• 한국콘텐츠학회논문지
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• 제11권3호
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• pp.100-107
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• 2011

휴리스틱 탐색에서 강화(Intensification)와 다양화(Diversification)의 조화는 중요한 연구 부분이다. 본 논문에서는 개미 집단 최적화(Ant Colony Optimization, ACO) 접근법의 하나인 개미 집단 시스템(Ant Colony System, ACS)에서 강화와 다양화의 조화를 통한 성능 향상시키는 방법을 제안한다. 제안 방법은 다양화 전략으로 전역 최적 경로가 향상되지 않는 경우 반복 탐색 구간을 고려해 상태전이 규칙의 파라미터를 변경해 탐색하고, 이러한 다양화 전략을 통해 발견된 전역 최적 경로에서 이전 전역 최적 경로와 현재 전역 최적 경로의 중복 간선에 대해 페로몬을 강화시켜 탐색하는 혼합된 탐색 방법을 제안한다. 그리고, 실험을 통해 제안된 방법이 기존 ACS-3-opt 알고리즘, ACS-Subpath 알고리즘, ACS-Iter 알고리즘, ACS-Global-Ovelap 알고리즘에 비해 최적 경로 탐색 및 평균 최적 경로 탐색의 성능이 우수함을 보여 준다.

• 생태와환경
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• 제47권4호
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• pp.302-311
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• 2014

Global climate change is significant issue in marine ecosystem and fishery market. According to rising of both seawater temperature and sea-level, global fishery environment and marine ecosystem are changing drastically. Moreover, over-exploitation in fishery areas is the most important issue in the marine ecosystem conservation. In analysis and statistics of global network, major fish populations are decreasing very fastly, but fish catch are increasing annually. It means balance between product and consume is not appropriate in the global market. China as emerging new fish consumer in the world is strongly developing fishery industry and technology. In this paper, I try to review a relationship between marine ecosystem and climate change in global scale according to references. I also suggested possibility of sustainable global fishery in changing marine ecosystem by analysis of some related reports of international global fishery.

• 대한기계학회논문집A
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• 제40권5호
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• pp.483-488
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• 2016

플러그인 디지털 프레임웍은 계의 구성요소가 블랙박스 형태로 구성되어 있을 때 계의 응답을 해석하는 도구이다. 일반적으로 구성요소를 연결하는 동역학계의 연결부는 계의 응답에 크게 영향을 미치게 되고, 많은 경우 연결부의 특성은 변위와 주파수에 따라 달라지는 특성을 보인다. 그러므로 연결부의 특성에 대한 민감도의 계산은 전역적으로 수행되어야 한다. 본 연구에서는 플러그인 디지털 프레임웍에서 연결부의 전역민감도를 계산하는 방법을 주파수응답함수 기반의 부분구조합성법을 기반으로 제시한다. 일차 전역민감도는 무작위균형설계법을 이용하여 적은 수의 샘플링으로 각 인자영향을 계산할 수 있다. 이 방법은 승용차의 실내소음에 대한 각 연결부 강성의 민감도를 계산하는 예에 적용함으로써 그 효용성을 검증하였다.

• 대한물리의학회지
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• 제9권1호
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• pp.83-91
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• 2014

PURPOSE: The purpose of this study was to investigate the effects of task oriented circuit exercise(TOCE) on the balance and cognition in mild dementia patients. METHODS: The subjects of the study were 30 patients with mild dementia and assigned to the TOCE(task oriented circuit exercise) group(n=15) and aerobic exercise(AE) group(n=15). TOCE group performed six task three times weekly for 12 weeks. AE group underwent the cycle ergometer and treadmill exercise three times a week during the experimental period respectively. Timed up and go test(TUG), Berg balance scale(BBS) and AP1153 Biorescue were used to assess the parameters for the balance. Korean-mini mental state examination and Global deterioration scale(GDS) were used to assess the parameters for the cognition. For the statistical analysis, paired t-test and independent t-test were used to compare the differences among two groups. RESULTS: Each group showed improvement in balance and possibility for improving cognitive function. TOCE group especially, there were significant improvements in limit of stability. CONCLUSION: The results of the study suggest that TOCE is a more diverse exercise programs introduced in the study. Furthermore, TOCE can be a helpful to improve the balance and cognition in mild dementia patients.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.1-7
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• 2010

Large quantity of bending deformation as well as irregular rotating torque fluctuation are the main struggles of the balance shaft module during a high speed rotation. Since two issues are much sensitive to the location of both supporting bearing and unbalance mass at a balance shaft, it is recommended to construct a design strategy on balance shaft at the early stage so as to save developing time and effort before approaches to the detailed design process. In this paper, an optimal design formulation is proposed to minimize the elastic strain energy due to bending as well as the kinematic energy of polar moment of inertia in rotation. Case studies of optimal design are conducted for different mass ratio as well as linear combination of objective function and its consequence reveals that global optimum of balance shaft model is existed over possible design conditions. Simulation shows that best locations of both supporting bearing and unbalance are globally 20% and 80%, respectively, over total length of a balance shaft.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.63-72
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• 2007

