• Title/Summary/Keyword: restitution

Search Result 113, Processing Time 0.023 seconds

An Analysis of Wind environment on the Basis of reclassified Zoning (주거지역 종세분화에 따른 바람환경 분석)

  • Lee, Jun-Young;Jung, Eung-Ho;Kim, Dae-Wuk;Cha, Jae-Gyu
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2009.11a
    • /
    • pp.109-112
    • /
    • 2009
  • Various environmental problems due to the rapid industralization and urbanization have been worsened as much as to threaten the environmental restitution of globe and become a critical international issue. Korean government presented the green growth as a new state vision for 60 years afterwards and is making efforts to solve the environmental problems. Daegu metropolitan city has faced various environmental problems including overpopulation of cities, traffic pollution, household wastes and green zone problem because of urbanization for the last decades. As such urbanism continues, the quality of residential environment is rapidly deteriorating and the intensive use of land leads to increase of building area raising the temperature of cities. Therefore there have been demands for the healthy, pleasant and satisfying residential environment and the improvement of residential environment and such recognition rises from society in full measure. Nevertheless the current residential complex concentrates only on raising the efficiency of land use. Related laws in the past(Daegu Metropolitan City, Urban Planning Municipal Ordinance as of October 10, 2003) tried to prepare a standard to segmentalize the building-to-land ratio, floor area ratio and regulations of number of floors vertically, but currently it is abolished and the regulations are becoming eased. The purpose of this study was to analyze the characteristics of the floating wind before and after the vertical segmentation of residential areas(Daegu Metropolitan City, Urban Planning Municipal Ordinance as of October 10, 2003) by using KLAM_21, a model that enables analysing and predicting the flow and generation of clod wind, and to present a plan to improve the quality of residential areas afterwards when developing building lot and re-developing housing areas.

  • PDF

A Study on the Collision Behavior of Fairy Cycle to Vehicle (어린이용 자전거의 차량 충돌거동에 관한 연구)

  • Kang, Dae-Min;Ahn, Seung-Mo
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.20 no.1
    • /
    • pp.106-111
    • /
    • 2012
  • Recently the usage of bicycle has increased steeply in Korea owing to traffic culture of well- being. In a car to bicycle accident investigation, the throw distance of bicycle is very important factor for reconstructing of the accident. The variables that influence on the throw distance of bicycle can be classified into the factors of vehicle and bicycle. Simulations and collision tests in actual car to bicycle accident were executed for obtaining throw distance of bicycle. The simulations were done by PC-$CRASH^{TM}$ and for actual crash tests sand bags were used for the behavior of bicyclist instead of dummy. Factors considered were vehicle velocity and the moving angles of bicycle, also the types of bicycle and vehicle were fairy cycle and automobile, respectively. From the results, the throw distances of a head-on tire collision of $0^{\circ}$ direction was longer than that of tire crash test of $45^{\circ}$ direction, and the throw distances of a head -on frame crash test of $90^{\circ}$ direction was longer than that of frame crash test of $45^{\circ}$ direction. In addition restitution coefficient between vehicle and bicycle was estimated as about 0.1 with based on actual crash tests. Finally the increaser vehicle velocity the longer the throw distances of bicycle, and the results of simulation were relatively good agreement to the experimental results.

A Study on Golf Ball Spin Mechanism at Impact (골프 공의 충돌 시 스핀 생성 원리 연구)

  • Roh, Woo-Jin;Lee, Chong-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.17 no.5 s.122
    • /
    • pp.456-463
    • /
    • 2007
  • It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and force. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail in the literature. In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.

A Study on Golf Ball Spin Mechanism at Impact (골프 공의 충돌 시 스핀 생성 원리 연구)

  • Roh, Woo-Jin;Lee, Chong-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2007.05a
    • /
    • pp.1017-1022
    • /
    • 2007
  • It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and force. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail in the literature. In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.

