• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.860-862
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• 2018

오늘날, 현대인들의 생활 속에서 스마트폰을 빼놓을 수 없을 만큼 스마트폰을 장시간 이용하는 사람들이 많다. 스마트폰 이용시간이 늘어날수록 목을 숙인 자세를 유지하게 되며, 이는 VDT 증후군 중 거북목증후군을 발생시킬 가능성이 높다. 본 논문에서는 사용자의 목 각도를 유추해 거북목 자세가 일정시간 유지될 때 알림기능을 제공하는 애플리케이션을 개발하였다. 애플리케이션을 통해 스마트폰 사용자들이 자신의 자세를 인지하고 올바른 자세로 교정할 수 있도록 유도하였다. 본 애플리케이션은 스마트폰의 기울기에 따라 사용자의 목각도를 추측하기 때문에, 스마트폰의 기울기와 목각도간의 상관성 분석 실험을 수행하여 애플리케이션의 유효성을 입증하였다.

• 재활복지
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• v.22 no.2
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• pp.213-230
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• 2018

The study looked at the impact on the health of the spine caused by the increasing addiction to smart phones, and examine the moderating effect of adjusting spinal health according to cognitive strength. All subjects used the smartphone by measuring the diagnostic scale of the smartphone addiction, the angle of forward inclination of the cervical spine, and the amplitude variation of the cognitive Gamma-Peak of the brain waves. As a result, as the use of smart phones increases, the spine angle significantly increased (p<0.001), as cognitive strength increased, the spine angle decreased significantly (p<0.01). The cognitive strength also showed the effect of adjusting the spine angle through interaction with the degree of use of a smartphone (p<0.05). This results in a higher degree of smartphone use in lower and middle cognition strength groups, which results in a higher angle of forward tilt in the cervical spine.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.501-502
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• 2015

본 논문에서는 3상 인버터 직류단에 하나의 shunt 저항을 삽입한 1-shunt 인버터의 평균 상전류를 추정하는 새로운 알고리즘을 제안한다. 2개의 영벡터와 6개의 유효전압 벡터의 조합으로 구현되는 SVPWM 방식에서, 각 스위칭 상태에 따른 상전류 기울기를 알 수 있다면, 유효전압 벡터 인가시간을 이용하여 평균 상전류를 추정할 수 있다. 본 논문에서는 각 스위칭 상태에서의 전류기울기와 인가시간을 이용하여 평균 상전류를 추정하고 이를 일반화 한다. 제안된 알고리즘의 정확성은 실험적 결과를 통해 증명한다.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.321-326
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• 2004

Many researchers have been studied texturing the 3D face model with front and side pictures of ordinary person. It is very important to exactly detect the psition of eyes, nose, mouth of a human from the side pictures. Previous results first found the position of eye, nose, or mouth and then extract the other face components using their positional correlation. The detection results greatly depend on the correct extraction of the neck from the images. Therefore, we present a new algorithm that remove the neck completely and thus improve the detection rates of face components. To do this, we will use the RGB values and its differences.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.265-271
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• 2021

This study aimed to define the diagnostic criteria for cervicogenic headache and propose an efficient method of clinical evaluation and physical therapy. Fifteen patients with cervicogenic headache and 15 healthy individuals were recruited and categorized into the test group and the control group, respectively. The groups were compared in terms of muscle characteristics, muscle activity and posture, and the intervariable correlations were analyzed for the test group. A significant between-group difference was found in the stiffness of the suboccipital muscle and the tone and stiffness of the upper trapezius muscle (p<.001). In posture comparison, a significant difference was noted in neck tilt angle and the T1 slope angle (p<.05). The activity of the sternocleidomastoid muscle was also significantly different between the groups (p<.001). When the correlations among the muscle characteristics, the posture, and the activity of the sternocleidomastoid muscle were analyzed for the test group, a positive correlation was found between the tone and the stiffness of the suboccipital muscle (p<.001) and between the tone and the stiffness of the upper trapezius muscle (p<.001). The findings of this study suggest a more efficient approach for the assessment and treatment of cervicogenic headache patients. It is considered that, further studies including more subjects of various job categories and comparing the outcomes.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.35-35
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• 2003