Current estimates of the ice-mass balance over the Greenland and the Antarctica using retrievals of time-varying gravity from GRACE are presented. Two different GRACE gravity data, UTCSR RL01 and UTCSR RL04, are used for the estimates to examine the impact of the relative accuracy of background models in the GRACE data processing for inter-annual variations of GRACE gravity data. In addition, the ice-mass balance is appraised from the conventional GRACE data, which represents global gravity, and the filtered GRACE data, which isolates the terrestrial gravity effect from GRACE gravity data. The former estimate shows that there exists similar negative trends of ice-mass balance over the Greenland from UTCSR RL01 and UTCSR RL04 while the time series from the both GRACE data over the Antarctica differ significantly from each other, and no apparent trends are observed. The result for the Greenland from the latter calculation is similar to the former estimate. However, the latter calculation presents positive trends of ice-mass balance for the Antarctica from both GRACE data. These results imply that residual oceanic geophysical signals, particularly for ocean tides, significantly corrupt the ice-mass estimate over the Antarctica as leakage error. In addition, the spatial alias of GRACE is likely to affect the ice-mass balance because the spatial spectrum of ocean tides is not conserved via GRACE sampling, and thus ocean tides contaminate terrestrial gravity signal. To minimize the alias effect, I suggest to use the combined gravity models from GRACE, SLR and polar motion.

• The Journal of Korean Physical Therapy
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• 제34권6호
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• pp.321-325
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• 2022

Purpose: Temporomandibular disorder (TMD) is a condition defined as pain and dysfunction of temporomandibular joints and masticatory muscles. Abnormal interconnections between temporomandibular muscles and cervical spine structures can cause the changes of postural alignment and balance ability. The aim of this study was to investigate changes in static balance ability in subjects with painrelated TMD. Methods: This study conducted on 25 subjects with TMD and 25 control subjects with no TMD. Pressure pain thresholds (PPTs) of the masseter and temporalis muscles were measured using a pressure algometer. Static balance ability was assessed during one leg standing using an Inertial Measurement Unit (IMU) sensor. During balance task, the IMU sensors measured motion and transfer movement data for center of mass (COM) motion, ankle sway and hip sway. Results: PPTs of masseter and temporalis muscles were significantly lower in the TMD group than in the control group (p<0.05). One leg standing, hip sway, and COM sway results were significantly greater in the TMD group (p<0.05), but ankle sways were not different between group. Conclusion: We suggest pain-related TMD is positively related to reduced PPTs of masticatory muscles and to static balance ability. These results should be considered together with global body posture when evaluating or treating pain-related TMD.

• Physical Therapy Rehabilitation Science
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• 제7권3호
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• pp.102-108
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• 2018

Objective: To investigate whether the Minimal Clinically Important Difference (MCID) clinically defines improvement of Berg Balance Scale (BBS) scores in people with acute stroke in response to rehabilitation. Design: Retrospective study. Methods: Seventy-three participants with acute stroke participated in the study. Balance evaluation was performed using the BBS. All patients received rehabilitation with physical therapy for 4 weeks, 5 times a week, for 2 hours and 20 minutes a day. An anchor-based approach using the clinical global impression was used to determine the MCID of the BBS. The MCID was used to define the minimum change in the BBS total score (postintervention-preintervention) that was needed to perceive at least a 3-point improvement on the global rating of change. Receiver operating characteristic (ROC) curves was used to define the cut-off values of the optimal MCID of the BBS in order to discriminate between improvement and no improvement groups. Results: The optimal MCID cut-off point for the BBS change scores was 12.5 points for males with a sensitivity (Sn) of 0.62 and a specificity (Sp) of 0.89, and 12.5 points for females with a Sn of 0.69 and Sp of 0.85. The area under the curve of the ROC curve for all participants were 0.84 (95% confidence interval [CI], 0.72; 0.95, p<0.001), and 0.89 (95% CI, 0.77; 1.00, p<0.001), respectively. Conclusions: The MCID for improvement in balance as measured by the BBS was 13.5 points, indicating that the MCID does clinically detect changes in balance abilities in persons with stroke.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.891-910
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• 2021

Previous QoS-aware service composition methods mainly focus on how to generate composite service with the optimal QoS efficiently for a single request. However, in the real application scenarios, there are multiple service requests and multiple service providers. It is more important to compose services with suboptimal QoS and maintain the load balance between services. To solve this problem, in this paper, we propose a service composition method, named as dynamically change and balancing composition method (DCBC). It assumes that the QoS of service is not static, and the services can adjust the value of QoS to gain more opportunities to be selected for composition. The method mainly includes two steps, which are the preprocessing step and the service selection step. In the preprocessing step, a backward global best QoS calculation is performed which regarding the static and dynamic QoS respectively; then guided by the global QoS, the feasible services can be selected efficiently in the service selection step. The experiments show that the DCBC method can not only improve the overall quality of composite services but also guarantee the fulfill ratio of requests and the load balance of services.

• Structural Engineering and Mechanics
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• 제66권4호
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• pp.543-555
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• 2018

Fiber Reinforced Polymer (FRP), which has a high strength to weight ratio, are now regularly used for strengthening of deficient reinforced concrete (RC) structures. While various researches have been conducted on FRP strengthening, an area that still requires attention is predicting the debonding failure load of prestressed FRP strengthened RC beams. Application of prestressing increases the capacity and reduces the premature failure of the beams largely, though not entirely. Few analytical methods are available to predict the failure loads under flexure failure. With this paucity, this research proposes a method for predicting debonding failure induced by intermediate crack (IC) for prestressed FRP-strengthened beams. The method consists of a numerical study on beams retrofitted with prestressed FRP in the tension side of the beam. The method applies modified Branson moment-curvature analysis together with the global energy balance approach in combination with fracture mechanics criteria to predict failure load for complicated IC-induced failure. The numerically simulated results were compared with published experimental data and the average of theoretical to experimental debonding failure load is found to be 0.93 with a standard deviation of 0.09.