• Title/Summary/Keyword: Cloud point

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A Study of 3D Modeling of Compressed Urban LiDAR Data Using VRML (VRML을 이용한 도심지역 LiDAR 압축자료의 3차원 표현)

  • Jang, Young-Woon;Choi, Yun-Woong;Cho, Gi-Sung
    • Journal of Korean Society for Geospatial Information Science
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    • v.19 no.2
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    • pp.3-8
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    • 2011
  • Recently, the demand for enterprise for service map providing and portal site services of a 3D virtual city model for public users has been expanding. Also, accuracy of the data, transfer rate and the update for the update for the lapse of time emerge are considered as more impertant factors, by providing 3D information with the web or mobile devices. With the latest technology, we have seen various 3D data through the web. With the VRML progressing actively, because it can provide a virtual display of the world and all aspects of interaction with web. It offers installation of simple plug-in without extra cost on the web. LiDAR system can obtain spatial data easily and accurately, as supprted by numerous researches and applications. However, in general, LiDAR data is obtained in the form of an irregular point cloud. So, in case of using data without converting, high processor is needed for presenting 2D forms from point data composed of 3D data and the data increase. This study expresses urban LiDAR data in 3D, 2D raster data that was applied by compressing algorithm that was used for solving the problems of large storage space and processing. For expressing 3D, algorithm that converts compressed LiDAR data into code Suited to VRML was made. Finally, urban area was expressed in 3D with expressing ground and feature separately.

Three-dimensional Digital Restoration and Surface Depth Modeling for Shape Analysis of Stone Cultural Heritage: Haeundae Stone Inscription (석조문화유산의 형상분석을 위한 3차원 디지털복원과 표면심도 모델링:해운대 석각을 중심으로)

  • Jo, Young-Hoon;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.28 no.1
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    • pp.87-94
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    • 2012
  • This study was focused on digital restoration and surface depth modeling applying the three-dimensional laser scanning system of the Haeundae Stone Inscription. Firstly, the three-dimensional digital restoration carried out acquiring of point cloud using wide range and precision scanner, thereafter registering, merging, filtering, polygon mesh and surveyed map drawing. In particular, stroke of letters, inscribed depth and definition appearing the precision scanning polygon was outstanding compared with ones of the wide range polygon. The surface depth modeling completed through separation from polygon, establishment of datum axis, selection of datum point, contour mapping and polygon merging. Also, relative inscribed depth (5~17mm) and outline by the depth modeling was well-defined compared with photograph and polygon image of the inscription stone. The digital restoration technology merging wide range and precision scanning restored the total and detailed shape of the Stone Inscription quickly and accurately. In addition, the surface depth modeling visibly showed unclear parts from naked eye and photograph. In the future, various deteriorations and surrounding environment change of the Stone Inscription will be numerically analyze by periodic monitoring.

Optimization and characterization of biodiesel produced from vegetable oil

  • Mustapha, Amina T.;Abdulkareem, Saka A.;Jimoh, Abdulfatai;Agbajelola, David O.;Okafor, Joseph O.
    • Advances in Energy Research
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    • v.1 no.2
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    • pp.147-163
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    • 2013
  • The world faces several issues of energy crisis and environmental deterioration due to over-dependence on single source of which is fossil fuel. Though, fuel is needed as ingredients for industrial development and growth of any country, however the fossil fuel which is a major source of energy for this purpose has always been terrifying thus the need for alternative and renewable energy sources. The search for alternative energy sources resulted into the acceptance of a biofuel as a reliable alternative energy source. This work presents the study of optimization of process of transesterification of vegetable oil to biodiesel using NaOH as catalyst. A $2^4$ factorial design method was employed to investigate the influence of ratio of oil to methanol, temperature, NaOH concentration, and transesterification time on the yield of biodiesel from vegetable oil. Low and high levels of the key factors considered were 4:1 and 6:1 mole ratio, 30 and $60^{\circ}C$ temperatures, 0.5 and 1.0 wt% catalyst concentration, and 30 and 60 min reaction time. Results obtained revealed that oil to methanol molar ratio of 6:1, tranesetrification temperature of $60^{\circ}C$, catalyst concentration of 1.0wt % and reaction time of 30 min are the best operating conditions for the optimum yield of biofuel from vegetable oil, with optimum yield of 95.8%. Results obtained on the characterizzation of the produced biodiesel indicate that the specific gravity, cloud point, flash point, sulphur content, viscosity, diesel index, centane number, acid value, free glycerine, total glycerine and total recovery are 0.8899, 4, 13, 0.0087%, 4.83, 25, 54.6. 0.228mgKOH/g, 0.018, 0.23% and 96% respectively. Results also indicate that the qualities of the biodiesel tested for are in conformity with the set standard. A model equation was developed based on the results obtained using a statistical tool. Analysis of variance (ANOVA) of data shows that mole ratio of ground nut oil to methanol and transesterification time have the most pronounced effect on the biodiesel yield with contributions of 55.06% and 9.22% respectively. It can be inferred from the results various conducted that vegetable oil locally produced from groundnut oil can be utilized as a feedstock for biodiesel production.

