• Title/Summary/Keyword: 과소적합

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Estimation of Waxy Corn Harvest Date over South Korea Using PNU CGCM-WRF Chain (PNU CGCM-WRF Chain을 활용한 남한지역 찰옥수수 수확일 추정)

  • Hur, Jina;Kim, Yong Seok;Jo, Sera;Shim, Kyo Moon;Ahn, Joong-Bae;Choi, Myeong-Ju;Kim, Young-Hyun;Kang, Mingu;Choi, Won Jun
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.23 no.4
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    • pp.405-414
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    • 2021
  • This study predicted waxy corn harvest date in South Korea using 30-year (1991-2020) hindcasts (1-6 month lead) produced by the Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF) chain. To estimate corn harvest date, the cumulative temperature is used, which accumulated the daily observed and predicted temperatures from the seeding date (5 April) to the reference temperature (1,650~2,200℃) for harvest. In terms of the mean air temperature, the hindcasts with a bias correction (20.2℃) tends to have a cold bias of about 0.1℃ for the 6 months (April to September) compared to the observation (20.3℃). The harvest date derived from bias-corrected hindcasts (DOY 187~210) well simulates one from observation (DOY 188~211), despite a slight margin of 1.1~1.3 days. The study shows the possibility of obtaining the gridded (5 km) daily temperature and corn harvest date information based on the cumulative temperature in advance for all regions of South Korea.

Comparative Study between Design Methods and Pile Load Tests for Bearing Capacity of Driven PHC Piles in the Nakdong River Delta (낙동강 삼각주에 항타된 PHC말뚝의 지지력을 위한 재하시험과 지지력 공식의 비교연구)

  • Dung, N.T.;Chung, S.G.;Kim, S.R.;Chung, J.G.
    • Journal of the Korean Geotechnical Society
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    • v.23 no.3
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    • pp.61-75
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    • 2007
  • Deep foundations have been popularly installed in hard stratum such as gravels or rocks in Korea. However, it is necessary to consider sand or sandy gravel layers that locate at the mid-depths as the bearing stratum of piles in the thick Nakdong River deltaic deposits, as done in the Chaophraya (Bangkok) and Mississippi River deltas. This study was focused on the finding of suitable methods for estimating bearing capacity when driving prestressed high-strength concrete (PHC) piles to a required depth in the deltaic area. Ground investigation was performed at five locations of two sites in the deltaic area. Bearing capacity of the driven piles has been computed using a number of proposed methods such as CPT-based and other analytical methods, based on the ground investigation and comparison one another other. Five PDA (pile driving analyzer) tests were systematically carried out at the whole depths of embedded piles, which is a well-blown useful technique for the purposes. As the results, the bearing capacities calculated by various methods were compared with the PDA and static load testing results. It was found that the shaft resistance is significantly governed by set-up effects and then the long-term value agrees well with that of the $\beta$ method. Also, the design methods for toe resistance were determined based on the SLT result, rather than PDA results that led to underestimation. Moreover, using the CPT results, appropriate methods were proposed for calculating the bearing capacity of the piles in the area.

Performance effectiveness of pediatric index of mortality 2 (PIM2) and pediatricrisk of mortality III (PRISM III) in pediatric patients with intensive care in single institution: Retrospective study (단일 병원에서 소아 중환자의 예후인자 예측을 위한 PIM2 (pediatric index of mortality 2)와 PRIMS III (pediatric risk of mortality)의 유효성 평가 - 후향적 조사 -)

