• Steel and Composite Structures
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• 제31권5호
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• pp.503-516
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• 2019

This work presents a dynamic investigation of functionally graded (FG) plates resting on elastic foundation using a simple quasi-3D higher shear deformation theory (quasi-3D HSDT) in which the stretching effect is considered. The culmination of this theory is that in addition to taking into account the effect of thickness extension (${\varepsilon}_z{\neq}0$), the kinematic is defined with only 4 unknowns, which is even lower than the first order shear deformation theory (FSDT). The elastic foundation is included in the formulation using the Pasternak mathematical model. The governing equations are deduced through the Hamilton's principle. These equations are then solved via closed-type solutions of the Navier type. The fundamental frequencies are predicted by solving the eigenvalue problem. The degree of accuracy of present solutions can be shown by comparing it to the 3D solution and other closed-form solutions available in the literature.

• Steel and Composite Structures
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• 제44권3호
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• pp.353-369
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• 2022

This study attempts to shed light on the coupled impact of types of loading, thickness stretching, and types of variation of Winkler-Pasternak foundations on the flexural behavior of simply- supported FG plates according to the new quasi-3D high order shear deformation theory, including integral terms. A new function sheep is used in the present work. In particular, both Winkler and Pasternak layers are non-uniform and vary along the plate length direction. In addition, the interaction between the loading type and the variation of Winkler-Pasternak foundation parameters is considered and involved in the governing equilibrium equations. Using the virtual displacement principle and Navier's solution technique, the numerical results of non-dimensional stresses and displacements are computed. Finally, the non-dimensional formulas' results are validated with the existing literature, and excellent agreement is detected between the results. More importantly, several complementary parametric studies with the effect of various geometric and material factors are examined. The present analytical model is suitable for investigating the bending of simply-supported FGM plates for special technical engineering applications.

• 대한물리치료과학회지
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• 제31권2호
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• pp.41-51
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• 2024

Background: The purpose of this study was to identify the effect of home-based exercise program in elderly with chronic diseases on balance, activities of daily living, depression and quality of life. Design: One group pretest-posttest design Methods: The subjects consisted of 21 elderly people over the age of 65 years with chronic diseases lived in seo-gu, Gwangju. Home-based exercise program was performed twice a week, for an hour, during 6 weeks under supervision of an experienced instructor. The home-based exercise program was structured to last a total of 1 hour, consisting of 10 minutes of warm-up, 30 minutes of main exercises, and 20 minutes of concluding exercises. For the warm-up, we performed range of motion, stretching, and flexibility exercises. The main exercises comprised of strength, weight-bearing and balance exercises, and endurance exercises. The concluding exercises were tailored to the individual's home environment and needs, including task-oriented daily living training such as getting up from bed, moving to the restroom, and walking indoors. The subjects were assessed before and after the exercise program with berg balance scale(BBS), Korean-version modified barthel index(K-MBI), euro quality of life questionnaire 5-dimensional classification(EQ-5D), and geriatric depression scale short form-Korea(GDSSF-K). The collected data was analyzed using SPSS Win 18.0 program. Results: The results showed statistically significant difference in all domains of the BBS, K-MBI, EQ-5D, GDSSF-K after the exercise program. Conclusion: These results suggest that Home-based exercise program has resulted in a significant improvement on ADL, depression and quality of life in elderly with chronic diseases.

