• Title/Summary/Keyword: Design Shape

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The Sensitivity Analysis and Safety Evaluations of Cable Stayed Bridges Based on Probabilistic Finite Element Method (확률유한요소해석에 의한 사장교의 민감도 분석 및 안전성 평가)

  • Han, Sung-Ho;Cho, Tae-Jun;Bang, Myung-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.1
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    • pp.141-152
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    • 2007
  • Considering uncertainties of random input data, it is more reasonable to use probabilistic method than the conventional deterministic method for the design of structures or for the assessment of the responses of structures, which are designed as safe even under extreme loads. Therefore, to assess the quantitative effects of the constructed cable stayed bridge by the input random variables, a sensitivity analysis is studied. Using perturbation method, an analysis program is developed for the iterative probabilistic finite element analyses and sensitivity analyses of the cable stayed bridge, except the initial shape analysis. Monte-Carlo Simulations were used for the verification of the developed program. The results of sensitivity analysis shows the governing effects of external loads. Because the results also provide the sensitive effects of the stiffness of members and the magnitudes of prestressing force of cables, the developed

Analysis of Effective Flexural Rigidity of Corrugated Steel-Concrete Composite Deck with I-beam Welded (I형강으로 보강된 강합성 절곡 바닥판의 유효 휨강성 분석)

  • Son, Chang-Du;Hong, Sung-Nam;Park, Jun-Myung;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.3 s.55
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    • pp.145-154
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    • 2009
  • Steel-Concrete Composite Deck with I-beam welded is lighter and easier to construct than conventional in situ reinforced concrete slabs due to the I-beam embedded in the corrugated slab. For the calculation of effective flexural rigidity of conventional reinforced concrete structures, methods suggested in Design Standard for Roads and Bridges and ACI have been used. In this paper, the calculation methods were applied to steel-concrete composite deck with I-beam welded and then results of the steel-concrete composite deck were compared with those of reinforced concrete slabs. In addition, applicability of the methods to steel-concrete composite deck with I-beam welded was estimated. In order to compare the effective flexural rigidity, flexural experiments were conducted. Fifteen slabs were built and the variables considered in the experiments were studs, length of the slab, shape of the section and connecting methods.

Heat transfer characteristics of an internal cooling channel with pin-fins and ribbed endwalls in gas turbine blade

  • Vu T.A. Co;Hung C. Hoang;Duy C.K. Do;Son H. Truong;Diem G. Pham;Nhung T.T. Le;Truong C. Dinh;Linh T. Nha
    • Advances in aircraft and spacecraft science
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    • v.11 no.2
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    • pp.153-175
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    • 2024
  • In jet engines, turbine blade cooling has an extremely important role. The pin-fin array, which is situated close to the trailing edge of the blade, aids in internal cooling of the gas turbine blades and preserves the structural integrity of the blade. Previous studies often focused on pin-fin configurations, but the current research focuses on improving the geometry at the endwalls to reduce wake vortices behind the pin-fins and enhance heat transfer at the endwalls location. Using the k-ω turbulence model, a numerical study was conducted on a ribbed shape situated on the walls between pin-fin arrays, spanning a Reynolds number range of 7400 to 36000, in order to determine the heat transport characteristics. The heat transfer efficiency coefficient and Nusselt number increase dramatically with the revised wall configuration, according to the numerical data. The channel's heat transfer efficiency is increased by enlarging the heat transfer areas near the pin-fins and by the interaction of the flow with the endwalls. The addition of ribs causes the Nusselt number of the new model to climb from 78% to 96% at the previously given Reynolds numbers, and the heat transfer efficiency index to rise from 60% to 73%. The height (Hr), position (Lr), forward width (Wf), and backward width (Wb) of the ribs are among the geometric elements that were looked at in order to determine how they affected the performance of heat transmission. In comparison to the reference design, the parametric study results demonstrate that the best forward width (Wf/R=18.75%) and backward width (Wb/R=31.25%) increase the heat transfer efficiency index by 0.4% and 1.3%, respectively.

