• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권1호
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• pp.29-36
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• 2017

본 논문에서는 손목형 가속도계를 이용하여 운동 가속도가 거의 없는 식사 행동을 인식하기 위한 방법을 제안한다. 먼저 손목 방향에 작용하는 중력 가속도를 이용하여 중력 방향과 손목 방향 간의 각도를 구하고, 특정 각도 영역에서 첨두값과 첨미값이 존재하는 경우 손목이 왕복하는 동작을 검출한다. 손목 왕복 동작 발생 횟수를 누적하여 그 횟수가 10회 이상일 경우 검출 시점으로 5분 전까지 식사 시간으로 간주하며, 그 지속시간이 7분 이상인 경우에만 식사 시간으로 추론한다. 대학원생 4명으로부터 수집한 2128분 데이터를 통해 식사 시간을 추론한 결과 95.63%의 정확도를 보인다.

• 한국정밀공학회지
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• 제17권1호
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• pp.145-152
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• 2000

X-ray diffraction method detects change of crystal lattice distance under material surface using diffraction angle 2$\theta$. This technique can be applied to the behavior on slip band and micro crack due to material degradation. The relation between half-value breadth and number of cycle has three stages which constitute rapid decrease in initial number of cycles, slight decrease in middle number of cycles and rapid decrease in final number of cycles. The ratio of half-value breadth takes a constant value on B/B$_{0}$-N diagram with loading condition except early part of fatigue life. The ratio of half-value breadth B/B$_{0}$ with respect to number of cycle to failure N$_{f}$ has linear behavior on B/B$_{0}$-log N$_{f}$ diagram. Therefore, in this paper the estimation of fatigue life by average gradient method has much less estimated mean error than the estimation of fatigue life by log B/B$_{0}$-log N/N$_{f}$ relation.elation.ation.

• Steel and Composite Structures
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• 제39권4호
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• pp.353-366
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• 2021

Cored moment resisting stub column (CMSC) was previously developed by the features of adopting a core segment which remains mostly elastic and reduced column section (RCS) details around the ends to from a stable hysteretic behavior with large post-yield stiffness and considerable ductility. Several full-scale CMSC components with various length proportions of the RCSs with respect to overall lengths have been experimentally investigated through both far-field and near-fault cyclic loadings followed by fatigue tests. Test results verified that the proposed CMSC provided very ductile hysteretic responses with no strength degradation even beyond the occurrence of the local buckling at the side-segments. The effect of RCS lengths on the seismic performance of the CMSC was verified to relate with the levels of the deformation concentration at the member ends, the local buckling behavior and overall ductility. Estimation equations were established to notionally calculate the first-yield and ultimate strengths of the CMSC and validated by the measured responses. A numerical model of the CMSC was developed to accurately capture the hysteretic performance of the specimens, and was adopted to clarify the effect of the surrounding frame and to perform a parametric study to develop the estimation of the elastic stiffness.

• Computers and Concrete
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• 제28권5호
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• pp.479-486
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• 2021

Reinforced concrete (RC) slabs are exposed to several static and dynamic effects during their period of service. Accordingly, there are many studies focused on the behavior of RC slabs under these effects in the literature. However, impact loading which can be more effective than other loads is not considered in the design phase of RC slabs. This study aims to investigate the dynamic behavior of two-way RC slabs under sudden impact loading. For this purpose, 3 different simply supported slab specimens are manufactured. These specimens are tested under impact loading by using the drop test setup and necessary measurement devices such as accelerometers, dynamic load cell, LVDT and data-logger. Mass and drop height of the hammer are taken constant during experimental study. It is seen that rigidity of the specimens effect experimental results. While acceleration values increase, displacement values decrease as the sizes of the specimens have bigger values. In the numerical part of the study, artificial neural networks (ANN) analysis is utilized. ANN analysis is used to model different physical dynamic processes depending upon the experimental variables. Maximum acceleration and displacement values are predicted by ANN analysis. Experimental and numerical values are compared and it is found out that proposed ANN model has yielded consistent results in the estimation of experimental values of the test specimens.