목적 : 세기변조방사선치료의 정도관리 중 선량 분포의 비교에 관한 새로운 정량적인 방법을 제시하였다. 이 과정 중에서 선량의 기울기가 큰 영역에서의 문제점을 해결하기 위하여 최적화 알고리듬을 사용하였다. 대상 및 방법 : 필름을 통해 측정된 선량분포와 컴퓨터를 통해 구해진 선량분포를 각각 5mm 간격과 lmm 간격의 해상도로 컴퓨터를 이용해 2 차원 선량분포로 구현한다. 그 후 두 선량분포사이의 차이를 각 선량분 포의 원점을 일치시킨 후 구해낸다. 이때 일반적으로 두 선량분포 사이의 차이는 선량의 기울기가 큰 영역에서 상당히 크게 나타나게 되는데 이것은 측정 장비의 원점을 구하는 과정에서 발생되는 이차원 상의 미세한 원점의 불일치 효과로 선량의 차이가 선량의 기울기가 큰 영역에서 더욱 커지기 때문이다. 이 불일치를 보정하기 위해서, 측정된 선량분포를 계산된 선량분포 위에서 lmm 간격으로 이동시켜가면서 선량의 차이를 계산하여 이 값이 최소가 되는 위치를 확인한다. 이때의 이동치는 가속기가 갖는 허용오차 이내에 있어야 하며 이 값은 2mm로 알려져 있다. 이 과정과는 독립적으로 이온 챔버를 통해 측정된 절대선량 값을 이용하여 두 선량분포 사이를 재 규격화한 뒤 차이를 구하게 되면 우리는 5mm 간격의 2 차원 절대선량 분포 비교를 실험상의 오차들 중 가장 크게 작용하는 원점 오차로 인한 오차를 제거한 뒤 수행한 것과 같은 결과를 얻게 된다. 여기서 계산된 선량분포의 해상도는 장비의 허용오차 보다 항상 작아야 한다. 결과 : 머리와 목에 환부를 갖는 여러 환자들에 대한 선량분포 비교 결과를 통해서, 측정된 선량분포와 계산된 선량분포사이의 허용오차 범위에 대한 일시적 기준을 마련하였다. 이 기준은 물론 더 많은 환자들에 대한 선량분포 비교를 통해 개선되어질 수 있다. 결론 : 측정 장비의 원점 불일치의 보정뿐만 아니라 측정 장비의 회전에 의한 오차 보정, 필름의 광학적 밀도에 관한 보정 등 여러 가지 계통적 오차들에 대한 보정들이 선량분포 확인과정의 이해와 그 기준마련에 도움이 되겠지만 우리가 다룬 원점 불일치에 비해서 상대적으로 무시할 수 있었다. 마지막으로 선량분포 확인의 최종목표인 3 차원 선량분포 확인의 실제 적용을 위한 연구가 최적화 알고리듬을 이용하여 실험 중에 있다.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.89-105
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• 2017

This study utilized 32,312 records of 17 linear type and 10 conformation traits(including final scores) of Hanwoo cows in the KAIA(Korea Animal Improvement Association) ('09~'10), with 60,556 animals in the pedigree file. Traits included stature, body length, strength, body depth, angularity, shank thickness, rump angle, rump length, pin bone width, thigh thickness, udder volume, teat length, teat placement, foot angle, hock angle, rear leg back view, body balance, breed characteristic, head development, forequarter quality, back line, rump, thigh development, udder development, leg line, and final score. Genetic and residual(co) variances were estimated using bi-trait pairwise analyses with EM-REML algorithm. Herd-year-classifier, year at classification, and calving stage were considered as fixed effects with classification months as a covariate. The heritability estimates ranged from 0.03(teat placement) to 0.42(body length). Rump length had the highest positive genetic correlation with pin bone width(0.96). Moreover, stature, body length, strength, and body depth had the highest positive genetic correlations with rump length, pin bone width, and thigh thickness(0.81-0.94). Stature, body length, strength, body depth, rump length, pin bone width, and thigh thickness traits also had high positive genetic correlations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.97-103
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• 2013

This study proposes a path generation technique for simultaneous five-axis driving for ball bar measurement, which is equivalent to cone frustum machining as mentioned in the NAS979 standard. The technique is generalized for a 3D circular path, and it is applicable to all machine tools regardless of their structural configurations. A mathematical machine input model that consists of a five-axis machine tool, ball-bar measurement and conical path information as inputs is presented for easy NC code generation, simulation for various test conditions, and a measurement test. The movement range of rotary axes, which depends on various conditions, is mathematically analyzed based on the proposed conical path model. Moreover, the effect of the movement range on various conditions (apex angle and inclination angle, ball bar tilting acceptance angle, offset position of workpiece ball, etc.) is analyzed.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.41-51
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• 2023

In this paper, we propose a technique of multi-time window feature extraction for anger detection in gait data. In the previous gait-based emotion recognition methods, the pedestrian's stride, time taken for one stride, walking speed, and forward tilt angles of the neck and thorax are calculated. Then, minimum, mean, and maximum values are calculated for the entire interval to use them as features. However, each feature does not always change uniformly over the entire interval but sometimes changes locally. Therefore, we propose a multi-time window feature extraction technique that can extract both global and local features, from long-term to short-term. In addition, we also propose an ensemble model that consists of multiple classifiers. Each classifier is trained with features extracted from different multi-time windows. To verify the effectiveness of the proposed feature extraction technique and ensemble model, a public three-dimensional gait dataset was used. The simulation results demonstrate that the proposed ensemble model achieves the best performance compared to machine learning models trained with existing feature extraction techniques for four performance evaluation metrics.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.7-17
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• 2007

Purpose: As increasing complexity of modern radiotherapy technique, more developing dosimetry is required. Polymer gel dosimeters offer a wide range of potential applications with high resolution and assured quality in the thee-dimensional verification of complex dose distribution such as intensity-modulated radiotherapy (IMRT). The purpose of this study is to find the most sensitive and suitable gel as a dosimeter by varying its composition ratio and its condition such as temperature during manufacturing. Materials and Methods: Each polymer gel with various ratio of composition was irradiated with the same amount of photon beam accordingly. Various polymer gels were analyzed and compared using a dedicated software written in visual C++ which converts TE images to R2 map images. Their sensitivities to the photon beam depending on their composition ratio were investigated. Results: There is no dependence on beam energy nor dose rate, and calibration curve is linear. Conclusion: The polymer gel dosimeter developed by using anti-oxidant in this study proved to be suitable for dosimetry.