• 대한토목학회논문집
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• 제13권4호
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• pp.39-49
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• 1993

전단변형(剪斷變形) 효과(效果)가 고려되는 공간(空間)뼈대 구조(構造)의 기하학적(幾何學的)인 비선형(非線形) 해석(解析)을 수행하기 위한 두 가지 방법 즉, 유한분절법(有限分節法)과 유한요소법(有限要素法)을 제시한다. 유한분절법(有限分節法)의 경우에는 평형방정식(平衡方程式)을 직접(直接) 적분(積分)하므로써 휨과 비틂거동(擧動)에 대한 엄밀(嚴密)한 접선강도(接線剛度) 매트릭스가 유도되는 반면에 유한요소법(有限要素法)의 경우에는 전단변형(剪斷變形)을 고려하는 Hermitian 다항식(多項式)을 형상함수(形狀函數)로 사용하므로써 탄성(彈性) 및 기하적(幾何的)인 강도(剛度)매트릭스가 산정된다. 또한 축방향력(軸方向力)이 영(零)인 경우에 휨 및 비틂거동으로 인한 부재양단의 길이변화를 보정하는 Bowing 함수와 불평형하중의 산정방법을 제시한다. 선택된 예제(例題)들을 해석(解析)한 결과들과 다른 문헌(文獻)의 결과들을 비교, 검토하므로써 본(本) 논문(論文)에서 제시된 이론(理論)의 정당성(正當性)을 입증(立證)한다.

• The Journal of Asian Finance, Economics and Business
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• 제9권6호
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• pp.389-402
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• 2022

The purpose of the study is to analyze the significant impacts of expectations, performance, complaints, and fairness that affect consumer satisfaction. The methodology involves reviewing and referencing relevant literature carefully, then proposing a model for customer satisfaction. This study is empirically based on a survey with 50 respondents who work in the field of import and export in the region stretching from the north to the south of Vietnam. The sampling method used in this study is the in-depth interview method. The results show that: (1) expectation has a specific impact on customer satisfaction, (2) performance has a positive impact on customer satisfaction, and (3) complaint which is an intermediary factor between expectation, performance, and fairness has an impact on satisfaction, (4) fairness has a positive effect on satisfaction, in addition, fairness is an extremely important feature when customers choose an import-export service. Research implies that increasing expectations, performance, and fairness results in an improved customer experience and satisfaction when they use the service. It is suggested that the complaint factor continue to be studied and looked into because it still has some effect on satisfaction and is an intermediate variable that changes how the other factors relate to each other.

• 대한정형도수물리치료학회지
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• 제29권2호
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• pp.77-91
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• 2023

Background: Congenital muscular torticollis results in reduced head mobility, such as cervical rotation, due to the abnormal size and contraction of the sternocleidomastoid muscle. Korea Pediatric integrative manual therapy and stretching are recommended to improve head rotation upper cervical spine mobility. Therefore, in this study, the effect of the new PIMT was investigated. Methods: The patient is a 3.5 month-old diagnosed with congenital muscular torticollis (CMT). Due to the limitation of head rotation and cervical spine rotation and flexion mobility, the child visited a rehabilitation center and after diagnosis, Pediatric integrative manual therapy (PIMT) treatment was performed five times a week for a total of 15 weeks. The child's head rotation and flexion limitation and plagiocephaly were evaluated. Results: In conclusion, this study shows that compared to other treatments, PIMT approach is a more effective treatment for improving head rotation and cervical limitation for range of motion in CMT infants. Conclusion: PIMT approach was effective in improving cervical rotation and Head lateral flexion mobility and plagiocephaly in CMT patients.

• 공업화학
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• 제9권2호
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• pp.207-213
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• 1998

