• Title/Summary/Keyword: Fixed target

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A Study on the Test Method of Autonomous Vehicle for Fixed Targets (고정목표에 대한 자율주행자동차 시험방법에 관한 연구)

  • Kim, Bong-Ju;Lee, Seon-Bong
    • Journal of Auto-vehicle Safety Association
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    • v.14 no.3
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    • pp.6-16
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    • 2022
  • Recent, the issue of the fourth industrial revolution triggered by technological advances has changed the automobile industry centered on internal combustion engines, and quantitative growth of the global automobile market, which has grown rapidly, has been slowing since 2015. These advances in technology are expected to develop beyond the advanced driver assistance system to autonomous driving technology. According to SAE-J3016 published by the Society of Automotive Engineers, the technology of autonomous vehicles is divided into a total of six stages according to the driver's intervention and automation level from 0 to 5. Securing safety for autonomous vehicles is important. But, research on safety evaluation theory and autonomous vehicle evaluation method based on real vehicle test is insufficient. In this study, the longitudinal distance theory equation and continuous test scenario were proposed for the test method of autonomous vehicles for fixed targets, and the real vehicle test was conducted. When comparing the theoretical values compared to the measured values, it was determined that it was reliable with a minimum error rate of 0.484% and a maximum error rate of 7.391%. Using the proposed theoretical equation, it is judged that it can be used as a safety evaluation method in an environment where real vehicle test is not possible because it can grasp the trend in the longitudinal direction in the development stage.

Characterizing Information Processing in Visual Search According to Probability of Target Prevalence (표적 출현확률에 따른 시각탐색 정보처리 특성)

  • Park, Hyung-Bum;Son, Han-Gyeol;Hyun, Joo-Seok
    • Korean Journal of Cognitive Science
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    • v.26 no.3
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    • pp.357-375
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    • 2015
  • In our daily life, the probability of target prevalence in visual search varies from very low to high. However, most laboratory studies of visual search used a fixed probability of target prevalence at 50%. The present study examined the properties of information processing during visual search where the probability of target prevalence was manipulated to vary from low (20%), medium (50%), to high (80%). The search items were made of simple shape stimuli, and search accuracy, signal detection measures, and reaction times (RTs) were analyzed for characterizing the effect of target prevalence on the information processing strategies for visual search. The analyses showed that the rates of misses increased whereas those of false alarms decreased in the search condition of low target prevalence, whereas the pattern was reversed in the high prevalence condition. Signal detection measures revealed that the target prevalence shifted response criterion (c) without affecting sensitivity (d'). In addition, RTs for correct rejection responses in the target-absent trials became delayed as the prevalence increased, whereas those for hits in the target-present trials were relatively constant regardless of the prevalence. The RT delay in the target-absent trials indicates that increased target prevalence made the 'quitting threshold' for search termination more conservative. These results support an account that the target prevalence effect in visual search arises from a shift of decision criteria and the subsequent changes in search information processing, while rejecting the account of a speed-accuracy tradeoff.

Fixed Pattern Noise Reduction in Infrared Videos Based on Joint Correction of Gain and Offset (적외선 비디오에서 Gain과 Offset 결합 보정을 통한 고정패턴잡음 제거기법)

  • Kim, Seong-Min;Bae, Yoon-Sung;Jang, Jae-Ho;Ra, Jong-Beom
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.2
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    • pp.35-44
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    • 2012
  • Most recent infrared (IR) sensors have a focal-plane array (FPA) structure. Spatial non-uniformity of a FPA structure, however, introduces unwanted fixed pattern noise (FPN) to images. This non-uniformity correction (NUC) of a FPA can be categorized into target-based and scene-based approaches. In a target-based approach, FPN can be separated by using a uniform target such as a black body. Since the detector response randomly drifts along the time axis, however, several scene-based algorithms on the basis of a video sequence have been proposed. Among those algorithms, the state-of-the-art one based on Kalman filter uses one-directional warping for motion compensation and only compensates for offset non-uniformity of IR camera detectors. The system model using one-directional warping cannot correct the boundary region where a new scene is being introduced in the next video frame. Furthermore, offset-only correction approaches may not completely remove the FPN in images if it is considerably affected by gain non-uniformity. Therefore, for FPN reduction in IR videos, we propose a joint correction algorithm of gain and offset based on bi-directional warping. Experiment results using simulated and real IR videos show that the proposed scheme can provide better performance compared with the state-of-the art in FPN reduction.

