• 항공우주시스템공학회지
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• 제14권2호
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• pp.28-35
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• 2020

In this paper, we present a design for a retraction-type actuator (ReACT) that has the characteristics of both thermomechanical metamaterials and displacement amplification mechanisms. The ReACT consists of an actuating bar, a diamond-shaped displacement amplification (DA) structure, and a slot for loading thin-film heaters formed through the actuating bar. When power is supplied to the thin film heater, the actuating bars contacting the heater thermally expand, and the diamond-shaped DA structures retract in the longitudinal direction. The performance characteristics of the ReACT, such as temperature distribution and retracting displacement, were calculated with thermomechanical analysis methods using the finite element method (FEM). Subsequently, the ReACTs were fabricated using a polymer-based 3D printer that can easily execute complex structures, and the performance of the ReACT was evaluated through repeated tests under various temperature conditions. The results of the performance evaluation were compared with the results of the FEM analysis.

• Structural Engineering and Mechanics
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• 제29권4호
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• pp.381-390
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• 2008

This paper proposed a conceptual design of bascule bridge, which is a new kind of movable bridge with an aim of reducing the weight of superstructure. Compared with the traditional bascule bridge, the light bascule bridge chooses cable-stayed bridge with inclined pylon as its superstructure; therefore, the functions of balance-weight and structure will fuse into one. Otherwise, it adopts moving counterweight to adjust its center of gravity (CG) to open or close the bridge. In order to lighten the superstructure, it uses contact springs to auxiliary retract, and intelligent prestressing system (IPS) to control the main girder's deformation. Simultaneously the vibration control scheme of structure is discussed. Starting from establishing the mechanical model of bridge, this article tries to analyze the conditions that the design parameters of structure and attachments should satisfy to. After the design procedure was presented, an example was also adopted to explain the primary design process of this kind bridge.

• 대한수학회보
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• 제52권4호
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• pp.1375-1382
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• 2015

We investigate what happens when we try to work with continuing block codes (i.e., left or right continuing factor maps) between shift spaces that may not be shifts of finite type. For example, we demonstrate that continuing block codes on strictly sofic shifts do not behave as well as those on shifts of finite type; a continuing block code on a sofic shift need not have a uniformly bounded retract, unlike one on a shift of finite type. A right eresolving code on a sofic shift can display any behavior arbitrary block codes can have. We also show that a right continuing factor of a shift of finite type is always a shift of finite type.

• 대한방사선치료학회지
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• 제29권2호
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• pp.93-100
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• 2017

목 적: 쇄골상부림프절(Supraclavicular Lymph Nodes, SCL)을 포함한 유방암 방사선 치료 시 조사야에 인접한 다엽 콜리메이터(Multileaf Collimator, MLC)가 접합부 선량에 미치는 영향을 평가하고자 한다. 대상 및 방법: 접선 조사 기법을 이용하여 SCL을 포함한 유방암 방사선 치료 환자 30명을 대상으로 120-leaf Millennium MLC가 장착된 21EX-S의 6 MV 광자선 에너지를 사용하였다. 치료계획은 유방조직과 SCL 조사야 접합부에 MLC가 모두 위치한 Plan1, 유방조직과 SCL 조사야에 MLC가 각각 위치한 Plan2, Plan3, 그리고 MLC를 모두 Retract 한 Plan4로 하였으며, SCL 조사야는 모든 계획에서 콜리메이터 각도를 $0^{\circ}$, $270^{\circ}$로 나누어 수립하였다. 치료계획에 대한 평가는 접합부 3 cm 깊이 선량(D3 cm)의 평균값으로 비교하였고, Map-CHECK을 이용하여 각 치료계획별 접합부 선량을 측정하였다. 결 과: 치료계획 비교 결과, D3cm의 평균값은 SCL 콜리메이터 $0^{\circ}$에서 4131.1, 4215.9, 4351.4, 4423.0 cGy였고, $270^{\circ}$에서 4044.3, 4246.7, 4291.1, 4441.2 cGy로 나타났다. 콜리메이터 각도에 따른 평균 선량 변화는 SCL 조사야에 MCL가 위치한 Plan1, Plan3 이 MLC가 Retract된 나머지에 비해 크게 나타났다. 그리고 접합부 선량 측정값 또한 치료계획과 같은 경향을 보였다. 결 론: 본 연구를 통해 SCL을 포함한 유방암 방사선 치료계획 시, MLC를 접합부로부터 5 mm Retract 시켜줌으로써 MLC가 접합부 선량에 미치는 영향을 줄일 수 있을 것으로 사료된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권2호
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• pp.207-215
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• 2008

Patients who have repaired cleft lip and palate generally undergo restriction of maxillary growth. Concave facial profile is often exhibited with relatively normalized mandible. Horizontal and sagittal deficiency of the maxilla could cause anterior and posterior crossbites. In growing patients, ortho-dontic and orthopedic treatment is acceptable with maxillary expansion and protraction. However, surgical approach has to be accompanied with orthodontic treatment in skeletally matured patients. We used SARPE and BSSRO to expand the constricted maxilla and retract the mandible in a patient who had cleft palate repaired in infancy. Through SARPE, orthodontic treatment and BSSRO, we sufficiently expanded the maxillla and improved facial profile.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.437-448
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• 2007

