• 제목/요약/키워드: physical objective function

검색결과 412건 처리시간 0.03초

Steel nitriding optimization through multi-objective and FEM analysis

  • Cavaliere, Pasquale;Perrone, Angelo;Silvello, Alessio
    • Journal of Computational Design and Engineering
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    • 제3권1호
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    • pp.71-90
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    • 2016
  • Steel nitriding is a thermo-chemical process leading to surface hardening and improvement in fatigue properties. The process is strongly influenced by many different variables such as steel composition, nitrogen potential, temperature, time, and quenching media. In the present study, the influence of such parameters affecting physic-chemical and mechanical properties of nitride steels was evaluated. The aim was to streamline the process by numerical-experimental analysis allowing defining the optimal conditions for the success of the process. Input parameters-output results correlations were calculated through the employment of a multi-objective optimization software, modeFRONTIER (Esteco). The mechanical and microstructural results belonging to the nitriding process, performed with different processing conditions for various steels, are presented. The data were employed to obtain the analytical equations describing nitriding behavior as a function of nitriding parameters and steel composition. The obtained model was validated, through control designs, and optimized by taking into account physical and processing conditions.

열 유입률을 고려한 자계-열계 다목적 위상최적설계 (Multi-objective Topology Optimization of Magneto-Thermal Problem considering Heat Flow Rate)

  • 심호경;왕세명;문희곤
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.138-139
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    • 2007
  • This research provides machine designers with some intuition to consider both, magnetic and heat transfer effects. A topological multi-objective function includes magnetic energy and heat inflow rate to the system, which equals to the total heat dissipation by conduction and convection. For the thermal field regarding the heat inflow, introduced as a reaction force, topology design sensitivity is derived by employing discrete equations. The adjoint variable method is used to avoid numerous sensitivity evaluations. As a numerical example, a C-core design excited by winding current demonstrates the strength of the multi-physical approach.

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흉곽출구증후군: 사각근 신장운동의 효과 (Thoracic Outlet Syndrome: The Effects of Scalenus Stretching Exercise)

  • 이문환
    • 한국전문물리치료학회지
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    • 제13권2호
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    • pp.43-51
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    • 2006
  • The term thoracic outlet syndrome (TOS) is used to describe patients with compressed subclavian arteries, veins, and brachial plexuses in the region of the thoracic outlet. The objective of this study was to evaluate a scalenus stretching exercise that aims to restore normal function to patients with TOS. This study consisted of 60 patients with symptoms of TOS, and divided the patients into 3 groups: one that received manual therapy, one that practiced self stretching, and a control group. Each group consisted of 20 patients. This study assessed the efficacy of scalenus stretching exercise by examining the resting pain, tenderness, spherical grip power, and pinch grip power of patients. The data were analyzed using one-way ANOVA, Scheffe post hoc test, and independent t-test. The results showed that resting pain was statistically significant within the manual therapy and self stretching groups (p<.05), and that the resting pain of the manual therapy group was more statistically significant than that of the self stretching group (p<.05). Tenderness, spherical grip power, and pinch grip were statistically significant within the manual therapy and self stretching groups (p<.05), but there was no statistically significant difference between the two groups (p>.05). Finally I could see that there were no statistical differences between manual therapy and self stretching to improve the symptoms of the patients with TOS. These results imply that self stretching by patients is as important as manual therapy by a physical therapist.

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Effects of aerobic exercise on antioxidants in rat models with cardiomyopathy

  • Kim, Eun-Jung;Hwang, Sujin
    • Physical Therapy Rehabilitation Science
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    • 제4권1호
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    • pp.17-21
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    • 2015
  • Objective: In this study, we aimed to test the hypothesis that aerobic exercise might exert its cardio-protective effect by preventing oxidative stress and improving cardiac function in rat models with doxorubicin-induced cardiomyopathy. Design: Randomized controlled trial. Methods: We randomly divided experimental rats into four groups: the normal group was used as a non-cardiomyopathy normal control (n=10); the control group included non-aerobic exercise after doxorubicin-induced cardiomyopathy (n=10); the experimental group I included aerobic exercise (3 m/min) after doxorubicin-induced cardiomyopathy (n=10); and experimental group II included aerobic exercise (8 m/min) after doxorubicin-induced cardiomyopathy. Rats in the treadmill training groups underwent treadmill training, which began at 2 weeks after the first intraperitoneal injection. At the end of the exercise period, we determined the heart weight change for each rat. Changes in the levels of oxidative stress enzymes (superoxide dismutase [SOD], thiobarbituric acid-reactive substances [TBARS], and catalase) in the cardiac tissue of rats from all four groups were examined at the end of the experiment. Results: Significant cardiac myocyte injury and increase in myocardial TBARS concomitant with a reduction in myocardial SOD and catalase were observed following cardiomyopathy (p<0.05). Significant cardiac tissue and increase in myocardial TBARS along with reduction in myocardial SOD and catalase were observed following cardiomyopathy (p<0.05). Oxidative parameters were significantly improved in the aerobic exercise groups compared with the control group. Conclusions: These findings indicate that aerobic exercise effectively prevents oxidative stress in rat models with cardiomyopathy.

