• Title/Summary/Keyword: shape factors

Search Result 2,328, Processing Time 0.038 seconds

Research on the Effects of Boundary Element Characteristics on Reconstruction Accuracy by BEM-based NAH

  • Zhang, Hai-Bin;Kim, Yang-Hann;Jiang, Wei-Kang
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2012.10a
    • /
    • pp.630-635
    • /
    • 2012
  • Nearfield acoustic holography method predicts an unmeasured sound field, therefore it depends on its prediction methods. In particular, if one has radiators or scatters, which cannot be expressed by simple geometry, then inverse boundary element method (BEM) is normally employed to reconstruct the sound field induced by sound sources with irregular profiles. The characteristics of boundary element, including the element shape, characteristic length, order of shape function and others, affect the reconstruction error. Investigating the errors by means of changing these factors will provide a guide line for selecting appropriate factors, associated with the elements of BEM. These factors are investigated by numerical simulations, and the accuracies with respect to the variant factors are compared. Novel suggestions for selecting appropriate boundary element factors are described based on the simulation results.

  • PDF

The Effect of Plunger Tip Shape on the Formability in Semi-Solid Die Casting Process (반용융 다이캐스팅 공정에 있어서 플런저 팁의 형상이 성형성에 미치는 영향)

  • 서판기;손영익;강충길
    • Transactions of Materials Processing
    • /
    • v.11 no.4
    • /
    • pp.312-322
    • /
    • 2002
  • In this study, an innovative semi-solid die casting technology to replace heavier cast iron compressor parts with lightweight aluminum castings was proposed, and the application possibility for home-appliance component was investigated. The most important factors regarding the semi-solid die casting process are the reheating process of the raw materials to the semi-solid state, specifications of the forming machine, the optimal injection conditions and die design. Materials used in this study were A3S7 and hSn alloys fabricated by the electromagnetic stirring process. The optimal injection conditions for semi-solid die casting process were Presented with the reheating conditions of the semi-solid materials. To investigate the effect of plunger tip shape on the formability and mechanical properties in semi-solid die casting process for complicated shape part, two kinds of plunger tip shape with long and short plunger tip taper are proposed.

A Study on Shape Design of NFR Suspension for Optimal Dynamic Characteristics (NFR 서스펜션의 동특성을 고려한 형상설계에 관한 연구)

  • Eun, Gil-Soo;Kim, Noh-Yu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2002.11b
    • /
    • pp.771-776
    • /
    • 2002
  • Optimal shape of the NFR suspension is studied and developed to improve the dynamic performance and reduce the vibration of the suspension system including a optical head slider. Since accurate position control and stability of the slider motion are highly required in NFR due to the narrower track width and the heavier slider than HDD slider with the low flying height, the dynamic characteristics of the suspension are very important to the mechanical performance of the system. The first natural frequencies in flexural and lateral motion of the suspension are critical factors affecting the dynamics and stability of the flying head, so that the dynamic parameters should be designed properly to avoid an excessive vibration or a crash of the slider on the disk. This paper optimizes the shape of the suspension based on homogenization method in NASTRAN and develops a new suspension shape for NFR system. The suspension is tested on experiment to verify the improvement of the dynamic characteristics.

  • PDF

Improvement of the Flow Around Airfoil/Flat-Plate Junctures by Optimization of the Leading-Edge Shape (날개-평판 접합부에서의 날개 앞전 형상 최적화를 통한 유동특성 향상)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.257-265
    • /
    • 2009
  • The present study deals with the leading edge shape on a wing-body junction to decrease a horseshoe vortex, one of the main factors to generate the secondary flow losses. The shape of leading-edge is optimized with design variables form the leading-edge shape. Approximate optimization design method is used for the optimization. The study is investigated using $FLUENT^{TM}$ and $iSIGHT^{TM}$. As the result, total pressure coefficient of the optimized design case was decreased about 9.79% compare to the baseline case.

  • PDF

A Study on the Compensation of Blood Pressure Caused by the Change of Arterial Pressure Shape (동맥압 형태변화에 따른 혈압 보정에 관한 연구)

  • Lim, S.S.;Park, K.L.;Lee, K.J.
    • Proceedings of the KOSOMBE Conference
    • /
    • v.1998 no.11
    • /
    • pp.177-178
    • /
    • 1998
  • This paper is a study on compensation for error in estimation of mean pressure according to the change of arterial pressure shape. Because arterial pressure shape affects the mean pressure and blood volume which are important factors for measurement of blood pressure(BP), change of arterial pressure shape cause BP measurement error. In order to solve this problem, we add the compensation function C($\alpha$), depending on arterial pressure shape, to mathematical oscillometric model. Consequently, we could accurately estimate the blood pressure by correcting of the error using compensation function.