  • Hwang, Hui Seung;Lee, Na Young;Han, Seung Beom;Kwak, Ga Young;Lee, Soo Young;Chung, Seung Yun;Kang, Jin Han;Jeong, Dae Chul
    • Clinical and Experimental Pediatrics
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    • v.51 no.11
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    • pp.1158-1164
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    • 2008
  • Purpose : To investigate the discriminative ability of pediatric index of mortality 2 (PIM2) and pediatric risk of mortality III (PRISM III) in predicting mortality in children admitted into the intensive care unit (ICU). Methods : We retrospectively analyzed variables of PIM2 and PRISM III based on medical records with children cared for in a single hospital ICU from January 2003 to December 2007. Exclusions were children who died within 2 h of admission into ICU or hopeless discharge. We used Students t test and ANOVA for general characteristics and for correlation between survivors and non-survivors for variables of PIM2 and PRISM III. In addition, we performed multiple logistic regression analysis for Hosmer-Lemeshow goodness-of-fit, receiver operating characteristic curve (ROC) for discrimination, and calculated standardized mortality ratio (SMR) for estimation of prediction. Results : We collected 193 medical records but analyzed 190 events because three children died within 2 h of ICU admission. The variables of PIM2 correlated with survival, except for the presence of post-procedure and low risk. In PRISM III, there was a significant correlation for cardiovascular/neurologic signs, arterial blood gas analysis but not for biochemical and hematologic data. Discriminatory performance by ROC showed an area under the curve 0.858 (95% confidence interval; 0.779-0.938) for PIM2, 0.798 (95% CI; 0.686-0.891) for PRISM III, respectively. Further, SMR was calculated approximately as 1 for the 2 systems, and multiple logistic regression analysis showed ${\chi}^2(13)=14.986$, P=0.308 for PIM2, ${\chi}^2(13)=12.899$, P=0.456 for PRISM III in Hosmer-Lemeshow goodness-of-fit. However, PIM2 was significant for PRISM III in the likelihood ratio test (${\chi}^2(4)=55.3$, P<0.01). Conclusion : We identified two acceptable scoring systems (PRISM III, PIM2) for the prediction of mortality in children admitted into the ICU. PIM2 was more accurate and had a better fit than PRISM III on the model tested.

연금충당부채 및 연금비용 회계정보 공시에 관한 연구 : 사학연기금을 중심으로

  • Seong, Ju-Ho
    • Journal of Teachers' Pension
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    • v.3
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    • pp.69-105
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    • 2018
  • 저출산과 고령화 이슈는 우리사회의 경제적 문제뿐만 아니라 공적연금의 재정지속가능성 여부와도 맞물려 있다. 실제로 우리나라 모든 공적연금은 사회보험역설(social insurance paradox)이 지속되기 힘든 새로운 도전에 직면하였다. 즉, 재정지속가능성은 제도 내적 연금개혁 혹은 제도 외적 재정지원이 없다면 항시적 수지불균형 상태가 누적될 것으로 예측된다. 이에 정부는 직접 고용과 관련된 공무원연금과 군인연금에 대해서만 연금충당부채를 산출하도록 규정하고 있다. 발생주의회계를 채택한 국제회계기준(종업원급여)을 참조하여 연금충당부채 산출을 위한 연금회계준칙(2011.8.3. 제정; 2011.1.1. 시행) 그리고 '연금회계 평가 및 공시 지침(2011.8.3. 고시 : 이하 편의상 연금회계지침이라 함)'을 신설하였다. 사학연금에 적용성 여부 논의에 앞서, 이들의 산출방법상의 문제점을 먼저 살펴보았다. 첫째, 공적연금은 공통적으로 세대 간 합의에 의해 운영되는 사회계약에 해당하므로 제도의 연속성을 전제로 한다. 하지만 연금회계준칙 및 지침은 제도의 청산을 전제로 현재 가입자(연금 미수령자, 연금 수령자)에 대해서 연금충당부채를 산출하는 폐쇄형측정(closed group valuation)을 채택하고 있다. 즉, 폐쇄형은 제도의 연속성 속성을 반영하고 있지 못하고 있어 기본 전제와 모순된다. 둘째, 공무원연금과 군인연금은 이미 기금 소진(최소한의 유동성기금만 보유함)이 되었고 정부의 보전금에 의해 수지 균형이 유지되는 순수부과방식 체계로 전환되었다. 따라서 연금충당부채는 해당 적립기금의 과소 여부를 판정하는 재정상태 기준 값에 해당하므로 기금소진이 진행된 현 상황에서는 산출의 목적, 필요성을 찾기가 힘들다. 부언하면, 제도 외적 재정지원(보전금)에 의한 수지균형방식이라면 발생주의회계보다는 현금주의회계가 회계의 목적적합성이 높다. 마지막으로 연금충당부채 산출에 있어 가장 민감한 할인율 설정 권한을 기재부장관에게 위임한 내용은 산출의 객관성, 일관성을 확보하기 힘들다고 판단된다. 이를 해소하기 위한 방안으로 본 연구에서는 5년마다 실시하고 있는 장기재정계산에서 예측된 명목 기금투자수익률을 연도별로 적용할 것을 권고하고 있다. 현행 정부회계기준을 사학연금제도에 그대로 적용하기에는 상당한 무리가 있다. 그 이유와 공시방안에 대해 살펴본다. 현재 사학연금은 기금소진 이슈로부터 상당부분 벗어나기 위해 2015년 연금개혁을 단행한 바가 있고 이를 통해 상당기간 부분적립방식 체계가 유지될 것이다. 물론 제도 외적 재정지원은 사학연금법 제53조의7에서 정부지원의 가능성만을 열어 놓은 상태이므로 미래기금소진의 가능성은 상존한다고 볼 수 있다. 먼 미래에는 순수부과방식 체계로 전환될 개연성이 높다. 이러한 재정의 양면성을 본 연구에서는 이중재정방식(dual financing system)이라고 한다. 이러한 속성을 고려하여 연금충당부채(연금채무라는 표현이 적합할 것으로 사료됨)를 산출하고 공시하여야 한다. 그 주요 연구 결과는 다음과 같이 요약된다. 먼저 현행 부분적립방식의 재정상태 검증을 위해 연금채무를 산정할 필요성이 있다. 이를 위해 본 연구에서는 기발생주의(예측단위방식 적용)에 근거한 폐쇄형 측정I(제도 종료를 전제로 현 가입자의 잠재연금채무(IPD) 산출에 초점을 둠) 그리고 미래발생주의(가입연령방식 적용)에 근거한 폐쇄형 측정II(추가적으로 현 가입자의 일정기간 급여 및 기여 발생 허용)을 제안하고 있다. 이를 통해 미적립채무의 규모 그리고 이를 해소하기 위한 상각부담률을 산출할 수 있다. 최종적으로 미래 가입자들까지 포함하고 기금소진 가능성까지 고려하는 개방형측정(open group valuation)을 다루고 있다. 단, 본 연구에서는 공무원연금처럼 기금부족분에 대해서 향후 정부보전금이 있다는 가정 하에 공시 방법을 제시하고 있다. 요약하면, 현행 사학연금제도는 현재와 미래의 재정 양면성을 모두 고려하여 연금채무 및 미적립채무를 공시하여야 한다. 부언하면, 현재 부분적립방식 재정상태를 반영하는 연금채무는 발생주의회계를 적용하고 미래에 도래할 순수부과방식 재정상태는 현금주의회계를 적용할 것을 최종 결론으로 도출하고 있다. 마지막으로 본 연구의 한계는 정부보전금의 가능성에 대한 법률적 해석과 병행하여 책임준비금 범위의 안정적 확대를 전제로 한 공시 논의 그리고 보전금의 책임한도 범위에 따른 공시 논의 등은 다루고 있지 않다는 점이다. 이러한 논의 사항은 향후 연구과제로 두고자 한다.

