• 제어로봇시스템학회논문지
• /
• 제22권11호
• /
• pp.977-983
• /
• 2016

This paper proposes a novel code-tracking scheme to track the fine code synchronization for BOC (pn,n)-modulated global navigation satellite system signals in a repeat-back jamming environment. The correlation function of BOC (pn,n)-modulated signals has several peaks. The correlation function in the advanced offset region remains almost unchanged due to the repeat-back signals being received later than a line-of-sight signal in the same multipath signal receiving case. Additionally, the combined pseudo-random noise signal can be treated as repeat-back jamming signals, like multipath signals. In this paper, we propose a novel code-tracking scheme utilizing the advantages of using a combined pseudo-random noise signal in the advanced offset region and verify its performance through simulation.

• 제어로봇시스템학회논문지
• /
• 제22권10호
• /
• pp.869-875
• /
• 2016

In this paper, a novel scheme with which to mitigate a repeat-back jamming effect is proposed for the GPS L1 coarse/acquisition signal. The proposed scheme estimates the code tracking bias caused by repeat-back jamming signals using a Combined Pseudo-random noise signal. It then mitigates the repeat-back jamming effect by subtracting the estimated code timing on a normal correlation channel from the estimated value. Through a Monte-Carlo simulation, the proposed scheme can diminish the running average of code tracking bias to less than 10% of the bias using the conventional scheme.

• 컴퓨터교육학회논문지
• /
• 제4권1호
• /
• pp.19-26
• /
• 2001

운영체제는 컴퓨터 시스템 자원의 관리 운용에 관한 과목으로서 컴퓨터 관련 전공자에게는 매우 중요하다. 운영체제의 내용 중에서 비동기 병행 프로세스 부분은 다른 부분에 비해서 매우 난이도가 높은 부분이다. 비동기 병행 프로세스 부분은 책의 설명이나 pseudo 코드만을 사용해서는 효과적인 학습효과를 거둘 수 없으므로 적절한 프로그래밍 언어로 구현된 병행 프로그램을 실행하는 것이 필요하다. 본 논문에서는 다양한 비동기 병행 코드를 자바 스레드로 구현하였고, 구현된 코드를 운영체제 교육에 활용할 것을 제안하였다.

• Structural Engineering and Mechanics
• /
• 제41권6호
• /
• pp.759-773
• /
• 2012

The objective of this paper is to present an energy-based method for calculating target displacement of RC structures. The method, which uses the Newmark-Hall pseudo-velocity spectrum, is called the "Pseudo-velocity Spectrum (PSVS) Method". The method is based on the energy balance concept that uses the equality of energy demand and energy capacity of the structure. First, nonlinear static analyses are performed for five, eight and ten-story RC frame structures and pushover curves are obtained. Then the pushover curves are converted to energy capacity diagrams. Seven strong ground motions that were recorded at different soil sites in Turkey are used to obtain the pseudo-acceleration and the pseudo-velocity response spectra. Later, the response spectra are idealised with the Newmark-Hall approximation. Afterwards, energy demands for the RC structures are calculated using the idealised pseudo-velocity spectrum. The displacements, obtained from the energy capacity diagrams that fit to the energy demand values of the RC structures, are accepted as the energy-based performance point of the structures. Consequently, the target displacement values determined from the PSVS Method are checked using the displacement-based successive approach in the Turkish Seismic Design Code. The results show that the target displacements of RC frame structures obtained from the PSVS Method are very close to the values calculated by the approach given in the Turkish Seismic Design Code.

• 대한전자공학회논문지SP
• /
• 제47권4호
• /
• pp.20-27
• /
• 2010

본 논문에서는 웨이블릿 패킷 변환(WPT) 기반의 컬러화 알고리즘에서 슈도랜덤코드(pseudo-random code) 정보의 삽입을 통해 복원된 컬러 영상에서 채도를 보상하는 방법을 제안한다. 우선 컬러 영상을 흑백 영상으로 변환하는 과정(컬러-그레이변환)에서 RGB 영상을 YCbCr 영상으로 변환한 후, Y 영상에 2레벨 웨이블릿 패킷 변환을 적용하여 정보량이 최소인 부영역(수평의 수직, 수직의 수평 부영역)에 CbCr 영상을 삽입한다. 이때 프린팅 및 스캐닝 과정에서 발생하는 채도 열화를 보상하기 위해 원본 영상 CbCr의 최대값 및 최소값을 슈도랜덤코드 형태로 변환하여 대각의 대각 부영역에 역시 삽입한다. 슈도랜덤코드는 CbCr의 최대값 및 최소값을 흰색 점의 개수로 표현한 영상으로, 컬러 복원 과정(그레이-컬러변환)에서 이를 추출하여 원본의 CbCr 최대값 및 최소값과 복원 영상의 CbCr 최대값 및 최소값과의 비를 가중치로 이용함으로써 채도 보상 알고리즘을 수행한다. 실험을 통해 제안된 방법이 복원된 컬러 영상에서 채도를 향상시킴을 색차와 PSNR 수치로 확인할 수 있었다.