Development and Flight Test of Variable-Camber and Variable-Chord Morphing Flap (가변캠버 가변시위 모핑 플랩의 개발 및 비행실험)

  • Jihyun Oh;Jae-Sung Bae;Hyun Chul Lee
    • Journal of Aerospace System Engineering
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    • v.18 no.4
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    • pp.34-42
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    • 2024
  • This study developed a morphing technology applicable to unmanned aerial vehicles (UAVs) with diverse flight characteristics. Existing morphing technologies require additional mechanisms and driving devices, posing challenges in constructing features such as ribs and spars within the wing structure, leading to structural instability. To address this, we developed a Variable-Camber and Variable-Chord (VCC) morphing flap that could maintains a continuously transforming surface during deformation, altering both camber shape and chord length simultaneously. Furthermore, we conducted design and fabrication of UAV wings incorporating these morphing flaps, ensuring structural stability by developing specialized shapes. Furthermore, structural experiments were conducted to simulate flight loads, followed by actual flight tests to validate performances of both morphing mechanism and wings. Finally, wind tunnel tests were conducted to compare results with aerodynamic analysis, confirming the effective applicability of this morphing technology.

Enhancing Automated Recognition of Small-Sized Construction Tools Using Synthetic Images: Validating Practical Applicability Through Confidence Scores

  • Soeun HAN;Choongwan KOO
    • International conference on construction engineering and project management
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    • 2024.07a
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    • pp.1308-1308
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    • 2024
  • Computer vision techniques have been widely employed in automated construction management to enhance safety and prevent accidents at construction sites. However, previous research in the field of vision-based approaches has often overlooked small-sized construction tools. These tools present unique challenges in data collection due to their diverse shapes and sizes, as well as in improving model performance to accurately detect and classify them. To address these challenges, this study aimed to enhance the performance of vision-based classifiers for small-sized construction tools, including bucket, cord reel, hammer, and tacker, by leveraging synthetic images generated from a 3D virtual environment. Three classifiers were developed using the YOLOv8 algorithm, each differing in the composition of the training dataset: (i) 'Real-4000', trained on 4,000 authentic images collected through web crawling methods (1,000 images per object); (ii) 'Hybrid-4000', consisting of 2,000 authentic images and 2,000 synthetic images; and (iii) 'Hybrid-8000', incorporating 4,000 authentic images and 4,000 synthetic images. To validate the performance of the classifiers, 144 directly-captured images for each object were collected from real construction sites as the test dataset. The mean Average Precision at an IoU threshold of 0.5 (mAP_0.5) for the classifiers was 79.6%, 90.8%, and 94.8%, respectively, with the 'Hybrid-8000' model demonstrating the highest performance. Notably, for objects with significant shape variations, the use of synthetic images led to the enhanced performance of the vision-based classifiers. Moreover, the practical applicability of the proposed classifiers was validated through confidence scores, particularly between the 'Hybrid-4000' and 'Hybrid-8000' models. Statistical analysis using t-tests indicated that the performance of the 'Hybrid-4000' model would either matched or exceeded that of the 'Hybrid-8000'model based on confidence scores. Thus, employing the 'Hybrid-4000' model may be preferable in terms of data collection efficiency and processing time, contributing to enhanced safety and real-time automation and robotics in construction practices.

A Study on Design Techniques of Palace Gardens presented in Donggwoldo (동궐도에 보이는 궁궐정원의 조영수법)

