• Title/Summary/Keyword: Ghost problem

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A Study on Signal Processing of Rear Radars for Intelligent Automobile (지능형 차량을 위한 후방 감시용 레이더 신호 처리 기법에 관한 연구)

  • Choi, Gak-Gyu;Han, Seung-Ku;Kim, Hyo-Tae;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.11
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    • pp.1070-1077
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    • 2011
  • This paper introduces a radar signal processing technique for intelligent rear view monitoring of an automobile. The linear frequency modulation-frequency shift keying(LFM-FSK) waveform, which is the combination of frequency modulation continuous wave(FMCW) and frequency shift keying(FSK) waveform, is employed to simultaneously estimate the range, relative aspect angle, and velocity of an automobile. Hence, it can be applied to monitor the rear view of an automobile. FMCW waveform has high range resolution capability, but it produces ghost targets under a multiple target environment. In contrast, FSK waveform can provide high velocity resolution and avoids the problem of ghost targets. However, it fails to identify multiple targets along the radar's line of sight. With LFM-FSK waveform, we can estimate the ranges and velocities of multiple targets with very high resolution, which avoids the ghost target problem of an FMCW waveform. Simulation result shows that LFM-FSK wavefrom is suitable for use in the lane change assistance system for an automobile.

Hole-Filling Method Using Extrapolated Spatio-temporal Background Information (추정된 시공간 배경 정보를 이용한 홀채움 방식)

  • Kim, Beomsu;Nguyen, Tien Dat;Hong, Min-Cheol
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.8
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    • pp.67-80
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    • 2017
  • This paper presents a hole-filling method using extrapolated spatio-temporal background information to obtain a synthesized view. A new temporal background model using non-overlapped patch based background codebook is introduced to extrapolate temporal background information In addition, a depth-map driven spatial local background estimation is addressed to define spatial background constraints that represent the lower and upper bounds of a background candidate. Background holes are filled by comparing the similarities between the temporal background information and the spatial background constraints. Additionally, a depth map-based ghost removal filter is described to solve the problem of the non-fit between a color image and the corresponding depth map of a virtual view after 3-D warping. Finally, an inpainting is applied to fill in the remaining holes with the priority function that includes a new depth term. The experimental results demonstrated that the proposed method led to results that promised subjective and objective improvement over the state-of-the-art methods.

A Study on Touch-screen Development Using Visible-ray (가시광선을 이용한 터치스크린 구현에 대한 연구)

  • Park, Jun-Woo;Jeong, Yong-Jin
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.3
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    • pp.50-61
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    • 2011
  • The Infrared touch method is generally used for a mid and large-size touch screen. But this method has several problems, such as difficulty with installation of a touch-object recognition device, limited application and coordinate error in multi-point touch system. Since we can take advantages of both color and local information when we use general cameras for a touch screen, a touch screen using general camera is more efficient than infrared one. It also has an advantage of easy installation of a touch-object device. However, it did not much appeal in a market because of several problems, such as color sensitivity, illumination and reflected light. In this paper, we study a method for a touch screen using a general camera and image processing method to recognize touch objects and coordinate calculation method to single and multi-point touch screen. It has the same recognition performance as an infrared touch screen for single-point method. And it does not have ghost point problem by using distance information of touch object and camera in multi-point touch system. But recognition performances of multi-point touch screen are less than single-point. If we improve execution time, this method can replace an infrared method for a single point touch screen, according to result of experience.

A multiple level set method for modeling grain boundary evolution of polycrystalline materials

  • Zhang, Xinwei;Chen, Jiun-Shyan;Osher, Stanley
    • Interaction and multiscale mechanics
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    • v.1 no.2
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    • pp.191-209
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    • 2008
  • In this paper, we model grain boundary evolution based on a multiple level set method. Grain boundary migration under a curvature-induced driving force is considered and the level set method is employed to deal with the resulting topological changes of grain structures. The complexity of using a level set method for modeling grain structure evolution is due to its N-phase nature and the associated geometry compatibility constraint. We employ a multiple level set method with a predictor-multicorrectors approach to reduce the gaps in the triple junctions down to the grid resolution level. A ghost cell approach for imposing periodic boundary conditions is introduced without solving a constrained problem with a Lagrange multiplier method or a penalty method. Numerical results for both uniform and random grain structures evolution are presented and the results are compared with the solutions based on a front tracking approach (Chen and Kotta et al. 2004b).

