• Title/Summary/Keyword: Symmetrical

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High Dispersion Line Profiles of the Planetary Nebula NGC 6833 and its Implication

  • Lee, Seong-Jae;Hyung, Siek
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.73.1-73.1
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    • 2010
  • Using the spectroscopic data secured with the Hamilton Echelle Spectrograph attached to a 3-m telescope at the Lick Observatory, we derived the expansion velocities from various line profiles in the 3600 $\AA$ to 10,000 $\AA$ based on the full width at half maximum and double peak of the high dispersion line profiles. The symmetrical shapes of the permitted line profiles indicate that the permitted line zone is symmetrical e.g., a spherical shell or bipolar + torus structures, which might be evidence of relatively recent ejection from the central star. Most other stronger forbidden lines might be coming from a main shell which appears as a bilateral symmetrical morphology, seen in HST and other ground-based telescopic images. The overall expansion velocities of this main shell structure that are responsible for most lines, seem to show the Hubble type expansion, i.e., accelerating shell. The faster expansion velocities of the permitted OII, NII, NIII and perhaps CII lines that do not suit to the Hubble type expansion, imply the existence of a somewhat smaller inner shell inside the outer main shell. We conclude that the nebular shell consists of a swiftly expanding inner shell and an outer normal shell excited by a central star of about 55,000K. The former compact zone appears to be responsible for the permitted C, N, and O lines while the latter extended shell appears to be responsible for H, He, and forbidden lines. We present some evidence that NGC 6833 be a member of the Galactic halo.

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A Modified Bresenham's Line Drawing Algorithm Using Symmetrical Property of Line Segment (직선 선분의 대칭성을 이용한 수정 브레제남 직선 그리기 알고리즘)

  • Lee, Sang-Rak;Hong, Yun-Sik
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.8
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    • pp.2213-2221
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    • 1999
  • A line segment has a symmetrical property about its midpoint. With this symmetrical property for a line segment we have proposed a variant of Bresenham's line drawing algorithm that selects two pixels at the same time. It implies that bi-directional line drawing toward the midpoint of line segment from each-end be possible. Besiders, it can select two pixels using only one decision parameter, instead of two different parameters for each pixel. We also present a theoretical proof for the correctness of such a selection. Thus, we can reduce the time of generating line segment by approximately less than 5% compared to the Bresenham's method. Also, our experimental results show that the shape of line segment generated by the proposed approach is the exactly same as that of Bresenham's method.

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The Effects of Symmetrical Scapular Alignment on Weight Bearing of Hemiplegic Patients During Standing Position (편마비 환자의 견갑골 대칭적 정렬상태가 선 자세에서 체중부하지지율에 미치는 영향)

  • You, Young-Youl;Ann, Chang-Sik
    • The Journal of Korean Physical Therapy
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    • v.21 no.2
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    • pp.23-29
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    • 2009
  • Purpose: This study examined the effects of the symmetrical scapular alignment on the weight bearing of hemiplegic patients in the standing position. Methods: PALM (PALpation Meter) test and Gaitview AFA-50 were used to measure the skeletal alignment of the scapula and the weight bearing loaded on the affected and unaffected sides before and after training. The data was analyzed using a paired t-test on the SPSS 12.0 program for descriptive statistics. A p value <0.05 was considered significant. Results: The mean difference in the scapular alignments on sup. & mid. & inf. area in the hemiplegic side before and after training was $0.93\pm0.50cm$ and $0.58\pm0.43cm$, respectively. There was a significant decrease after training rather than that before (p<0.05). The mean weight bearing on the foot area in the hemiplegic patients before and after training was $9.12\pm5.51N/cm^2$ and $4.36\pm4.11N/cm^2$, respectively,. There was a significant decrease after training rather than that before (p<0.05). The scapuar alignments and weight bearing data on the standing position were grouped around the average (to central point) in the distribution graph. Conclusion: These findings suggest that the symmetrical scapular alignment can serve as an effective means of improving the weight bearing ability of hemiplegic patients.

