• Earthquakes and Structures
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• v.18 no.3
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• pp.297-312
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• 2020

The KiK-net by NIED is a vertical array measurement system. In the database of KiK-net, singular pulse waves were observed in the seismic record at the borehole of TTRH02 during the mainshock (the magnitude of Japan Meteorological Agency (M_J) 7.3, M_W 6.8) and aftershock (M_j 4.2) of Tottori-ken Seibu earthquake in 2000. Singular pulse waves were also detected in the seismic records at the borehole of IWTH25 during the Iwate-Miyagi Nairiku earthquake in 2008 (M_J 7.2, M_W 6.9). These pulse waves are investigated by using the wave shape analysis methods, e.g., the non-stationary Fourier spectra and the double integrated displacement profiles. Two types of vibration modes are discriminated as the occurrence mechanism of the singular pulse waves. One corresponds to the reversal points in the displacement profile with the amplitude from 10^-4 m to 10^-1 m, which is mainly related to the fault activity and the amplification pass including the mechanical amplification (collision) of the seismograph in the casing pipe. The other is the cyclic pulse waves in the interval of reversal points, which is estimated as the backlash of the seismograph itself with the amplitude from 10^-5 m to 10^-4 m.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1426-1432
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• 2018

This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 photo-multiplier and a homemade preamplifier. The detector qualities which include the energy linearity, efficiency response and neutron/gamma discrimination are guaranteed for neutron detection in the energy range from 0 to 3000 keVee. Regarding the neutron/gamma discrimination capability, four pulse shape discrimination (PSD) methods which are the threshold crossing time (TCT), pulse gradient analysis (PGA), charge comparison (CC) and correlation pattern recognition (CPR), were evaluated and discussed; among of these, the CPR method provides the best neutron/gamma discrimination.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.2
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• pp.113-120
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• 2021

The Distance Measuring Equipment (DME) is a ground-based aircraft navigation system and is considered as an infrastructure that ensures resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS) outage. The main problem of DME as a GNSS back up is a poor positioning accuracy that often reaches over 100 m. In this paper, a novel approach of applying deep reinforcement learning to a DME pulse design is introduced to improve the DME distance measuring accuracy. This method is designed to develop multipath-resistant DME pulses that comply with current DME specifications. In the research, a Markov Decision Process (MDP) for DME pulse design is set using pulse shape requirements and a timing error. Based on the designed MDP, we created an Environment called PulseEnv, which allows the agent representing a DME pulse shape to explore continuous space using the Soft Actor Critical (SAC) reinforcement learning algorithm.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.283-285
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• 2007

본 논문에서는 WCDMA 환경에서의 수신기 Filter에 의한 SNR개선에 대해 연구하였다 WCDMA환경에서 여러 사용자의 다중경로 신호들이 더해져서 수신되는데 원하는 사용자에 동기를 맞춰 chip rate의 정수배로 sampling하고 수신기 필터를 통과시킴으로써 배율 정도에 따른 이득을 얻게 된다. 하지만 송신 신호의 pulse shape에 따라 이득이 달라진다. pulse shape에 따라 필터에 대한 윈하는 사용자 신호와 AWCN의 아득이 서로 달라지고 SNR이득이 포화되는 시점도 다르기 때문이다. 따라서 pulse shape에 따라 최적의 SNR이득을 얻기 위한 최적의 sampling 배출을 구할 수 있다. 분 논문에서는 signal shape에 따른 SNR 이득에 대해 해석식 도출 및simulation을 통해 최적 수신기 구조를 도출하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.42-45
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• 1994

In this paper, we will report on the effect of the pointed end shape of an electrode, discharge energy, pulse width and discharge current on machining characteristics. The results obtained are as tollows: 1)As the discharge Energy increases, the diameter and the depth of the discharged crater becomes larger and deeper. 2) The discharge energy is not constant during discharge but varies depending on the pointed end shape of th8 electrode. 3) The shape of crater depends on the pulse width and discharge current.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.173-180
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• 2016

This paper presents a method to suppress multipath induced by pulses using supervised learning. In modern electronics, pulses have been used for various purposes such as communication or distance measurements. Like other signals, pulses also suffer from multipath. When a pulse and a multipath are overlapped, the original pulse shape is distorted. The distorted pulse could result in communication failures or distance measurement errors. However, a large number of samples available from a pulse can be used to effectively reject multipath by using a supervised learning method. This paper introduces how a supervised learning method can be applied to Distance Measuring Equipment. Simulation results show that multipath induced distance measuring error can be suppressed by 10 ~ 45 percent depending on the allowed pulse shape variation allowed in a standard.

• 전기의세계
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• v.11
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• pp.14-17
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• 1963

정확하게 control된 pulse의 용도는 과학과 공업이 발달될수록 날로 많아져 가고 있는데 그의 일부는 대전력을 취급하는 경우로서, Radar에 대한 응용을 들 수 있다. 한편, 요지음 gallium-arsenide등 반도체 diode를 사용해서 Laser action을 일으킬 수 있다는것이 발견되어 G.E. 및 IBM등에서 개발되고 있다. 이 경우에, continuous emission도 가능하지만 흔히, intermittent operation을 시켜야 할 때가 많기 때문에 timed pulse source가 필요하게 된다. 또 한편, spot welding의 경우에도 이러한 pulse source가 필요하게 된다. 이들을 크게 나누어 source를 AC로 할 경우와 DC로 할 경우가 있는데, 전자의 경우는 thyratron을 사용할 경우가 많게 될 것이다. DC의 경우나 AC의 경우에나 잘 shape되고 time된 pulse source를 만들어 놓으면 진공관이나 thyratron이나 같은 모양으로 drive할 수 (thyratron의 경우는 trigger)있을 것이기 때문에, 이러한 pulse source를 만들 필요가 있게 된다.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.4
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• pp.155-160
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• 2003

In this study, an Alexandrite laser system for hair removal adopting a multi-discharge method in which three flash lamps are turned on consecutively was designed and fabricated to examine the pulse width and the pulse shape of the laser beams depending upon the changes in the lamp turn-on time. Specifically, this study demonstrates a technology that makes it possible to formulate various pulse shapes by turning on three flashlamps consecutively on a real-time basis with the aid of a PIC (program integrated circuit) one-chip microprocessor. With this technique, the lamp turn-on delay time can be varied more diversely from 0 to 10 ms and real-time control is possible with an external keyboard, enabling an assortment of pulse shapes. In addition, longer pulses can be more widely used for industrial processing as well as for numerous medical purposes.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1677-1686
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• 2023

As the demand for the detection of special nuclear materials (SNMs) increases, the use of imaging instruments that can sensitively image both gamma-ray and neutron signatures has become necessary. This study compared the pulse shape discrimination (PSD) performance of gamma/neutron events when employing either a pixelated stilbene or a plastic (EJ-276) scintillator array coupled to a silicon photomultiplier (SiPM) array in a dual-particle imager. The stilbene array allowed a lower energy threshold above which neutron and gamma-ray events can be clearly distinguished. A greater number of events can, therefore, be used when forming both gamma-ray and neutron images, which shortens the time required to acquire the images by nearly seven times.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.88-99
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• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Because it can generate up to 60kV pulse output voltage without any step- up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation and rectangular pulse shape. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. To reduce component for gate power supply, a simple and robust gate drive circuit is proposed. For gating signal synchronization, full bridge invertor and pulse transformer generates on-off signals of IGBT gating with gate power simultaneously and it has very good characteristics of short circuit protection.