  • Chin, Sang-Chul
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.4
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    • pp.26-37
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    • 2015
  • This paper aims to review all landscaping elements of Donggwoldo by building and identify the palatial garden landscaping characteristics and landscaping methods in a bid to explore landscaping methods applicable for modern-time gardens of Korea through Succession of Tradition. The research methodology was adopted by which the palatial gardens appearing in Donggwoldo were observed according to garden elements to identify their characteristics. Garden elements in Donggwoldo include oddly shaped stones, ponds, buildings and Madang, borders and areas, and trees. Their characteristics were analyzed, and as a result they are outlined as follows. Location : Buildings in Donggwoldo were located in the optimal areas within the Myungdang (the best location), with the building sites being created by transforming the natural topography positively according to the existing topography and uses. Tree planting : The construction of the buildings involved using the existing trees. There were no specific principle and method of planting trees, and no specific criteria for choosing the kind of tree. Symmetrical planting was adopted and its is considered embracing the viewpoint of making gardens based on the expression of Yin and Yang. Strongly symbolical kinds of trees were also adopted. Bangji : it takes a nearly circular shape in palatial gardens, and such shapes represent conceptual and abstract symbols. They were also frequently used as the place of public entertainment. Pavilions : they did not take a certain standard shape. They had diverse shapes, including a triangle, square, pentagon, hexagon, and octagon and cross. Oddly shaped stones : Oddly shapes stones and stone cases were deployed mainly near the bedroom and the crow prince's residence and in the rear garden. Hwagye : it appeared mainly in the back of the bedroom, the crown prince's residence, the princess's residence, and other women's quarters. Chwibyeong : it was installed for the purpose of drawing the natural energy like a natural inlet instead of being the nature-dividing wall. Korea's garden composition method was very different from the Western and Chinese method. Overall, Chosun palatial garden style was characterized by strict and Confucian features, while the garden construction method adopted the Taoism thought. Yet, the gardens had a carefree aspect.

Digital painting: Image transfonnation, simulation, heterologie and transfonnation (현대회화에서의 형태와 물질 -Digital Transfiguration에 관한 연구-)

  • Jeong, Suk-Yeong
    • Journal of Science of Art and Design
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    • v.10
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    • pp.161-181
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    • 2006
  • The words which appeared in my theoretical study and work are image transformation to digital painting, simulation, heterologie and transfiguration, etc. Firstly, let's look into 'digital era' or 'new media era'. Nowadays, the image world including painting within the rapid social and cultural change, which is called as digital era, is having the dramatic change. Together with the development of scientific technology, large number of events which was deemed to be impossible is happening as real in image world Moreover, these changes in image world is greatly influencing to our life. The word which compresses this change of image world and shows is 'digital'. Digit, which means fingers in Latin, indicates separately changing signal, and to be more narrow, it indicates the continual signal of '0' and ' 1' in computer. The opposite word is 'analogue'. As analogue is the word meaning 'infer' or 'similarity', it indicates the signal or form which continuously changes along the series of time when it is compared to digital. Instead of analogue, digital is embossed as a major ruler along the whole area of our current culture. In whole culture and art area, and in whole generalscience, digital is appearing as it has the modernism and importance. The prefix, 'digital', e.g. digital media, digital culture, digital design, digital philosophy, etc, is treated as the synonym of modernism and something new. This advent of digital results the innovative change to the image world, creates the new beauty experience which we could not experience before, and forecasts the formation of advanced art and expansion of creative area. Various intellectual activities using computer is developing the whole world with making the infrastructure. Computer in painting work immediately accomplishes the idea of painters, takes part in simulation work, contingency such as abrupt reversal, extraction, twisting, shaking, obscureness, overlapping, etc, and timing to stimulate the creativity of painters, and provides digital formative language which enables new visual experience to the audience. When the change of digital era, the image appeared in my work is shown in 'transfiguration' like drawing. The word, 'transfiguration' does not indicate the completed and fixed real substance but indicate endlessly moving and floating shape. Thus, this concept is opposite to the substantial consideration, so that various concepts which is able to replace this in accordance with the similar cases are also exist such as change, deterioration, mutation, deformity of appearance and morphing which is frequently used in computer as a technical word. These concepts are not clearly classified, and variably and complicatedly related. Transfiguration basically means the denial of "objectivity' and '(continual) stagnation' or deviation from those. This phenomenon is appeared through the all art schools of art ever since the realism is denied in the 19th century. It is called as 'deformation' in case of expressionism, futurism, cubism, etc, in the beginning of the century, which its former indication is mostly preserved within the process of structural deviation and which has the realistic limit which should be preserved. On the contrary, dramatic transfiguration which has been showing in the modern era through surrealism is different in the point that dramatic transfiguration tends to show the deterioration and deviation rather than the preservation of indicated object. From this point, transfiguration coming out from morphing using computer deteriorates and hides the reality and furthermore, it replaces the 'reality'. Moreover, transfiguration is closely approached to the world of fake or 'imaginary' simulation world of Baudrillard. According to Baudrillard, the image hides and deteriorates the reality, and furthermore, expresses 'not existing' to 'imaginary' under the name of transfiguration. Certain reality, that is, image which is absent from the reality is created and overflowed, so that it finally replaces the reality. This is simulation as it is said by Baudrillard. In turn, Georges Bataille discusses about the image which is produced by digital technology in terms of heterologie. Image of heterologie is the visual signal which is established with the media. Image of media is to have the continuous characteristics of produce, extinction, and transformation, and its clear boundary between images becomes meaningless. The meaning of composition, excess, violation, etc of digital image is explained to heterological study or heteologie suggested as important meaning of Georges Bataille who is a heretic philosopher. As the form and image of mutation shows the shape in accordance with mechanical production, heterologie is introduced as very low materialism (or bas materialisme), in this theory. Heterologie as low materialism which is gradually changing is developing as a different concept and analysis because of the change of time in the late 20s century beside high or low meaning. Including my image, all images non-standardizes and transforms the code. However, reappearance and non-standardization of this code does not seem to be simple. The problem of transformation caused by transfiguration which appears in my digital drawing painting, simulation, heterologie, etc, are the continual problems. Moreover, the subject such as existence of human being, distance from the real life, politics and social problems are being extended to actual research and various expressing work. Especially, individual image world is established by digital painting transfiguration technique, and its change and review start to have the durability. The consciousness of observers who look at the image is changing the subject. Together with theoretical research, researchers are to establish the first step to approach to various image change of digital era painting through transfiguration technique using our realistic and historical image.

