• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.115-116
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• 2006

UWB 시스템은 실내 LBS 에 가장 유망한 기술로 각광받고 있다. 그러나 실내건물을 이루는 손실성 매질로 인해서 신호에 지연이 발생, 거리오차가 발생하게 된다. 본 문제를 해결하기 위해서 공기중의 채널과 매질의 채널정보를 통해서, 신호의 지연을 추정하려고 하였다. 신호의 스팩트럼의 주파수에 관한 손실기울기는 투과한 매질의 두께에 비례하여, 깊어진다는 것을 사용하여, 매질 투과로 인한 신호의 지연시간을 추정하는 기술과 손실기울기를 측정하기 위한 RAKE 수신기를 소개한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.431-433
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• 2018

This paper proposes the system that offer super-wideband speech which is made by artificial bandwidth extension technique using wideband speech signal in time-domain. wideband excitation signal and line spectrum pair(LSP) are extracted based on source-filter model in time-domain. Two parameters are extended by each bandwidth extension algorithms, and then, super-wideband speech parameters are estimated. and synthesized. Subjective test shows super-wideband speech is better speech quality than wideband speech signal.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.33-42
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• 2007

The current left-turn split model adopted in COSMOS has an inherent limitation when a loop detector in the left-turn lanes was disconnected for a period of time. In this instance, the current model always allocated minimum green time to the left-turn phase, thus optimal split and efficient signal operation for the intersection was not guaranteed. In this paper, four mathmatical models using detector information of the intersection and four empirical models using historical profiles were developed and investigated for different traffic conditions to improve the operational efficiency of the intersection. From the model evaluation test, the empirical model using a four-week historical profile produced the least error among the eight models investigated. NETSIM simulation test results also showed that the proposed model could give significantly reduced delay time as compared to the current model. From these results, the operational efficency of the signalized intersections under the real-time control can be greatly improved by using the model proposed in case of the left-turn detector failure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.909-915
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• 2008

Researches for time delay estimation had been studied broadly. However studies about factors for time delay estimation are insufficient, especially in case of real environment application. In 1997, Brandstein and Siverman announced that performance of time delay estimation deteriorates as reverberant time of room increases. Even though reverberant time of room is same, performance of estimation is different as the specific part of signals. In order to know that reason, we studied and analyzed the factors for time delay estimation using speech signal and room impulse response. In result, we can know that performance of time delay estimation is changed by different R/D ratio and signal characteristics in spite of same reverberant time.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.480-487
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• 2003

To improve environmental control in various plants, signal characteristics of plants have been studied by a nondestructive technique. In this paper, the acoustic emission (AE) from plants was analyzed for water stress dependency. AE signals were taken from gymnosperm and angiosperm. AE sensor detected AE signals from the plant stem underneath the plant surface below the sensor. AE hit-event counts in daytime were more than those in night time, and it was found that the daily hit counts pattern was strongly affected by the water stress in the plant. frequency bands of AE signals from the angiosperm was different from those from the gymnosperm. Frequency bands of AE in outdoor condition were in accord with those in indoor having similar conditions.

• 전기의세계
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• v.44 no.3
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• pp.3-8
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• 1995

신호처리 방법이 다양해지고 복잡해짐에 따라서, 신호를 보다 정확하게 처리하고자 하는 관심이 높아지고 있다. 특히, 실세계에 존재하는 신호들의 통계적특성이 비정상성을 나타내고 있기 때문에 이를 위한 새로운 해석방법이 많이 연구되고 있다. 본 글에서는 최근들어서 신호처리의 여러 영역에서 사용되고 있는 웨이브렛 변환과 웨이브렛 변환평면에서의 신호처리 기술에 대해서 언급하였다. 웨이브렛 변환은 고주파 신호성분에 대해서는 짧은 윈도우를 사용하므로써 시간분해능을 좋게하기 때문에 스파이크형태를 갖는 고주파 신호를 분리하기에 용이하게하고, 저주파 신호성분에 대해서는 긴 윈도우를 사용하므로써 주파수 분해능을 좋게하여 관측시간이 길어야 하는 저주파 신호의 분리가 용이하다. 특히, 하나의 모 웨이브렛의 병진과 스케일에 의해서 가변적인 윈도우가 생성되기 때문에 해석방법이 간단하며, 필터뱅크를 이용하여 구현하므로써 적은 연산량으로 손쉽게 구현이 가능하다는 장점을 갖고 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.655-657
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• 2010

