• 제목/요약/키워드: Critical period

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활성탄의 자연발화에 있어서 발화유도시간과 온도분포에 관한 연구 (A Study on the Ignition Induction Time and Temperature Distribution at Spontaneous Ignition of Activated Carbon)

  • 최재욱;김상렬;이상록;최광재
    • 한국안전학회지
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    • 제8권3호
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    • pp.44-49
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    • 1993
  • The spontaneous ignition induction time and temperature distribution were observed by performing experiments for granulated activated carbon. As the results of the experiments at the same amplitude, the critical spontaneous ignition temperature was decreased with increase of the time period, while, the ignition induction time was increased with the increase of the time period. The critical spontaneous ignition temperature was decreased with the increase of the amplitude for the shorter period. The temperature distribution of the sample showed the highest around ignition-point at center of the vessel and after ignition the highest temperature was moved toward surface of the vessel.

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Sensitive Period of Auditory Perception and Linguistic Discrimination

  • Cha, Kyung-Whan;Jo, Hannah
    • 말소리와 음성과학
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    • 제6권1호
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    • pp.59-67
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    • 2014
  • The purpose of this study is to scientifically examine Kuhl's (2011), originally Johnson and Newport's (1989) critical period graph, from a perspective of auditory perception and linguistic discrimination. This study utilizes two types of experiments (auditory perception and linguistic phoneme discrimination) with five different age groups (5 years, 6-8 years, 9-13 years, 15-17 years, and 20-26 years) of Korean English learners. Auditory perception is examined via ultrasonic sounds that are commonly used in the medical field. In addition, each group is measured in terms of their ability to discriminate minimal pairs in Chinese. Since almost all Korean students already have some amount of English exposure, the researchers selected phonemes in Chinese, an unexposed foreign language for all of the subject groups. The results are almost completely in accordance with Kuhl's critical period graph for auditory perception and linguistic discrimination; a sensitive age is found at 8. The results show that the auditory capability of kindergarten children is significantly better than that of other students, measured by their ability to perceive ultrasonic sounds and to distinguish ten minimal pairs in Chinese. This finding strongly implies that human auditory ability is a key factor for the sensitive period of language acquisition.

중규모 하천유역에서 임계지속기간 특성 분석 (A Characteristic Analysis of Critical Duration of Design Rainfall in Medium Sized Catchment)

  • 이정식;박종영;김석동
    • 한국방재학회 논문집
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    • 제9권1호
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    • pp.135-144
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    • 2009
  • 본 연구에서는 대표단위도가 작성되어 있는 중규모 하천유역을 대상으로 첨두유량을 발생시키는 임계지속기간을 결정하고 임계지속기간과 관련된 수문요소들에 대한 평가를 수행하였다. 임계지속기간과 유역특성인자, 유역응답시간 특성인자 그리고 단위도 특성인자들과의 상관분석을 실시하였다. 분석결과, 재현기간을 제외한 나머지 수문요소(확률강우강도식, 유출량 산정방법, 유효우량 산정방법, 강우시간분포)이 임계지속기간에 영향을 미치는 것으로 판단되었다. 상관분석을 통하여 유역면적, 유로연장, 유로경사, 유역경사가 임계지속기간과 상관성이 높은 것으로 나타났다. 상관성이 높은 유역특성인자와 임계지속기간과의 다중회귀 분석을 실시하고 7가지 형태의 회귀식을 제시하였으며, 유도된 회귀식의 결정계수가 모두 $0.96{\sim}0.97$으로 나타나 매우 높은 상관관계를 갖는 것으로 나타났다.

중증 뇌 손상환자를 위한 바비튜레이트 혼수요법의 표준임상지침(Critical Pathway) 개발 (Development of a Critical Pathway of Barbiturate Coma Therapy in the Management for Severe Brain Damage)

  • 김정숙
    • 간호행정학회지
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    • 제16권1호
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    • pp.59-72
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    • 2010
  • Purpose: This study is a descriptive research to analyze prognostic factors of barbiturate coma therapy (BCT) for severe brain damage patients, to develop a critical pathway (CP) based on the results of analysis and to examine the effect of its clinical application. Method: We analyzed medical records of 76 patients who received BCT for more than three days between January 1999 to July 2005. Based on the results of the analysis, we developed a CP and applied it to 12 people during August-December of 2005. Result: By application of BCT CP, the mortality rate decreased from 31.6% to 16.7%. It was found that the period of staying at ICU and total period of hospitalization were shortened by 2.78 (13.9%) days and 16.43 (29.4%) days, respectively. The Glasgow coma scale of the recovery group by CP application was 9.03 (4.64) at 72 hours post of BCT and 14.28 (1.82) at discharge from hospital, and DRS was 6.62 (6.38) points. Conclusion: By verifying clinical validity of the suggested CP, we believe that we have obtained visible effects standardizing the treatment pathway of BCT for brain damage patients.