전편의 연구결과[1]를 토대로 또 다른 방법으로써 폴리이미드의 구조를 변화시켜 방향족 폴리벤즈이미다졸(PBI)과의 블렌드들의 상용성 및 상용성을 가져다 주는 상호작용의 세기를 상대적으로 비교하였다. 이 연구에서 방향족 폴리이미드(PI)는 두 개의 디아민인 4,4'-methylene dianiline (4,4'-MDA)과 4,4'-oxydianiline (4,4'-ODA)을 dianhydride인 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA)와의 축합반응을 통하여 용매인 DMAc로 폴리아믹산(PAA)을 합성한 후 열경화하여 얻었다. 이들 폴리아믹산(PAA)을 poly2,2-(m-phenylene)-5,5'-bibenzimidazole (PBI)와 용액 블렌딩하여 PBI/PAA 블렌드를 열경화시켜 PBI/PI의 블렌드로 전환시킨후 상용성을 조사하고 전편의 블렌드에 사용된 폴리이미드[1]와 이 연구에 사용된 폴리이미드의 구조변화에 대한 상호작용의 상대적인 크기를 조사하였다. 연구에 사용된 두 가지 블렌드인 PBI/DSDA+4.4'-MDA (Blend-V)와 PBI/DSDA+4.4'-ODA (Blend-VI)는 사용성을 보였다. 이는 성현된 필름이 투명하고, 전 블렌드 조성에 대해서 하나의 $T_g$를 가지며, 또한 블렌드 조성에 따른 N-H ($3418cm^{-1}$)와 C=O 스트레칭 밴드(1730 및 $1780cm^{-1}$)의 주파수 이동폭이 각각 $39{\sim}40cm^{-1}$, $5{\sim}6cm^{-1}$와 $3{\sim}4cm^{-1}$이었다. 이 연구에 사용된 블렌드들에 대하여 두 성분 고분자간 상호작용의 세기를 실험치와 Fox식으로 계산된 유리전이온도차로 생긴 면적(A), Gordon-Taylor 식에서의 ${\kappa}$ 값, 그리고 관능기인 N-H와 카보닐기의 주파수 이동폭의 변화로 살펴보았다. 이들에 대한 결과로 먼저, 면적 (A)와 ${\kappa}$ 값에 있어서 Blend-V와 Blend-VI이 전편의 블렌드 [1]인 Blend-III와 Blend-IV에 비해 작은 값을 보였다. 또한 관능기의 주파수 이동에 있어서도 이에 대한 결과와 유사한 결과를 보였다. 따라서 블렌드에 사용된 PI의 구조변화에 따라 상호작용이 다른 것은 PI 합성시에 사용된 서로 다른 dianhydride의 구조에서 페닐링 사이에 존재하는 linkage인 C=O보다 $SO_2$가 존재할 때[Fig. 2] 블렌드를 이루는 두 고분자사이의 상호작용인 수소결합력을 약화시키는 spacer로 작용한 것으로 사료된다. 다시 말하면, 전자가 후자보다 더 큰 입체장애를 일으켰기 때문이라 사려된다.

• 대한임상검사과학회지
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• 제50권3호
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• pp.297-303
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• 2018

본 연구는 대사성질환 관련 위험 인자를 가지고 있는 제주 지역주민을 대상으로 마을 기반 건강프로그램의 효과성을 입증하기 위해 수행되었다. 50명의 실험군은 BMI가 25 이상인 지역주민으로 3주 동안 고유수용성신경근촉진(PNF) 트레이닝과 스트레칭을 포함한 운동요법 7회, 영양관리 식습관 개선을 위한 쿠킹테라피 프로그램 4회 그리고 대체의학활용 프로그램인 힐링터치 마사지 프로그램 3회의 건강중재프로그램에 참여하였다. 건강프로그램 중재의 효과성 평가를 위해 프로그램 중재 전과 후에 체 성분, 혈액의 지질 프로파일, 혈당 및 허리둘레를 측정하여 비교하였다. 건강프로그램 중재 후에는 중재 전에 비해 TC, HbA1C, 이완기혈압, 체지방 그리고 허리둘레가 크게 감소하여 거의 정상수치가 되었고 특히 HbA1C, 체지방 그리고 허리둘레는 유의한 수준으로 감소 (P<0.001)되었다. 그러나 반대로 건강프로그램 중재를 받지 않은 대상군의 경우 HbA1C, 체지방 및 허리둘레가 유의한 수준으로 증가 (P<0.001)하는 부정적 결과를 보였다. 이상의 결과로부터 대사성질환 관련 인자들은 건강프로그램의 중재로 개선되어 호전될 수 있음을 알 수 있었다. 본 연구에서는 건강중재프로그램인 운동과 쿠킹테라피 효과를 구분하여 조사하지는 않았지만 3주간의 단기간에 보여진 효과가 두 가지를 병행해서 수행함으로써 나타난 결과임을 암시하며 식사조절과 운동을 병행하는 것이 대사성질환 개선에 보다 효과적임을 제시하고자 한다.

