• Title/Summary/Keyword: instability analysis

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A Mechanism of AMOC Decadal Variability in the HadGEM2-AO (HadGEM2-AO 모델이 모의한 AMOC 수십 년 변동 메커니즘)

  • Wie, Jieun;Kim, Ki-Young;Lee, Johan;Boo, Kyung-on;Cho, Chunho;Kim, Chulhee;Moon, Byung-kwon
    • Journal of the Korean earth science society
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    • v.36 no.3
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    • pp.199-209
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    • 2015
  • The Atlantic meridional overturning circulation (AMOC), driven by high density water sinking around Greenland serves as a global climate regulator, because it transports heat and materials in the climate system. We analyzed the mechanism of AMOC on a decadal time scale simulated with the HadGEM2-AO model. The lead-lag regression analysis with AMOC index shows that the decadal variability of the thermohaline circulation in the Atlantic Ocean can be considered as a self-sustained variability. This means that the long-term change of AMOC is related to the instability which is originated from the phase difference between the meridional temperature gradient and the ocean circulation. When the overturning circulation becomes stronger, the heat moves northward and decreases the horizontal temperature-dominated density gradients. Subsequently, this leads to weakening of the circulation, which in turn generates the anomalous cooling at high latitudes and, thereby strengthening the AMOC. In this mechanism, the density anomalies at high latitudes are controlled by the thermal advection from low latitudes, meaning that the variation of the AMOC is thermally driven and not salinity driven.

Arthroscopic Versus Mini-Open Salvage Repair of the Rotator Cuff Tear : Outcome Analysis at Two to Six Years Follow-up (회전개근 순수 관절경적 봉합술과 국소절개 구제봉합술 비교분석 : 2~6년 추시결과 분석)

  • Kim, Seung-Ho;Ha, Kwon-lck;Park, Jong-Hyuk;Kang, Jin-Seok;Oh, Sung-Kyun;Oh, Ir-Vin;Yoo, Jae-Chul
    • Clinics in Shoulder and Elbow
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    • v.5 no.2
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    • pp.88-97
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    • 2002
  • The purpose of this study was to compare the outcomes between arthroscopir repair and mini-open repair of medium and large rotator cuff tears in which arthroscopic repair was technically unsuccessful. We evaluated 76 patients of full-thickness rotator cuff tears, among them 42 patients had all-arthroscopic and 34 patients had mini-open salvage repairs. Patients who had acromioclavicular arthritis, subscapularis tear, or instability were excluded. There were 39 males and 37 females with mean age of 56 years (range,42 to 75 years). At a mean follow-up of 39 months (range, 24 to 64 months), the results of both groups were compared with regard to the UCLA and ASES shoulder rating scale s. Shoulder scores improved in all ratings in both groups (p > 0.05). Overall, sixty-six patients showed excellent or gr)of and ten patients showed fair or poor scores by the UCLA scale. Seventy-two patients satisfactorily returned to prior activity. Four showed unsatisfactory return. The range of motion, strength, and patient's satisfaction were improved postoperatively. There were no difference in shoulder scores, pain, and activity return between the arthroscopic and mini-open salvage groups (p > 0.05). However, Patients with larger size tear showed lower shoulder scores and less predictive recovery of the strength and function (p < 0.05). Postoperative pain was not different with respect to the size of the tear (p : 0.251). Arthroscopic repair of medium and large full-thickness rotator cuff tears had iln equal outcome to technically unsuccessful arthroscopic repairs, which were salvaged by conversion to a mini- open repair technique. Surgical outcome depended on the size of the tear, rather than the method of repair.

Analysis on the Physical Property of Para-Aramid Filament according to the ATY processing Cordition (ATY 공정조건에 따른 Para Aramid 필라멘트의 물성분석)

