• 제목/요약/키워드: cant

검색결과 166건 처리시간 0.018초

The influence of age on lip-line cant in adults: a cross-sectional study

  • Choi, Sung Hwan;Kim, Jung Suk;Kim, Cheol Soon;Hwang, Chung Ju
    • 대한치과교정학회지
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    • 제46권2호
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    • pp.81-86
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    • 2016
  • Objective: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. Methods: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). Results: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had $1.6^{\circ}$ of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). Conclusions: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.

음운론적 변이에 의한 신조 상말의 생성에 대하여 (A Study on Newly-coined Cant creations in compliance with Phonological Variation)

  • 박철주
    • 대한음성학회:학술대회논문집
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    • 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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    • pp.87-90
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    • 2007
  • We encounter new cant in these days. The cant is classified as 'variation cant' which is used in the communication language. Therefore, this Study will focus on the aspects and the actual conditions of the cant in communication language.

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곡선부 통과 차량의 진동특성 및 안전성 평가 (A Safety Assessment and Vibration Characteristics of Railway Vehicle Passing Curves)

  • 박광수;이승일;이희성
    • 한국소음진동공학회논문집
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    • 제17권10호
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    • pp.993-1001
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    • 2007
  • An analysis model has been developed to assess running safety of railway vehicle passing curves. By using ADAMS/Rail, a computer analysis has been conducted by changing various parameters according to the track conditions. Analysis results show as follows: A derailment coefficient of left wheel was increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A unload rate of left wheel was also increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A wear number of left wheel was increased according to increase of cant at all speed, but only at 35 m/s, it was decreased as increase of cant. A friction coefficient of left wheel was Increased according to increase of cant at all speed, but only at 35 m/s. it was decreased as increase of cant.

일반철도의 저속 및 고속열차 혼용구간 최소곡선반경 및 설정캔트범위 검토 (Review of Minimum Curve Radius and Cant Range Setting for Mixed Section of Low and High speed Trains in Conventional Railway Line)

  • 이재혁;김정혁;박용걸
    • 한국산학기술학회논문지
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    • 제21권10호
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    • pp.345-353
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    • 2020
  • 일반철도의 경우 운행속도가 다양한 여객열차와 화물열차가 혼용되기 때문에 차량이 곡선구간을 주행할 경우에는 승객의 승차감과 열차의 주행안전성을 확보하기 위하여 최소곡선반경을 설정하고 운행속도에 적합한 균형캔트, 부족캔트 및 초과캔트 설정범위를 만족하는 캔트를 설정하여야 한다. 본 논문에서는 선로의 곡선반경, 캔트, 열차속도의 상관관계를 분석하여 열차종별 운행속도, 부족캔트와 초과캔트에 대한 기준을 만족하는 캔트범위를 분석하고 곡선반경에 대한 현재 설계기준의 적정성을 검토하여 최적의 최소곡선반경을 제시하고자 한다. 또한, 회귀분석을 통한 열차혼용시 운행 빈도에 따른 열차운행속도를 산정하여 고속열차 횟수비에 따른 균형캔트와 곡선반경별 설정캔트 범위를 산정하였다. 위의 결과를 바탕으로 최소곡선반경과 설정캔트의 적정범위를 제시함으로써 노반과 궤도설계에 반영하여 운영노선의 속도향상, 부족캔트에 의한 승차감저하 및 탈선위험을 방지하고, 초과캔트에 의한 하중편중을 최소화하여 곡선선로를 주행하는 열차의 주행안전성 확보와 선로유지관리 효율성을 향상하고자 하였다.

레일 캔트 변화에 따른 주행특성에 관한 연구 (A Study on the Running Characteristic by Rail cant variation)

  • 엄범규;김영규;이승일;이희성
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.1142-1147
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    • 2011
  • The rail cant produces a wider bearing area between the wheel and the rail by moving the wheel-rail contact area away from the gauge towards the centre of the railhead, thus improving the wear pattern of the railhead and wheel treads. It is essential to keep the rail cant within the allowable range to ensure optimum track geometry. Neglecting the rail cant geometrical parameters in a track quality evaluation can cause safety of railway vehicle and serviceability problems. In this paper, we examined the effect of the rail cant in general geometry state of the railway track using VI-Rail and analyzed running safety when the railway vehicle passing through curves depending on change of the rail cant and running speed.

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철도곡선구간에 있어서 캔트 설정에 관한 연구 (A Study on the Cant Setting in Railway Curve Section)

  • 이남수
    • 한국측량학회지
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    • 제11권1호
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    • pp.1-6
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    • 1993
  • 철도곡선구간의 일부에서 캔트 설정이 잘못됨으로 인해 가끔 곡선관리에 혼돈이 발생한다. 본 연구에서는 곡률반경별, 캔트체감 길이별 캔트량을 조사하여 직선체감 이론과 비교, 분석해봄으로써 철도곡선구간에 있어 효율인 관리 방법을 제시하였다.

