• Journal of Korean Orthopaedic Sports Medicine
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• v.7 no.2
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• pp.75-83
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• 2008

과사용 증후군은 정상적인 조직에 최대하 부하(submaximal stress)가 지속되어 발생하는 것이다. 이와 같은 현상은 연부조직의 접합부(junction)에서 주로 일어나며 힘의 전달이 집중되는 곳, 조직의 역학적 성질이 변화되는 곳, 그리고 성장시 빨리 변화하는 성질이 있는 곳에 주로 생긴다. 근육의 불균형이 과사용 증후군의 가장 많은 원인이다. 과거의 부상 이후 부적절한 재활치료 및 각형성 또는 회전 부정정렬(angular and rotational malalignment) 등이 과사용 증후군의 원인이 될 수 있다. 스포츠 훈련 방법의 실수로도 과사용 증후군이 생길 수 있다. 전방 슬관절 동통시 감별해야 할 질환들은 jumper's knee, 슬개건염 혹은 대퇴 사두건염, Osgood-Schlatter 병, Sinding-Larsen-Johansson 병, 슬개골 연골 연화증, 슬개골 전(prepatellar) 혹은 슬개골 하(infrapatellar) 점액낭염, Hoffa's fat pad의 염증, 그리고 특발성 전방 슬관절 동통 증후군(idiopathic anterior knee pain syndrome)등이 있다. 후방 슬관절 통증의 원인 질환으로는 만성 슬와근 염좌, 슬괵건 점액낭염, 경골 골간단의 피로 골절 등이 포함되며 외측 슬관절 통증의 원인으로는 장경대 충돌 증후군(iliotibial band friction syndrome)등이 있을 수 있다. 이외 과사용 증후군과 관련된 슬관절 통증의 원인으로 다분 슬개골(multipartite patella), 내측 경골 스트레스 증후군(medial tibial stress syndrome), 박리성 골연골염, 반월상 연골의 퇴행성 변화 등이 있을 수 있다. 과사용 증후군의 진단 및 치료의 일반적인 접근법은 다섯가지 단계의 프로그램으로 요약될 수 있다. 첫째, 원인 요소를 확인하고, 둘째, 요소를 변경시키고, 셋째, 통증을 조절하고, 넷째, 능동적 재활을 시키고, 그리고 다섯째, 유지시키는 것이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2019-2028
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• 1997

It has been well established that resistant force and wear that occur during rolling motion depend on several factors such as material type, hardness, subsurface microstructure, applied load, and speed. The purpose of this work is to investigate the effect of microstructure and the state of deformed layer on the rolling contact characteristics in dry and lubricated rolling contacts. The results of this work show that the rolling resistance behavior depends on the state of the deformed layer. Also, lubrication can reduce the plastic flow at the surface but may still have an effect on the subsurface strain. The cross-sectional view of the microstructure shows that surface traction has a difinite effect on the morphology of the surface region. That is, significant slip seems to have taken place between the ball than those of the dry rolling case. The surface generation effects were significantly less compared to the case of dry rolling contact.

• Smart Media Journal
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• v.1 no.3
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• pp.15-21
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• 2012

Depth information is necessary for various three dimensional contents generation. Depth acquisition techniques can be categorized broadly into two approaches: active, passive depth sensors depending on how to obtain depth information. In this paper, we take a look at several ways of depth acquirement. We present not only depth acquisition methods using discussed ways, but also hybrid methods which combine both approaches to compensate for drawbacks of each approach. Furthermore, we introduce several matching cost functions and post-processing techniques to enhance the temporal consistency and reduce flickering artifacts and discomforts of users caused by inaccurate depth estimation in 3D video.