  • Kim, Seung-Jin;Park, Mi-Ra;Ma, Hye-Young;Choi, La-Hee;Park, Sung-Woo;Kang, Yoon-Hwa
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2011.03a
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    • pp.29-29
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    • 2011
  • 아라미드 섬유는 열에 강한 튼튼한 방향족 폴리아마이드 섬유이다. 아마이드는 "85%이상의 아미드(CO-NH)기가 두 개의 방향족 고리에 직접 연결된 합성 폴리아미드로부터 제조된 섬유"로 정의된다. 아라미드 섬유는 크게 파라계와 메타계로 대별되는데 본 연구에서 사용한 파라계 아라미드는 인장강도, 강인성, 내열성이 뛰어나며 고강력 고탄성률을 지니고 있다. 일반적인 유기 섬유와는 다른 우수한 성질을 바탕으로 부직포, UD laminatig, staple 등의 형태로 크게 섬유보강 고무 복합재료 등의 각종 복합재료, 로프, 케이블, 방탄방호용과 같은 산업자재의 용도로 자동차, 우주항공, 정보통신, 국방, 등 다양한 관련 산업분야에서 사용이 확대되고 있는 고부가 소재이며 가격대비 성능비가 우수하기 때문에 세계적으로 산업용 섬유 및 초고성능 섬유시장에서 비중이 증가될 것으로 예상되고 있다. 본 연구에서는 Para-Aramid 필라멘트를 이용하여 ATY를 생산할 때 제조공정조건에 따른 ATY 물성을 알아보고 고강도를 요구하는 방화복, 고무 보강용 섬유 등의 소재에 맞는 ATY 사가공 최적공정조건을 도출하여 체계화된 data-base를 구축하여 생산성 향상 및 품질개선과 함께 산업자재용 직물개발에 응용하고자 한다. 아라미드를 ATY로 제조할 경우, 표면에 생기는 loop로 인하여 타소재와 접착시, 접착제 담지 성능이 향상되어 접착력이 상승되는 반면, 아라미드 ATY가 기존의 아라미드의 물성보다 저하되는 약점을 가지고 있으므로 이를 보완하기 위해 본 연구에서는 ATY 제조공정에서 중요 공정인자인 사속, heater 온도, over feed ratio를 변화시켜 시료를 제조하여 이들의 물성을 분석하여 최적의 물성을 갖는 ATY 사가공 공정을 도출함으로써 물성이 저하되는 문제를 보완 가능할 것으로 기대된다. 물성분석은 강신도, 초기탄성률을 각각 측정하여 인장특성을 확인하였으며, 습열수축률과 건열수축률을 측정하여 시료의 열수축률에 대해 측정을 하였다. 표면의 루프 발현 정도를 보기 위하여 Crimp Rigidity(CR%), 형태 불안정성(instability)등을 측정하였으며, 영상 현미경 시스템을 사용하여 ${\times}40$ 배율로 표면특성을 측정하였다.

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Teaching Competencies of University Professors in Future Society (미래 사회 대학 교원의 교수(teaching)역량 프레임 제안)

  • Baek, Jongnam;Baek, Yoojin;Kim, Seyeon;Choi, Sookyoung
    • Journal of the Korea Convergence Society
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    • v.11 no.6
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    • pp.349-357
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    • 2020
  • This study explored the theoretical basis of the teaching competency of university professors in the future society represented by the Fourth Industrial Revolution through literature analysis and the researcher's council. To this end, this study first derived the implications for cultivating of teaching competency of university professors according to the social needs of future social universities. Next, according to the social needs of future social universities, the teaching competency required for university professors was presented. Finally, based on this theoretical argument, the concept of teaching competency of professors in the future society was defined and its sub-elements were presented. As a result of this study, the teaching competency frame of professors in the future society was proposed with 8 capabilities in 3 areas including 2 ability to respond to change, 2 ability to promote innovation, and 4 ability to instruct. Through the theoretical basis proposed in this study, it is hoped that the university professors' teaching competency development plan will be established to prepare for the instability of the uncertain future in the era of the fourth industrial revolution. In addition, it is expected that innovation and change strategies of each university will be established, and class innovation strategies will be established to meet the needs of students.

Synoptic Analysis on Snowstorm Occurred along the East Coast of the Korean Peninsula during 5-7 January, 1997 (1997년 1월 5-7일에 발생한 동해안 대설에 관한 지역별 종관 특성)