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An Analysis of Body Shapes in Aged Abdominal Obese Women for Apparel Pattern Design (복부비만 노년 여성의 의복패턴설계를 위한 체형연구)

  • Kim, Soo-A;Choi, Hei-Sun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.12 s.159
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    • pp.1690-1696
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    • 2006
  • The purpose of this study is to provide the basic data useful in designing apparel patterns for aged abdominal obese women. The body measurements of 318 women were taken at random, whose ages were over 60 and fields of action were colleges, sports centers, or business sites in Seoul and the neighboring districts. A total of 33 features in the upper body and lower body were used fer the anthropometric measurement and analysis using anthropometry. The collected measurement data were processed statistically using the SPSS 12.0 program for technical statistical analysis, t-test, frequency analysis, correlation analysis. The results of the study are as follows. 1. Subjects were classified into two groups as a result of analysis for measurement data. It was revealed that 251(about 79 percent) women of total subjects(n=318) have a characteristic of abdominal obese body type and elderly women of these group usually had big abdomen rather than hip. The criteria of abdominal obesity based on waist-hip ratio, WHR(=0.85). 2. Aged abdominal obese women have shown much larger size in most body measurements except items of some vertical length, such as bust ponit-bust point, font interscye, back interscye with circumference and depth of armscye, bust, waist, abdomen and hip while showing no difference in height, biacrominal breadth, hip width, neck shoulder point to breast point, crotch length. 3. Vervaeck index(=100.1) and Rohrer index(=1.7) indicated that the abdominal obese women were fat in overall body. And aspect ratio of waist(=0.86), abdomen(=0.92) and hip(=0.75) also appeared high that the shape of cross sections in those regions was similar to a figure of circle 4. In view of the correlation coefficient between hip circumference and the rest measurement items, and between hip circumference inclusively of the abdomen protrusion and the rest measurement items, there were found some differences for each group. In case of Group (abdominal obese group), the former is smaller than the other. 5. In case of Abdominal obese women, hip circumference inclusively of the abdomen protrusion is more mutually related to the rest items related to make apparel pattern as waist circumference, depth of armscye and so on than what hip circumference is. This result indicated which must be considered hip circumference inclusively of the abdomen protrusion to make apparel patterns for abdominal obese women unlike women of common body types.

