• 센서학회지
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• 제32권2호
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• pp.110-117
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• 2023

Reconstructing underwater geometry in real time with forward-looking sonar is critical for applications such as localization, mapping, and path planning. Geometrical data must be repeatedly calculated and overwritten in real time because the reliability of the acoustic data is affected by various factors. Moreover, scattering of signal data during the coordinate conversion process may lead to geometrical errors, which lowers the accuracy of the information obtained by the sensor system. In this study, we propose a three-step data processing method with low computational cost for real-time operation. First, the number of data points to be interpolated is determined with respect to the distance between each point and the size of the data grid in a Cartesian coordinate system. Then, the data are processed with a nonlinear interpolation so that they exhibit linear properties in the coordinate system. Finally, the data are transformed based on variations in the position and orientation of the sonar over time. The results of an evaluation of our proposed approach in a simulation show that the nonlinear interpolation operation constructed a continuous underwater geometry dataset with low geometrical error.

• 스마트미디어저널
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• 제12권4호
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• pp.41-46
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• 2023

UWB는 실내 측위를 위해 사용되는 기술의 일종으로 RSSI 기반의 기법들보다 정확도가 높은 특징이 있다. ROS(Robot Operating System) 기반으로 동작하는 이동체 장비는 라이다와 카메라를 사용하여 장비 주변의 환경을 모니터링할 수 있다. 이러한 모니터링 과정에서 처음 시작하는 위치를 파악하는 루프 클로징 기법 적용 시 기존의 방법은 영상 상에 특징점이 있어야 클로징 작업이 일어나기 때문에 정확도가 낮은 문제가 있다. 본 논문에서는 이러한 문제를 해결하기 위해 이동체 장비에 UWB 태그를 탑재하여 위치 정보를 제공함으로써 루프 클로징 작업의 정확도를 높이는 시스템을 설계하였다. 또한 실험을 통해서 UWB 기반 실내 측위 시스템의 정확도를 평가하였고 이를 루프 클로징 기법에 활용할 수 있는지 검증하였다.

• Geomechanics and Engineering
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• 제29권4호
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• pp.471-486
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• 2022

The effect of segmental joints is one of main importance for the segmental lining design when tunnels are excavated by a mechanized process. In this paper, segmental tunnel linings are analyzed by two numerical methods, namely the Beam-Spring Method (BSM) and the Solid-Interface Method (SIM). For this purpose, the Tehran Subway Line 6 Tunnel is considered to be the reference case. Comprehensive 2D numerical simulations are performed considering the soil's calibrated plastic hardening model (PH). Also, an advanced 3D numerical model was used to obtain the stress relaxation value. The SIM numerical model is conducted to calculate the average rotational stiffness of the longitudinal joints considering the joints bending moment distribution and joints openings. Then, based on the BSM, a sensitivity analysis was performed to investigate the influence of the ground rigidity, depth to diameter ratios, slippage between the segment and ground, segment thickness, number of segments and pattern of joints. The findings indicate that when the longitudinal joints are flexible, the soil-segment interaction effect is significant. The joint rotational stiffness effect becomes remarkable with increasing the segment thickness, segment number, and tunnel depth. The pattern of longitudinal joints, in addition to the joint stiffness ratio and number of segments, also depends on the placement of longitudinal joints of the key segment in the tunnel crown (similar to patterns B and B').

• 예술인문사회 융합 멀티미디어 논문지
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• 제5권5호
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• pp.167-176
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• 2015

지중해 지역은 다양한 관광자원으로 인하여 매년 전 세계의 수많은 관광객들이 방문하고 있다. 본 논문에서는 아랍의 봄 등과 같은 특정 사건이 이러한 지중해 지역의 관광에 어떻게 영향을 미치는가를 분석하는 것이다. 세부적으로 사진 공유 웹 사이트인 파노라미오에서 추출한 지오태그 사진 데이터를 기반으로 위치 및 시간정보를 추출하여 밀도지도를 제작한다. 그리고 이 밀도지도를 이용하여 특정 사건이 지중해 관광에 미치는 영향을 분석한다. 이를 위하여 먼저 사진 공유 사이트에서 지중해 지역 관련 사진들의 위치 및 시간 정보를 이용하여 데이타베이스를 구축한 후에, GIS 도구의 기능을 활용하여 밀도 분석 및 밀도 지도를 생성한다. 그리고 이 밀도 지도를 기반으로 지중해 관광을 아랍의 봄 사건을 기준으로 이전과 진행, 이후로 구분하여 시각적으로 분석한다.