  • PDF

A Application Method of Plotting Original Data (도화원도의 활용방안)

  • Lee, Yong-Wook
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.29 no.5
    • /
    • pp.441-448
    • /
    • 2011
  • Lately, digital restitution was became common using digital aerial photos. Therefore, we can obtain three-dimensional data. As a plotting-maker is checked by naked eye, plotting original data is very useful for making reliable three-dimensional data including contour and elevation point layers. In this study, we want to make precise and accurate digital elevation model using plotting original data. Contour and elevation point layers was extracted in digital map and break line was extracted in plotting original data. And then, compared both of results. For comparison, we selected slight slope and complex topography area like a residence area, mountain and agricultural land. We extracted break line deleting layer until obtaining ideal digital elevation model. As the results, We could extract contour, elevation points, eight road and two boundary layers using break lines. And We could obtain precise elevation model. Editing break lines, the distortion of digital elevation model could be minimized in the complex and sharp slope area.

Automobile Collision Reconstruction Using Post-Impact Velocities and Crush Profile (충돌 후 속도와 충돌 변형으로부터 자동차 충돌 재구성)

  • 한인환
    • Journal of Korean Society of Transportation
    • /
    • v.18 no.4
    • /
    • pp.107-115
    • /
    • 2000
  • We suggest a method which solves the planar, two vehicle collision reconstruction problem. The method based on the Principle of impulse and momentum determines the pre-impact velocity components from Post-impact velocity components, vehicle Physical data and collision geometry. A novel feature is that although the impact coefficients such as the restitution coefficient and the impulse ratio are unknown, the method can estimate automatically the coefficients and calculate the pre-impact velocity components. This reverse calculation is important for vehicle accident reconstruction, since the pre-impact velocities are unknown and Post-impact Phase is the starting Point in a usual collision analysis. However. an inverse solution is not always Possible with the analytical rigid-body impact model. Mathematically, one does not exist under the common velocity condition. On the other hand, our method has a capability of reverse calculation under the condition if the absorbed energy during the collision process can be estimated using the crush profile. To validate the developed collision reconstruction a1gorithm, we use car-to-car collision test results. The analysis and experimental results agree well in the impact coefficients and the Pre-impact velocity components.

  • PDF

Barrett's Esophagus and β-carotene Therapy: Symptomatic Improvement in GERD and Enhanced HSP70 Expression in Esophageal Mucosa

  • Dutta, Sudhir K.;Agrawal, Kireet;Girotra, Mohit;Fleisher, A. Steven;Motevalli, Mahnaz;Mah'moud, Mitchell A.;Nair, Padmanabhan P.
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.12
    • /
    • pp.6011-6016
    • /
    • 2012
  • Introduction: Epidemiological studies suggest a protective role for ${\beta}$-carotene with several malignancies. Esophageal adenocarcinoma frequently arises from Barrett's esophagus (BE). We postulated that ${\beta}$-carotene therapy maybe protective in BE. Materials and Method: We conducted a prospective study in which 25 mg of ${\beta}$-carotene was administered daily for six-months to six patients. Each patient underwent upper endoscopy before and after therapy and multiple mucosal biopsies were obtained. Additionally, patients completed a gastroesophageal reflux disease (GERD) symptoms questionnaire before and after therapy and severity score was calculated. To study the effect of ${\beta}$-carotene at molecular level, tissue extracts of the esophageal mucosal biopsy were subjected to assessment of heat-shock protein 70 (HSP70). Results: A significant (p<0.05) reduction in mean GERD symptoms severity score from $7.0{\pm}2.4$ to $2.7{\pm}1.7$ following ${\beta}$-carotene therapy was noted. Measurement of Barrett's segment also revealed a significant reduction in mean length after therapy. In fact, two patients had complete disappearance of intestinal metaplasia. Furthermore, marked enhancement of HSP70 expression was demonstrated in biopsy specimens from Barrett's epithelium in four cases that were tested. Conclusions: Long-term ${\beta}$-carotene therapy realizes amelioration of GERD symptoms along with restitution of the histological and molecular changes in esophageal mucosa of patients with BE, associated with concurrent increase in mucosal HSP70 expression.

