• Smart Structures and Systems
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• 제29권3호
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• pp.395-420
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• 2022

A new hybrid quasi-3D and 2D high-order shear deformation theory is studied in this mathematical formulation, for an investigation of the bending, free vibrations and buckling influences on a functionally graded material plate. The theoretical formulation has been begun by a displacement field of five unknowns, governing the transverse displacement across the thickness of the plate by bending, shearing and stretching. The transverse shear deformation effect has been taken into consideration, satisfying the stress-free boundary conditions, especially on plate free surfaces as parabolic variation through its thickness. Thus, the mechanical properties of the functionally graded plate vary across the plate thickness, following three distributions forms: the power law, exponential form and the Mori-Tanaka scheme. The mechanical properties are used to develop the equations of motion, obtained from the Hamilton principle, and solved by applying the Navier-type solution for simply supported boundary conditions. The results obtained are compared with other solutions of 2D, 3D and quasi-3D plate theories have been found in the literature.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1127-1133
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• 2022

Recently, the use of aircraft structures using Ti alloy (Ti-6Al-4V), a lightweight high-strength alloy material, is rapidly increasing due to the weight reduction of aircraft. However, high-strength materials such as Ti alloys require high energy for cutting and are classified as difficult-to-cut materials. Also, research on Laser Assisted Machining (hereinafter referred to as LAM), a cutting processing technology that utilizes improved machinability, is being actively researched. Therefore, in this paper, in order to confirm the proper temperature distribution using a laser, the finite element method is used to determine the temperature distribution according to the calorific value condition to derive the appropriate condition, and the thermal load generated at this time is used as a structural analysis. It is intended to be used as basic data for LAM processing conditions by measuring the amount of residual stress and thermal deformation caused by heat.

• Smart Structures and Systems
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• 제32권2호
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• pp.123-133
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• 2023

This paper proposes a thermography-based coating thickness estimation method for steel structures using model-agnostic meta-learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured using an infrared (IR) camera. The measured heat responses are then analyzed using model-agnostic meta-learning to estimate the coating thickness, which is visualized throughout the inspection surface of the steel structure. Current coating thickness estimation methods rely on point measurement and their inspection area is limited to a single point, whereas the proposed method can inspect a larger area with higher accuracy. In contrast to previous ANN-based methods, which require a large amount of data for training and validation, the proposed method can estimate the coating thickness using only 10- pixel points for each material. In addition, the proposed model has broader applicability than previous methods, allowing it to be applied to various materials after meta-training. The performance of the proposed method was validated using laboratory-scale and field tests with different coating materials; the results demonstrated that the error of the proposed method was less than 5% when estimating coating thicknesses ranging from 40 to 500 ㎛.

• 소성∙가공
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• 제32권1호
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• pp.5-11
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• 2023

The aim of this study is to manufacture an aluminum pipe yoke of automotive steering system for lightweight. In a multistage cold forging process for aluminum pipe yoke, the surface defects frequently occur due to excessive deformation or friction during extrusion process for forming hollow pipe part. It is import to reduce the friction between the material and the forging die. This study investigated a multistage forging process with sliding die to reduce friction for aluminum pipe yoke. After evaluating by FE analysis, the forging experiment with the sliding die was carried out. As a result, it was possible to manufacture a sound aluminum pipe yoke.

• 한국위험물학회지
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• 제3권1호
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• pp.28-36
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• 2015

In early 2011, the Fukushima nuclear power plant had greater damage due to earthquake in Japan, and the awareness of safety has increased. In particular, special response systems should be required to handle disaster situations in plant sites which are likely to occur for large disasters. In this study, a program is designed to set up optimum escape routes, by a smart phone application, when a disaster situation occurs. This program could get information of the cumulative damage from sensors and display the escape route of the smallest damage in real-time on the screen. Utilizing our application in real-time evacuation has advantage in reducing cumulative damage. The optimal evacuation route, focusing on horizontal path, is calculated based on getting the data of fire, detected radioactivity and hazardous gas. Thus, using our application provides information of optimal evacuation to people who even can not hear sensor alarms or do not know geography, without requiring additional costs except fixed sensors or server network deployment cost. As a result, being informed of real-time escape route, the user could behave rapidly with suitable response to individual situation resulting in improved evacuation than simply reacting to existing warning alarms.