Multipath Ghosts in Through-the-Wall Radar Imaging: Challenges and Solutions

  • Abdalla, Abdi T.;Alkhodary, Mohammad T.;Muqaibel, Ali H.
    • ETRI Journal
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    • v.40 no.3
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    • pp.376-388
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    • 2018
  • In through-the-wall radar imaging (TWRI), the presence of front and side walls causes multipath propagation, which creates fake targets called multipath ghosts. They populate the scene and reduce the probability of correct target detection, classification, and localization. In modern TWRI, specular multipath exploitation has received considerable attention for reducing the effects of multipath ghosts. However, this exploitation is challenged by the requirements of the reflecting geometry, which is not always available. Currently, the demand for a high radar image resolution dictates the use of a large aperture and wide bandwidth. This results in a large amount of data. To tackle this problem, compressive sensing (CS) is applied to TWRI. With CS, only a fraction of the data are used to produce a high-quality image, provided that the scene is sparse. However, owing to multipath ghosts, the scene sparsity is highly deteriorated; hence, the performance of the CS algorithms is compromised. This paper presents and discusses the adverse effects of multipath ghosts in TWRI. It describes the physical formation of ghosts, their challenges, and existing suppression techniques.

Culture Contents Adaptational Aspects of Jeju Myth "Chasabonpuri" (제주신화 <차사본풀이>의 문화콘텐츠 변용 양상)

  • Kim, Jin-Chul
    • The Journal of the Korea Contents Association
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    • v.15 no.8
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    • pp.85-95
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    • 2015
  • This study examined adaptational aspects by analyzing culture contents, which use Jeju myth "Chasabonpuri" as a writing material. "Chasabonpuri" has a heroic narration of Ganglim, who becomes the grim reaper by solving the serious problem through a journey to the world beyond. Also, it has a value as an archetypal narration because of its reflection on Korean world view of afterlife. Culture contents, which use "Chasabonpuri" as a writing material, have features of 'accurate reproduction of heroic narration' (Ganglim who becomes the grim reaper), 'tragic conversion of narration through humanization' (The way home), 'extension of narration through merging with traditional and modern elements'(Together with God), 'Unique view of the world that reflects the contemporary trend' (Ghost Messenger).

The Durability of Polybutylene Succinate Monofilament for Fishing Net Twines by Outdoor Exposure Test (옥외 노출시험에 의한 PBS 단일섬유 망사의 내구성 변화)

  • Park, Seong-Wook;Kim, Seong-Hun;Lim, Ji-Hyun;Choi, Hea-Sun
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.4
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    • pp.766-774
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    • 2013
  • Biodegradable polybutylene succinate(PBS) is a kind of environmentally friendly plastics for fisheries, because it can mitigate the ghost fishing problem caused by gill-net and trap fisheries. To evaluate durability of PBS monofilament, each of different diameter 3 types of monofilaments were spun and exposed to 56 month outdoor and then their gravity, modification of surface, breaking strength, and elongation were analysed. The gravity of PBS monofilament was estimated to be approximately 1.24 when spinning ratio from 4.8 to 6.1. PBS monofilaments did not show any crack after 56 month exposed to outdoor and load-elastic elongation curve was showed sigmoid type. Decreasing ratio of elongation was appeared in the thinnest monofilament 0.2mm diameter and breaking strength was in the thickest monofilament 0.4mm diameter. Breaking strength and elongation at break were decreased rapidly after 48 month exposed to outdoor. Breaking strength reduced linearly after 48 month exposure, while no such linear relationship was found in the case of elongation at break. In results, it was investigated that the durability of PBS monofilament nets for gillnet and trap were 24, 50 month when keep to land, respectively.