체질별(體質別) 식품표(食品表)에 근거한 태음인(太陰人), 소음인(少陰人), 소양인(少陽人) 당뇨식단(1800kcal)의 초보(初步)적 제시

  • Kim, Ji-Yeong;Go, Byeong-Hui
    • Journal of Sasang Constitutional Medicine
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    • v.8 no.1
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    • pp.395-411
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    • 1996
  • 1. 연구배경 사상체질의학(四象體質醫學)을 창시하여 개인(個人)의 차별성(差別性)을 강조한 동무(東武) 이제마(李濟馬)는 양생(養生)의 방법(方法)에서도 체질별(體質別) 요법(療法)을 말하고 있는데 체질별(體質別)로 과소지장(過小之臟)의 기능(機能)이 정상적(正常的)으로 이루어지는 상황을 완실무병(完實無病)의 조건으로 제시(提示)하였고 이를 위한 수단(手段)으로 성정(性情)과 함께 약물(藥物), 식품(食品) 등을 이용하였다. 특히 식이요법(食餌療法)에 있어서도 체질(體質)에 따른 구별(區別)의 필요성(必要性)을 말하고 있는데 식품(食品)이라 하더라도 그 음식(飮食)을 섭취하여 과대(過大)한 장기(臟器)의 기능(機能)은 유제(柳制)하고 과소(過小)한 기능(機能)은 보완(補完)받음으로써 불균형(不均衡)을 조정(調整)한 것이다. 당뇨병의 식단 작성은 평생동안 열량(熱量)과 영양소(營養素) 필요치(必要置)을 맞출 것을 권장하고 당뇨병학회에서 편집한 식품교환표(食品交換表)를 사용(使用)하는 것이 일반적(一般的)인데 식품교환표(食品交換表)는 많은 식품(食品)들중에 같은 영양소를 가진 식품(食品)들을 한 그룹으로 묶어 환자(患者)의 기호(嗜好)에 따라 교환(交煥)해 가면서 먹을 수 있도록 고안(考案)한 것이니 이에 지시한 수량(數量)만 섭취해도 저(低)cal식(食)으로 관양(管養)의 균형(均衡)이 잘 이루어진다. 본 연구는 체질별로 이로운 식품표에 근거하여 식이요법(食餌療法)이 특히 강조되고 하루 섭취열량이 제한되는 성인병중의 하나인 당뇨병(糖尿病)의 식단(1800kcal)을 식단작성법에 따라 구성(構成)하여 몇가지 예를 제시해 보았다. 구체적으로 태음인(太陰人), 소음인(少陰人), 소양인(少陽人)의 당뇨 환자 1800kcal에 대한 식단을 구성하여 제시했는데 즉, 태음인(太陰人)의 식단은 태음인(太陰人)에 유리(有利)한 식품(食品)들로 구성하고 해(害)로운 식품(食品)들은 제외시키는 방법(方法)을 이용하였다. 이 식단은 다분히 이론적(理論的)인 식단으로 임상(臨床)에 이용(利用)하여 본 바는 없으나 동량(同量)의 열량(熱量)을 섭취(攝取)하더라도 체질(體質)에 적합(適合)한 식품(食品)으로 구성된 식사(食事)가 각 체질의 섭생(攝生)에 더 유리(有利)하지 않올까 하는 단순(單純)한 사고(思考)에 바탕을 둔 것이다. 2. 연구방법 1) 후세가(後世家)가 주장(主張)한 체질별(體質別) 식품(食品) 분류(分類)를 종합, 정리한 체질별(體質別) 식품표(食品表)를 제시한다. 박석언의 동의사상대전, 박인상의 동의사상요결, 송일병의 알기 쉬운 사상의학, 홍순용의 사상진료보원, 홍순용, 이을호의 사상의학원론에서 체질별로 유익한 식풍을 조사하여 곡류, 과일류, 채소류, 어패류, 육류로 분류하여 살펴본다. 2) 당뇨병(糖尿病) 식이요법의 식단 작성법의 개요(槪要)를 제시한다. 3) 1)의 체질별(體質別) 식품표(食品表)로 태음인(太陰人), 소음인(少陰人), 소양인(少陽人)의 당뇨 식단 1800kcal을 작성해 제시(提示)한다. 