• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.87-93
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• 2013

A baby-step giant-step algorithm divides n by n blocks that possess $m={\lceil}\sqrt{n}{\rceil}$ elements, and subsequently computes and stores $a^x$ (mod n) for m elements in the 1st block. It then calculates mod n for m blocks and identifies each of them with those in the 1st block of an identical elemental value. This paper firstly proposes a modified baby-step giant-step algorithm that divides ${\lceil}m/2{\rceil}$ blocks with m elements applying $a^{{\phi}(n)/2}{\equiv}1(mod\;n)$ and $a^x(mod\;n){\equiv}a^{{\phi}(n)+x}$ (mod n) principles. This results in a 50% decrease in the process of the giant-step. It then suggests a reverse baby-step giant step algorithm that performs and saves ${\lceil}m/2{\rceil}$ blocks firstly and computes $a^x$ (mod n) for m elements. The proposed algorithm is found to successfully halve the memory and search time of the baby-step giant step algorithm.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.309-310
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• 2021

본 연구는 건강 이상 감지를 위해 보폭 이상을 판단하는 신발과 어플리케이션을 연동하여 알츠하이머 등의 뇌손상으로 인한 보폭 이상을 미연에 예방하고 개선하는데 목적이 있다. 보행 이상 감지를 위해 보폭을 판단하는 건강진단신발은 측정부가 설치되며, 알츠하이머 등의 뇌손상에 의해 보폭이 줄어드는 경우 보폭이 좁아지는 것을 경고함으로써 장소와 시간에 구애받지 않고 신발착용자 스스로 보행 진단 및 교정이 이루어질 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.331-332
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• 2022

본 논문에서는 3축 가속도와 3축 각속도 센서로 구성된 관성 측정 장치(IMU)와 압력센서가 내장되어있는 스마트 인솔을 착용하여 얻어진 보행 데이터를 통해 보폭을 추정하는 방법을 제안한다. 먼저 압력센서를 활용하여 한 걸음 주기로 나눈 뒤 나누어진 가속도와 각속도 센서 데이터를 LSTM과 Attention 계층을 결합한 딥러닝 모델에 학습하여 보폭 추정을 시행하였다. LSTM-Attention 모델은 기존 LSTM 모델보다 약 1.14%의 성능 향상을 보였다.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.213-219
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• 2008

The purpose of this study is to propose frame analysis method for flat plate slabs having edge beam under lateral loads. Flat plate system is defined as the system only with slab of uniform thickness and column. However, the slab system generally incorporate edge beams at exterior connection in actual design. ACI 318 (2005) allows three methods for conducting flat plate system analysis subjected to lateral loads. There are the finite element method (FEM), the equivalent frame method (EFM), and the effective beam width method (EBWM). Among methods, the EBWM enables us to analyze practically by substituting the actual slab to beam element. In this model, the beam element has a thickness equal to that of the slab, and effective beam width equal to some fraction of the slab transverse width. However, the established EBWM was generally proposed for variables of geometry or stiffness reduction factor and seldom proposed for the effect of edge beams. This study verifies that, in the case of flat plate system having edge beams at exterior connections, the lateral stiffness is considerably larger than without edge beams. Therefore it need to analysis method for considered the effect of edge beams. In this study, an analysis model is proposed for the flat plate system having edge beams under lateral loads by considering the effect of edge beams. To verify the accuracy of proposed model, this study compared results of the proposed EBWM with results of FEM of flat plate systems having edge beams under lateral loads. Also, the proposed approach is compared with experimental results of former research.

• Physical Therapy Korea
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• v.5 no.4
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• pp.30-40
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• 1998

이 연구의 목적은 젊은 아시아인과 코카시아 여성의 보행패턴 중 보폭시간(step time) 과 보폭 (step length)을 비교하고 두 집단의 골반넓이와 보폭과 상관관계가 있는지 알아보는 것이다. 연구대상자는 15명의 아시아인과 15명의 코카시아 여성이었으며 나이는 23세에서 35세 범위에 있었다. 보행분석을 위해서는 GAITRite System을 사용하였으며 분석방법으로는 인종(아시아인대 코카시아인)과 신체부위(좌측, 우측)를 요인으로 하여 반복측정에 의한 분산분석을 하였다. 아시아인 여성보다 코카시아인 여성의 보폭, 다리길이, 골반 넓이가 통계학적으로 유의하게 높았고 왼쪽 다리의 걸음과 오른쪽 다리의 걸음에 있어서는 통계학적으로 유의한 차이가 없었다. 그리고 보폭시간, 속도, 걸음수(cadence)에 있어서도 두 여성 인종간에 통계학적으로 유의한 차이가 없었다. 이러한 결과는 보행변수 중에서 걸음수나 속도와 같은 시간변수에 았어서는 아시아인 여성과 코카시아인 여성간에 차이가 없음을 의미한다.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.556-563
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• 2015

