• Title/Summary/Keyword: Engineering Offsets

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Measurements of Socket roughness and Vertical Offsets for Large Foundations (대형기초의 굴착공벽면 거칠기 및 연직도 측정)

  • Park, Bong-Geun;Nam, Moon-S.;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2007.09a
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    • pp.105-114
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    • 2007
  • Recently, construction of high-rise buildings have been increased all around the world, and their foundation are designed to carry heavy loads form superstructures. For this reason, the use of drilled shafts have been increased, and the proper understanding of drilled shafts have been issued, especially for socket roughness and vertical offsets. In this study, the BKS-LRPS using laser sensor was developed for the measurement of socket roughness and vertical offsets for the first time in Korea. The BKS-LRPS was applied for measuring of socket roughness and also vertical offsets at the specific field sites. Based on this study, BKS-LRPS was successfully applied for measurement of socket roughness and vertical offsets the in the fields, and more appropriate quality control for the vertical offsets have to be needed.

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Evaluation of rigid-end offset effect on seismic behavior of a structure subjected to Van earthquake

  • Bekiroglu, Serkan;Sahina, Abdurrahman;Sevima, Baris;Ayvaz, Yusuf
    • Structural Engineering and Mechanics
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    • v.47 no.6
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    • pp.857-879
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    • 2013
  • Numerical damage assessment of Van train station building consisting of three RC blocks due to 2011 Van Earthquakes by nonlinear dynamic analysis is presented. The structural model is created with rigid-end offsets and plastic hinges for nonlinear analysis. Rigid-end offsets are considered for connection areas and proposed for wall-supported elements. In wall-supported elements, walls take place in a limited part of the columns. Nonlinear dynamic analysis of the building with and without rigid-end offsets is performed by using real earthquake records and results are compared. The results show that rigid-end offsets have significant effects on the seismic behavior of the structures.

Low-Complexity Watermarking into SAO Offsets for HEVC Videos

  • Wu, Xiangjian;Jo, Hyun-Ho;Sim, Donggyu
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.4
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    • pp.243-249
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    • 2016
  • This paper proposes a new watermarking algorithm to embed watermarks in thr process of sample adaptive offsets (SAO) for high efficiency video coding (HEVC) compressed videos. The proposed method embeds two-bit watermark into the SAO offsets for each coding tree unit (CTU). To minimize visual quality degradation caused by embedding watermark, watermark bits are embedded into SAO offset depending on the SAO types of block. Furthermore, the embedded watermark can be extracted by simply adding four offsets and checking their least significant bits (LSB) at the decoder side. The experimental results show that the proposed method achieves 0.3% BD-rate increase without much visual quality degradation. Two-bit watermark for each CTU is embedded for more bit watermarking. In addition, the proposed method requires negligible computational load for watermark insertion and extraction.

ICI Cancellation of OFDM System with Multiple Frequency offsets (직교 주파수 분할 다중화 시스템에서 다중 주파수 옵셋에 의한 채널간 간섭 제거기법)

  • Won, Yu-Jun;Seo, Bo-Seok
    • Journal of Broadcast Engineering
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    • v.15 no.2
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    • pp.217-223
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    • 2010
  • In this paper, an interchannel interference (ICI) cancellation method is proposed for multiple frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. When several same signals are received from different transmitters simultaneously, multiple frequency offsets may occur at the receiver because of the frequency difference of the oscillators of the two transmitters and the receiver. This causes degradation of system performance because OFDM systems are very sensitive to the frequency offsets. In this paper, we propose a method to eliminate the effect of the multiple frequency offsets for OFDM systems. The method is accomplished in two steps: compensation of the frequency offset in the time domain and subsequent cancellation of the ICI in the frequency domain. Through computer simulations, we verify the effectiveness of the proposed ICI cancellation method.

Defending and Detecting Audio Adversarial Example using Frame Offsets

  • Gong, Yongkang;Yan, Diqun;Mao, Terui;Wang, Donghua;Wang, Rangding
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.4
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    • pp.1538-1552
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    • 2021
  • Machine learning models are vulnerable to adversarial examples generated by adding a deliberately designed perturbation to a benign sample. Particularly, for automatic speech recognition (ASR) system, a benign audio which sounds normal could be decoded as a harmful command due to potential adversarial attacks. In this paper, we focus on the countermeasures against audio adversarial examples. By analyzing the characteristics of ASR systems, we find that frame offsets with silence clip appended at the beginning of an audio can degenerate adversarial perturbations to normal noise. For various scenarios, we exploit frame offsets by different strategies such as defending, detecting and hybrid strategy. Compared with the previous methods, our proposed method can defense audio adversarial example in a simpler, more generic and efficient way. Evaluated on three state-of-the-arts adversarial attacks against different ASR systems respectively, the experimental results demonstrate that the proposed method can effectively improve the robustness of ASR systems.