체질별(體質別)로 유익(有益)한 식품(食品)은 1)의 식품표에 근거(根據)하고 체질별(體質別)로 해(害)로운 식품(食品)은 노정우(盧正祐), 한동석(韓東錫)의 주장에 근거(根據)한다. 3. 결과 체질별(體質別) 식품표(食品表)는 후세가의 연구를 종합하여 제시(提示)하였고, 식품(食品)을 분류(分類)한 후(後) 약명(藥名)과 성미(性味), 귀경(歸經)을 찾아 도표화 하였다. 체질별 식품들은 대부분 소음인(少陰人)의 경우 신감(辛甘) 온열(溫熱)하며 비위(脾胃)로 귀경(歸經)하고 태음인(太陰人)의 경우 감신(甘辛) 온열(溫熱)하며 폐간(肺肝)으로 귀경(歸經)하고 소양인(少陽人)의 산고(酸苦) 양한(凉寒)하고 신(腎)으로 귀경(歸經)함이 우세(優勢)함을 알 수 있다. 즉, 체질적으로 양성(陽性)인 소양인(少陽人)은 식품의 성질이 음성(陰性)인 것이 유리(有利)하고 체질적으로 음성(陰性)인 태음인(太陰人), 소음인(少陰人)은 식품의 성질이 양성(陽性)인 것이 유리(有利)하다. 다양한 식품(食品)을 섭취하고자 하는 환자의 욕구(慾求)에 맞추면서도 식품교환의 범위를 체질별로 유익한 식품들로 제한하여 동일(同一)한 열량(熱量)의 식단이라도 체질에 맞는 식품으로 차별성(差別性)을 두었는데 식단의 작성은 전문 영양사의 의견을 거쳤다. 제시된 식단은 다소 이론적(理論的)으로 작성(作成)된 단계이고 임상적(臨床的) 검증을 거친 바 없으나 활용하기에 따라 실용성을 얻을 수 있으리라 본다. <식단예> 태음인의 식단: 곡류 : 콩, 율무, 밀가루, 밀, 수수, 들깨, 고구마, 땅콩, 기장, 옥수수, 두부, 설탕등 태음인에 유리한 식품으로 교환한다 어때류 : 우렁이, 대구, 조기, 민어, 청어, 오정어, 낙지, 미역, 김, 다시마등으로 교환한다 육류 : 소고기, 우유등으로 교환한다 과일류 : 밤, 배, 호도, 은행, 잣, 살구, 매실, 자두등으로 교환한다 채소류 : 무우, 도라지, 연근, 토란, 마, 고사리, 더덕, 목이버섯, 송이버섯, 석이버섯등으로 교환한다 해로운 음식 : 닭, 돼지, 모밀, 배추, 사과, 염소고기, 조개, 계란, 곳감, 커피등은 피한다 * 아침 ; 콩나물죽, 대구포묶음, 우령이무침, 갓김치, 우유, 자두 점심 ; 기장밥, 콩나물두부찌게, 장어양념구이, 도라지나물, 열무김치, 배 저녁 ; 수수밥, 두부명란, 더덕양념구이, 깍두기 * 아침 ; 비빔국수, 토란국, 알타리김치, 두유, 살구주스 점심 ; 율무밥, 낙지전골, 김무생채, 느타리나물무침, 동치미, 귤 저녁 ; 콩밥, 감자북어국, 두부묶음, 열무김치 소음인의 식단: 곡류 : 찹쌀, 좁쌀, 차조, 감자등 소음인에 유익한 식품으로 교환한다 어패류 : 명태, 미꾸라지, 뱀장어, 뱀, 메기등 육류 : 닭, 개, 꿩, 염소, 양, 참새고기등 과일류 : 사과, 귤, 복숭아, 대추등 채소류 : 미나리, 파, 마늘, 후추, 시금치, 양배추, 생강, 고추, 당근, 양파, 감자, 쑥갓등 해로운 음식 : 메밀, 호도, 계란, 고구마, 녹두, 돼지고기, 밤, 배, 배추, 보리, 쇠고기, 수박, 오이, 참외, 팥등은 피한다. * 아침 ; 찰밥, 닭찜, 감자전, 쑥갓나물, 부추김치, 사과 점심 ; 감자밥, 메기매운탕, 명태조림, 미나리, 고들빼기김치, 사과주스 저녁 ; 좁쌀밥, 양배추감자국, 병어양념구이, 연근양념조림, 귤, 인삼차.

