• Title/Summary/Keyword: System Failure

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A study on the structural behaviour of shotcrete and concrete lining by experimental and numerical analyses (숏크리트 및 콘크리트 라이닝의 역학적 거동에 관한 실험 및 수치해석적 연구)

  • 김재순;김영근
    • Tunnel and Underground Space
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    • v.8 no.4
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    • pp.307-320
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    • 1998
  • Tunnel lining is the final support of a tunnel and reflects the results of the interaction between ground and support system. Recently it is very difficult to support and manage the tunnel because the cracks on tunnel lining cause many problems in supporting and managing tunnels. Therefore the analysis of the cracks is quite strongly required. In this study, mechanical behaviour of a tunnel lining was examined by model tests and by numerical analyses. Especially the model test was examined for double linings including shotcrete and concrete lining. The model tests were carried out under various conditions taking different loading shapes, horizontal stresses, thicknesses of linings and double lining, vault opening behind the concrete lining and rock-like medium surrounding the lining. Due to horizontal stress, compressive stress prevailed on the lining. Thus the bearing capacity of the lining increased. The existence of a vault opening behind the concrete lining reduced the bearing capacity by the similar amount of reduction of concrete lining thickness. Rock-like medium cast around the side wall of the lining restrained the deflection of the lining, and the bearing capacity for cracking and failure increased vary much. In numerical analyses a algorithm which can analysis the double lining by introduction of interface element was developed. And the results of the numerical analyses were compared with the results of the model tests.

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Does Additional Aortic Procedure Carry a Higher Risk in Patients Undergoing Aortic Valve Replacement?

  • Kim, Tae-Hun;Park, Kay-Hyun;Yoo, Jae Suk;Lee, Jae Hang;Lim, Cheong
    • Journal of Chest Surgery
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    • v.45 no.5
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    • pp.295-300
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    • 2012
  • Background: With growing attention to the aortopathy associated with aortic valve diseases, the number of candidates for accompanying ascending aorta and/or root replacement is increasing among the patients who require aortic valve replacement (AVR). However, such procedures have been considered more risky than AVR alone. This study aimed to compare the surgical outcome of isolated AVR and AVR combined with aortic procedures. Materials and Methods: A total of 86 patients who underwent elective AVR between 2004 and June 2010 were divided into two groups: complex AVR (n=50, AVR with ascending aorta replacement in 24 and the Bentall procedure in 26) and simple AVR (n=36). Preoperative characteristics, surgical data, intra- and postoperative allogenic blood transfusion requirement, the postoperative clinical course, and major complications were retrospectively reviewed and compared. Results: The preoperative mean logistic European System for Cardiac Operative Risk Evaluation (%) did not differ between the groups: $11.0{\pm}7.8%$ in the complex AVR group and $12.3{\pm}8.0%$ in the simple AVR group. Although complex AVR required longer cardiopulmonary bypass ($152.4{\pm}52.6$ minutes vs. $109.7{\pm}22.7$ minutes, p=0.001), the quantity of allogenic blood products did not differ ($13.4{\pm}14.7$ units vs. $13.9{\pm}11.2$ units). There was no mortality, mechanical circulatory support, stroke, or renal failure requiring hemodialysis/filtration. No difference was found in the incidence of bleeding (40% vs. 33.3%) which was defined as red blood cell transfusion ${\geq}5$ units, reoperation, or intentional delayed closure. The incidence of mediastinitis (2.0% vs. 0%), ventilator ${\geq}24$ hours (4.0% vs. 2.8%), atrial fibrillation (18.0% vs. 25.0%), mean intensive care unit stay (34.5 hours vs. 38.8 hours), and median hospital stay (8 days vs. 7 days) did not differ, either. Conclusion: AVR combined with additional aortic or root replacement showed an excellent outcome and recovery course equivalent to that after isolated AVR.