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Modeling on asymmetric circular data using wrapped skew-normal mixture (겹친왜정규혼합분포를 이용한 비대칭 원형자료의 모형화)

  • Na, Jong-Hwa;Jang, Young-Mi
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.2
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    • pp.241-250
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    • 2010
  • Over the past few decades, several studies have been made on the modeling of circular data. But these studies focused mainly on the symmetrical cases including von Mises distribution. Recently, many studies with skew-normal distribution have been conducted in the linear case. In this paper, we dealt the problem of fitting of non-symmetrical circular data with wrapped skew-normal distribution which can be derived by using the principle of wrapping. Wrapped skew-normal distribution is very flexible to asymmetical data as well as to symmetrical data. Multi-modal data are also fitted by using the mixture of wrapped skew-normal distributions. To estimate the parameters of mixture, we suggested the EM algorithm. Finally we verified the accuracy of the suggested algorithm through simulation studies. Application with real data is also considered.

Effects of Zero-Sequence Transformations and Min-Max Injection on Fault-Tolerant Symmetrical Six-Phase Drives with Single Isolated Neutral

  • Munim, Wan Noraishah Wan Abdul;Tousizadeh, Mahdi;Che, Hang Seng
    • Journal of Power Electronics
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    • v.19 no.4
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    • pp.968-979
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    • 2019
  • Recently, there has been increased interest in the study of multiphase machines due to their higher fault-tolerant capability when compared to their conventional three-phase counterparts. For six-phase machines, stator windings configured with a single isolated neutral (1N) provide significantly more post-fault torque/power than two isolated neutrals (2N). Hence, this configuration is preferred in applications where post-fault performance is critical. It is well known that min-max injection has been commonly used for three-phase and multiphase machines in healthy condition to maximize the modulation limit. However, there is a lack of discussion on min-max injection for post-fault condition. Furthermore, the effects in terms of the common-mode voltage (CMV) in modulating signals has not been discussed. This paper investigates the effect of min-max injection in post fault-tolerant control on the voltage and speed limit of a symmetrical six-phase induction machine with single isolated neutral. It is shown that the min-max injection can minimize the amplitude of reference voltage, which maximizes the modulation index and post-fault speed of the machine. This in turn results in a higher post-fault power.

Electrical Variable Capacitor based on Symmetrical Switch Structure for RF Plasma System (대칭적인 스위치 구조 기반 RF 플라즈마 시스템 적용 전기적 가변 커패시터)

  • Min, Juhwa;Chae, Beomseok;Kim, Hyunbae;Suh, Yongsug
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.3
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    • pp.161-168
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    • 2019
  • This study introduces a new topology to decrease the voltage stress experienced by a 13.56 MHz electrical variable capacitor (EVC) circuit with an asymmetrical switch structure applied to the impedance matching circuit of a radio frequency (RF) plasma system. The method adopts a symmetrical switch structure instead of an asymmetrical one in each of the capacitor's leg in the EVC circuit. The proposed topology successfully reduces voltage stress in the EVC circuit due to the symmetrical charging and discharging mode. This topology can also be applied to the impedance matching circuit of a high-power and high-frequency RF etching system. The target features of the proposed circuit topology are investigated via simulation and experiment. Voltage stress on the switch of the EVC circuit is successfully reduced by more than 40%.

Dual-innervated multivector muscle transfer using two superficial subslips of the serratus anterior muscle for long-standing facial paralysis