• 패션비즈니스
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• 제27권5호
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• pp.1-12
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• 2023

The purpose of this study was to investigate impact of wearing low-level current wrist guards on pain scale, range of motion (ROM), and muscle strength in elderly women with Carpal Tunnel Syndrome (CTS). Subjects were 12 elderly women aged between 65 and 85 years who were diagnosed with CTS symptoms. Measurements included grip strength and wrist ROM. Wrist ROM was assessed through flexion and dorsiflexion. Wrist guards were worn. After two weeks, pain level was assessed using the Visual Analogue Scale (VAS). Results showed a significant reduction in VAS score in the MES group after stimulation, whereas there was no difference in the control group. However, there was no significant difference in ROM between the MES group and the control group. Grip strength increased in the MES group after two weeks (p ≤ 0.001). In conclusion, clinical trials suggest that MES wrist guards might be provided as an adjunctive treatment method for CTS patients. This study provides foundational data for the design and use of auxiliary devices such as gloves in the field of MES research for pain reduction, ROM improvement, and muscle strength enhancement resulting from CTS.

• 패션비즈니스
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• 제28권2호
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• pp.109-124
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• 2024

The aim of this paper is to design and evaluate calf braces that are equipped with Electrical Muscle Stimulation (EMS) modules. These braces are intended to alleviate calf pain in PARA Taekwondo athletes. The paper also seeks to assess the effects of different textile electrode designs. PARA Taekwondo participants are at a heightened risk of injuries and pain due to the nature of this exercise, which is designed for individuals with disabilities. Additionally, there is a significant risk of strain on the lower limb muscles in PARA Taekwondo compared to regular Taekwondo. To address this issue, calf taping methods are commonly used. In this study, we develop calf EMS protective gear and aim to examine the effects of different textile electrode designs inspired by taping methods. We evaluate the differences in the effects of three different textile electrode designs through visual analog scale (VAS) and range of motion (ROM) measurements. The results show that EMS protective gear has the potential to reduce calf pain among PARA Taekwondo athletes, with electrode designs inspired by kinesiology taping providing the most effective pain relief. This research suggests that these findings may be applicable to other sports disciplines, body areas, and everyday pain relief scenarios.

• 지능정보연구
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• 제19권2호
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• pp.177-189
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• 2013