Stabilization of Short Juxta-articular Fractures Using a Circular External Skeletal Fixator System in Dogs (개에서 원형외고정장치를 이용한 관절주위 골절의 안정화)

  • Cheong, Hye-Yeon;Kim, Joo-Ho;Cha, Jae-Gwan;Seol, Jae-Won;Kim, Min-Su;Lee, Hae-Beom
    • Journal of Veterinary Clinics
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    • v.31 no.6
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    • pp.523-526
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    • 2014
  • Three dogs were admitted for repair of bone fracture. Case 1 (Maltese, 1.8 kg, intact female, 5-month-old) and case 2 (poodle, 3.0 kg, intact female, 6-month-old) had non-weight bearing lameness in the left pelvic limb, and case 3 (mixed, 3.3 kg, intact female, age unknown) had non-weight-bearing lameness in the left thoracic limb. On orthopedic examination, there was pain, crepitus, palpable instability and substantial soft tissue swelling on the affected side. No neurological deficits were identified. Radiographs revealed left proximal metaphyseal tibial and fibular fractures in cases 1 and 2, and left proximal metaphyseal radial and ulnar fractures in case 3. All cases had closed long-bone fractures with short juxta-articular fracture segments. Under fluoroscopic guidance, proper placement of the ring fixation elements was confirmed during surgery. Two or three rings were used to stabilize fractures with traditional circular external skeletal fixators (CESF). Postoperative radiographs showed acceptable alignment and apposition of the previously identified fracture. Time to radiographic union ranged from 5 to 14 weeks and there were no signs of implant failure or pin tract infection. Functional outcomes were excellent in all cases. CESF can be successfully used to reduce short juxta-articular fractures in which bone plates or external skeletal fixation cannot be applied.

A Study on Compensation for Damage in Civil Litigation of Japanese Long-term Care Facilities (개호사고에서 손해배상책임에 관한 연구 -일본의 판례를 중심으로-)

  • Jeong, Da-Young
    • The Korean Society of Law and Medicine
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    • v.19 no.2
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    • pp.173-207
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    • 2018
  • Japan is a super-aged society where the proportion of the people aged over 65 is exceeded 20%. Therefore, there are many accidents that occur in long-term care facilities in Japan, and there are many civil litigations. The Japanese court has acknowledged in many cases that the long-term facility is responsible for the damage to the elderly who is injured in the facility. The cases can be divided into ① tumbling down, ② wandering, ③ suffocation, ④ bedsore, and ⑤ accidents among the facility-users. In most cases, the court found that the facility violated its obligation to protect their users. This is not only the case where the manager or the employee of the facility violates the obligation to watch and care for the elderly, but in some cases, the failure to maintain the human and material system itself is recognized. The basis for such judgment is whether the facility can predict the possibility of an accident and whether the facility has taken measures to prevent accidents. Also, the Japanese court recognizes the transfer of burden of proof in order to expedite the victims' rights. However, the liability of the facility for damages should not be so heavy that it would be hesitant to allow a person to enter the facility and make a contract.

A Case of Atypical Thrombotic Microangiopathy (비전형적 혈전성 미세병증 1례)

  • Oh, Ji Young;Park, Se Jin;Kim, Ki Hwan;Lim, Beom Jin;Jeong, Hyeon Joo;Ki, Jung Hye;Kim, Kee Hyuck;Shin, Jae Il
    • Childhood Kidney Diseases
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    • v.17 no.2
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    • pp.149-153
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    • 2013
  • We report the case of a 14-year-old girl, diagnosed with atypical thrombotic microangiopathy (TMA). The patient presented with persistent fever, nausea, and newly developed peripheral edema. Her laboratory findings indicated chronic anemia with no evidence of hemolysis, thrombocytopenia, or elevated serum creatinine level. A few days after hospitalization, acute renal failure and fever worsened, and proteinuria developed. On day 40 of hospitalization, she experienced a generalized tonic seizure for 5 min, accompanied by renal hypertension. Brain magnetic resonance imaging revealed posterior reversible leukoencephalopathy syndrome. After steroid pulse therapy, a renal biopsy was performed because of delayed recovery from thrombocytopenia. The biopsy findings showed features of thrombotic microangiopathic hemolysis with fibrinoid change restricted. Current diagnostic criteria for TMA have focused on thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, and diagnosis is based on the clinical presentation and etiology, with the consequence that idiopathic and atypical forms of TMA can be overlooked. Developing effective tools to diagnose TMA, such as studying levels of ADAMTS13 or testing for abnormalities in the complement system, will be the first step to improving patient outcomes.

