared to the conventional individual measurement. The results of the proposed simultaneous measurement had smaller standard deviations than those in the individual measurement. These results validate that the proposed approach improves the efficiency and reliability of ultrasonic elastic constant measurement by reducing the complexity of the measurement system, its operating procedures, and the number of data.

Mixing matrix estimation method for dual‐channel time‐frequency overlapped signals based on interval probability

Zhipeng Liu,Lichun Li,Ziru Zheng 한국전자통신연구원 2019 ETRI Journal Vol.41 No.5

For dual‐channel time‐frequency (TF) overlapped signals with low sparsity in underdetermined blind source separation (UBSS), this paper proposes an effective method based on interval probability to estimate and expand the types of mixing matrices. First, the detection of TF single‐source points (TF‐SSP) is used to improve the TF sparsity of each source. For more distinguishability, as the ratios of the coefficients from different columns of the mixing matrix are close, a local peak‐detection mechanism based on interval probability (LPIP) is proposed. LPIP utilizes uniform subintervals to optimize and classify the TF coefficient ratios of the detected TF‐SSP effectively in the case of a high level of TF overlap among sources and reduces the TF interference points and redundant signal features greatly to enhance the estimation accuracy. The simulation results show that under both noiseless and noisy cases, the proposed method performs better than the selected mainstream traditional methods, has good robustness, and has low algorithm complexity.

실험 데이터 기반 터보팬엔진 회전 신호 모사

김채연(Chae Yeon Kim),전하민(Ha Min Jeon),유강민(Kang Min Yu),유창경(Chang-Kyung Ryoo) 한국항공우주학회 2022 한국항공우주학회 학술발표회 논문집 Vol.2022 No.11