The relation between Movement working as a Grouping clue in Moving Picture and Semantic structure forming (동영상에서 그룹핑(grouping) 단서로 작용하는 움직임(Movement)과 의미구조 형성의 관계)

  • Lee, Soo-Jin
    • Archives of design research
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    • v.19 no.5 s.67
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    • pp.119-128
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    • 2006
  • The scale of visual expression has expanded from freeze frame to motion picture as media have developed. Moving pictures such as animation, movies, TV CM and GUI become formative elements whose movement is necessary compared to freeze frame as apparent movement phenomenon and unit structure such as short and scene appear. Therefore, of formative elements such as a shape, color, space, size and movement, movement is importantly distinguished in the moving image. The expression and form of image as a relationship between the signified and signifier explained by Saussure are accepted as a sign by mutual complement even though they limit the content. This makes it possible to infer that the formal feature of movement participates in the message content. To verify this, the result of moving picture visual perception experiment based on the gestalt grouping principle result shows that 70-80 percent of subjects think that 'movement' is the important grouping clue in perception. Movement affects the maintenance of the context of message content in the communication process when the meaning structure of moving picture is analyzed based on the structural feature. The identity can be maintained with if there is a movement with similar directive point even if the color and shape of people, things and background are changed. Second, the clarity of the content is elevated by a distinguished object as a figure by movement. Third, it acts as a knowledge representation which can predict similar movement process of next information processing. Forth, movement gives the content consistency even though more than two scenes have fast switch and complicated editing structure like cross-cutting. Movement becomes a clue which can make grouping information input by visual perception reaction. Also, it gives the order to the visual expression which can be used improperly by formation of structural frame of image message and has the effectiveness which elevates the clarity of signification. Moving picture has discourse with several mixed unit structures because it fundamentally contains time and the common and distinguished expression is needed by media-mix circumstances. Therefore, by the application of gestalt grouping principle to moving picture field, movement becomes the more distinguished than other formative elements and affects the formation of meaning structure. This study propose a viewpoint that develops structural formative beauty and new image expression in the media image field.

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A study of Brachytherapy for Intraocular Tumor (안구내 악성종양에 대한 저준위 방사선요법에 관한 연구)

  • Ji, Gwang-Su;Yu, Dae-Heon;Lee, Seong-Gu;Kim, Jae-Hyu;Ji, Yeong-Hun
    • The Journal of Korean Society for Radiation Therapy
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    • v.8 no.1
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    • pp.19-27
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    • 1996
  • I. Project Title A Study of Brachytherapy for intraocular tumor II. Objective and Importance of the project The eye enucleation or external-beam radiation therapy that has been commonly used for the treatment of intraocular tumor have demerits of visual loss and in deficiency of effective tumor dose. Recently, brachytherapy using the plaques containing radioisotope-now treatment method that decrease the demerits of the above mentioned treatment methods and increase the treatment effect-is introduced and performed in the countries, Our purpose of this research is to design suitable shape of plaque for the ophthalmic brachytherapy, and to measure absorbed doses of Ir-192 ophthalmic plaque and thereby calculate the exact radiation dose of tumor and it's adjacent normal tissue. III. Scope and Contents of the project In order to brachytherapy for intraocular tumor, 1. to determine the eye model and selected suitable radioisotope 2. to design the suitable shape of plaque 3. to measure transmission factor and dose distribution for custom made plaques 4. to compare with the these data and results of computer dose calculation models IV. Results and Proposal for Applications The result were as followed. 1. Eye model was determined as a 25mm diameter sphere, Ir-192 was considered the most appropriate as radioisotope for brachytherapy, because of the size, half, energy and availability. 2. Considering the biological response with human tissue and protection of exposed dose, we made the plaques with gold, of which size were 15mm, 17mm and 20mm in diameter, and 1.5mm in thickness. 3. Transmission factor of plaques are all 0.71 with TLD and film dosimetry at the surface of plaques and 0.45, 0.49 at 1.5mm distance of surface, respectively. 4. As compared the measured data for the plaque with Ir-192 seeds to results of computer dose calculation model by Gary Luxton et al. and CAP-PLAN (Radiation Treatment Planning System), absorbed doses are within ${\pm}10\%$ and distance deviations are within 0.4mm Maximum error is $-11.3\%$ and 0.8mm, respectively. As a result of it, we can treat the intraocular tumor more effectively by using custom made gold plaque and Ir-192 seeds.

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