Spinocerebellar ataxia 7 (SCA7) (척수소뇌성 운동실조증 제7형)

  • Seon-Yong, Jeong;Seok-Hun, Jang;Hyon-J., Kim
    • Journal of Genetic Medicine
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    • v.4 no.1
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    • pp.22-37
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    • 2007
  • The autosomal dominant spinocerebellar ataxias (SCAs) are a group of neurodegenerative diseases, clinically and genetically heterogeneous, characterized by degeneration of spinocerebellar pathways with variable involvement of other neural systems. At present, 27 distinct genetic forms of SCAs are known: SCA1-8, SCA10-21, SCA23, SCA25-28, DRPLA (dentatorubral-pallidoluysian atrophy), and 16q-liked ADCA (autosomal dominant cerebellar ataxia). Epidemiological data about the prevalence of SCAs are restricted to a few studies of isolated geographical regions, and most do not reflect the real occurrence of the disease. In general a prevalence of about 0.3-2 cases per 100,000 people is assumed. As SCA are highly heterogeneous, the prevalence of specific subtypes varies between different ethnic and continental populations. Most recent data suggest that SCA3 is the commonest subtype worldwide; SCA1, SCA2, SCA6, SCA7, and SCA8 have a prevalence of over 2%, and the remaining SCAs are thought to be rare (prevalence <1%). In this review, we highlight and discuss the SCA7. The hallmark of SCA7 is the association of hereditary ataxia and visual loss caused by pigmentary macular degeneration. Visual failure is progressive, bilateral and symmetrical, and leads irreversibly to blindness. This association represents a distinct disease entity classified as autosomal dominant cerebellar ataxia (ADCA) type II by Harding. The disease affectsprimarily the cerebellum and the retina by the moderate to severe neuronal loss and gliosis, but also many other central nervous system structures as the disease progresses. SCA7 is caused by expansion of an unstable trinucleotide CAG repeat in the ATXN7 gene encoding a polyglutamine (polyQ) tract in the corresponding protein, ataxin-7. Normal ATXN7 alleles contain 4-35 CAG repeats, whereas pathological alleles contain from 36->450 CAG repeats. Immunoblott analysis demonstrated that ataxin-7 is widely expressed but that expression levels vary among tissues. Instability of expanded repeats is more pronounced in SCA7 than in other SCA subtypes and can cause substantial lowering of age at onset in successive generations termed ‘anticipation’ so that children may become diseased even before their parents develop symptoms. The strong anticipation in SCA7 and the rarity of contractions should have led to its extinction within a few generations. There is no specific drug therapy for this neurodegenerative disorder. Currently, therapy remains purely symptomatic. Cellular models and SCA7 transgenic mice have been generated which constitute valuable resources for studying the disease mechanism. Understanding the pathogenetic mechanisms of neurodegeneration in SCAs should lead to the identification of potential therapeutic targets and ultimately facilitate drug discovery. Here we summarize the clinical, pathological, and genetic aspects of SCA7, and review the current understanding of the pathogenesis of this disorder. Further, we also review the potential therapeutic strategies that are currently being explored in polyglutamine diseases.

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Policy and Strategy for Intelligence Information Education and Technology (지능정보 교육과 기술 지원 정책 및 전략)

  • Lee, Tae-Gyu;Jung, Dae-Chul;Kim, Yong-Kab
    • KIPS Transactions on Computer and Communication Systems
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    • v.6 no.8
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    • pp.359-368
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    • 2017
  • What is the term "intelligence information society", which is a term that has been continuously discussed recently? This means that the automation beyond the limits of human ability in the whole societies based on intelligent information technology is a universalized social future. In particular, it is a concept that minimizes human intervention and continuously pursues evolution to data (or big data) -based automation. For example, autonomous automation is constantly aiming at unmanned vehicles with artificial intelligence as a key element. However, until now, intelligent information research has focused on the intelligence itself and has made an effort to improve intelligence logic and replace human brain and intelligence. On the other hand, in order to replace the human labor force, we have continued to make efforts to replace workers with robots by analyzing the working principles of workers and developing optimized simple logic. This study proposes important strategies and directions to implement intelligent information education policy and intelligent information technology research strategy by suggesting access strategy, education method and detailed policy road map for intelligent information technology research strategy and educational service. In particular, we propose a phased approach to intelligent information education such as basic intelligence education, intelligent content education, and intelligent application education. In addition, we propose education policy plan for the improvement of intelligent information technology, intelligent education contents, and intelligent education system as an important factor for success and failure of the 4th industrial revolution, which is centered on intelligence and automation.