The Relationship between GMS-5 IR1 Brightness Temperature and AWS Rainfall: A heavy rain event over the mid-western part of Korea for August 5-6, 1998 (GMS-5 IR1 밝기온도와 AWS 강우량의 관계성: 1998년 8월 중서부지역 집중호우 사례)

  • 권태영
    • Korean Journal of Remote Sensing
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    • v.17 no.1
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    • pp.15-31
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    • 2001
  • The relationship between GMS-5 IR1 brightness temperature (CTT:cloud top temperature) and AWS (automatic weather station) rainfall is investigated on a heavy rain event over the mid-western part of Korea for August 5-6, 1998. It is found that a temporal variability of the heavy rain can be described in detail y the time series of rain area and rain rates over the study area that are calculated from AWS accumulated rainfalls for 15 minutes. A time period of 0030-0430 LST 6 August 1998 is chosen in the time series as a heavy rain period which has relatively small rain area (20~25%) and very strong rain rates(6~9 mm/15 min.) with a good time continuity. In the heavy rain period, CTT of a point and AWS 15-minute rainfall beneath that point are compared. From the comparison, AWS rainfalls are shown to be not closely correlated with CTT. In the range of CTT lower than -5$0^{\circ}C$ where most AWS with rain are distributed, the probability of rain is at most about 30%. However, when the satellite images are shifted by 2~3 pixels southward and 3 pixels westward for the geometric correction of images, AWS rainfalls are shown to be statistically correlated with CTT (correlation coefficient:-0.46). Most AWS with rain are distributed in the much lower CTT range(lower than -58$^{\circ}C$), but there is still not much change in the rain probability. Even though a temporal change of CTT is taken into account, the rain probability amount to at most 50~55% in the same range.

A Study on the Application of a Drone-Based 3D Model for Wind Environment Prediction

  • Jang, Yeong Jae;Jo, Hyeon Jeong;Oh, Jae Hong;Lee, Chang No
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.39 no.2
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    • pp.93-101
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    • 2021
  • Recently, with the urban redevelopment and the spread of the planned cities, there is increasing interest in the wind environment, which is related not only to design of buildings and landscaping but also to the comfortability of pedestrians. Numerical analysis for wind environment prediction is underway in many fields, such as dense areas of high-rise building or composition of the apartment complexes, a precisive 3D building model is essentially required in this process. Many studies conducted for wind environment analysis have typically used the method of creating a 3D model by utilizing the building layer included in the GIS (Geographic Information System) data. These data can easily and quickly observe the flow of atmosphere in a wide urban environment, but cannot be suitable for observing precisive flow of atmosphere, and in particular, the effect of a complicated structure of a single building on the flow of atmosphere cannot be calculated. Recently, drone photogrammetry has shown the advantage of being able to automatically perform building modeling based on a large number of images. In this study, we applied photogrammetry technology using a drone to evaluate the flow of atmosphere around two buildings located close to each other. Two 3D models were made into an automatic modeling technique and manual modeling technique. Auto-modeling technique is using an automatically generates a point cloud through photogrammetry and generating models through interpolation, and manual-modeling technique is a manually operated technique that individually generates 3D models based on point clouds. And then the flow of atmosphere for the two models was compared and analyzed. As a result, the wind environment of the two models showed a clear difference, and the model created by auto-modeling showed faster flow of atmosphere than the model created by manual modeling. Also in the case of the 3D mesh generated by auto-modeling showed the limitation of not proceeding an accurate analysis because the precise 3D shape was not reproduced in the closed area such as the porch of the building or the bridge between buildings.