The effects of virtual reality-based physical therapy in stroke patients

  • Kim, Charyong;Min, Won-Kyu
    • Physical Therapy Rehabilitation Science
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    • 제2권1호
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    • pp.7-11
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    • 2013
  • Objective: Final goal of nerve advancement therapy is to provide maximum ability to function independently in life to patients. This paper appraises and describes basic concepts of the virtual reality (VR) based exercise program to improve functional movement for neurologically impaired patients. Design: Review article. Methods: Stroke patients from the physical therapy department while wearing comfortable clothing receive therapy and also VR based motion therapy administered by the therapist in charge. After evaluation of stroke patients, therapy includes an exercise program that is suitable for use with stroke patients; stroke patients wear head-mounted display while in front of the computer, where the camera is located; they follow the action on the screen and the computer perceives the operation of the stroke patients according to subject accomplishment. Results: According to obstacle condition of stroke patients using the method, which is various environments after setting, in stroke patients, there is a possibility of presenting suitable therapeutic environments. The display presentation of the method, which is identical, causes difficulty for all stroke patients. According to subject accomplishment; stroke patients result in execution of repetition training and deepening study, which leads to mobility. Conclusions: The VR based rehabilitation training programs is a difference of the existing video training program, is immediate feedback and compensation method. It will provide rehabilitation training services for the family of the patient whose condition could be improved with rehabilitative therapy where it is a continuous circumstance as a matter of the social welfare facility therapy.

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The Influence of Hand Muscle Fatigue and Fatigue Recovery on Joint Position Sense in Healthy Subjects

  • Lee, Na-Kyung;Son, Sung-Min
    • The Journal of Korean Physical Therapy
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    • 제26권6호
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    • pp.425-429
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    • 2014
  • Purpose: The first purpose of this study was to evaluate whether hand muscle fatigue alters sensorimotor control of the hand in healthy subjects, using hand position sense. The second objective was to assess the repositioning variables during a 7.5-min period after the fatigue protocol. Methods: Participants performed a repeated handgrip movement to induce the fatigue condition as fast as possible, until they could no longer continue. Recordings were performed before (pre-fatigue) and after the completion of the fatigue exercises (immediately: post-fatigue, after a 2.5 min recovery, after a 5 min recovery and after a 7.5 min recovery). Results: The joint reposition test of the MP joint in the post-fatigue condition showed higher reposition errors than the prefatigue condition (p<0.05). Additionally, there was a significant difference in recovery of joint reposition errors after fatiguing exercises of the hand muscle, among groups (p<0.05). Conclusion: The fatigue of the hand muscles affected joint position sense by an alteration of somatosensory and proprioceptive information. Nonetheless, the effect of hand muscle fatigue was short-lived, since joint reposition errors decreased to post-fatigue values after 7.5 min of recovery.

Effect of Robot-Assisted Wearable Exoskeleton on Gait Speed of Post-Stroke Patients: A Systematic Review and Meta-Analysis of a Randomized Controlled Trials