• 영어영문학
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• 제56권5호
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• pp.823-850
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• 2010

In this paper, I will explore disparate voices embedded in the interactions of stories in which personal, cultural, historical, and mythical consciousness brings up diverse ideas about the experiences of Native Americans. The accommodation of differences and changes is clearly manifested through the healing ceremony of Tayo, which poses some practical questions: what could be the authentic tradition of Native Americans?; which direction should it be led to? As these questions suggest, Tayo needs to think over and work through the way that Native oral stories will enrich the signification of being Indian within multicultural U. S. society. In other words, Tayo should transfer the oppositional relationship between Anglo and Native American world into an interactive one to bring forth new meanings concerning their interactions. As a hybrid, Tayo begins to recognize that his fragmented consciousness could represent the pervasive but surmountable anxiety about the cultural clash between Native and White Americans. Going through the multiple layers of his stories, Tayo learns that Native Americans need to hold a balanced viewpoint firmly: this demonstrates that storytelling brings restoration and renewal to him. As a result of Betonie's healing ceremony and his intimate relationship with Ts'eh, Tayo comes to have a holistic comprehension about how all the living things are interconnected to one another. After acquiring this recognition, Tayo succeeds in his quest to get back Josiah's cattle and recovers his identity as a Laguna Pueblo Indian, still letting diverse voices, cultures, and stories flow into the process of storytelling. As the last scene in which the conversations among Tayo, Auntie, and Grandmother took place illustrates, Tayo has newly secured a position that will require him to create a new, alternative story, not just repeating previous stories.

• Clinical Pain
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• 제18권2호
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• pp.92-96
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• 2019

Torticollis is an abnormal, asymmetric head or neck position which usually caused by imbalance of paracervical muscles. The traumatic torticollis can be caused by following events; atlantoaxial rotatory subluxation, atlantoaxial dislocation, cervical vertebral fractures, and injury to the cervical musculature. Especially, acute traumatic atlantoaxial rotatory subluxation usually presents limitation of cervical range of motion without pain or neurologic deficit. We report a case of a 58 year-old man who developed the acute atlantoaxial rotatory subluxation right after the chiropractic therapy, which induced the limitation of cervical range of motion to 52.5% of normal range. The magnetic resonance image revealed the facture of the odontoid process and the partial injury in transverse ligaments of the atlas. He underwent intramuscular botulinum toxin injection and 10 days of continuous cervical traction 15 hours a day using a 5 kg weight. The range of the cervical motion restored up to 90.2% of normal range.

• 무역학회지
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• 제46권2호
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• pp.19-38
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• 2021

This study aims to analyze the foreign asset leverage effect on Korean oil & gas companies' foreign profits and to maintain the appropriate foreign asset volume for reducing exchange risk. For a long time, large Korean companies, including oil companies, overheld foreign currency liabilities. For this reason, most large companies have been burdened to hedge exchange risk and this excess limit holding deteriorated total profit and reduced foreign currency asset management efficiency. Our paper proceeds in presenting a three-stage analysis considering diversified exchange risk factors through estimation on transformation of foreign transactions a/c including annual trends of foreign asset and industry specifics. We also supplement incomplete the estimation method through a practical hedging case investigation. Our research parts are differentiated on the analyzing four periods considering period-specifics The FER value of the oil firms ranged from -0.3 to +2.3 over the entire period. The results of the FER Value are volatile and irregular; those results do not represent the industry standard comparative index. The Korean oil firms are over the credit limit without accurate prediction and finance high interest rate funds from foreign-owned banks on the basis on a biased relationship. Since the IMF crisis, liabilities of global firms have decreased. Above all, oil firms need to finance a minimum limit without opportunity losses on the demand forecast and prepare for uncertainty in the market. To reduce exchange risk from the over-the-limit position, we must consider factors that affect the corporate exchange risk on the entire business process, including the contract phase.