Volumetric modulated arc therapy for carotid sparing in the management of early glottic cancer

  • Kim, Young Suk;Lee, Jaegi;Park, Jong In;Sung, Wonmo;Lee, Sol Min;Kim, Gwi Eon
    • Radiation Oncology Journal
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    • v.34 no.1
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    • pp.18-25
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    • 2016
  • Purpose: Radiotherapy of the neck is known to cause carotid artery stenosis. We compared the carotid artery dose received between volumetric modulated arc therapy (VMAT) and conventional fixed-field intensity-modulated radiotherapy (IMRT) plans in patients with early glottic cancer. Materials and Methods: Twenty-one early glottic cancer patients who previously underwent definitive radiotherapy were selected for this study. For each patient, double arc VMAT, 8-field IMRT, 3-dimensional conformal radiotherapy (3DCRT), and lateral parallel-opposed photon field radiotherapy (LPRT) plans were created. The 3DCRT plan was generated using lateral parallel-opposed photon fields plus an anterior photon field. VMAT and IMRT treatment plan optimization was performed under standardized conditions to obtain adequate target volume coverage and spare the carotid artery. Dose-volume specifications for the VMAT, IMRT, 3DCRT, and LPRT plans were calculated with radiotherapy planning system. Monitor units (MUs) and delivery time were measured to evaluate treatment efficiency. Results: Target volume coverage and homogeneity results were comparable between VMAT and IMRT; however, VMAT was superior to IMRT for carotid artery dose sparing. The mean dose to the carotid arteries in double arc VMAT was reduced by 6.8% compared to fixed-field IMRT (p < 0.001). The MUs for VMAT and IMRT were not significantly different (p = 0.089). VMAT allowed an approximately two-fold reduction in treatment delivery time in comparison to IMRT (3 to 5 minutes vs. 5 to 10 minutes). Conclusion: VMAT resulted in a lower carotid artery dose compared to conventional fixed-field IMRT, and maintained good target coverage in patients with early glottic cancer.

Polymer 기판상에 제작된 AZO/Ag/AZO 다층박막

  • Kim, Sang-Mo;Im, Yu-Seung;Geum, Min-Jong;Kim, Gyeong-Hwan
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2007.06a
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    • pp.207-210
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    • 2007
  • We prepared Al doped ZnO/Ag/Al doped ZnO on the polymer substrate by Facing Target Sputtering (FTS). FTS featured Facing Target Sputtering featured that deposition is stable at the low pressure, it has high plasma density and suppresses the substrate damage from energetic particles. We fixed to 50nm up and down thickness of AZO layer, respectively and that of intermediate Ag layer was adjusted with deposition time. In the result, AZO/Ag/AZO multilayer thin films have much better electrical conductivity than AZO single layer thin film. As increasing the thickness of Ag layer, the transmittance decreased.

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Crystallography properties of $ZnO/AZO/SiO_2/Si$ thin film for FBAR (FBAR용 $ZnO/AZO/SiO_2/Si$ 박막의 결정학적 특성에 관한 연구)

  • Kang, Tai-Young;Keum, Min-Jong;Son, In-Hwan;Kim, Kyung-Hwan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.880-883
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    • 2003
  • ZnO thin films for Film Bulk Acoustic Resonator(FBAR) were prepared by FTS (Facing Target Sputtering) system. The FTS methode enable to generate high density plasma, and it has a high deposition rate at 1mTorr pressure. Therefore, the ZnO thin films were deposited on $AZO/SiO_2/Si$ substrates with oxygen gas flow rate, and the other sputtering conditions were fixed such as a sputtering current of 0.8A, a substrate temperature at room temperature. AZO bottom electrode were deposited on $SiO_2/Si$ substrate and by Zn:Al(Al:2wt%) metal target. ZnO thin film thickness and the c-axis preferred orientation of ZnO thin film were evaluated by ${\alpha}-step$ and XRD.

