• Journal of electromagnetic engineering and science
• /
• 제7권1호
• /
• pp.1-6
• /
• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• 한국통신학회논문지
• /
• 제22권6호
• /
• pp.1302-1310
• /
• 1997

In this paper, we propose a dynamic code allocation strategy using voice activity detection and evaluate the performance of a dynamic code allocation strategy using voice activeity detection in DS-CDMA system. Proposed method allocates code to mobile terminal according to the residual capacity computed by SIR in the base station. In hot spot traffic loading cell, we find that the performance of proposed method is better than that of a fixed code assignment strategy using voice activity detection. Also, we find that the proposed method provide much improvement in blocking probability against the dynamic code assignment strategy withoug voice activity detection.

• Nuclear Engineering and Technology
• /
• 제29권2호
• /
• pp.158-166
• /
• 1997

Integrated performance test of Chemical and Volume Control System was successfully performed in 1994. However, an extensive effort to correct hardware and software problems in the letdown line was required mainly due to the lack of adequate simulation code to predict the test accurately. Although the LTC computer code was used during the YGN 3'||'&'||'4 NSSS design process, the code can not satisfactorily predict the test due to it insufficient letdown line modeling. This study developed a numerical model to simulate the letdown test by modifying the current LTC code, and then verified the model by comparing with the test data. The comparison shows that the modified LTC computer code can predict the transient behavior of letdown system lese very well. Especially, the model was verified to be able to predict the "Stiction (composition of stick and friction)" phenomena which caused instantaneous fluctuations in the letdown backpressure and flowrate. Therefore, it is concluded that the modified LTC computer code with the ability of calculating the "Stiction" phenomena will be very useful for future plant design and test predictions.predictions.

• Journal of Positioning, Navigation, and Timing
• /
• 제7권1호
• /
• pp.1-14
• /
• 2018

The Global Positioning System (GPS) provides more accurate positioning estimation performance by processing L1 and L2 signals simultaneously through dual frequency signal processing technology at the L-band rather than using only L1 signal. However, if anti-spoofing (AS) mode is run at the GPS, the precision (P) code in L2 signal is encrypted to Y code (or P(Y) code). Thus, dual frequency signal processing can be done only when the effect of P(Y) code is eliminated through the L2 signal processing technology. To do this, a codeless technique or semi-codeless technique that can acquire phase measurement information of L2 signal without information about W code should be employed. In this regard, this paper implements L2 signal processing technology where two typical codeless techniques and four typical semi-codeless techniques of previous studies are applied and compares their performances to discuss the optimal technique selection according to implementation environments and constraints.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
• /
• pp.217-220
• /
• 2001

Turbo codes of long block sizes have been known to show very good performance in an AWGN channel and the turbo code has been strongly recommended as error correction code for IMT-2000 in 3GPP(3$^{rd}$ Ceneration Partnership Project). Recently, turbo codes of short block sizes suitable for real time communication systems have attracted a lot of attention. Thus in this paper we consider the turbo code of 1/3 code rate and short frame size of 192 bits in ITU-R channel model. We analyzed the performance of W-CDMA systems of 10MHz bandwidths employing RAKE receiver with not only MRC diversity but also turbo code..

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
• /
• pp.273-276
• /
• 2001

본 논문에서는 산업용으로 주로 사용되고 있는 바코드(code 73)글 비전시스템을 이용하여 자동으로 인식할 수 있는 알고리즘을 제안하였다. 제안된 알고리즘은 입력된 바코드 영상에 대해 회전에 관계없이 각도를 자동 추출하여, 모듈 (module)을 구성하는 화소들을 추출한다. 각 모듈에 대해 적응적인 방법으로 바(bar)와 스페이스(space)를 구성하는 엘리먼트(element) 값을 구하고, 심벌 문자들의 엘리먼트 값을 9개의 그룹으로 나누어 바코드 값을 인식한다. 여러 종류의 바코드 영상을 대상으로 모의실험을 수행하여, 제안한 알고리즘의 성능을 검증하였다.

• 한국통신학회논문지
• /
• 제22권3호
• /
• pp.506-514
• /
• 1997

In this paper, we implement digital circuit of despreading delay lock loop for GPS receiver. The designed system consists of Epoch signal generator, two 13bit correlators which correlates the received C/A code and the locally generated C/A code in the receiver, the C/A code generator which generates C/A code of selected satellite, and the direct digital clock synthesizer which generates the clock of the C/A code generator to control the phase and clock rate, the clock controller, and the clock divider. The designed circuit has the function of the acquisition and tracking by the autocorrelation characteristics of Gold code. The controller generates each other control signals according to the correlation value. The designed circuit is simulated to verify the logic functional performance. By using the simulator STR-2770 that generates the virtual GPS signal, the deigned FPGA chip is verified the circuit performance.

• 한국항공우주학회지
• /
• 제36권12호
• /
• pp.1180-1185
• /
• 2008

다단 연소를 수행하는 위성 발사체 액체 로켓 엔진의 예연소기 성능을 모사한 in-house code가 개발되고 검증되었다. CEA (Chemical Equilibrium with Applications)의 해석 알고리듬을 바탕으로 하여 예연소기의 화학 반응을 모델링 하였고, gas dynamics 모델링과 연동시켜 예연소기의 성능을 모사하였다. CEA와 비교한 결과 아주 높거나 아주 낮은 O/F ratio를 제외하고는 계산 값들이 거의 일치함을 보여 주었다. 또한 실제 엔진 (RD-8)의 성능곡선과 비교한 결과 개발된 in-house code의 계산 값들이 타당한 범위 내에서 모사되었고, 정상상태에서는 거의 비슷한 결과 값을 보였다.

• Nuclear Engineering and Technology
• /
• 제53권6호
• /
• pp.1893-1908
• /
• 2021

In light of the importance of helium production in influencing the behaviour of fast reactor fuels, in this work we present a burn-up module with the objective to calculate the production of helium in both in-pile and out-of-pile conditions tracking the evolution of 23 alpha-decaying actinides. This burn-up module relies on average microscopic cross-section look-up tables generated via SERPENT high-fidelity calculations and involves the solution of the system of Bateman equations for the selected set of actinide nuclides. The results of the burn-up module are verified in terms of evolution of actinide and helium concentrations by comparing them with the high-fidelity ones from SERPENT, considering two representative test cases of (U,Pu)O₂ fuel in fast reactor conditions. In addition, a code-to-code comparison is made with the independent state-of-the-art module TUBRNP (implemented in the TRANSURANUS fuel performance code) for the same test cases. The herein presented burn-up module is available in the SCIANTIX code, designed for coupling with fuel performance codes.

• 한국정보통신학회논문지
• /
• 제16권6호
• /
• pp.1187-1192
• /
• 2012

본 논문에서는 네 방향으로 스캔 방향을 늘려 QR코드 파인더를 인식하는 방법을 제안한다. QR코드 인식의 첫 과정은 파인더 인식이다. 만약 파인더를 인식하지 못한다면 QR코드를 인식 할 수 없다. 기존의 QR코드 인식방법은 정면에서 촬영하지 않으면 QR코드를 인식하지 못한다는 문제점을 가지고 있다. 이러한 문제점을 극복하기 위해서 네 방향으로의 스캔과 후보군 영상을 사용하여 정확하게 파인더의 위치를 찾는다. 또한 모폴로지 연산을 이용하여 파인더의 위치를 다시 추려낸다. 제안된 방법을 입증하기 위해 기존의 인식 방법과 비교 실험을 수행하였고 그 결과 제안한 방법이 기존 방법보다 QR코드 파인더 인식률에서 우수함을 입증하였다.