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부족캔트량과 레일마모의 상관관계 고찰 (A Study on a Mutual Relation of Cant Deficiency/Rail Wear in Metro Lines)

  • 홍철기;양신추;김연태
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2001년도 추계학술대회 논문집
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    • pp.481-487
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    • 2001
  • In this study, the relation between cant deficiency(C') and rail wear in Seoul Metro Line 5 with STEDEF track structure(concrete bed) is studied. As a result, it is found that cant deficiency have a direct influence on rail wear, and under the condition that other negative effects are neglected, the cant deficiency in Metro Lines is demanded to set as little as possible.

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Characterization of facial asymmetry phenotypes in adult patients with skeletal Class III malocclusion using three-dimensional computed tomography and cluster analysis

  • Ha, Sang-Woon;Kim, Su-Jung;Choi, Jin-Young;Baek, Seung-Hak
    • 대한치과교정학회지
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    • 제52권2호
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    • pp.85-101
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    • 2022
  • Objective: To classify facial asymmetry (FA) phenotypes in adult patients with skeletal Class III (C-III) malocclusion. Methods: A total of 120 C-III patients who underwent orthognathic surgery (OGS) and whose three-dimensional computed tomography images were taken one month prior to OGS were evaluated. Thirty hard tissue landmarks were identified. After measurement of 22 variables, including cant (°, mm), shift (mm), and yaw (°) of the maxilla, maxillary dentition (Max-dent), mandibular dentition, mandible, and mandibular border (Man-border) and differences in the frontal ramus angle (FRA, °) and ramus height (RH, mm), K-means cluster analysis was conducted using three variables (cant in the Max-dent [mm] and shift [mm] and yaw [°] in the Manborder). Statistical analyses were conducted to characterize the differences in the FA variables among the clusters. Results: The FA phenotypes were classified into five types: 1) non-asymmetry type (35.8%); 2) maxillary-cant type (14.2%; severe cant of the Max-dent, mild shift of the Man-border); 3) mandibular-shift and yaw type (16.7%; moderate shift and yaw of the Man-border, mild RH-difference); 4) complex type (9.2%; severe cant of the Max-dent, moderate cant, severe shift, and severe yaw of the Man-border, moderate differences in FRA and RH); and 5) maxillary reverse-cant type (24.2%; reverse-cant of the Max-dent). Strategic decompensation by pre-surgical orthodontic treatment and considerations for OGS planning were proposed according to the FA phenotypes. Conclusions: This FA phenotype classification may be an effective tool for differential diagnosis and surgical planning for Class III patients with FA.

기존선의 선형조건을 고려한 틸팅차량의 허용속도 평가 (Allowable Speed of Tilting Car in the Conventional Line)

  • 유영화;엄주환;엄기영
    • 한국철도학회논문집
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    • 제6권4호
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    • pp.246-251
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    • 2003
  • A quantitative analysis on the amounts of cant and lateral displacement of gravitational center due to the introduction of high-speed tilting car was carried out, based on the current alignment of the conventional line. In addition, the maximum allowable speed in curve and the level of improvement in maximum speed of tilting car were evaluated through the comparison with the maximum speed of locomotive. It was found that the tilting car produces an equivalent amount of cant, which corresponds to 47.5 % of current actual cant. This effect could be explained by the fact that 1.34 m, which is the height of gravitational center of tilting car from the rail level, is much lower than that of locomotive and thus guarantees much higher level of safety in curve. The equivalent amount of cant due to the lateral displacement of gravitational center followed by tilting in curve was 2.4 mm. It was small but not enough to be neglected and must be included in calculating the maximum speed in curve. It could be concluded that the 15 % speed-up of the conventional line is reasonable under the current condition of alignment.

Frankfort horizontal plane is an appropriate three-dimensinal reference in the evaluation of clinical and skeletal cant

  • Oh, Suseok;Ahn, Jaemyung;Nam, Ki-Uk;Paeng, Jun-Young;Hong, Jongrak
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제39권2호
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    • pp.71-76
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    • 2013
  • Objectives: In three-dimensional computed tomography (3D-CT), the cant is evaluated by measuring the distance between the reference plane (or line) and the tooth. The purpose of this study was to determine the horizontal skeletal reference plane that showed the greatest correlation with clinical evaluation. Materials and Methods: The subjects were 15 patients who closed their eyes during the CT image taking process. The menton points of all patients deviated by more than 3 mm. In the first evaluation, clinical cant was measured. The distance from the inner canthus to the ipsilateral canine tip and the distance from the eyelid to the ipsilateral first molar were obtained. The distance between the left and right sides was also measured. In the second evaluation, skeletal cant was measured. Six reference planes and one line were used for the evaluation of occlusal cant: 1) FH plane R: Or.R - Or.L - Po.R; 2) FH plane L: Or.R - Or.L - Po.L; 3) F. Ovale plane R: Rt.F.Ovale - Lt.F.Ovale - Or.R; 4) F. Ovale plane L: Rt.F.Ovale - Lt.F.Ovale - Or.L; 5) FZS plane R: Rt.FZS - Lt.FZS - Po.R; 6) FZS plane R: Rt.FZS - Lt.FZS - Po.L, and; 7) FZS line: Rt.FZS - Lt.FZS. Results: The clinical and skeletal cants were compared using linear regression analysis. The FH plane R, FH plane L, and FZS line showed the highest correlation (P<0.05). Conclusion: The FH plane R and FH plane L are the most appropriate horizontal reference plane in evaluation of occlusal cant on 3D-CT.