• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4002-4018
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• 2023

An integrated neutron interrogation system has been developed for non-destructive assay of highly-radioactive special nuclear materials, to accumulate knowledge of the method through developing and using it. The system combines a differential die-away (DDA) measurement system for the quantification of nuclear materials and a prompt gamma-ray analysis (PGA) system for the detection of neutron poisons which disturb the DDA measurements; a common D-T neutron generator is used. A special care has been taken for the selection of materials to reduce the background gamma rays produced by the interrogation neutrons. A series of measurements were performed to test the basic performance of the system. The results show that the DDA system can quantify plutonium of as small as 20 mg and it is not affected by intense neutron background up to 1.57 × 10⁷ s^-1 and gamma ray of 4.43 × 10¹⁰ s^-1. The gamma-ray background counting rate at the PGA detector was reduced down to 3.9 × 10³ s^-1 even with the use of the D-T neutron generator. The test measurements show that the PGA system is capable of detecting 0.783 g of boron and about 86.8 g of gadolinium in 30 min.

• 한국항행학회논문지
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• 제21권2호
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• pp.179-186
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• 2017

본 논문은 항공용 다변측정 감시시스템의 감시영역으로 진입하는 항공기에 대해 능동적 공역확보를 위한 질문시나리오 구성이 가능한 질문기에 대한 것이다. 항공용 다변측정 감시시스템에서 질문기는 감시공역 내의 항공기를 향해 적절한 감시 시나리오로 질문을 수행하는데 사용하는 중요한 장치이다. 일정 반경 내에서 비행하는 항공기에 대해 질문하는 기존의 2차 감시레이다 (SSR; secondary surveillance radar)의 질문 방식과 달리, 항공용 다변측정 감시시스템은 감시범위에 진입하는 항공기에 대해 원거리에서 부터 근거리까지 순차적으로 또는 운용 시나리오에 따라 능동적으로 질문이 가능한 질문 시스템이 필요하다. 본 논문을 통해 구현된 질문기는 위스퍼-샤웃 제어 알고리즘을 적용하여 실제 운용거리에 따라 출력전력을 가변하여 방사함으로써 감시공역 별 항공기에 대한 질문 및 감시에 능동적으로 활용이 가능하다.

• Composites Research
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• 제20권6호
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• pp.21-27
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• 2007

복합재 보강판에 영구히 부착된 배열 압전 능동 센서를 사용하여 저속 충격 손상을 탐지하였다. 압전 능동센서를 사용하여 구조에 램파를 전파시키기 위한 다양한 진단신호를 생성하였으며, 손상으로 인한 구조 진동의 특성 변화를 탐지하기 위하여 그 응답을 측정하였다. 이 신호 변화 특징을 한 개의 손상 지수로 표현하기 위하여 3가지 알고리즘-ADI(Active Damage Interrogation), TD RMS (Time Domain Root Mean Square), STFT(Short Time Fourier Transform) -이 검토되었다. 손상 탐지시험을 수행하여, 사용한 기법과 진단신호로 저속 충격으로 인한 두 개의 층간분리를 탐지하였으며, 그 위치를 추정하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.571-577
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• 2000

This paper is designed for the identification system of the train using RFID(radio Frequency Identification) in the 134.2㎑. The reader of transmitter transmits an interrogation signal to the tag, then the tag of receiver retransmits the defined data to the reader after receiving the interrogation signal from it. The system is also applied to the reflection communication as a backscatter modulation and selected the passive Pouter system which does not need an active electrical power device. It is useful that ore can effectively manage and control of the information of train such as materials loaded in the train. We make the reader of the identification system for the train which can communicate with the tag installed under the train.

• 비파괴검사학회지
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• 제27권3호
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• pp.217-223
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• 2007

This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure.

• Smart Structures and Systems
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• 제5권4호
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• pp.457-468
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• 2009

A novel approach for integrating active sensing data interrogation algorithms for structural health monitoring (SHM) applications is presented. These algorithms cover Lamb wave propagation, impedance methods, and sensor diagnostics. Contrary to most active-sensing SHM techniques, which utilize only a single signal processing method for damage identification, a suite of signal processing algorithms are employed and grouped into one package to improve the damage detection capability. A MATLAB-based user interface, referred to as HOPS, was created, which allows the analyst to configure the data acquisition system and display the results from each damage identification algorithm for side-by-side comparison. By grouping a suite of algorithms into one package, this study contributes to and enhances the visibility and interpretation of the active-sensing methods related to damage identification. This paper will discuss the detailed descriptions of the damage identification techniques employed in this software and outline future issues to realize the full potential of this software.