  • Kwak, Byung-Chull;Yoon, Ill-Hee
    • Journal of the Korean earth science society
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    • v.21 no.3
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    • pp.258-275
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    • 2000
  • The purpose of this study is to investigate diurnal variations of snowstorm occurred along the East Coast of the Korean Peninsula. The snowstorm which occurred on 5${\sim}$7 January 1997 have been analyzed. The pressure patterns were analyzed through surface and upper-air chart(850hPa). Diurnal variations of four areas, i. e. Youngdong, Mt. Taebaek, Youngseo and Kyungbuk regions were analyzed through wind direction and speed, cloud amounts, surface temperature, dewpoint temperature, relative humidity and sea level pressure. And snowfall amounts over four areas were analyzed through regional distribution, daily and temporal variations. The snowfall which occurred on January 5 was caused by the weak low pressure which is located in Kyusu region of Japan. The snowfall of January 6 occurred due to the Siberian high's expansion and instability. And northeasterly wind is one factor of the snowstorm which occurred in Mt. Taebaek region on 7 January. Heavy snowfall was caused by westerly wind but easterly wind occurred weak snowfall in Youngdong area. The precipitation of Kyungbuk region(eapecially, Pohang) was less than that of Youngdong region because the air mass which was not modified had influence on Kyungbuk region on 6${\sim}$7 January, 1997.

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Socio-Economic Effects on Brain Functions and Symptoms of Child Behavioral Problems (사회경제적 차이가 아동의 뇌기능과 문제행동증후에 미치는 영향)

  • Park, Hee-Rae;Park, Pyongwoon;Song, Giwon;Lim, Giyong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.462-470
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    • 2015
  • This study examined for which socio-economic difference effects on brain function and Problem behavior syndrome in children. About a children with no disorders, diseases or cognitive dysfunction-30 were from LIC children and another 30, from MC ones, the study was conducted by measuring and analyzing the data using brain function analysis and K-CBCL from January to April, 2013. The results of the study are as follows. First, it was found that the ratio of LIC's theta(${\Theta}$) and SMR waves and that of delta(${\delta}$), high beta(${\beta}h$), alpha(${\alpha}$) and low beta(${\beta}l$) waves showed significantly higher values than MC children. Second, concerning the symptoms of child behavioral problems, LIC showed significantly higher values than MC children in symptoms of the body, depression and anxiety, social immaturity, thinking problems, attention problems, aggression, internalization, externalization, overall behavioral problems, and emotional instability. MC children showed significantly higher values than LIC chidren in symptoms of social, academic-performance, total social skills. In conclusion, the significant difference of the brain functions and the symptoms of child behavioral problems between LIC and MC children showed that the socio-ecnomic difference has an influence on the same functions and symptoms above.

Weathering Properties and Slope Stability Evaluations of Bedrock under the Chokseongnu Pavilion, Jinjuseong Fortress, Korea (진주성 촉석루 성곽지반의 풍화특성과 사면안정성 평가)

  • Jo, Young-Hoon;Lee, Myeong-Seong;Lee, Sun-Myung;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.20
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    • pp.89-103
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    • 2007
  • The bedrock beneath the Chokseongnu pavilion consists of sandstone with alternate dark-gray to light-brown siltstone and dark-gray shale of the Jinju Formation, where bedding is well developed toward the Chokseongmun gate. Large to small joints and overbreak from the erosion weathering have been developed in the bedrock. Besides, water leakage from development of discontinuity planes, fragmentation of shale, crack and joint by tree roots are observed on the bedrock. While shale and siltstone showed high sensitivity in physical and chemical weathering, respectively, sandstone indicated the highest weathering sensitivity in both. As the results of structural stability analysis, the whole bedrock has high instability in wedge failures, and especially section No. II slope is more instable than section No. I. Therefore, it is necessary for the bedrock to be strengthened by improvement method for soft foundations and the surface reinforcement. The trees causing mechanical collapse of the bedrock should be also removed and a water flow prevention measure or a water exhaust are required.

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Analysis on the Recent Simulation Results of the Pilot Carbon Emission Trading System in Korea (국내 온실가스 배출권거래제도 시범도입방안에 관한 소고(小考))

  • Lee, Sang-Youp;Kim, Hyo-Sun;Yoo, Sang-Hee
    • Environmental and Resource Economics Review
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    • v.13 no.2
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    • pp.271-300
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    • 2004
  • We investigate the two recent simulations of the proto-type domestic carbon emission trading system in Korea and draw some policy implications. The first simulation includes the 5 electric power companies based on baseline and credit. But the second one is with the 7 energy-intensive companies based on cap and trade. The voluntary approaches in this paper revealed the instability of market equilibrium, i.e., price volatility or distortion, excess supply or demand. These phenomena stems from excess incentives to the players, asymmetric information, players' irresponsible strategic behaviors, and non acquaintance of trading system. This paper suggests the basic design for domestic carbon trading system in future and a stepwise introduction strategy for it including the incentive auction scheme, the total quantity of incentive needed, and how to finance it. Meantime, the further simulations on the various sectors based on voluntary participation must be essential for learning experiences and better policy design.