• Journal of Welding and Joining
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• v.6 no.2
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• pp.56-63
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• 1988

The effects of PWHT (poste weld heat treatment) and stress simulating the residual stress during PWHT in weld HAZ of low and high strength steels on corrosion fatigue crack growth were evaluated. The obtained results are summarized as follows. 1. Fatigue crack growth rate of HAZ in air and 3.5% NaCl solution was slower than that of parent due to the signgularity in weld HAZ. 2. In the case of HT-80, 3.5% NaCl solutio nacts to accelerate the crack growth for all specimens, and the sensitivity of as-weld to corrosion environment was the greatest among other PWHT specimens. 3. Corrosion fatigue crack growth of parent, as-weld and PWHT speciments ofr SS41 as well as SM53B was retarded in comparison with the fatigue crack growth in air. 4. There was a tendency that crack growth of PWHT specimens subjected $10kg/mm^2$ was faster than that of PWHT specimens without stress during PWHT. 5. The retardation phenomenon of crack growth in corrosion environment is attributed to the crack branching decreased .DELTA.K due to the corrosion products and multi-cracks.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.334-338
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• 1994

This report details the microscopic aspects of grain boundary cracking in Pb-Sn eutecticduring displacement-controlled mechanical tests performed over a range of low frequency ($10^{-3}-10^{-5}$/s)and moderate strain range (0.2 - 1 %) where is the most technologically relevant to solder jointssubjected to thermal cycling. It is shown that intergranular cracking begins with the appearance ofcrack-like features (CLF's), which can be seen due in part because they are associated with grainboundary sliding, and is able to be described by certain stages of isolated crack growth. In the initialstages CLF's are not ture cracks but instead what I shall call "proto-cracks" where grain boundarysliding begins to damage the gram boundary at the surface. At some point during the initiation stagesonce proto-cracks become ture cracks, they develop into isolated cracks and the growth of isolatedcracks is eventually accomplished by coalescence, resulting in 5 stages of cracking.ing in 5 stages of cracking.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.329-333
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• 1994

A large number of grain boundaries were seen to crack in near-eutectic solder joints of leadless ceramic chip carriers (LLCC's) during thermal cycling at temperature ranges from -$35^{\circ}C$ to +$125^{\circ}C$ with lhr time period. One potential explanation for this type of cracking might be the presence of embrittling species on the boundary. Although there do not appear to be any instances reported in the literature of solders being embrittled by small amounts of contaminating species, the possibility of such an occurrence exists. The potential presence of impurities located at crack surfaces was inspected using Scanning Auger Microprobe(SAM) and it was found that intergranular cracking could be accomplished by the oxidation of the grain boundary. A physical model for fatigue crack growth was introduced, in which grain boundary separation took place under oxidation facilitated by sliding.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.11
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• pp.983-989
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• 2005

[ $PZT(Pb(Zr,Ti)O_3)$ ] thin films were deposited by multi-target reactive sputtering method on $RuO_2$ substrates. Pure perovskite phase PZT films could be obtained by introducing Ti-oxide seed layer on the $RuO_2$ substrates prior to PZT film deposition. The PZT films deposited on the $RuO_2$ substrates showed highly voltage-shifted hysteresis loop compared with the films deposited on the Pt substrates. The surface of $RuO_2$ substrate was found to be reduced to metallic Ru in vacuum at elevated temperature, which caused the formation of oxygen vacancies at the initial stage of PZT film deposition and gave rise to the voltage shift in the P-E hysteresis loop of the PZT capacitor. The fatigue characteristics of the PZT capacitors under unipolar wane electric field were different from those under bipolar wane. The fatigue test under unipolar wane showed the increase of polarization. It was thought that the ferroelectric domains which had been pinned by charged defects such as oxygen vacancies and the charged defects were reduced in number by combining with the electrons injected from the electrode under unipolar wave, resulting in the relaxation of the ferroelectric domains and the increase of polarization.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.76-88
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• 1997