The purpose of this study was to analyzed body movement of the right and left directions relative to stance width. Seven college students(male, height $174.9{\pm}4.8cm$, weight $70.9{\pm}6.6kg$) participated in this study. For the purpose of this study, nine high-speed cameras and two force plates was utilized. Stance width was limited into small stance width(mean 42.9cm) and large stance width(mean 65cm). The results showed that (1) the small stance width took shorter time than the large stance during landing of the right feet to toe-off; (2) the small stance width was took longer movement of the right feet after split step comparing to the large stance; (3)there was no significant difference in the speed of center of gravity between toe-off and maximum speed; (4) the small stance width was greater angles to hip joint and knee joint during toe-off of the right feet comparing to the large stance; (5) the was no significant difference in values for force plates between the small stance and the large stance width during toe-off of the right feet.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.35-43
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• 2013

Exercise such as walking is helpful to manage one's own weight and to counter life habit diseases such as obesity. Calorie consumption is usually calculated based on the distance walked. One way to measure the distance is by using steps and stride length. Most pedometers, including some applications in smart devices, are inaccurate, because they use a common value as the average stride length, even though each person has a different stride length. Moreover, the stride length differs depending on the walking pace, which will further increase the error. To address this, in this paper, I classify paces into three categories. Following that, I introduce a customized measurement of stride length, which is calculated based on the stride length corresponding to each pace category after obtaining x, y, z values from a 3-axis accelerometer in the smart device. In addition to this, I developed an application running on the smart device designed for the proposed measurement of stride. I have conducted three experiments for the assessment of the proposed measurement. In conclusion, I confirmed the effectiveness of this system.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.661-668
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• 2009

Effective beam width model(EBWM) has been used for analysis of post-tensioned(PT) flat plate slab frames under lateral loads. The accuracy of this model in predicting lateral drifts and unbalanced moments strongly depends on the estimated effective stiffness of PT flat plate slabs. As moments on the slab due to lateral loads increases, cracks occur which leads to stiffness reduction in slabs. For analyzing PT flat plate slab structure under lateral loads with good precision, reduction in slab stiffness has to be accurately estimated for EBWM. For this purpose, this study collected test results of PT flat plate system conducted by former researches. And this study reduced the width of slab so that the stiffness of the EBWM converged into the lateral stiffness of each test specimens by trial and error. By conducting nonlinear regression analysis using the stiffness ratio of the reduced width of slab to the effective width of EBWM with respect to the level of slab moments, an equation for calculating stiffness reduction factor for slab is proposed. For verifying the accuracy of the proposed equation, this study compared with the test result of the PT flat plate frame. It is shown that the EBWM with the proposed equation predicts the actual stiffness of the PT specimen which varied according to the level of applied moment.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.548-552
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• 2017

본 논문에서는 얀센 메커니즘을 활용한 보행 로봇의 궤적을 최적화 하기 위한 알고리즘을 연구하였다. 궤적의 최적화 목표는 지면에 닿는 시간이 길고 지면에 평행하며 빠른 이동을 위해 넓은 보폭을 생성 하는 것으로 두었다. 초기 값은 Edison design의 m.sketch를 사용하여 결정하였고 최적화 과정에서는 MATLAB을 사용하였으며 가능한 빠른 계산이 가능한 것에 초점을 두고 알고리즘을 작성하였다. 최적화된 결과 값에서는 지면에 닿는 궤적의 범위와 보폭의 크기, 궤적의 높이가 가장 큰 값을 결정하였다.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.615-622
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• 2002

To reasonably predict the behaviors for RC flat-plate structures, analysis model considering the flexural stiffness of slabs is required. FEMA 273 and ACI 318-99 refer to theoretical analysis models of two-way slab systems under lateral loading but the actual application method is not suggested. In this study, the modeling and application methods of the flat-plates using effective beam concept are suggested. The results of this study are as follows. 1) The effective beam width model suggested in this study is very useful to model flat-Plate structures subjected to seismic loading for three dimensional analysis 2) The result of analysis for idealized flat-plate example using the effective beam widths considering the effect of the slab crack is shown upper value for displacements. Whereas the model considering effective beam width coefficients only is shown upper value for unbalanced moments