  • PDF

Body Weight and Body Image: A Risk Factor Analysis in Korea

  • Kim, Sang-Wook
    • Survey Research
    • /
    • v.12 no.3
    • /
    • pp.143-172
    • /
    • 2011
  • The relationship between body weight and body image, an objective and subjective measure of body shape, respectively, has long been a recurrent concern in the area of medical sociology and health-related studies. This concern stems from the argument and findings in the literature indicating that the two are not necessarily likely to be strongly correlated due mostly to the fact that one's own idea or conception about his/her body shape could be pretty different from one's actual shape. This study tries to empirically address the two issues based on the analysis of a national sample survey data in Korea: to what extent body weight and body image are correlated with or deviated from each other, on the one hand, and what factors help to account for the relationship between the two, on the other. The latest(2010) national sample data of KGSS(Korean General Social Survey) is used to evaluate the issues. Results of data analysis demonstrate that body weight and image have a moderate amount of correlation, and that the correlation tends to vary to a large extent depending on a few major socio-demographic and socio-economic characteristics. Most important, the risk factor analysis attempted in this study could identify several salient risk factors, which include gender, age, chronic diseases, smoking, physical exercises, and medical checkup. To be precise, those who may be best characterized as particularly risky to weight gains are females, who are in their 20's, who have chronic diseases, non-smokers, who exercise regularly, and who conduct medical checkups on a regular basis. To extrapolate, the findings suggest that the most typically risky kinds of individuals in Korea are "young women who care very much for their health." The findings are interpreted and discussed with suggesting a recommendation for further studies.

  • PDF

Upper Body Somatotype Classification and Discrimination of Elderly Women according to Index (지수치를 이용한 노년 여성의 상반신 체형 분류와 판별에 관한 연구)

  • 김수아;최혜선
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.28 no.7
    • /
    • pp.983-994
    • /
    • 2004
  • The aim of this study is to provide fundamental data on the development of ready-to-wear clothes appropriate for the body types of elderly women. The study was conducted targeting 318 elderly women over 60 years of age whose fields of action were colleges for the elderly, sports centers, or business sites in Seoul and the neighboring districts. A total of 44 features in the upper body were used for the anthropometric measurement and analysis using anthropometry and photometry. The results of the study are as follows: 1. Somatotypes were classified into three types according to a cluster analysis using height and weight indices. Type 1 is the group with long and undersized upper body and straight body type since the face of the upper body is long relative to height and width, girth and depth are the smallest relative to weight, the breasts are somewhat fat, with a small extent of drooping and a straight back. Type 2 is the group that is considered fat relative to the body, has broad shoulders, drooping breasts with a wide space between them, and a back-bent upper body. Type 3 is the group that has a bent shape, the shortest upper body relative to height, and showing average obesity factors. 2. Indices of height and weight were used for factor analysis, cluster analysis, and discriminant analysis in order to classify upper body somatotype according to shape while excluding size factors of elderly women's upper body somatotype. The same method was used to compare and verify the result according to the absolute measurement and height index. Classification based on height and weight indices demonstrate that such somatotype classification minimizes the personal equation of body shape and it induces better classification based on shape as the results showed the highest cumulative sum of square(CUSUM) at 78.38% while six factors showed the smallest result and the hit rate for the classified three groups showed the highest result at 95.30%.

Korean Adolescents' Clothing Behavior as Related to Self-Consciousness and Weight Control Practices (청소년기의 자의식 및 체중조절행동자 의복행동과의 관련연구)