A Simplified Blind Decision Method of Modulation Type in impaired AWGN Channel Environment (Impaired AWGN 채널에서의 간단한 Blind 변조 신호 구분 방식)

  • Kim, Young-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.1
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    • pp.1-6
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    • 2007
  • In this paper, a simplified new modulation classification method that utilizes likelihood function for received signal in an impaired AWGN channel environment. The proposed method provides the superior to ML method, although the likelihood under the assumption that each modulated signal is sent utilized. On the other hand, the ML method gets the performance characteristics of high computational complexity and weakness to channel impairment such as phase offsets and frequency offsets. The proposed method has lower computational complexity than that of the ML method. Moreover, the proposed method is robust to the channel impairment such as phase offsets and frequency offsets. The correct classification probabilities of the proposed method and the ML method are given for an AWGN channel with phase offsets and frequency offsets, which were simulated with extensive Monte-Carlo simulation. As shown in simulation resole, a more accurate classification performance both in phase offset environment and in frequency offset can be achieved with the low computational complexity of the proposed method.

A Calibration Technique for Array antenna based GPS Receivers (배열 안테나 기반 GPS 수신기에서의 교정 방안)

  • Kil, Haeng-bok;Joo, Hyun;Lee, Chulho;Jeong, Eui-Rim
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.4
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    • pp.683-690
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    • 2018
  • In this paper, a new signal processing technique is proposed for calibrating gain, phase, delay offsets in array antenna based anti-jamming minimum variance distortionless response (MVDR) global-positioning-system (GPS) receivers. The proposed technique estimates gain, phase and delay offsets across the antennas, and compensates for the offsets based on the estimates. A pilot signal with good correlation characteristics is used for accurate estimation of the gain, phase and delay offsets. Based on the cross-correlation, the delay offset is first estimated and then gain/phase offsets are estimated. For fine delay offset estimation and compensation, an interpolation technique is used, and specifically, the discrete Fourier transform (DFT) is employed for the interpolation technique to reduce the computational complexity. The proposed technique is verified through computer simulation using MATLAB. According to the simulation results, the proposed technique can reduce the gain, phaes and delay offset to 0.01 dB, 0.05 degree, and 0.5 ns, respectively.

A Study on a Performance Progress of Direct-Conversion Receiver as removing DC offset. (Direct-Conversion 수신기에서 DC offset 제거에 따른 성능 개선에 관한 연구)

  • 김철성;박성진;조형래
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2000.10a
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    • pp.162-165
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    • 2000
  • This paper presents the analysis of the effect which DC offsets produced in the direct-conversion receiver system under the AWGN circumstance exercise on the system performance. Then, as a method which improve the system performance by removing the DC offsets, we proposed the plan which can copes with the time variant DC offsets occurrences according to taking accumulation and average through the loop signals which DC offsets are produced.

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Improvement in Electrical Stability of poly-Si TFT Employing Vertical a-Si Offsets

  • Park, J.W.;Park, K.C.;Han, M.K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.67-68
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    • 2000
  • Polycrystalline silicon (poly-Si) thin film transistors (TFT's) employing vertical amorphous silicon (a-Si) offsets have been fabricated without additional photolithography processes. The a-Si offset has been formed utilizing the poly-Si grain growth blocking effect by thin native oxide film during the excimer laser recrystallization of a-Si. The ON current degradation of the new device after 4 hour's electrical stress was reduced by 5 times compared with conventional poly-Si TFT's.

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Ranging Performance for Spoofer Localization using Receiver Clock Offset

  • Lee, Byung-Hyun;Seo, Seong-Hun;Jee, Gyu-In;Yeom, Dong-Jin
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.3
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    • pp.137-144
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    • 2016
  • In this paper, the performance of ranging measurement, which is generated using two receiver clock offsets in one receiver, was analyzed. A spoofer transmits a counterfeited spoofing signal which is similar to the GPS signal with hostile purposes, so the same tracking technique can be applied to the spoofing signal. The multi-correlator can generate two receiver clock offsets in one receiver. The difference between these two clock offsets consists of the path length from the spoofer to the receiver and the delay of spoofer system. Thus, in this paper, the ranging measurement was evaluated by the spoofer localization performance based on the time-of-arrival (TOA) technique. The results of simulation and real-world experiments show that the position and the system clock offset of the spoofer could be estimated successfully.