Constant .DELTA.K fatigue crack growth rate experiments were performed by applying an intermediate single and multiple overload for structural steel, SM45C. The purpose of the present study is to investigate the influence of multiple overloads at various stress intensity factor ranges and the effect of statistical variability of crack retardation behavior. The normalized delayed load cycle, delayed crack length and the minimum crack growth rate are increased with increasing baseline stress intensity factor range when the overload ratio and the number of overload application were constant. The crack retardation under low baseline stress intensity factor range increases by increasing the number of overload application, but the minimum crack growth rate decreases by increasing the number of overload application. A strong linear correlation exists between the minimum crack growth rate and the number of overload applications. And, it was observed that the variability in the crack growth retardation behavior are presented, the probability distribution functions of delayed load cycle, delayed crack length and crack growth life are 2-parameter Weibull. The coefficient of variation of delayed load cycle and delayed crack length for the number of 10 overload applications data are 14.8 and 9.2%, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.589-591
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• 2022

시니어를 위한 메디컬 가상현실 서비스 개발을 목표로 하고 있으며, 시니어가 쉽고 안전하게 체험할 수 있는 가상현실 콘텐츠를 제작하는 것이 주된 목표이다. 본 연구의 최종 목표로는 체험에 집중하기 위한 환경을 조성하기 위해 안전시스템 구축 및 가족/친구와의 연결을 통한 소통 서비스를 개발한다. 시니어를 대상으로 가상현실 체험을 제공할 때 컨트롤러를 쥐고 상호작용을 해야하는 부분을 핸드트래킹 기술을 연구하여 컨트롤러 없이 물리적으로 양손을 자유롭게 하면서 피로감을 줄이는 것은 물론, 주변의 물건을 내려치거나 컨트롤러를 놓쳐 사고로 이어질 소지도 없애 체험에 집중하게 할 수 있는 환경을 제공하고 체험 중 신체에 이상현상이 나타날 경우 즉시 이를 알릴 수 있도록 콘텐츠 내에서 특정 제스쳐나 긴급 버튼을 통하여 체험시 발생할 돌발상황에 대한 대비를 위해 별도의 앱을 개발하고 체험과 상시 연결하여 체험중인 상황을 관제할 수 있도록 시스템을 구축하고, 알림을 통해 조기에 즉각 대처할 수 있도록 한다. 또한, 몸이 불편하거나 요양원 거주등으로 인해 사회적 단절의 해소를 위해 별도의 앱을 통해 체험중인 콘텐츠와 연결이 가능하도록 설계하고 상호간에 아바타를 통한 감정 표현 및 음성 채팅을 할 수 있게 하여 소통을 할 수 있는 서비스 개발하고자 한다.

• Journal of Hospice and Palliative Care
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• v.16 no.4
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• pp.205-215
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• 2013

Most terminally ill cancer patients experience various physical and psychological symptoms during their illness. In addition to pain, they commonly suffer from fatigue, anorexia-cachexia syndrome, nausea, vomiting and dyspnea. In this paper, I reviewed some of the common non-pain symptoms in terminally ill cancer patients, based on the National Comprehensive Cancer Network (NCCN) guidelines to better understand and treat cancer patients. Cancer-related fatigue (CRF) is a common symptom in terminally ill cancer patients. There are reversible causes of fatigue, which include anemia, sleep disturbance, malnutrition, pain, depression and anxiety, medical comorbidities, hyperthyroidism and hypogonadism. Energy conservation and education are recommended as central management for CRF. Corticosteroid and psychostimulants can be used as well. The anorexia and cachexia syndrome has reversible causes and should be managed. It includes stomatitis, constipation and uncontrolled severe symptoms such as pain or dyspnea, delirium, nausea/vomiting, depression and gastroparesis. To manage the syndrome, it is important to provide emotional support and inform the patient and family of the natural history of the disease. Megesteol acetate, dronabinol and corticosteroid can be helpful. Nausea and vomiting will occur by potentially reversible causes including drug consumption, uremia, infection, anxiety, constipation, gastric irritation and proximal gastrointestinal obstruction. Metoclopramide, haloperidol, olanzapine and ondansetron can be used to manage nausea and vomiting. Dyspnea is common even in terminally ill cancer patients without lung disease. Opioids are effective for symptomatic management of dyspnea. To improve the quality of life for terminally ill cancer patients, we should try to ameliorate these symptoms by paying more attention to patients and understanding of management principles.