현재 코골이를 방지하는 위한 기구로는 양압 산소호흡기, 스프레이, 전기자극기, 수술, 구강내 보조기구가 있으나 개인용으로 사용하기에는 가격이 너무 고가이어서 일반적인 코골이 환자에게 적용하기에는 무리가 있으며 사용자에 따라 부작용의 위험이 있다. 본 논문에서는 정확하고 안정적인 코골이 신호인식을 위해 시계열 분석방법을 통해서 선형적인 성질보다 비선형적인 성질이 강한 코골이 신호의 카오틱 신호 유무를 해석하였다. 본 논문에서 사용한 시계열 데이터는 30대 성인남자로부터 수면시간 6시간중중 발생하는 코골이 음성신호를 마이크를 통해 샘플링 주파수 22kHz, 모노 형태로 수집한 것이다. 위상공간의 궤적 분석, 매입차원에 의한 상관적분 분석, 파워 스펙트럼과 자기상관함수 분석 등의 정량 및 정성적 분석방법을 통해서 수집한 코골이 신호의 분석결과 신호가 부분적으로 주기적 성질을 가지는 카오스 신호임을 확인하였다.

• KIISE Transactions on Computing Practices
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• v.22 no.2
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• pp.113-118
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• 2016

The walking speed of handicapped people generally is slower than that of normal people. So it is difficult for them to cross at crosswalks within the allotted time provided by the traffic light. This problem can be solved by expanding the time of the traffic light. However, if the latency of the traffic light is increased without distinguishing the handicapped among all other pedestrians, the efficiency of traffic signal lights will decrease. In this paper, we propose a smart traffic signal connecting mechanism between the previous pedestrian traffic signal and a pedestrian's device (smartphone). This Smart pedestrian traffic light, through this mechanism, minimizes traffic congestion by providing additional walking time only to the handicapped among pedestrians. This crosswalk traffic light recognizes the handicapped using a technique called Internet of things (IOT). In this paper, we extract the data necessary to build an effective smart crosswalk traffic light mechanism through simulation techniques. We have extracted different kinds of traffic signal times with our virtual simulation environment to verify the efficiency of the smart crosswalk pedestrian traffic light system. This approach can validate the effective delay time of the traffic signal time through a comparison based on number of pedestrians.

• Journal of KSNVE
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• v.6 no.3
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• pp.341-347
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• 1996

Vibration analysis is one of the most powerful tools available for the detection and isolation of incipient faults in mechanical systems. The methods of vibration analysis in use today and under continuous study are broad band vibration monitoring, time domain analysis, and frequency domain analysis. In recent years, great interest has been generated concerning the use of time- frequency repesentation and its application for a machinery diagnostics and condition monitoring system. The objective of the study described in this paper was to develop a new diagnostic tool for the rotating machinery. This paper introduces a new time frequency representation. Directional Winger-Ville Distribution, which analyese the time-frequency structure of the rotating machinery vibration.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.8
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• pp.12-19
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• 2017

In this paper a super-resolution time delay estimation algorithm that estimates the time delays of spread spectrum signals using sparse signal reconstruction approach is introduced. So far, the correlation method has been mostly used to estimate the time delays of spread spectrum signals. However it fails to accurately estimate the time delays in the case where the signals are spaced within approximately 1 PN chip duration and a further processing should be applied to the correlation outputs in order to enhance the resolution capability. Recently sparse signal approaches attract much interest in the area of directions-of-arrival estimation, of which SPICE is the most representative. Thus we introduce a super-resolution time delay estimation algorithm based on the SPICE approach and compare its performance with that of MUSIC algorithm by applying them to the ISO/IEC 24730-2.1 RTLS system.