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The Development of the Korean Form of Childhood Attention Problem(CAP) Scale: A Study on the Reliability and Validity (한국형 소아기 집중력 문제척도: 신뢰도 및 타당도 연구)

  • Seo, Wan-Seok;Lee, Jong-Bum;Park, Hyung-Bae;Suh, Hyea-Soo;Lee, Kwang-Hun;SaKong, Jeong-Kyu
    • Journal of Yeungnam Medical Science
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    • v.14 no.1
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    • pp.123-136
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    • 1997
  • The purpose of this study was to examine the reliability and validity of a Korean form of Childhood Attention Problem(CAP) scale. CAP were administered to 98 normal elementary school students as control group and 98 attention deficit hyperactivity disorder patients. Male students showed high scores than female students in both subscale and total scores, but not statistically significant. There were no significant difference in CAP scale between male students and female students in attention deficit hyperactivity disorder patients. In the reliability test, the test-retest reliability coefficient was highly satisfactory and that of inattention subscale was 0.83, impulsivity subscale was 0.70 and total score was 0.82. In the reliability test by internal consistency, the Cronbach $\alpha$ coefficient was highly satisfactory and that of inattention subscale was 0.91, overactivity subscale was 0.89(p<0.05). The concurrent validity between CAP scale and ADDES-BV scale was 0.85 in attention deficit hyperactivity disorder patient group and 0.73 in normal control group(p<0.05). In discriminant validity test between attention deficit hyperactivity disorder patient group and normal control group, the patient group showed higher score(p<0.05). The total discriminant capacity of the patient group in CAP was 93.4%. In this point of view, CAP scale showed high reliability and validity in applying to Korean subjects and was proved to be the good and simple screening test tool for attention deficit hyperactivity disorder research and can help many young patient to treat early.