The Analysis Accuracy of Mapping using Direct Georeferencing (Direct Georeferencing을 이용한 도화 정확도 분석)

  • Song Youn-Kyung;Lee Jae-One
    • Spatial Information Research
    • /
    • v.13 no.1 s.32
    • /
    • pp.31-41
    • /
    • 2005
  • In order to carry out aerial photogrammetry using GPS/INS, it is necessary to apply exterior orientation parameters, obtained while making a photo, to the editing process. It should be noted that the verification process of aerial mapping result is the most crucial process at the GPS/INS based digital photogrammetry. To this end, this study has compared the mapping result by the ways of AT results, plotter, and orientation, which is from basis of the Analytical raw map produced by the existing AT results. When comparing the horizontal and vertical accuracy of the analytical mapping with that of digital restitution, it could be found that the latter is more accurate than that of the former. In addition, it was reveled that the horizontal error was bigger than that of vertical one. Even though the accuracy of the GPS/INS based AT Direct orientation was three times poorer than the of indirect one, it was recognized that the photogrammetry process was effectively performed in the application of scale 1:5000 mapping with satisfying the allowance errors.

  • PDF

Protective Effect of Lactobacillus fermentum LA12 in an Alcohol-Induced Rat Model of Alcoholic Steatohepatitis

  • Kim, Byoung-Kook;Lee, In-Ock;Tan, Pei-Lei;Eor, Ju-Young;Hwang, Jae-Kwan;Kim, Sae-Hun
    • Food Science of Animal Resources
    • /
    • v.37 no.6
    • /
    • pp.931-939
    • /
    • 2017
  • Alcoholic liver disease (ALD) is a complex multifaceted disease that involves oxidative stress and inflammation as the key mediators. Despite decades of intensive research, there are no FDA-approved therapies, and/or no effective cure is yet available. Probiotics have received increasing attention in the past few years due to their well-documented gastrointestinal health-promoting effects. Interestingly, emerging studies have suggested that certain probiotics may offer benefits beyond the gut. Lactobacillus fermentum LA12 has been previously demonstrated to play a role in inflammatory-related disease. However, the possible protective effect of L. fermentum LA12 on ALD still remain to be explored. Thus, the aim of this study was to evaluate the possible protective effect of L. fermentum LA12 on alcohol-induced gut barrier dysfunction and liver damage in a rat model of alcoholic steatohepatitis (ASH). Daily oral administration of L. fermentum LA12 in rat model of ASH for four weeks was shown to significantly reduced intestinal nitric oxide production and hyperpermeability. Moreover, small intestinal histological- and qRT-PCR analysis further revealed that L. fermentum LA12 treatment was capable of up-regulating the mRNA expression levels of tight junction proteins, thereby stimulating the restitution of barrier structure and function. Serum and hepatic analyses also revealed that the restoration of epithelial barrier function may prevent the leakage of endotoxin into the blood, subsequently improve liver function and hepatic steatosis in the L. fermentum LA12-treated rats. Altogether, results in this study suggest that L. fermentum LA12 may be used as a dietary adjunct for the prevention and treatment of ASH.

The Digital Drawing Production Using Digital Camera (디지털 카메라를 이용한 수치도면작성)

  • Choi, Seung-Pil;Park, Jong-Sun;Choi, Chul-Soon
    • Journal of Korean Society for Geospatial Information Science
    • /
    • v.12 no.3 s.30
    • /
    • pp.91-97
    • /
    • 2004
  • As for the former analogue method of photogrammetry, We have obtained final digital drawing by creating the stereo model from overlapped images through orientation process using plotting instrument and processing restitution procedure. However, digital photogrammetry batch processes such using small computer system thus We make an attempt automatization of the procedures. And without the production of stereo model, We could obtain 3D digital data through analysis method. Therefore, an objective of this study was to implement a surveying system that could 3D surveying positions using the digital image to reduce limitations of control point surveying and photographing conditions more efficiently to produce digital drawing. By the result, photogrammetry can practice and make out digital drawing to a computer by digital camera of a comparative low-cost. Small scale area can become practical use to drawing production etc. for facilities management because area can make out digital drawing economically than general surveying.

  • PDF