중소하천유역의 임계지속시간 결정에 관한 연구 (Study on the Critical Storm Duration Decision of the Rivers Basin)

  • 안승섭;이효정;정도준
    • 한국환경과학회지
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    • 제16권11호
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    • pp.1301-1312
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    • 2007
  • The objective of this study is to propose a critical storm duration forecasting model on storm runoff in small river basin. The critical storm duration data of 582 sub-basin which introduced disaster impact assessment report on the National Emergency Management Agency during the period from 2004 to 2007 were collected, analyzed and studied. The stepwise multiple regression method are used to establish critical storm duration forecasting models(Linear and exponential type). The results of multiple regression analysis discriminated the linear type more than exponential type. The results of multiple linear regression analysis between the critical storm duration and 5 basin characteristics parameters such as basin area, main stream length, average slope of main stream, shape factor and CN showed more than 0.75 of correlation in terms of the multi correlation coefficient.

농업용 저수지에서 저수량 예측 모형과 연계한 저수지 운영 개선 방안의 모색 (A Reservoir Operation Plan Coupled with Storage Forecasting Models in Existing Agricultural Reservoir)

  • 안태진;이훈자;이재영;이재응;윤용남
    • 한국수자원학회논문집
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    • 제37권1호
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    • pp.77-86
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    • 2004
  • 본 연구에서는 농업용 저수지에서 저수량 예측모형과 함께 저수지의 목표저수량 및 한계저수량을 유지하기 위한 저수지 운영방안을 제시하였다. 대상저수지인 금강저수지에서 1990년부터 200l년까지의 저수량 자료를 이용하여 갈수빈도해석을 적용하고, 2년빈도 한발저수량을 목표저수량(target storage)으로, 10년빈도 한발저수량을 한계저수량(critical storage)으로 설정하였다. 농업용 저수지의 운영의 효율화를 위해서는 우선 합리적인 방법을 통하여 장래 저수량을 예측하여야 한다. 예측된 저수량은 저수지 운영에 관한 계획을 수립하는데 기초자료로 활용될 수 있다. 본 연구에는 저수량 예측모형으로 ARIMA 모형과 자기회귀오차모형을 적용하였다. ARIMA 모형은 과거 저수량 자료만을 근거로 하여 저수량을 예측함으로서 예측정도가 상대적으로 낮은 것으로 나타난 반면, 자기회귀오차모형은 저수량과 관련 있는 설명변수들을 이용함으로써 예측의 효과를 높일 수 있었다. 농업용 저수지의 저수량은 이전 저수량, 강수량, 평균온도, 최고온도, 관개면적, 풍속, 습도의 영향을 받으므로 자기회귀오차모형을 적용하여 저수량과 저수량에 영향을 미치는 요인과의 관계를 분석하였다. 자기회귀오차모형에 의한 저수량 예측 관계식은 저수지의 연속방정식과 유사한 관계식으로 유도되어 실제 적용성이 높을 것으로 판단되며, 금광저수지에서 예측된 2002년도 저수량과 관측된 저수량을 비교한 결과, 양호한 예측결과를 보여 주었다.

동절기 골조공사 시행이 마감공사의 주공정선에 미치는 영향 -아파트 공사의 사례분석을 중심으로- (Influence of the Structural Framework on the Critical Path of Finish Works in Winter Season -Focusing on Case Study of High-rise Apartment Housing-)

  • 한충희;방종대
    • 한국건설관리학회논문집
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    • 제7권1호
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    • pp.148-158
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    • 2006
  • 공공발주기관의 동절기 공사불능기간의 운영은 공사기간을 길게 하고, 건설사업비를 증가시킨다 또한, 건설인력의 활용을 어렵게 하여 근로소득을 감소시킴으로써 국가 경제에도 나쁜 영향을 미친다. 그러므로 동절기에도 골조공사는 시행되어야 할 것이다. 그러나 동절기에 골조공사만 시행하고 마감공사를 시행하지 않을 경우, 골조공사의 빠른 진척이 마감공사의 주공정선에 영향을 미치게 됨으로 이에 대한 규명이 필요하다. 본 연구에서는 동절기 골조공사 시행이 마감공사의 주공정선의 작업기간에 미치는 영향을 규명하였다. 이를 위해 가상현장을 설정한 후, 이 현장을 대상으로 마감공사의 공정표와 주공정선, 전체 공정표 및 주공정선을 작성하고, 공정시뮬레이션을 실시하였다. 본 연구결과는 동절기 골조공사 시행 시 아파트 공사의 공기산정에 유용하게 활용될 수 있을 것이다.