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Effects of Level of Dietary Protein or Carbohydrate on the Economic Characters and Amylase Activity of the Silkworm, Bombyx mori (인공사료의 단백질 및 탄수화물 수준이 가잠의 실용형질과 Amylase활성에 미치는 영향)

  • 문재유
    • Journal of Sericultural and Entomological Science
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    • v.16 no.2
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    • pp.35-53
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    • 1974
  • A series of experiment was conducted to investigate the effects of the level of dietary Protein (soybean meal) and carbohydrate (sucrose) on the growth rate, feed efficiency, nutrients digestibility and amylase activity of larvae at 5th instar. The results obtained from the experimentation are summarized as follow: (1) It was found that the body weight gain, cocoon quality and feed efficiency of the 5th instar larvae were significantly affected by the level of protein and carbohydrate in the artificial diet. Present data revealed that the proper level of dietary protein and carbohydrate would be the most important factor for the optimum growth of larvae. (2) In the amount of diet consumption, the group of larvae gained more body weight consumed more diet than the group gained less amount of body weight. (3) Digestibility of nutrients was improved as the level of protein in the diet increased, although the level of dietary carbohydrate did not exert any positive results. (4) It was observed that the amylase activity in digestive juice was stimulated by the increasement of dietary carbohydrate. However, no correlation between the level of dietary protein and carbohydrate was detected in the amylase activity. (5) Analytical data indicated that the amount of protein or carbohydrate excreted through feces and urine was proportional to the content of protein or carbohydrate in artificial diet. The group o( larvae consumed the diet contained high protein excreted more protein and less nitrogen free extract than did the group received low protein diet. Likewise, the group of larvae fed high dietary carbohydrate excreted more nitrogen free extract and less protein through excreta than the group consumed low carbohydrate diet group. (6) Although the amylase activity of the larvae received the artificial diet was higher than the larvae received natural diet (mulberry leaf), the rate of body weight gam and the quality of cocoon produced from the natural diet group was better than the artificial diet group. It is, thus, concluded that feeding the larvae by the artificial diet may net be recommendable. (7) It was determined that the best level of protein (soybean meal) and carbohydrate (sucrose) in artificial diet was found to be 40g and 0g, respectively when it was fed to the 5th instar larvae. (8) It may be concluded from the results obtained that the artificial diet that could stimulate the activity of amylase nay not be recommendable for the practical larvae feeding Purpose due simply to the Poor economic return from this diet than natural diet.

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An Investigation of Reliability and Safety Factors in RC Flexural Members Designed by Current WSD Standard Code (현행(現行) 허용응력설계법(許容應力設計法)으로 설계(設計)되는 RC 휨부재(部材)의 신뢰성(信賴性)과 안전율(安全率) 고찰(考察))

  • Shin, Hyun Mook;Cho, Hyo Nam;Chung, Hwan Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.1 no.1
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    • pp.33-42
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    • 1981
  • Current standard code for R.C. design consists of two conventional design parts, so called WSD and USD, which are based on ACI 318-63 and 318-71 code provisions. The safety factors of our WSD and USD design criteria which are taken primarily from ACI 318-63 code are considered to be not appropriate compared to out country's design and construction practices. Furthermore, even the ACI safety factors are not determined from probabilistic study but merely from experiences and practices. This study investigates the safety level of R.C. flexural members designed by the current WSD safety provisions based on Second Moment Reliability theory, and proposes a rational but efficient way of determining the nominal safety factors and the associated flexural allowable stresses of steel bars and concretes in order to provide a consistent level of target reliability. Cornell's Mean First-Order Second Moment Method formulae by a log normal transformation of resistance and load output variables are adopted as the reliability analysis method for this study. The compressive allowable stress formulae are derived by a unique approach in which the balanced steel ratios of the resulting design are chosen to be the corresponding under-reinforced sections designed by strength design method with an optimum reinforcing ratio. The target reliability index for the safety provisions are considered to be ${\beta}=4$ that is well suited for our level of construction and design practices. From a series of numerical applications to investigate the safety and reliability of R.C. flexural members designed by current WSD code, it has been found that the design based on WSD provision results in uneconomical design because of unusual and inconsistent reliability. A rational set of reliability based safety factors and allowable stress of steel bars and concrete for flexural members is proposed by providing the appropriate target reliability ${\beta}=4$.

