• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.3A
• /
• pp.281-289
• /
• 2007

In this paper, a novel pseudo noise (PN) code acquisition scheme called the phase-shift-network-based differential sequential estimation (PDSE) is proposed, in the presence of data modulation in code division multiple access (CDMA) systems. The PDSE has even less complexity compared with that of the dual correlating sequential estimation (DCSE), and the reduction in complexity becomes more significant as the period of PN code increases. Numerical results demonstrate that the PDSE performs equivalently to the DCSE with less complexity.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.4
• /
• pp.1024-1040
• /
• 2014

The theoretical background and a numerical solution procedure for a time domain hydroelastic code are presented in this paper. The code combines a VOF-based free surface flow solver with a flexible body motion solver where the body linear elastic deformation is described by a modal superposition of dry mode shapes expressed in a local floating frame of reference. These mode shapes can be obtained from any finite element code. The floating frame undergoes a pseudo rigid-body motion which allows for a large rigid body translation and rotation and fully preserves the coupling with the local structural deformation. The formulation relies on the ability of the flow solver to provide the total fluid action on the body including e.g. the viscous forces, hydrostatic and hydrodynamic forces, slamming forces and the fluid damping. A numerical simulation of a flexible barge is provided and compared to experiments to show that the VOF-based flow solver has this ability and the code has the potential to predict the global hydroelastic responses accurately.

• Journal of Digital Contents Society
• /
• v.5 no.3
• /
• pp.219-224
• /
• 2004

In This paper, we have analyzed the power spectrum of DS-TH Ulhawideband (Direct Sequence-Time Hopping UWB) system which used pseudo-noise (PN) code. The DS-TH UWB system proposed in this paper multiplies the information signal with PN code to construct pulse train with random pattern and then the chips in pulse train are bundled into several groups to map to the particular value. The (+)/(-) pulse is tented in the time slot of frame by comparing a particular value with timing information that was stored in the lookup table. Thus, the energy spark (Comb Line) which is generated certainly in convantional system can be suppressed efficiently by PN code. And we knew that the proposed DS-TH UWB System even could have very smoothing power spectrum ctaracteristic without applying high speed Time-Hopping code.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.24 no.2
• /
• pp.59-64
• /
• 2024

The small tracking radar randomly changes the transmission period to avoid deceptive signals such as RGPO (Range Gaet Pull Off) operated on the target. Since the code repeats after a specific section, it becomes difficult to avoid a deceptive signal when the repetition is exposed. In this paper, a more realistic transmission pulse code is generated by adding random code generation through FPGA and system white noise. We present the research results of code generation that generates PRF that can avoid repetition while using pseudo-random code in EPROM using FPGA. Also, the result of designing random PRF pulse was confirmed by applying it to tracking radar.

• Journal of KIISE:Software and Applications
• /
• v.33 no.10
• /
• pp.886-895
• /
• 2006

Fingerprint classification reduces the number of matches required in automated fingerprint identification systems by categorizing fingerprints into a predefined class. Support vector machines (SVMs), widely used in pattern classification, have produced a high accuracy rate when performing fingerprint classification. In order to effectively apply SVMs to multi-class fingerprint classification systems, we propose a novel method in which SVMs are generated with the one-vs-all (OVA) scheme and dynamically ordered with $na{\ddot{i}}ve$ Bayes classifiers. More specifically, it uses representative fingerprint features such as the FingerCode, singularities and pseudo ridges to train the OVA SVMs and $na{\ddot{i}}ve$ Bayes classifiers. The proposed method has been validated on the NIST-4 database and produced a classification accuracy of 90.8% for 5-class classification. Especially, it has effectively managed tie problems usually occurred in applying OVA SVMs to multi-class classification.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.10A
• /
• pp.816-829
• /
• 2003