• Coupled systems mechanics
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• 제8권4호
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• pp.299-313
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• 2019

The paper represents computer modeling of the deformed state of physically nonlinear transversally isotropic bodies with hole. In order to describe the anisotropy of the mechanical properties of transversally-isotropic materials a structurally phenomenological model has been used. This model allows representing the initial material in the form of the coupled isotropic materials: the basic material (binder) considered from the positions of continuum mechanics and the fiber material oriented along the anisotropy direction of the original material. It is assumed that the fibers perceive only the axial tensile-compression forces and are deformed together with the base material. To solve the problems of the theory of plasticity, simplified theories of small elastoplastic deformation have been used for a transversely-isotropic body, developed by B.E. Pobedrya. A simplified theory allows applying the theory of small elastoplastic deformations to solve specific applied problems, since in this case the fibrous medium is replaced by an equivalent transversely isotropic medium with effective mechanical parameters. The essence of simplification is that with simple stretching of composite in direction of the transversal isotropy axis and in direction perpendicular to it, plastic deformations do not arise. As a result, the intensity of stresses and deformations both along the principal axis of the transversal isotropy and along the perpendicular plane of isotropy is determined separately. The representation of the fibrous composite in the form of a homogeneous anisotropic material with effective mechanical parameters allows for a sufficiently accurate calculation of stresses and strains. The calculation is carried out under different loading conditions, keeping in mind that both sizes characterizing the fibrous material fiber thickness and the gap between the fibers-are several orders smaller than the radius of the hole. Based on the simplified theory and the finite element method, a computer model of nonlinear deformation of fibrous composites is constructed. For carrying out computational experiments, a specialized software package was developed. The effect of hole configuration on the distribution of deformation and stress fields in the vicinity of concentrators was investigated.

• 대한물리치료과학회지
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• 제31권1호
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• pp.1-15
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• 2024

Background: This study was conducted to apply active release techniques to male youth basketball players to help improve physical development and damage prevention and improve performance through improved balance and functional movement. Design: Randomized control trial. Methods: The subjects included 33 youth basketball players who were randomly assigned to the experimental group (n=17) and the control group (n=16). For the experimental group, the active release technique was applied to the hip muscles, calf muscles, posterior thigh muscles based on the distribution of injuries surveyed in youth basketball players in the Korean Basksetball League. The Y-balance test and the functional reach test (FRT) were used to assess balance and the Functional Movement Screen (FMS) was used to assess functional movement. Interventions were conducted twice a week for 4 weeks at 40 minutes per session. The experimental group was the active release technique group, and static stretching, a common exercise therapy technique, and self-myofascial release using a foam roller were applied for 20 minutes. The control group received general exercise therapy and placebo active release technique. The placebo active release technique applies pressure only. results:The experimental group showed a greater improvement in balance, as evidenced by the FRT, compared to the control group, which received general exercise treatment. However, there was no statistically significant difference in improvement between the 2 groups. In the case of the experimental group, the difference in the Y balance test before and after the intervention was larger than that of the control group, but there was no statistically significant difference. Significant improvement was found in functional movement, as evidence by the FMS, for the trunk stability test (p < 0.05), in-line lunge test (p < 0.05), rotational stability test (p < 0.05), total score (p < 0.05). Conclusion: In this study, the active release technique improved the balance and functional movement of young basketball players more than general exercise therapy. The application of the active release technique is therefore expected to assist in physical development, prevent damage, and improve the performance of youth basketball players.