Modified Seam Finding Algorithm based on Saliency Map to Generate 360 VR Image (360 VR 영상 제작을 위한 Saliency Map 기반 Seam Finding 알고리즘)

  • Han, Hyeon-Deok;Han, Jong-Ki
    • Journal of Broadcast Engineering
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    • v.24 no.6
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    • pp.1096-1112
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    • 2019
  • The cameras generating 360 VR image are too expensive to be used publically. To overcome this problem, we propose a way to use smart phones instead of VR camera, where more than 100 pictures are taken by smart phone and are stitched into a 360 VR image. In this scenario, when moving objects are in some of the pictures, the stitched 360 VR image has various degradations, for example, ghost effect and mis-aligning. In this paper, we proposed an algorithm to modify the seam finding algorithms, where the saliency map in ROI is generated to check whether the pixel belongs to visually salient objects or not. Various simulation results show that the proposed algorithm is effective to increase the quality of the generated 360 VR image.

Integrity of Authorship and Peer Review Practices: Challenges and Opportunities for Improvement

  • Misra, Durga Prasanna;Ravindran, Vinod;Agarwal, Vikas
    • Journal of Korean Medical Science
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    • v.33 no.46
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    • pp.287.1-287.14
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    • 2018
  • Integrity of authorship and peer review practices are important considerations for ethical publishing. Criteria for authorship, as delineated in the guidelines by the International Committee of Medical Journal Editors (ICMJE), have undergone evolution over the decades, and now require fulfillment of four criteria, including the need to be able to take responsibility for all aspects of the manuscript in question. Although such updated authorship criteria were published nearly five years ago, still, many major medical and specialist journals have yet to revise their author instructions to conform to this. Inappropriate authorship practices may include gift, guest or ghost authorship. Existing literature suggests that such practices are still widely prevalent, especially in non-English speaking countries. Another emerging problem is that of peer review fraud, mostly by authors, but also rarely by handling editors. There is literature to suggest that a proportion of such fake peer review may be driven by the support of some unscrupulous external editing agencies. Such inappropriate practices with authorship malpractices or disagreement, or peer review fraud, have resulted in more than 600 retractions each, as identified on the retractions database of Retractionwatch.com. There is a need to generate greater awareness, especially in authors from non-English speaking regions of the world, about inappropriate authorship and unethical practices in peer review. Also, support of any external editing agency should be clearly disclosed by authors at the time of submission of a manuscript.

A Study on the Direction for Revision of the Assembly and Demonstration Act - 'around the Article 6 and Article 8 of 2016 Revised Assembly and Demonstration Act' - (집회 및 시위에 관한 법률 개정 방향에 관한 연구 - '2016 개정 집시법 제6조·제8조를 중심으로 -)

  • Cho, Se-hee
    • Korean Security Journal
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    • no.49
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    • pp.39-63
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    • 2016
  • After its decision of 'constitutional nonconformity' about a night assembly on September 24th, 2009, then the Korean Constitutional Court decided the 'limited violation of constitution' saying, 'Even a night demonstration should be allowed to be held up to the midnight' on March 27th, 20104. Since such a decision, the revision of Assembly and Demonstration Act has not been done, and the revised act is currently pending on the National Assembly on October, 2016. Amid the controversy about the 'Legislative Deficiency', some articles of the Assembly and Demonstration Act are revised and created like the imposition of the fine about a ghost assembly and the notice duty of fact to hold an assembly, the police superintendent's recommendation about the assembly place and partitioned assembly holding by time in order to protect the people's basic rights and convenience. However, this revised bill of Assembly & Demonstration Act limits the duty of assembly withdrawal report only to overlapping assemblies and a police superintendent can only recommend about the partition of assembly place and time, but has not a certain authority to forcibly enforce, so it is expected that the recommendation will be eventually ended to a formal procedure. And as this revised act has no punishment article concerning the violation of the notice duty within 1 hour before holding an assembly in this revised act, so there is a problem that the police can't force an assembly to follow the article. This study proposed some political suggestions concerning the articles to be supplemented and corrected in the Assembly & Demonstration Act after analyzing its articles around its 2016 revised Act. The Assembly & Demonstration Act has several problems to be continually corrected and supplemented further including the matter of 'Night Assembly & Demonstration' which is in the condition of 'Legislative Deficiency' since 2009.

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