National Agenda Service Model Development Research of Policy Information Portal of National Sejong Library (국립세종도서관 정책정보포털 국정과제 서비스 모형개발 연구)

  • Younghee, Noh;Inho, Chang;Hyojung, Sim
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.33 no.4
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    • pp.73-92
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    • 2022
  • This study intends to design a model that can effectively service policy data necessary for the implementation of new national agenda in order to provide high-quality policy information services that go beyond those of the existing Policy Information Portal (POINT) of National Sejong Library. To this end, it was determined that providing an integrated search environment, in lieu of data search through individual access, was necessary. Subsequently, four possible models for a national agenda service model were presented. First, designing a computerized system for both interface and electronic information source aspects was proposed for the national agenda service system operation. Second, designing the Linked Open Data system and the time-series service system for national policy information, providing the translation service of overseas original data, and securing the researcher's desired data were presented for the national agenda service information source operation. Third, strengthening public relations for policy users, building and promoting the site brand, operating SNS channels, and reinforcing the activation of auxiliary materials and the accessibility of external services were proposed for public relations of national agenda service. Fourth, expanding the information network with Open API, cloud service, and overseas libraries was proposed for collaborating and cooperating with the agenda service.

Utilization of Drone LiDAR for Field Investigation of Facility Collapse Accident (붕괴사고 현장조사를 위한 드론 LiDAR 활용)

  • Yonghan Jung ;Eontaek Lim ;Jaewook Suk;Seul Koo;Seongsam Kim
    • Korean Journal of Remote Sensing
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    • v.39 no.5_2
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    • pp.849-858
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    • 2023
  • Investigating disaster sites such as earthquakes and landslides involves significant risks due to potential secondary disasters like facility collapse. In situations where direct access is challenging, there is a need to develop methods for safely acquiring high-precision 3D disaster information using light detection and ranging (LiDAR) equipped drone survey systems. In this study, the feasibility of using drone LiDAR in disaster scenarios was examined, focusing on the collapse accident at Jeongja Bridge in Bundang-gu, Seongnam City, in April 2023. High-density point clouds for the accident bridge were collected, and the bridge's 3D terrain information was reconstructed and compared to the measurement performance of 10 ground control points. The results showed horizontal and vertical root mean square error values of 0.032 m and 0.055 m, respectively. Additionally, when compared to a point cloud generated using ground LiDAR for the same target area, a vertical difference of approximately 0.08 m was observed, but overall shapes showed minimal discrepancies. Moreover, in terms of overall data acquisition and processing time, drone LiDAR was found to be more efficient than ground LiDAR. Therefore, the use of drone LiDAR in disaster sites with significant risks allows for safe and rapid onsite investigations.

Scaling Attack Method for Misalignment Error of Camera-LiDAR Calibration Model (카메라-라이다 융합 모델의 오류 유발을 위한 스케일링 공격 방법)

  • Yi-ji Im;Dae-seon Choi
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.33 no.6
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    • pp.1099-1110
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    • 2023
  • The recognition system of autonomous driving and robot navigation performs vision work such as object recognition, tracking, and lane detection after multi-sensor fusion to improve performance. Currently, research on a deep learning model based on the fusion of a camera and a lidar sensor is being actively conducted. However, deep learning models are vulnerable to adversarial attacks through modulation of input data. Attacks on the existing multi-sensor-based autonomous driving recognition system are focused on inducing obstacle detection by lowering the confidence score of the object recognition model.However, there is a limitation that an attack is possible only in the target model. In the case of attacks on the sensor fusion stage, errors in vision work after fusion can be cascaded, and this risk needs to be considered. In addition, an attack on LIDAR's point cloud data, which is difficult to judge visually, makes it difficult to determine whether it is an attack. In this study, image scaling-based camera-lidar We propose an attack method that reduces the accuracy of LCCNet, a fusion model (camera-LiDAR calibration model). The proposed method is to perform a scaling attack on the point of the input lidar. As a result of conducting an attack performance experiment by size with a scaling algorithm, an average of more than 77% of fusion errors were caused.