스마트교육에서 디지털교과서의 역할은 학습자와 대면하는 교육미디어로써 그 중요성은 재론의 여지없다. 이러한 디지털교과서는 학습자의 편의와 더불어 교수자, 콘텐츠 제작자, 유통업자를 위하여 표준화되어야 활성화되고 산업화될 수 있다. 본 연구에서는 다음과 같은 3가지 목표를 지향하는 디지털교과서 표준화 방안을 모색한다. (1) 디지털교과서는 온-오프 수업을 모두 지원하는 혼합학습 매체의 역할을 해야 하며, 특별한 전용뷰어 없이 표준을 준수하는 모든 EPUB 뷰어에서 실행가능 해야 하며, 기존의 이러닝 학습 콘텐츠와 학습관리시스템를 활용할 수 있도록 하며, 디지털 교과서를 사용하는 학습자의 정보를 추적 관리할 수 있는 트랙킹기능이 있으면서도, 오프라인 동안의 정보를 축적하여 서버와 통신할 수 있는 기능도 필요하다. 디지털교과서의 표준으로서 EPUB을 고려하는 이유는 디지털교과서가 책의 형태를 가져야 하는데 이를 위해서 따로 표준을 정할 필요가 없으며, EPUB 표준을 채택함으로써 풍부한 콘텐츠, 유통구조, 산업기반을 활용할 수 있기 때문이다. (2) 디지털교과서는 오픈소스를 적극 활용하여 저비용으로 현재 사용가능한 서비스를 구성하여 표준과 더불어 실제 실행 가능한 프로그램으로 제시되어야 하며, 관련 학습 콘텐츠가 오픈마켓의 형태로 운영될 수 있어야 한다. (3) 디지털교과서는 학습자에게 적절한 학습 피드백을 제공하기 위하여 모든 학습활동 정보를 축적하고 관리될 수 있는 인프라를 표준에 따라 구축하여 교육 빅데이터 처리의 기반을 제공하여야 한다. 이북 표준인 EPUB 3.0을 기반으로 하는 오픈 디지털교과서는 (1) 학습활동 정보를 기록하고 (2) 이 학습활동 지원을 위한 서버와 통신하여야 한다. 현재 표준으로 정해져 있지 않은 이북의 기록과 통신 기능을 EPUB 3.0의 JavaScript로 구현하여 현재 EPUB 3.0 뷰어에서도 활용하면서 이를 차세대 이북 표준 또는 교육을 위한 이북 표준(EPUB 3.0 for education)으로 제안하여 향후 제정된 표준 이북 뷰어에서는 JavaScript없이도 처리되도록 하는 전략이 필요하다. 향후 연구는 제안한 오픈 디지털교과서 표준에 의한 오픈소스 프로그램을 개발하고, 개발된 오픈 디지털교과서의 학습활동정보를 활용한 새로운 교육서비스 방안(교육 빅데이터 활용방안 포함)을 제시하는 것이다.

• 청정기술
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• 제18권3호
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• pp.301-306
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• 2012

급성장하고 있는 태블릿 PC와 스마트 폰과 같은 모바일 기기들은 제품 표면 보호를 위해 강한 소재인 터치스크린패널을 장착하고 있다. 따라서, 화학강화유리의 수요는 증가하게 되었고, 수요가 증가함에 따라 화학강화유리의 폐기량도 증가하게 되었다. 이 연구의 목적은 물질전과정평가(material life cycle assessment, MLCA) 기법을 사용하여 터치스크린패널에 사용되는 화학강화유리의 환경영향평가를 하는 것이다. MLCA의 소프트웨어로는 그란타의 씨이에스(CES), 시마프로(SimaPro), 가비(Gabi)를 사용하였다. 씨이에스 소프트웨어(CES software)를 통하여 2.7, 5.7, 10.3 inch 두께의 화학강화유리의 환경영향평가를 2가지 경우(폐기, 재사용)를 고려하여 수행하였다. 그 결과, 2.7, 5.7, 10.3 inch 화학강화유리를 재사용할 경우에 사용되는 에너지 값과 $CO_2$값은 폐기할 경우에 비해 약 51.4%, 46.6% 감소하는 것을 확인하였다. 시마프로 소프트웨어(SimaPro software)를 통해서는 11가지 영향범주를 평가하였는데, 11가지 영향범주 중에서 화석연료(fossil fuels), 무기물(inorganics)과 기후변화(climate change)가 주된 환경부하의 원인으로 나타났다. 그리고 가비(Gabi) 소프트웨어를 통해서 환경영향의 주된원인이 안티몬(antimony), 불화수소(hydrogen fluoride)라는 것을 알 수 있었다.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.93-98
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• 2015

Recently, Radon has been gotten attention for problems of Nuclear Generating Station and a variety of nuclear. It is naturally arises that is accumulated in the interior through the soil with radioactive materials. People exposed to indoor a Radon increase the high risks of lung cancer. The data are consisted of regional Country, The Location, Average Radon pCi/L, Geo Mean and Geo S.D etc. The research is experimented using E-M algorithm. The research result appears to make a division of soil distance, regional and cluster. It requires in effort to minimize exposure to people who live in areas with high radon levels. A country must apprise to people about Radon risk and needs to work out measures plan.