• 한국통신학회논문지
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• 제17권11호
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• pp.1299-1310
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• 1992

최근에, 디지탈 데이터 전송을 위한 수신기 타이밍 검출 회로의 디지탈화에 관한 관심이 점점 증가하고 있다. 타이밍 검출 회로의 디지탈화의 결과로 인하여, 타이밍 에러 검출을 위한 새로운 디지탈 알고리즘이 필요하게 된다. 본 논문에서는, 직접 QPSK변조 기법에 적용할 수 있는 Angular Form(AF) Algorithm을 제시하였다. AF Algorithm은 기본적으로 복조된 각 (Detected Angle)과 천이논리표 (Transition Logic Table)등의 개념을 근거로 하여 개발되었다. Gaussian과 Impulsive 잡음을 모델링하여, 이들 두 잡음환경하에서 Monte-Carlo 시뮬레이션을 통하여 알고리즘 성능평가를 하였다. 성능평가 결과, AF Algorithm이 Gardner Algorithm보다 BER, RMS Jitter, S-curve등에서 성능이 개선됨을 알 수 있었다.

• 대한방사선기술학회지:방사선기술과학
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• 제42권3호
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• pp.175-180
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• 2019

In this study, we have researched the effectiveness of silicone pad. A distribution of scatter ray in mammography was evaluated using Monte-Carlo (MC) simulation technique and then a silicone pad was applied to remove the scatter ray for improving image quality. Molybdenum target and Molybdenum filter combination made a difference of 59.8% to a number of photon at 17.5 keV. On the other hand, Tungsten target and Rhodium filter showed a variation of 24.5% at 20 keV. Mean 68 of SNR was increased in Selenia and mean 1.04 of SNR was raised in Senographe. Silicone pad was significantly effective to reduce the scatter ray that was generated by primary X-ray. It can decrease an absorption rate of scatter ray to patient body and whilst it improve the image quality from increasing SNR.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.539-545
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• 2019

Yttrium-90 is a useful therapeutic radioisotope for tumor treatment because of its high-energy-emitting beta rays. However, it has been difficult to select appropriate collimators and main energy windows for Y-90 Bremsstrahlung imaging using gamma cameras because of the broad energy spectra of Y-90. We used a Monte Carlo simulation to investigate the effects of collimator selection and energy windows on Y-90 Bremsstrahlung imaging. We considered both MELP and HE collimators. Various phantoms were employed in the simulation to determine the main energy window using primary-to-scatter ratios (PSRs). Imaging performance was evaluated using spatial resolution indices, imaging counts, scatter fractions, and contrast-to-noise ratios. Collimator choice slightly affected energy spectrum shapes and improved PSRs. The HE collimator performed better than the MELP collimator on all imaging performance indices (except for imaging count). We observed minor differences in SR and SF values for the HE collimator among the five simulated energy windows. The combination of an HE collimator and improved-PSR energy window produced the best CNR value. In conclusion, appropriate collimator selection is an important component of Bremsstrahlung Y-90 photon imaging and main energy window determination. We found HE collimators to be more appropriate for improving the imaging performance of Bremsstrahlung Y-90 photons.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1330-1338
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• 2024

Information on isotopic composition and geometric structure is necessary for identifying a true warhead. Nevertheless, such classified information should be protected physically or electronically. With a novel Hash encryption algorithm, this paper presents a Monte Carlo-based design of a neutron activation analysis verification module. The verification module employs a thermal neutron source, a non-uniform mask (physically encrypting information about isotopic composition and geometric structure), a gamma detector array, and a Hash encryption algorithm (for electronic encryption). In the physical field, a non-uniform mask is designed to distort the characteristic gamma rays emitted by the inspected item. Furthermore, as part of the Hash algorithm, a key is introduced to encrypt the data and improve the system resolution through electronic design. In order to quantify the difference between items, Hamming distance is used, which allows data encryption and analysis simultaneously. Simulated inspections of simple objects are used to quantify system performance. It is demonstrated that the method retains superior resolution even with 1% noise level. And the performances of anti-statistical attack and anti-brute force cracking are evaluated and found to be very excellent. The verification method lays a solid foundation for nuclear disarmament verification in the upcoming era.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.106-109
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• 1998

Wireless communication systems, in particular, must operate in a crowded electro-magnetic environmnet where in-band undesired signals are treated as noise by the receiver. These interfering signals are often random but not Gaussian Due to nongaussian noise, the distribution of the observables cannot be specified by a finite set of parameters; instead r-dimensioal sample space (pure noise samples) is equiprobably partitioned into a finite number of disjointed regions using quantiles and a vector quantizer based on training samples. If we assume that the detected symbols are correct, then we can observe the pure noise samples during the training and transmitting mode. The algorithm proposed is based on a piecewise approximation to a regression function based on quantities and conditional partition moments which are estimated by a RMSA (Robbins-Monro Stochastic Approximation) algorithm. In this paper, we develop a diversity combiner with modified detector, called Non-Linear Detector, and the receiver has a differential phase detector in each diversity branch and at the combiner each detector output is proportional to the second power of the envelope of branches. Monte-Carlo simulations were used as means of generating the system performance.

• 한국통신학회논문지
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• 제41권3호
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• pp.304-306
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• 2016

본 논문에서는 펄스 재머의 영향에 대해 코히런트 무선 광통신 시스템에서 비트오류율을 분석한다. 유도된 수식은 닫힌형태로 쉽게 코히런트 광 통신 시스템 성능을 확인할 수 있다. 또한 최적의 공격을 위한 재머를 작동시키는 심볼 시간 비율을 계산한다. 결과를 통해서, 유도된 비트오류율이 정확한 것을 확인한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.57-60
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• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.

• 대한전자공학회논문지
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• 제26권9호
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• pp.1453-1461
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• 1989

The modified ESPRIT(MESPRIT) method for harmonic retrieval is presented and analyzed. The estimation of frequencies of sinusoidal signals corrupted by white or colored measurement noise is considered for the MESPRIT method. Monte-carlo simulations are conducted for the comparison of MESPRIT method with TK method in terms of sampled mean, root mean square and relative bias.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.135-142
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• 2009

In this paper the Simplified Refined Instrumental Variable (SRIV) identification algorithm for SISO systems is extended to MIMO systems described by a Left Matrix Fraction Description (LMFD). The performance of the extended algorithm is compared to the well-known MIMO four-step instrumental variable (IV4) algorithm. Monte Carlo simulations for different signal to noise ratios are conducted to assess the performance of the algorithm. Moreover, the algorithm is applied to a simulated quadruple tank process.

• Journal of Electrical Engineering and information Science
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• 제1권2호
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• pp.39-44
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• 1996

An efficient interacting multiple mode(IMM) approach for tracking a maneuvering target with kinematic constraints is described based on the square root information filter(SRIF). The SRIF is employed instead of the conventional Kalman filter since it exhibits more efficient features in handling the kinematic constraints and improved numerical characteristics. The kinematic constraints are considered in the filtering process as pseudomeasurements where the degree of uncertainty is represented by the magnitude of the pseudomeasurement noise variance. The Monte Carlo simulations for the constant speed, maneuvering target are provided to demonstrate the improved tracking performance of the proposed algorithm.