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Resource Circulation Plan using Material Flow Analysis of Waste Metals of Cobalt and Palladium (코발트와 팔라듐 폐금속자원의 흐름분석을 통한 자원순환 활성화 방안)

  • Lee, Hi Sun;Lee, Jeongmin;Yi, Sora
    • Resources Recycling
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    • v.27 no.1
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    • pp.14-21
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    • 2018
  • The rapid increase in the consumption of products that contain rare metals has highlighted the importance of recycling and recovering resources from these products when they enter the waste stream. Among various metal resources that can be recovered, this study analyzes the waste streams of cobalt and palladium to determine how their waste resource circulation can be improved at each stage of the waste stream. The findings of this study point to improvements and strategies that can be made at individual stages. First, at the discharge/import stage, the implementation of tariff quotas for specific recycled metal resources is suggested to allow the systemic categorization of waste metals as resources. At the collection/discarding stage, a major problem is the instability in the supply of scrap metals, which may be better managed by changing the bidding process for the scrap metals. At the pretreatment stage, possible areas for improvement are uncovered concerning technical areas, such as technological development and improving the efficiency of material recycling, as well as policy-wise, for instance, expanding the regulation for manufacturers to produce products that are designed to facilitate resource recovery, increasing incentive for closed recycling, and refining the guidelines and standards for recycling. At the resource recovery stage, as the waste metal recycling industry consists of businesses that vary in size, policies to promote cooperation and coexistence between large and smaller enterprises will benefit the industry in the long-run. Lastly, at the product production/export stage, a tariff on exporting waste resources that contain cobalt and palladium will help control the amount of waste metals that are shipped abroad.

Establishment of Early Diagnosis and Surgical Operative Method in Puppies with Congenital Patellar Luxation (선천성 슬개골탈구를 지닌 자견의 조기 진단법 및 외과적 수술법 확립)

  • 정순욱;박수현
    • Journal of Veterinary Clinics
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    • v.16 no.2
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    • pp.309-320
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    • 1999
  • Medial patellar luxation in dogs is one of the most common patellar problems presented to the veterinary practitioner. It is observed in toy and miniature breed and the majority of cases is a congenital form. Because of extensor mechanism's instability, it causes deformity and disorder in the growth of the affected limb when the luxation is left without treatment As lameness is not easily detectable in puppies, early diagnosis and correction are essential for therapy. Up to now, there has not been any reports refering to the diagnostic methods and the optimal age for correction in young dogs. Thirteen 45-90 days old puppies, have grade I and/or II medial patellar luxation. Only by palpation, all 13 dogs were diagnosed of patelar luxation. Skyline radiographic view was useful to interpret patellar morphology and depth of trochlear groove only above 60 days old. However, it was difficult to make definite diagnosis patellar luxation. The caudocranial and lateral radiographic view as well as ultrasonographic skyline view were not showed of patellar luxation. 2 puppies had unilateral patellar luxation and 11 puppies had bilateral patellar luxation which more serious on the left than on the right. Only 3 puppies among 11 puppies with bilateral patellar luxation were observed of lameness degree 1. Regardless of grade of patellar luxation and lameness, we performed trochlear chondroplasty using a U-shape sculpture blade to minimize cartilage injury, transposition of tibia tuberosity with No. 1 Supramid to align extensor mechanism and lateral imbrication. After surgery, we examined the operated animal daily for 10 days and on 15, 30 and 60 days after surgery respectively. After operation, pain and fever became normal on 7 days, swelling on 10 days, respectively. On 10 days after surgery, dogs showed normal standing position, and normal walking was observed in 15 days after surgery. In force plate analysis, the operated legs were normal weight bearing at 30 days after operation. After surgery, not only patellar luxation and clinical signs have been gradually reduced but also bone growth have become normal without showing growth physeal plate injury. The survival rate of puppies over 62 days old was 100%, while 42-45 days old 37.5%. The above results suggest that optimal age for surgical correction of congenital medial patellar luxation is recommended over 60 days old. In conclusion, combination of trochlear chondroplasty, transposition of tibia tuberosity, and lateral retinacular imbrication is appropriate for over 60 days old puppies to efficiently correct patellar luxation.

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