  • Sakuma, Hisashi;Tanaka, Ichiro;Yazawa, Masaki;Oh, Anna
    • Archives of Plastic Surgery
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    • v.48 no.3
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    • pp.282-286
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    • 2021
  • Recent reports have described several cases of double muscle transfers to restore natural, symmetrical smiles in patients with long-standing facial paralysis. However, these complex procedures sometimes result in cheek bulkiness owing to the double muscle transfer. We present the case of a 67-year-old woman with long-standing facial paralysis, who underwent two-stage facial reanimation using two superficial subslips of the serratus anterior muscle innervated by the masseteric and contralateral facial nerves via a sural nerve graft. Each muscle subslip was transferred to the upper lip and oral commissures, which were oriented in different directions. Furthermore, a horizontal fascia lata graft was added at the lower lip to prevent deformities such as lower lip elongation and deviation. Voluntary contraction was noted at roughly 4 months, and a spontaneous smile without biting was noted 8 months postoperatively. At 18 months after surgery, the patient demonstrated a spontaneous symmetrical smile with adequate excursion of the lower lip, upper lip, and oral commissure, without cheek bulkiness. Dual-innervated muscle transfer using two multivector superficial subslips of the serratus anterior muscle may be a good option for long-standing facial paralysis, as it can achieve a symmetrical smile that can be performed voluntarily and spontaneously.

The Effect of Symmetrical and Asymmetric Bilateral Training for Chronic Stroke Patients in Upper Extremity Recovery (만성 뇌졸중 환자의 대칭적, 비대칭적 양측성 상지훈련의 상지기능회복 효과)

  • Kim, Sun Ho;Han, Dae Sung
    • Therapeutic Science for Rehabilitation
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    • v.6 no.1
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    • pp.35-43
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    • 2017
  • Objective : To identify the effect of symmetrical and asymmetric bilateral training For stroke patients in upper extremity recovery. Methods : 15 patients with stroke, randomized to an in- phase group(n =7) and anti-phase group(n =8). Each groups received symmetrical and asymmetric bilateral training, 30-min sessions per a day for 5 weeks, total 20 session.Accelerometer was used to evaluate the amount used for both groups. Y-BAT was used to evaluate performance status and satisfaction, ARAT was used to evaluate hand function. Results : the amount used of symmetrical movement training showed significant changes in affected and unaffected side. asymmetric bilateral training. there is a significant difference in affected side before and after receiving asymmetric bilateral training. Also, There was a significant difference between the groups on the affected side. Both training, there was no significant difference in performance, satisfaction, and upper limb function between group but, there was significant differences within-groups, Conclusions : Symmetric training showed higher motor performance than asymmetric training, but, To obtain a clearer difference, it would be necessary to use a neuromuscular assessment tool such as fMRI. Also, need a clearer training protocol and the need for follow-up studies on more stroke patients is suggested.

The Effects on Symmetrical Figures Learning and Self-Directed Learning Attitude of Mathematical Instruction Using GSP (GSP를 활용한 수학 수업이 도형의 대칭 학습과 자기 주도적 학습 태도에 미치는 효과)

  • Choi, Ju Young;Park, Sung Sun
    • Journal of Elementary Mathematics Education in Korea
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    • v.18 no.3
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    • pp.459-474
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    • 2014
  • The purpose of this study was to investigate the effects of mathematical instruction using GSP program on the symmetrical figures learning and self-directed learning attitude. According to the pretest result, the experiment group and the comparison group showed to be homogeneous groups. The experiment group has learned symmetrical figures for 9 hours using the GSP program and the comparison group has learned for 9 hours using the traditional method(paper and pen lesson). As the posttests, self-directed learning attitude test and symmetry figure understanding test were performed. The results obtained in this research are as follows; First, there was a significant difference in symmetry figure understanding test between the experiment group which learned through GSP program and the comparison group which learned through traditional method. Since there showed a very high achievement in the experiment group which learned using GSP, it can be inferred that GSP was very effective in the lessons of symmetrical movements. Second, there was a significant difference in self-directed learning attitude test between the experiment group and the comparison group. This seems to be because the length of the sides of the figures, size of the angles of the figures etc can be verified instantly and the students can correct by themselves and give feedbacks when they use GSP program. Students preferred drawing using the GSP over drawing using rulers and pencils, and they showed interest in the GSP program and they did not have burden in being wrong in their study and studied in various methods. And as they become familiar with the GSP program, they even studied other contents beyond the scope presented in the textbook.

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