In this paper, we evaluate the performance of PN (Pseudo Noise) code based time hopping sequences for M-ary UWB (Ultra Wide Band) multiple access systems using the equicorrelated signal sets. In particular, we consider two different types of M-ary UWB systems in UWB indoor wireless multipath channels: The first type of the systems (System #1) has identical symbol transmission rate regardless of the number of symbols M since the length of signal pulse train is fixed while M increases, and the second type of the systems (System #2) has the same bit transmission rate regardless of M since the length of signal pulse train is extended according to the increase of M. We compare the proposed systems with those using the ideal random time hopping sequence in terms of the symbol error rate performance. Simulation results show that the PN code based time hopping sequence achieves quite good performance which is favorably comparable to that of the ideal random sequence. Moreover, as M increases, we observe that System #2 shows better robustness against multiple access interference than System # 1.

• Earthquakes and Structures
• /
• v.17 no.1
• /
• pp.39-48
• /
• 2019

This paper presents an experimental study on a 1/2 scale steel frame with archaized-style under the pseudo-dynamic loading. Four seismic waves, including El Centro wave, Taft wave, Lanzhou wave and Wenchuan wave, were input during the test. The hysteresis characteristic, energy dissipation acceleration response, displacement response, strength, stiffness and strain were analyzed. Based on the experiment, the elastoplastic dynamic time-history analysis was carried out with the software ABAQUS. The stress distribution and failure mode were obtained. The results indicate that the steel frame with archaized-style was in elastic stage when the peak acceleration of input wave was no more than 400 gal. Under Wenchuan wave with peak acceleration of 620 gal, the steel frame enters into the elastoplastic stage, the maximum inter-story drift was 1/203 and the bearing capacity still tended to increase. During the loading process, Dou-Gong yielded first and played the role of the first seismic fortification line, and then beam ends and column bottom ends yielded in turn. The steel frame with archaized-style has good seismic performance and meets the seismic design requirement of Chinese code.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.27 no.3
• /
• pp.139-145
• /
• 2023

It is essential to determine a proper earthquake time history as a seismic load in a seismic design for a critical structure. In the code, a seismic load should satisfy a design response spectrum and include the characteristic of a target fault. The characteristic of a fault can be represented by a definition of a type of possible earthquake time history shape that occurred in a target fault. In this paper, the pseudo-basis function is proposed to be used to construct a specific type of earthquake, including the characteristic of a target fault. The pseudo-basis function is derived from analyzing the earthquake time history of specific fault harmonic wavelet transform. To show the feasibility of this method, the proposed method was applied to the faults causing the Gyeong-Ju ML5.8 and Pohang ML5.3 earthquakes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.2A
• /
• pp.164-169
• /
• 2009

This paper presents a fast and accurate ranging algorithm for the WiBro system. The proposed algorithm detects a received ranging code and estimates its propagation delay using the correlation characteristics of the PRBS (Pseudo Random Binary Sequence) and the circular shift property of the discrete Fourier transform operator. The proposed ranging algorithm was applied to array antenna systems to show how it could improve the ranging performance of an array antenna system compared to a conventional base station system, which uses only a single antenna.

• Journal of Information Processing Systems
• /
• v.14 no.6
• /
• pp.1331-1346
• /
• 2018

Aiming at the problem that the gradient-based edge detection operators are sensitive to the noise, causing the pseudo edges, a triqubit-state measurement-based edge detection algorithm is presented in this paper. Combing the image local and global structure information, the triqubit superposition states are used to represent the pixel features, so as to locate the image edge. Our algorithm consists of three steps. Firstly, the improved partial differential method is used to smooth the defect image. Secondly, the triqubit-state is characterized by three elements of the pixel saliency, edge statistical characteristics and gray scale contrast to achieve the defect image from the gray space to the quantum space mapping. Thirdly, the edge image is outputted according to the quantum measurement, local gradient maximization and neighborhood chain code searching. Compared with other methods, the simulation experiments indicate that our algorithm has less pseudo edges and higher edge detection accuracy.