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The Study on the Gas Temperature Set by Calculating the Sensitivity of Slab Temperature in Reheating Furnace (소재온도 감도계산을 통한 가열로내 분위기온도 설정방안 연구)

  • Gang, Deok-Hong;Kim, Gi-Hong;Lee, Yong-Guk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.8
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    • pp.1030-1036
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    • 2001
  • A new mathematical model to determine the optimal gas temperatures in reheating furnace was proposed for the good quality of products. This model employs sensitivity method to calculate the optimal gas temperatures in each zone for heating the slab up to its discharging target temperature and for heating it uniformly. This method was validated by showing that the calculated discharging temperature of the slab was in a good agreement with its prescribed discharging target one through an off-line simulation.

Fitting Enhancement of AAM Using Synthesized Illumination Images (조명 영상 합성을 통한 AAM 피팅 성능 개선)

  • Lee, Hyung-Soo;Kim, Dai-Jin
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.10c
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    • pp.409-414
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    • 2007
  • Active Appearance Model is a well-known model that can represent a non-rigid object effectively. However, since it uses the fixed appearance model, the fitting results are often unsatisfactory when the imaging condition of the target image is different from that of training images. To alleviate this problem, incremental AAM was proposed which updates its appearance bases in an on-line manner. However, it cannot deal with the sudden changes of illumination. To overcome this, we propose a novel scheme to update the appearance bases. When a new person appears in the input image, we synthesize illuminated images of that person and update the appearance bases of AAM using it. Since we update the appearance bases using synthesized illuminated images in advance, the AAM can fit their model to a target image well when the illumination changes drastically. The experimental results show that our proposed algorithm improves the fitting performance over both the incremental AAM and the original AAM.

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Multi-Channel Speech Enhancement Algorithm Using DOA-based Learning Rate Control (DOA 기반 학습률 조절을 이용한 다채널 음성개선 알고리즘)

  • Kim, Su-Hwan;Lee, Young-Jae;Kim, Young-Il;Jeong, Sang-Bae
    • Phonetics and Speech Sciences
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    • v.3 no.3
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    • pp.91-98
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    • 2011
  • In this paper, a multi-channel speech enhancement method using the linearly constrained minimum variance (LCMV) algorithm and a variable learning rate control is proposed. To control the learning rate for adaptive filters of the LCMV algorithm, the direction of arrival (DOA) is measured for each short-time input signal and the likelihood function of the target speech presence is estimated to control the filter learning rate. Using the likelihood measure, the learning rate is increased during the pure noise interval and decreased during the target speech interval. To optimize the parameter of the mapping function between the likelihood value and the corresponding learning rate, an exhaustive search is performed using the Bark's scale distortion (BSD) as the performance index. Experimental results show that the proposed algorithm outperforms the conventional LCMV with fixed learning rate in the BSD by around 1.5 dB.

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Determination of the Economical Target Value Through Sampling Inspectioni (샘플링 검사를 통한 경제적 공정 목표 값 결정에 관한 연구)

  • 이동철;윤덕균
    • Journal of the Korean Operations Research and Management Science Society
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    • v.25 no.2
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    • pp.67-76
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    • 2000
  • We consider the determinant of the most economical target value through the sampling inspection by two consecutive machines. The machine sequence is fixed as products have to be processed by machine 1 first and then by machine 2 next, In this paper we assume that if quality of a unit is lower than inspection lower specification limited then the goods is not accepted, otherwise it is accepted. And we assume that the quality characteristics is larger-the-better characteristics and its distribution is the normal distribution whose standard deviation is known. This paper ends up with an numerical example by using the total expected profit function model that consider the scales profits inspection costs and material costs. And we analyze the variation of the total expected profit by changing coefficients of the functions.

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