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Fundamental Study on Establishing the Subgrade Compaction Control Criteria of DCPT with Laboratory Test and In-situ Tests (실내 및 현장실험를 통한 DCPT의 노상토 다짐관리기준 정립에 관한 기초연구)

  • Choi, Jun-Seong
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.103-116
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    • 2008
  • In this study, in-situ testing method, Dynamic Cone Penetration Test(DCPT) was presented to establish a new compaction control criteria with using mechanical property like elastic modulus instead of unit weight for field compaction control. Soil chamber tests and in-situ tests were carried out to confirm DCPT tests can predict the designed elastic modulus after field compaction, and correlation analysis among the DCPT, CBR and resilient modulus of sub grade were performed. Also, DCPT test spacing criteria in the construction site was proposed from the literature review. In the result of laboratory tests, Livneh's equation was the best in correlation between PR of DCPT and CBR, George and Pradesh's equation was the best in the predicted resilient modulus. In the resilient modulus using FWD, Gudishala's equation estimates little larger than predicted resilient modulus and Chen's equation estimates little smaller. And KICT's equation estimates the modulus smaller than predicted resilient modulus. But using the results of laboratory resilient modulus tests considering the deviatoric and confining stress from the moving vehicle, the KICT's equation was the best. In the results of In-situ DCPT tests, the variation of PR can occur according to size distribution of penetrate points. So DCPT test spacing was proposed to reduce the difference of PR. Also it was shows that average PR was different according to subgrade materials although the subgrade was satisfied the degree of compaction. Especially large sized materials show smaller PR, and it is also found that field water contents have influence a lot of degree of compaction but a little on the average PR of the DCPT tests.

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Evaluation of Perfusion and Image Quality Changes by Reconstruction Methods in 13N-Ammonia Myocardial Perfusion PET/CT (13N-암모니아 심근관류 PET/CT 검사 시 영상 재구성 방법에 따른 관류량 변화와 영상 평가)

  • Do, Yong Ho;Lee, Hong Jae;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.1
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    • pp.69-75
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    • 2014
  • Purpose: The aim of this study was to evaluate changes of quantitative and semi-quantitative myocardial perfusion indices and image quality by image reconstruction methods in $^{13}N$-ammonia ($^{13}N-NH_3$) myocardial perfusion PET/CT. Materials and Methods: Data of 14 (8 men, 6 women) patients underwent rest and adenosine stress $^{13}N-NH_3$ PET/CT (Biograph TruePoint 40 with TrueV, Siemens) were collected. Listmode scans were acquired for 10 minutes by injecting 370MBq of $^{13}N-NH_3$. Dynamic and static reconstruction was performed by use of FBP, iterative2D (2D), iterative3D (3D) and iterative TrueX (TrueX) algorithm. Coronary flow reserve (CFR) of dynamic reconstruction data, extent(%) and total perfusion deficit (TPD) (%) measured in sum of 4-10 minutes scan were evaluated by comparing with 2D method which was recommended by vendor. The image quality of each reconstructed data was compared and evaluated by five nuclear medicine physicians through a blind test. Results: CFR were lower in TrueX 18.68% (P=0.0002), FBP 4.35% (P=0.1243) and higher in 3D 7.91% (P<0.0001). As semi-quantitative values, extent and TPD of stress were higher in 3D 3.07%p (P=0.001), 2.36%p (P=0.0002), FBP 1.93%p (P=0.4275), 1.57%p (P=0.4595), TrueX 5.43%p (P=0.0003), 3.93%p (P<0.0001). Extent and TPD of rest were lower in FBP 0.86%p (P=0.1953), 0.57%p (P=0.2053) and higher in 3D 3.21%p (P=0.0006), 2.57%p (P=0.0001) and TrueX 5.36%p (P<0.0001), 4.36%p (P<0.0001). Based on the results of the blind test for image resolution and noise from the snapshot, 3D obtained the highest score, followed by 2D, TrueX and FBP. Conclusion: We found that quantitative and semi-quantitative myocardial perfusion values could be under- or over-estimated according to the reconstruction algorithm in $^{13}N-NH_3$ PET/CT. Therefore, proper dynamic and static reconstruction method should be established to provide accurate myocardial perfusion value.

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