• 전자공학회논문지S
• /
• 제34S권8호
• /
• pp.37-44
• /
• 1997

We implemented a code searcher which is used for the PN(pseudo noise) code acquisition in CDMA cellular mobile station. To reduce the reuired hardware and the code acquisition time, we used the double dwell structure which is an effective serial code acquisition metho. We designed a code acquisition has acquired within 1/2 PN chip range. The code searcher is implemented using 0.8 micron code searcher is successfully working in CDMA cellular mobile station and it satisfies the code acquisition time specified in IS-95 standard.

• 전자공학회논문지 IE
• /
• 제44권3호
• /
• pp.23-34
• /
• 2007

각다중화 방법과 함께 널리 사용되고 있는 위상다중화의 방법으로 PSC(pseudo random code)를 제안하고 기존의 위상부호인 PRC(pure random code), ERC(equivalent random code), HAM(Hadamard matrix)등과 성능을 비교분석 하였다. 프로그램적으로 $32{\times}32$의 동일한 화소수로 각 위상부호를 발생시키고, 실제 광시스템에서 공간광변조기의 비선형적 위상변조 특성을 고려하여 0%, 5%, 10%, 15%, 20%, 25%의 에러율을 갖는 위상값을 의도적으로 부가함으로써 네 가지 형태의 위상부호들을 구한 다음 각각의 자기상관 및 상호상관 성분을 시뮬레이션 하였다. 이를 통해 위상부호간의 영상누화 및 신호대 잡음비를 비교, 분석하였다. 그 결과 $32{\times}32$의 화소수에 대해서는 PSC의 상호상관에 의한 평균값이 0.067로 다른 형태의 위상부호들의 신호대 잡음비와 비교하여 가장 작게 나타났으며, 임의의 어드레스빔에 의한 순간적인 영상누화를 나타내는 표준편차값도 PSC가 0.0113으로 가장 작게 나타났다. 또한, 어드레스의 빔크기에 해당되는 화소수를 $32{\times}32$, $64{\times}64$, $128{\times}128$, $256{\times}256$ 등과 같이 변화시키면서 화소수에 따른 영향을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권10호
• /
• pp.5144-5160
• /
• 2019

Secret sharing is an effective way of protecting secret messages. However, the traditional secret sharing schemes are considered meaningless due to malicious people attention which might raise risks. To overcome the weakness, this paper presents an effective secret sharing scheme with the functionality of cheater identification, based on meaningful QR code. The secret message will be split and concealed in the padding region of cover QR codes with the assistance of Latin square and it can be completely restored when all the involved participants cooperate. The concealing strategy exploits the characteristic of Reed-Solomon (RS) code to ensure the strong robustness of generated QR code pseudo-shares. The meaningful QR code pseudo-shares help to reduce the curious of unrelated persons. Some experiments were done to evaluate the performance of proposed scheme. The results showed that the proposed scheme is feasible, efficient and secure compared to the other existing schemes. It also achieves a higher secret payload and maintains stronger robustness.

• Journal of Positioning, Navigation, and Timing
• /
• 제4권3호
• /
• pp.107-114
• /
• 2015

Binary Offset Carrier (BOC) signal planned for future Global Navigation Satellite System (GNSS) provided better positioning accuracy and smaller multipath error than GPS C/A signal. However, due to the multiple side peaks in the auto-correlation function (ACF) of the BOC modulated signals, a receiver may false lock onto one of the side peaks in the tracking mode. This false lock would then result in a fatal tracking error. In this paper, we propose an unambiguous tracking method for composite BOC (CBOC) signals to mitigate this problem. It aims to reduce the side peaks of the ACF of CBOC modulated signals. It is based on the combination of traditional CBOC correlation function (CF) and reference CF of unmodulated pseudo- random noise code (PRN code). First, we present that cross-correlation function (CCF) with unmodulated PRN code is close to the secondary peaks of the traditional CBOC. Then, we obtain an unambiguous correlation function by subtracting traditional CBOC ACF from these CFs. Finally, the tracking performance for the CBOC signals is examined, and it is shown that the proposed method has better performance than the traditional unambiguous tracking method in additive white Gaussian noise (AWGN) channel.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2002년도 춘계 학술발표회 논문집
• /
• pp.250-257
• /
• 2002

Pseudo dynamic test is an on-line computer control method to achieve the realism of shaking table test with the economy and versatility of the conventional quasi-static approach Pseudo dynamic tests of six full-size RC bridge piers have been carried out to investigate their seismic performance. For the purpose of precise evaluation, the experimental investigation was conducted to study the seismic performance of the real size specimen, which is constructed for highway bridge piers in Korean peninsula. Since it is believed that Korea belongs to the moderate seismicity region, five test specimens were designed in accordance with limited ductility design concept. Another one test specimen was nonseismically designed according to a conventional code. Important test parameters were transverse reinforcement and lap splicing. Lap splicing was frequently used in the plastic hinge region of many bridge columns. Furthermore, the seismic design code is not present about lap splice in Korean Roadway Bridge Design Code. The results show that specimens designed according to the limited ductility design concept exhibit higher seismic resistance. Specimens with longitudinal steel lap splice in the plastic hinge region appeared to significantly fail at low ductility level.