  • Chankyu Kim;Hyun-Joong Kim
    • Physical Therapy Rehabilitation Science
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    • 제11권4호
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    • pp.471-477
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    • 2022
  • Objective: The greatest motor impairment after stroke is a decreased ability to walk. Most stroke patients achieve independent gait, but approximately 70% do not reach normal speed, making it difficult to reach a standard of daily living. Therefore, a wearable exoskeleton is recommended for optimal independent gait because different residual disorders hinder motor function after stroke. This review synthesized the effect on gait speed in randomized controlled trials (RCTs) in which gait training using a wearable exoskeleton was performed on post-stroke patients for qualitative and quantitative analysis. Design: A systematic review and meta-analysis of a randomized controlled trials Methods: RCTs using wearable exoskeletons in robotic rehabilitation of post-stroke patients were extracted from an international electronic database. For quality assessment and quantitative analysis, RevMan 5.4 was used. Quantitative analysis was calculated as the standardized mean difference (SMD) and presented as a random effect model. Results: Five studies involving 197 post-stroke patients were included in this review. As a result of the analysis using a random effect model, gait training using a wearable exoskeleton in post-stroke patients showed a significant improvement in gait speed compared to the non-wearing exoskeleton (SMD=1.15, 95% confidence interval: 0.52 to 1.78). Conclusions: This study concluded that a wearable exoskeleton was more effective than conventional gait training in improving the gait speed in post-stroke patients.

재생 활성탄의 물성 및 흡착능 평가 (Evaluation of Physical Properties and Adsorption Capacity of Regeneration GAC)

  • 문지영;채선하;왕창근
    • 상하수도학회지
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    • 제23권4호
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    • pp.407-416
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    • 2009
  • The objective of this study was to evaluate the variation of physical properties and adsorption capacity after regeneration of Granular Activated Carbon (GAC). It was found that the loss rate of regenerated carbon was related to the usage time of GAC. The correlations between iodide number and loss rate also determined. Effective size and uniformity coefficient for regenerated GAC were within a similar range compared to virgin GAC. This result indicated that the function as media is recovered. Although iodide number and specific surface area for regenerated GAC were not completely recovered compared to that of virgin GAC, cumulative pore volumes of regenerated GAC were increased. Removal efficiency of organic matter in regenerated GAC was resulted the same or slightly higher than that of virgin GAC. This result indicates that the number of mesopore responsible for removal of organic matter was increased after regeneration.

Effect of kinesio taping on gait function in elderly individuals with knee osteoarthritis: A pilot study

  • Park, Jaeyoung;Paik, Youngrim;Oh, Donghwan
    • 국제물리치료학회지
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    • 제10권3호
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    • pp.1830-1833
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    • 2019
  • Background: Knee osteoarthritis (OA) causes not only pain during walking but also walking disorders. Therefore, intervention for older patients with OA is important. Objective: To study investigated the effects of kinesio taping (KT) on pain and walking ability in elderly persons with knee OA. Design: One group, pre-post design Methods: This study enrolled 12 community-dwelling elderly people with knee OA. KT was applied on the surrounding structures, including the patellar and bilateral lateral ligaments. Assessment was made using the visual analog scale and GAITRite system to measure pain and walking ability during KT and non-KT conditions. Results: In this study, compared to the non-KT condition, the KT condition showed a significant improvement in walking ability and pain reduction during walking (velocity, cadence, step length, and stride length) (p < 0.05). Conclusion: This study demonstrated that knee KT has a positive effect on pain reduction and walking ability of the elderly with OA.

여자고등학생의 학교체육복 착용실태 조사 (A Survey on the Physical Training School Uniform of Female High School Students)

  • 정혜인;강여선
    • 복식
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    • 제60권8호
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    • pp.67-85
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    • 2010
  • School uniform has improved greatly in terms of fit, size, function, and design due to steep competition in the market and the strong interest of researcher, while little effort has been made for physical training uniform, so the objective of this study is to provide basic research data of the training uniform for the improvement of its design and fitness. For this purpose, 327 high school girls provided information on size and design of their uniform, level of satisfaction, the recognized ease in uniform. Most students wore the physical training uniform in another classes and the long sleeved shirt were the most popular one. They often used the uniform for the protection from cold and for comfortable activeness. For a long sleeved shirt, most students preferred raglan sleeve, zip-up collar, straight waist line, and ribbed sleeve cuffs and hem. For long pants, students preferred elastic waist band and ribbed pants cuffs. Currently, the short-sleeved shirt mostly had a shirts collar, ribbed hem, straight waist line with raglan sleeve, but students wanted a round neck and set-in sleeve. For overall level of satisfaction, students showed high satisfaction in terms of function and psychological effect, while aesthetic quality of the uniform was needed to be much improved. Most students evaluated that the circumference of uniforms properly fit or had a little ease, and students considered waist size the most suitable. The long pants length evaluated properly fit or a little long. Students accepted that the ease of summer uniform was more suitable than winter uniform's both at circumference and at length. Depending on students' height distribution, the length of long pants and short pants varied significantly.