A Study on the Excavated Sab(a funeral fan) from Lime-filled Tomb and Lime-layered Tomb during the Joseon Dynasty (조선시대 회격·회곽묘 출토 삽(翣)에 대한 고찰)

  • Yi, Seung Hae;An, Bo Yeon
    • Korean Journal of Heritage: History & Science
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    • v.41 no.2
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    • pp.43-59
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    • 2008
  • Sap(?, a funeral fan) is a funeral ceremonial object used in association with a Confucian ceremonial custom, which was crafted by making a wooden frame, attaching a white cloth or a thick paper onto it, drawing pictures on it, and making a holder for a handle. According to Liji(Records of Rites), Sap was used since the Zhou Dynasty, and these Chinese Sap examples are no big different than the Korean Sap examples, which were described in Joseon Wangjo Sillok(Annals of the Joseon Dynasty), Gukjo Oryeui(the Five Rites of the State), and Sarye Pyeollam(Handbook on Four Rituals). This study explored Sap excavated in lime-filled tombs and lime-layered tombs of aristocrats dating back to Joseon, as well as their historical records to examine Sap's characteristics according to their examples, manufacturing methods, and use time. The number and designs of Sap varied according to the deceased' social status aristocrats used mainly one pair of 亞-shaped Bulsap, and a pair of Hwasap with a cloud design depicted on it. A Sap was wrapped twice with Chojuji paper or Jeojuji paper, and for the third time with Yeonchangji paper. Then, it was covered with a white ramie, a hemp, a cotton, a silk satin, etc. Bobul(an axe shape and 亞-shape design) was drawn on both sides of Sap, and a rising current of cloud was drawn at the peripheral area mainly with red or scarlet pigments. Sap, which were excavated from aristocrats'lime-filled and lime-layered tombs, are the type of Sap which were separated from its handle. These excavated Sap are those whose long handles were burnt during the death carriage procession, leaving Sap, which later were erected on both sides of the coffin. The manufacturing process of excavated relics can be inferred by examining them. The excavated relics are classified into those with three points and those with two points according to the number of point. Of the three-point type(Type I), there is the kind of relic that was woven into something like a basket by using a whole wood plate or cutting bamboo into flat shapes. The three-point Sap was concentrated comparatively in the early half of Joseon, and was manufactured with various methods compared with its rather unified overall shape. In the meantime, the two-point Sap was manufactured with a relatively formatted method; its body was manufactured in the form of a rectangle or a reverse trapezoid, and then its upper parts with two points hanging from them were connected, and the top surface was made into a curve(Type II) or a straight line(Type III) differentiating it from the three-point type. This manufacturing method, compared with that of the three-point type, is simple, but is not greatly different from the three-point type manufacturing method. In particular, the method of crafting the top surface into a straight line has been used until today. Of the examined 30 Sap examples, those whose production years were made known from the buried persons'death years inscribed on the tomb stones, were reexamined, indicating that type I was concentrated in the first half of the $16^{th}$ century. Type II spanned from the second half of the $16^{th}$ century to the second half of the $17^{th}$ century, and type III spanned from the first half of the $17^{th}$ century to the first half of the $18^{th}$ century. The shape of Sap is deemed to have changed from type I to type II and again from type II to type III In the $17^{th}$ century, which was a time of change, types II and III coexisted. Of the three types of Sap, types II and III re similar because they have two points; thus a noteworthy transit time is thought to have been the middle of the $16^{th}$ century. Type I compared with types II and III is thought to have required more efforts and skills in the production process, and as time passed, the shape and manufacturing methods of Sap are presumed to have been further simplified according to the principle of economy. The simplification of funeral ceremonies is presumed to have been furthered after Imjinwaeran(Japanese invasion of Joseon, 1592~1598), given that as shown in the Annals of King Seonjo, state funerals were suspended several times. In the case of Sap, simplification began from the second half of the $16^{th}$ century, and even in the $18^{th}$ century, rather than separately crafting Sap, Sap was directly drawn on the coffin cover and the coffin. However, in this simplification of form, regulations on the use of Sap specified in Liji were observed, and thus the ceremony was rationally simplified.