  • 심정은;고애란
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.21 no.8
    • /
    • pp.1334-1345
    • /
    • 1997
  • The purpose of this study were 1) to identify the effects of age and sex of Korean adolescents on the psychological variables(body attitudes, public/private self-consciousness, self-esteem), weight control practices, and clothing behaviors, and 2) to identify the relation- ships between psychological variables and weight control practices, and the effects of the variables on clothing behaviors in the adolescent' groups classified by sex and age. The results of this study were as follows: 1) Two factors of body attitudes were identified: Body-shape consciousness and Physical attractiveness. Four factors of clothing attitudes were identified: Clothing interest/dressing for others, Clothing exhibition, Dressing for self, and Psychological clothing-dependerlce. 2) There were significant effects of sex on all of the research variables. Age was found to have effects on Physical attractiveness, self-esteem, public/private self-consciousness, Clothing exhibition, and Psychological clothing- dependence. 3) In the relationships between psychological variables and weight control practices, Body-shape consciousness was negatively correlated with Physical attractiveness in all groups. Also, Body-shape consciousness had effects on weight control practice in all subject groups. 4) Public self-consciousness had direct/indirect effects on the Clothing interest/dressing for others in all subject groups. Private self-consciousness had direct/ indirect effects on dressing for self in high school boys and girls. Body-shape consciousness had indirect effects on Preference for up-to date style in male college students group, whereas weight control practices had effects on the Preference for up-to date style in female college students group. Self-esteem was found to have the effects on clothing behavior in college students groups. Among clothing attitude factors, Clothing exhibition had distinct effects on the Preference for up-to date style in all subject groups, and Clothing interest/dressing for others had effects on Clothing exhibition and Psychological clothing-dependence in high school boys and girs.

  • PDF

An analysis on the factors responsible for relative position of interproximal papilla in healthy subjects

  • Kim, Joo-Hee;Cho, Yun-Jung;Lee, Ju-Youn;Kim, Sung-Jo;Choi, Jeom-Il
    • Journal of Periodontal and Implant Science
    • /
    • v.43 no.4
    • /
    • pp.160-167
    • /
    • 2013
  • Purpose: This study examined the factors that can be associated with the appearance of the interproximal papilla. Methods: One hundred and forty-seven healthy interproximal papillae between the maxillary central incisors were examined. For each subject, a digital photograph and periapical radiograph of the interdental embrasure were taken using a 1-mm grid metal piece. The following parameters were recorded: the amount of recession of the interproximal papilla, contact point-bone crest distance, contact point-cemento-enamel junction (CEJ) distance, CEJ-bone crest distance, inter-radicular distance, tooth shape, embrasure space size, interproximal contact area, gingival biotype, papilla height, and papilla tip form. Results: The amount of recession of the interproximal papilla was associated with the following: 1) increase in contact point-bone crest, contact point-CEJ, and CEJ-bone crest distance; 2) increase in the inter-radicular distance; 3) triangular tooth shape; 4) decrease in the interproximal contact area length; 5) increase in the embrasure space size; and 6) flat papilla tip form. On the other hand, the amount of gingival recession was not associated with the gingival biotype or papilla height. In the triangular tooth shape, the contact point-bone crest distance and inter-radicular distance were longer, the interproximal contact area length was shorter, and the embrasure space size was larger. The papilla tip form became flatter with increasing inter-radicular distance and CEJ-bone crest distance. Conclusions: The relative position of the interproximal papilla in healthy subjects was associated with the multiple factors and each factor was related to the others. A triangular tooth shape carries a higher risk of recession of the interproximal papilla because the proximal contact point is positioned more incisally and the bone crest is positioned more apically. This results in an increase in recession of the interproximal papilla and flat papilla tip form.

Classification of Torso Shape According to Abdominal Protrusion of Middle-Aged Women (중년 여성 복부 돌출 정도에 따른 토르소 형태 분류)

  • Do, Wolhee;Lee, Jeongeun
    • Fashion & Textile Research Journal
    • /
    • v.23 no.2
    • /
    • pp.226-236
    • /
    • 2021
  • The purpose of this study was to classify the torso shape based on abdominal protrusion caused by changes in the physical characteristics of middle-aged women. This study analyzed 3D shape data of 401 females ranging in age from 40 to 59 years who participated in the 6th Size Korea project. Based on the Size Korea 3D measurement standard, 27 additional items such as height, protrusion, and angle were measured in the 3D scan data. Nine factors were extracted from the analysis of constituent factors of the torso: "vertical size of torso," "flatness and protrusion of abdomen," "torso front extrusion," "upper body height," "bust size and flatness," "size of belly and angle of lower abdomen," "hip length," "hip flatness," and "horizontal size of bust." As a result of the cluster analysis using these nine factors, the torsos of middle-aged women were classified into three types. Type 1 has upper abdominal deposition with a small and long upper body and an advanced abdomen; type 2 has lower abdominal deposition with a small and short torso and a small belly and hip flexion; and type 3 has central abdominal deposition with a big and long torso, large breasts, and protruding abdo¬men front. The middle-aged women were mostly distributed in Type 2. The above results will be useful as basic data for the development of clothing with improved fit to accommodate the changed physical characteristics of middle-aged women.