• 대한임베디드공학회논문지
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• 제17권4호
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• pp.191-197
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• 2022

This study proposes an image-based Pose Intention Network (PIN) algorithm for rehabilitation via patients' intentions. The purpose of the PIN algorithm is for enabling an active rehabilitation exercise, which is implemented by estimating the patient's motion and classifying the intention. Existing rehabilitation involves the inconvenience of attaching a sensor directly to the patient's skin. In addition, the rehabilitation device moves the patient, which is a passive rehabilitation method. Our algorithm consists of two steps. First, we estimate the user's joint position through the OpenPose algorithm, which is efficient in estimating 2D human pose in an image. Second, an intention classifier is constructed for classifying the motions into three categories, and a sequence of images including joint information is used as input. The intention network also learns correlations between joints and changes in joints over a short period of time, which can be easily used to determine the intention of the motion. To implement the proposed algorithm and conduct real-world experiments, we collected our own dataset, which is composed of videos of three classes. The network is trained using short segment clips of the video. Experimental results demonstrate that the proposed algorithm is effective for classifying intentions based on a short video clip.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.479-482
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• 1999

The tension stiffening effect, which means the maintaining a part of stiffness after cracking of concrete in tensile, exists at a reinforced concrete member because of the concrete softening and bonding stress between cracks. It is required to consider it for precise analysis and evaluation o structural behavior, due to the possibility of discrepancy between the actual behavior and the analysis without considering the tension stiffening effect. Making and adopting a tension stiffening model is the most simple and effective way for considering it at nonlinear analysis which indicated the estimation from models and experimental results were similar each others. The comparisons on RC beam were, also performed in order to analyzed the influence of concrete strength and steel ratio into the structural behavior. They indicated that the results from analysis estimated quite closely to the test results at low steel ratio, however, overestimated at high steel ratio. The overestimation increase linearly as concrete strength or steel ratio increased.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.185-190
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• 2002

It has made a special study of bending behavior of F.R.P sandwich beams with bonded 2nd-reinforced plies. Specimens were made of Chopped Mat 300-450, Roving Clothes 570 and the mixture weight ratio of Resin versus hardener was 55:45 for bending tests. it was fabricated by hand lay-up method, hardened for 24 hours in nature, cut specimens according to ASTM standard C393-94 Knowing exact behavior of bonded area's stress and strain depends upon various bonded F.R.P length on which covered lap joint. We also considered shear stress in adhered area and have done computational estimation by ANSYS as well. This study reveals that the length of plies covered lap joint are longer, Failure stresses are remarkably larger.

• 한국철도학회논문집
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• 제9권2호
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• pp.137-144
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• 2006

The Extradosed PSC bridge is one of the best alternates which not only covers the longer span than PSC box girder and also performs the role of landmark facility with much cheaper cost than cable stayed bridge. Since the cable-stayed long span bridge is more flexible than general medium span bridges and railway bridges can be experienced resonance phenomenon by repeated equidistant axle loading of the train, it is inevitable to consider the dynamic behavior on impact, deflection and so on. In the present study, the dynamic behavior of an Extradosed PSC railway bridge subjected to moving train forces is analyzed. As well as trains which operate in conventional railway tines, KTX train is also considered. For the estimation of dynamic performances of the Extradosed PSC bridge, vertical deflection, accelerations of the slab, end rotation of the girder and impact on pylons and cables are discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1102-1107
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• 2004

High-speed railway bridges subject to effect of statical loads by temperature change as well as dynamic loads by interaction between vehicle load which run specially fast and behavior of bridges, If suitable longitudinal expansion by temperature change of bridge does not happened, it can cause unhealthy condition for the parts of bridges as well as can generate addition stress to bridges, For these reason, Analysis and Estimation of data about behavior of bridges occupies important factor in that estimate the remaining life of bridges and select the maintenance, repair and retrofit. In this paper, Analysis for the long-term behavior of bridges using Longitudinal displacement and Temperature data that is actuality measured data to the bridges of Seoul-Busan high speed railroad test section has been made.

• 가정과삶의질연구
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• 제21권6호
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• pp.97-106
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• 2003

This study explored the relationship between housing values and condominium purchasing behavior. The participants of this study were married women who had bought a condominium at least once and who also were dwelling in one. Survey questionnaires were conducted on 1103 married women from three residential areas in Daegu. The analytical methods used in this study were frequency, mean, standard deviation, factor analysis, 1-test, one-way ANOVA, post-hoc estimation (Scheff test), and correlation analysis. The results show that the more the women were oriented toward convenience, education, and investment, the more likely they were to make a rational purchase. Also, the more the women's values were oriented toward conspicuous consumption and investment, the more they were likely to make an investment and ostentatious purchase. The women who valued ostentation and location tended to rely on other people's opinions and advertisement more, and were more likely to be impulsive shoppers. Women who valued convenience, education, and location, made their purchase decisions based on the housing prices.