A Transcendental Pragmatic Interpretation on the Notion of 'Injon' in Daesoon Thought (대순사상의 인존(人尊)에 대한 화용론적(話用論的) 해석)

  • Baek, Choon-hyoun
    • Journal of the Daesoon Academy of Sciences
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    • v.39
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    • pp.33-67
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    • 2021
  • This paper aims at revealing the core concept of Injon (Human Nobility). The concept of Injon is one of the salient fundamental ideas which makes Daesoon Jinrihoe recognizable as Daesoon Jinrihoe. The concept of Injon has the basic meaning of 'human nobility,' but within the context wherein the nobility of humankind is considered to be greater than the nobility of Heaven and Earth. Although the religious and ideological interpretations of Injon (human nobility) that have developed over time have been quite diverse and abundant, these interpretations are all limited in that they generally assume the relationship between 'Heaven and Earth' and 'Humanity' to be antagonistic. However, if human nobility is relativized in that manner, it can reduce the potential broader meanings of mutual beneficence and the earthly paradise of the later world. These interpretations are grounded in the view of semiotic interpretation. Such interpretations have composed their view point via the semiotic meaning of the words. The semiotic point of view suggests that meanings of words consist in the relation of the word and the object to which it denotes. We will introduce a new view point which can be termed the transcendental view point. This view focuses on how the exact interpretation of words and sentences depends on the comprehension of the triad of systematic relations among the word, object, and speaker. In the Daesoon Thought, the Former World is considered to be the world wherein all creations unfolded according to the principle of mutual contention. This led to the accumulation of grievances and grudges which condensed and filled the Three Realms of Heaven, Earth, and Humanity. The Former World was dominated by Western material civilization, selfishness, and exclusivism. It was also a world where humans suffered from various natural disasters such as floods, droughts, plagues, and wildfires. The Former World lost the constant Dao and was overwhelmed with all kinds of disasters and calamities. That world fell into various kinds of wretchedness. The causes which made the Former World so cruel came from humans misunderstanding their relation to nature and life in general; including human life. The anthropocentric modern cosmology insisted that the human race was the only one to have the powers and rights to exercise dominion over nature. On the other hand, there is the Later World, which means the ideal and perfect, immanent eternal world for all humankind in Daesoon Thought. This world consists of life, peace, and equality and is also characterized by three typical attributes: goodness, peace, and all kinds of life. All living beings previously struggled for survival, but in the Later World, those lifeforms will embrace each other; even across different realms. In Daesoon Thought, the world and cosmos contain diverse forms of life, and human have both an earthly life and life in the after world should they die before the Later World. There are also the lives of divine beings and animals, and other such living entities. Daesoon Thought subsumes pan-vitalism, which allows they acknowledgement of myriad possible lifeforms. The concept of the Later World in Daesoon Thought, which mainly revealed in The Canonical Scripture and the words of Sangje (Kang Jeungsan), suggests that all kinds of life, including humans, animals, and even spirits in the afterworld, can live together in a perfect coming earthly paradise which is immanent. The concept of Injon can be interpreted though the view of transcendental pragmatics as an alternative to the typical views discussed in Daesoon Thought. Thinkers should attempt to improve current discourse on Injon in Daesoon Thought by focusing on the point that all kinds the original teachings demonstrate a value of all lifeforms. Therein, Injon would indicate not only the human nobility and dignity but also the nobility and dignity of divine beings, divine humans, and all other forms of life that have existed across time. The dimension of time allows for recognition of lifeforms from the Former World, the afterworld, and the Later World. This revised appraisal of Injon could further accommodate denizens of the afterworld, animals, ghosts and spirits, the earth and cloud souls of humans, and other lifeforms held to exist in the cosmology of Daesoon Thought.