• 한국응용과학기술학회지
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• 제40권5호
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• pp.1163-1175
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• 2023

Cholesterol is prone to oxidation, which results in the formation of cholesterol oxidation products (COPs). This occurs because it is a monounsaturated lipid with a double bond on C-5 position. Cholesterol in foods is mostly non-enzymatically oxidized by reactive oxygen species (ROS)-mediated auto-oxidative reaction. The COPs are found in many common foods of animal-origin and are formed during their manufacture process. The formation of COPs is mainly related to the temperature and the heating time the food is processed, storage condition, light exposure and level of activator present such as free radical. The level of COPs in processed foods could reach up to 1-10 % of the total cholesterol depending on the foods. The most predominant COPs in foods including meat, eggs, dairy products as well as other foods of animal origin were 7-ketocholesterol, 7 α-hydroxycholesterol (7α-OH), 7β-hydroxycholesterol (7β-OH), 5,6α-epoxycholesterol (5,6α-EP), 5,6β-epoxycholesterol (5,6β-EP), 25-hydoxycholesterol (25-OH), 20-hydroxycholesterol (20-OH) and cholestanetriol (triol). They are mainly formed non-enzymatically by cholesterol autoxidation. The COPs are known to be potentially more hazardous to human health than pure cholesterol. The procedure to block cholesterol oxidation in foods should be similar to that of lipid oxidation inhibition since both cholesterol and lipid oxidation go through the same free radical mechanism. The formation of COPs in foods can be stopped by decreasing heating time and temperature, controlling storage condition as well as adding antioxidants into food products. This review aims to present, discuss and respond to articles and studies published on the topics of the formation and inhibition of COPs in foods and key factors that might affect cholesterol oxidation. This review may be used as a basic guide to control the formation of COPs in the food industry.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.149-156
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• 2011

The performance measurement of construction firms is considered as a competitive advantage to develop and improve their performance to have place in the market and stay able to face the continuous challenge. Egyptian construction firms (ECF) started recently to adopt quality management system (QMS) as a way to develop and improve their performance as previous studies showed. However, measuring that performance to include all the firm's aspects in a competitive way is a crucial process for the ECF's culture. The research is trying to indicate the role of the QMS implementation in measuring performance (MP) through developing a model for measuring performance on the organization level, and explore its impact on the organization that adopt quality management system. This model is based on specific elements and their related indicators which have been derived from national approaches and models of measuring performance (benchmarking, quality awards and six sigma).Elements determination and the status of their real practice has been investigated through a questionnaire to a representative sample of ECF. This model determines the performance level (PL) of the organization that measured by a mean of a point system. Weights of the elements in the point system considered both the elements' importance in the international models and its real practice in the Egyptian construction firms. So, the final outcome of the model reveals the level of firm performance that helps the firm to identify the weak points against the strong ones, Confirm the priorities and identify new opportunities for developing, and Check the position of the company in the market among the others. Another questionnaire has been developed to be distributed on a group of Experts on measuring performance for the purpose of model validation. The majority of surveyed experts agreed that the proposed model can be applied effectively.

• 한국컴퓨터정보학회논문지
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• 제29권1호
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• pp.77-84
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• 2024

본 논문에서는 컴퓨터 비전을 사용하여 6가지 측정값(눌린 단자의 길이, 단자 끝의 치수(폭), 눌린부분(와이어 부분, 코어 부분)의 폭)을 계산하여 와이어 하네스의 결함을 정확하고 빠르게 탐지할 것을 제안한다. 두 가지 유형의 데이터에서 Harris 코너 검출을 활용하여 물체의 위치를 탐지하고 측정 영역별 특징과 배경과 물체 사이의 음영 차이를 활용하여 각 샘플의 기울기를 반영하는 측정값을 추출하기 위한 기준점을 생성한다. 이후 유클리드 거리 방법과 보정 계수를 사용하여 예측값을 계산하는 방법을 통해 와이어의 위치 변화에 관계 없이 측정값을 예측할 수 있다. 각 측정 유형별로 99.1%, 98.7%, 92.6%, 92.5%, 99.9%, 99.7% 정확도를 달성하였으며, 모든 측정값에서 평균 97%의 정확도로 우수한 결과를 얻었다. 해당 검사 방법은 기존 검사 방법인 육안 검사의 문제점을 보완하고, 작은 양의 데이터만을 이용하여 우수한 결과를 도출 가능하다. 또한 이미지 처리만 이용하기 때문에 딥러닝 방법보다 더 적은 데이터와 비용으로 적용 가능할 것으로 기대된다.