Behavior of RC Beam Strengthened with Advanced Lifting Hole Anchorage System (개선된 인양홀을 이용한 정착장치로 보강된 RC 보의 거동)

  • Oh, Min-Ho;Kim, Tae-Wan;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.3
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    • pp.91-99
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    • 2010
  • In order to strengthen RC structures, various strengthening methods have been used. Particularly, external tendon strengthening method is very popular method to strengthen damaged structures in terms of efficiency, ease, economics. In this study, improved anchorage elements using the lifting hole were proposed to strengthen PSC or RC girder without any damage. Two types of anchorage elements were proposed and these elements were applied on six RC beams. Also, three types of existing anchorage elements were applied on three RC beams. Otherwise, any anchorage element was not applied on one RC beam to used as a control beam. To analyse behavior of these elements, static load tests were carried out. Test variables were anchorage shapes, prestressing level on the steel bar and tendon profiles. Deflections, strains and modes of failure were recorded to examine the strengthening effects of the beams. Ductility index and tendon stress were analyzed by comparing cracking load, yielding load and ultimate load. As a result, proposed anchorage elements using lifting hole were superior to existing anchorage elements in terms of strengthening effect and furthermore, they showed ductile behavior based on energy method.

China's Economic Slow-down and the Middle-Income Trap Controversy (중국의 저성장과 '중진국함정론'에 근거한 위기요인 분석)

  • Kim, Eui-Dong
    • International Area Studies Review
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    • v.20 no.2
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    • pp.113-140
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    • 2016
  • This paper first extracts the main basis for the Middle-Income Trap(MIT) to apply these grounds to reality of the Chinese economy. And then confirmed crisis factors of China economy. Also discussed then the economic reforms of China in order to not fall into the MIT. After reviewing previous research extracted six factors the results will correspond to comply with the Chinese economy. Those are 'Over-investment', 'excess capacity' 'reduction of TFP continued,' 'disappearance and the aging of the population bonus', 'excessive debt and structural adjustment and financial instability of the company', 'income unequal expansion', 'low financial and information infrastructure accessibility', and 'low transparency index'. China's policy direction to avoid the MIT generally set properly, but proof that implementation process not easy, was appearing everywhere. After all, China economy should be modified now to a reforms of 'government failure' and promotion of function for ongoing restructuring system in the market. Because of the SDR incorporation from 2015, it is inevitable to face major constraints in the external aspects.

Investigation of the Current Clinical Result of Korean Medical Treatment of Infertility -In Major University Korean Medicine Hospitals and Local Korean Medicine Clinics Participated in the Research- (한방 난임 치료의 특성과 결과에 대한 분석 -2011년 주요 한의과대학 부속한방병원 및 연구 참여 한의원을 중심으로-)

  • Lee, Dong-Nyung;Choi, Min-Sun;Kim, Dong-Il
    • The Journal of Korean Obstetrics and Gynecology
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    • v.27 no.4
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    • pp.69-87
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    • 2014
  • Objectives: We analyzed retrospective clinical data of Korean medical institutes for infertility care and investigated current status and outcome of the Korean medical treatment of infertility as a part of foundational research for verifying validity of constructing national support system and developing appropriate policy on Korean medical treatment of infertility. Methods: We investigated data uploaded on the homepage of The Society of Korean Medicine for Subfertility (http://www.okinfertility.org) by Korean medical institutes for infertility care to get informations such as patients' age, body height, weight, methods of Korean medical treatment, cost and duration of treatment, success or failure of pregnancy and result of treatment. Results: The average age of patients was $33.1{\pm}3.8$ and the average body height was $161.2{\pm}5.3cm$ and the average body weight was $55.2{\pm}8.5kg$. The method of Korean medical treatment was Herbal medicine (97.5%), acupuncture (80.4%), moxibustion (57.7%), cupping (32.7%). The average cost of treatment was $1,160,625{\pm}882,499$ won, and the average medical cost per visit was $357,845{\pm}241,602$ won. The average duration of treatment was $11.26{\pm}10.58$ weeks, and the average number of visits per patient was $4.78{\pm}6.10$ times. The average duration of treatment was the longest in the group of infertile patients with the highest average medical cost per visit. The average pregnancy success rate was 30.9% overall, and that of the group of infertile patients was 25.8%. Conclusions: When we develop the standard project model with expectation for about 25% success rate of pregnancy and delivery in the group of patients who have idiopathic and ovulatory factors, it is desirable to perform acupuncture and moxibustion treatment 1-2 times a week with herbal medicine. The treatment period is set to at least 12 weeks. Average treatment fee maybe calculated by converting the averaged treatment cost of clinic's one month worth of daily treatment fee and medical hospital's ten day treatment fee into weekly treatment cost.