Does the Use of Asthma-Controller Medication in Accordance with Guidelines Reduce the Incidence of Acute Exacerbations and Healthcare Costs?

  • Lee, Suh-Young;Kim, Kyungjoo;Park, Yong Bum;Yoo, Kwang Ha
    • Tuberculosis and Respiratory Diseases
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    • 제85권1호
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    • pp.11-17
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    • 2022
  • Background: In asthma, consistent control of chronic airway inflammation is crucial, and the use of asthma-controller medication has been emphasized. Our purpose in this study is to compare the incidence of acute exacerbation and healthcare costs related to the use of asthma-controller medication. Methods: By using data collected by the National Health Insurance Review and Assessment Service, we compared one-year clinical outcomes and medical costs from July 2014 to June 2015 (follow-up period) between two groups of patients with asthma who received different prescriptions for recommended asthma-controller medication (inhaled corticosteroids or leukotriene receptor antagonists) at least once from July 2013 to June 2014 (assessment period). Results: There were 51,757 patients who satisfied our inclusion criteria. Among them, 13,702 patients (26.5%) were prescribed a recommended asthma-controller medication during the assessment period. In patients using a recommended asthma-controller medication, the frequency of acute exacerbations decreased in the follow-up period, from 2.7% to 1.1%. The total medical costs of the controller group decreased during the follow-up period compared to the assessment period, from $3,772,692 to $1,985,475. Only 50.9% of patients in the controller group used healthcare services in the follow-up period, and the use of asthma-controller medication decreased in the follow-up period. Conclusion: Overall, patients using a recommended asthma-controller medication showed decreased acute exacerbation and reduced total healthcare cost by half.

장죽수로 조류발전건설시 작업특성에 따른 산업잠수 작업한계 (Critical Limits of Commercial Diving on the Construction of Tidal Current Power in Jangjuk Channel)

  • 김원석
    • 수산해양교육연구
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    • 제25권3호
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    • pp.733-742
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    • 2013
  • The Korea has significant tidal current energy resources, but it is so hard to work underwater for tidal turbine installation. Therefore commercial diving work is very important for tidal current generator. Also, Jangjuk channel is vary famous as proper area to generate tidal current energy. Nevertheless, no one is studied about characteristics of commercial diving works with installation of tidal current generator. The purpose of this study is to introduce commercial diving with work types and investigate critical limits of diving working under the conditions, which are working only to minutes at slack tide during the neap tide. As the results, work types are five as like mooring installation, OMAS(Offshore Maintenance Access System), support structure installation, cable and turbine installation. Here, the original construction period is expected about 4 months, but the construction take 18 months to complete. The cause of extends construction period is insufficiency of researching tidal current conditions at the site and ignorance of slack tide which need to secure diving working time. Total diving working times are 110th during 18 months, the highest percentage of diving times is turbine installation about 43.6 %, and cable, mooring installation and support structure construction are 27.3 %, 15.5 %, 13.6 %, respectively. On the basis of this study, estimation of times of commercial diving is possible with work types of tidal current power, and has a significance as basic data to determining construction period.

Seismic characteristics of a Π-shaped 4-story RC structure with open ground floor

  • Karabini, Martha A.;Karabinis, Athanasios J.;Karayannis, Chris G.
    • Earthquakes and Structures
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    • 제22권4호
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    • pp.345-353
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    • 2022
  • The configuration of an open ground floor (pilotis) is a common and very critical irregularity observed in multistory reinforced concrete frame structures. The characteristics and the geometrical formation of the beams of the first story proved to be a critical parameter for the overall seismic behavior of this type of Reinforced Concrete (RC) structures. In this work the combination of open ground floor (pilotis) morphology with very strong perimetrical beams at the level of the first story is studied. The observation of the seismic damages and the in situ measurements of the fundamental period of four buildings with this morphology and Π-shaped plan view are presented herein. Further analytical results of a pilotis type Π-shaped RC structure are also included in the study. From the measurements and the analytical results yield that the open ground floor configuration greatly influences the fundamental period whereas this morphology in combination with strong beams can lead to severe local shear damages in the columns of the ground floor. The structural damage was limited in the columns of the ground floor and yet based on the changes of the in situ measured fundamental period the damaged level is assessed as DI=88%. Furthermore, due to the Π-shape of the plan view the tendency of the parts of the building to move independently strongly influences the distribution of the damages over the ground floor vertical elements.