Suppose K is a nonempty closed convex nonexpansive retract of a real uniformly convex Banach space E with P as a nonexpansive retraction. Let $T_1,\;T_2\;and\;T_3\;:\;K{\rightarrow}E$ be nonexpansive mappings with nonempty common fixed points set. Let $\{\alpha_n\},\;\{\beta_n\},\;\{\gamma_n\},\;\{\alpha'_n\},\;\{\beta'_n\},\;\{\gamma'_n\},\;\{\alpha'_n\},\;\{\beta'_n\}\;and\;\{\gamma'_n\}$ be real sequences in [0, 1] such that ${\alpha}_n+{\beta}_n+{\gamma}_n={\alpha}'_n+{\beta'_n+\gamma}'_n={\alpha}'_n+{\beta}'_n+{\gamma}'_n=1$, starting from arbitrary $x_1{\in}K$, define the sequence $\{x_n\}$ by $$\{zn=P({\alpha}'_nT_1x_n+{\beta}'_nx_n+{\gamma}'_nw_n)\;yn=P({\alpha}'_nT_2z_n+{\beta}'_nx_n+{\gamma}'_nv_n)\;x_{n+1}=P({\alpha}_nT_3y_n+{\beta}_nx_n+{\gamma}_nu_n)$$ with the restrictions $\sum^\infty_{n=1}{\gamma}_n<\infty,\;\sum^\infty_{n=1}{\gamma}'_n<\infty,\; \sum^\infty_{n=1}{\gamma}'_n<\infty$. (i) If the dual $E^*$ of E has the Kadec-Klee property, then weak convergence of a $\{x_n\}$ to some $x^*{\in}F(T_1){\cap}{F}(T_2){\cap}(T_3)$ is proved; (ii) If $T_1,\;T_2\;and\;T_3$ satisfy condition(A'), then strong convergence of $\{x_n\}$ to some $x^*{\in}F(T_1){\cap}{F}(T_2){\cap}(T_3)$ is obtained.

• Archives of Plastic Surgery
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• 제37권4호
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• pp.499-530
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• 2010

Purpose: Lateral osteotomy is an essential step in the correction of nasal bony asymmetry. Direct visualization allows accurate repositioning of the nasal bones compared to blind techniques, which require precision and manual dexterity. We propose direct visualization procedures in open corrective rhinoplasty. Methods: The technique was used on 16 patients. All patients underwent open rhinoplasty with a columellar incision. The marginal incisions were extended on either side to allow access to the piriform aperture. A double hook was used to caudally retract the lower lateral cartilages and the fibrous connections between the upper and lower lateral cartilages were released until the piriform aperture was visualized. Through the incision, lateral osteotomy was performed using a reciprocating saw at that time with direct visualization. Additional procedures including augmentation rhinoplasty, hump resection, septoplasty and tip plasty were performed simultaneously. Results: This method provided excellent exposure to the lateral nasal bones and allowed the lateral osteotomy to be carried out precisely using the reciprocating saw. Conclusion: This extended open rhinoplasty method is suitable for most individuals, allowing a wide surgical field.

• 한국정밀공학회지
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• 제27권3호
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• pp.89-94
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• 2010

The pretensioner is used to retract the belt webbing and tighten up any slack in the event of a crash. The retracting force of the pretensioner helps move the passenger into the optimum crash position in his or her seat. In this paper, the new concept of an operating mechanism of the pretensioning system is presented. The internal gear design program is developed using MATLAB. Two kinds of numerical analysis model are created. The first one, the rigid body dynamic model, is used to estimate the performance of several gear pairs. The initial performance of the new operating mechanism is analyzed and the best combination of the gear pairs is selected. The second one, the structural dynamic model, is used to calculate the deformation of the gear teeth. To decrease the deformation and interference of the teeth, the shape of the gear pairs is changed.

• 대한치과교정학회지
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• 제23권4호
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• pp.619-631
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• 1993

Tooth movement by segment is one of the means which are frequently used in daily orthodontic practice. When we retract or intrude a tooth or teeth, we should recognize the center of resistance of the certain tooth or teeth. There have been many studies about the center of resistance of a single tooth, not so much was about the tooth-segment. At the present study the center of resistance of the maxillary anterior segment is experimentally investigated by using laser reflection technique and metal splints on the human dry skull. The variables of intrusive force magnitude are divided into two groups, 50g and 100g groups. The results were as follows ; 1. The center of resistance of the maxillary anterior segment composed of the central and lateral incisors was at the mesial portion of canine crown at the coronal level. 2. The center of resistance of the maxillary anterior segment composed of the central and lateral incisors and canines is between the canine and the 1st premolar crowns at the coronal level.

• 한국중재학회지:중재연구
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• 제26권3호
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• pp.93-119
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• 2016

Park Tae-hwan, the Korean Olympic gold medal swimmer, was suspended for eighteen months by the International Swimming Federation (FINA) in September 2014. Park completed his suspension in March 2016, but the Korea Olympic Committee (KOC), relying on its Article 5.6, then prohibited him from joining the national team for an additional three years for the same doping violation. The KOC's penalty exceeded that provided by the World Anti-Doping Code, which governs the Olympics and most international sports federations, and contravened well-established precedent from the Court of Arbitration for Sport (CAS). The KOC, along with the Korea Swimming Federation, maintained the suspension until decisions by the Seoul Eastern District Court and CAS forced them to retract the penalty. We describe the sports regulations and arbitration decisions governing the Park case, how each side used the law to support their positions, the flaws in the KOC's legal analysis, and the case's resolutions by the Korean court and CAS. Finally, because this legal conflict has damaged the KOC's reputation, created uncertainty over the committee's doping penalties, and undercut the authority of the World Anti-Doping Code and the CAS in Korea, we recommend institutional changes in Korea's sports jurisprudence.