• Tuberculosis and Respiratory Diseases
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• 제65권6호
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• pp.487-494
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• 2008

연구배경: p53 유전자의 돌연변이가 모든 조직형의 폐암에서 가장 흔한 유전적 이상으로 알려져 있다. 이전의 연구에도 불구하고, 폐암 조직에서 p53 단백질의 과발현과 생존과의 관계에 대해서는 아직도 논란이 있다. 본 연구의 목적은 수술로 절제한 병리학적 병기 1기인 비소세포폐암 환자에서 p53 단백질 과발현과 관련된 임상적 특징을 평가하고, p53 단백질 과발현과 예후와의 관계를 평가하는 것이다. 방 법: 본 연구는 삼성서울병원에서 2003년 1월부터 2004년 6월까지 폐암으로 치료 받은 환자 중 병리학적 병기 제 1기의 비소세포폐암 환자를 대상으로 한 후향적 연구이다. 폐암 환자의 종양 조직을 이용하여 p53 단백질에 대한 면역조직화학 염색이 시행되었다. 성별, 연령, 흡연력, 조직형 및 병기 등의 임상적 특징들에 따른 p53 과발 현 여부를 단변량 및 다변량 분석으로 평가하였다. 한편, p53의 과발현 여부에 따른 DFS, DSS 및 OS은 Kaplan-Meier 방법으로 평가하였고, 군간 비교는 log-rank test를 이용하였다 결 과: 125명의 연구 대상 환자에서 p53 면역 염색양성 종양 세포 빈도의 중앙값은 10%였다. 편평세포암에서 p53 과발현(${\geq}10%$)의 빈도가 66%로 선암의 38%보다 통계적으로 유의하게 증가되어 있었다(p=0.002). 병리학적 병기가 IB인 경우 p53 과발현의 빈도가 59%로 IA의 38%보다 증가되어 있었다(p=0.024). 흡연의 기간은 p53이 과발현 된 경우(27년)에 그렇지 않은 경우(20년)보다 통계적으로 유의하게 길었다(p=0.032). 25갑년 이상의 흡연력도 p53이 과발현 된 경우(58%)에 그렇지 않은 경우(38%)보다 더 흔하게 관찰되었다(p=0.024). 다변량 분석에서 p53 과발현과 관련된 인자는 편평세포암의 조직형뿐인 것으로 평가 되었다(p=0.002). 한편, p53 과발현 여부에 따른 DFS, DSS 및 OS의 차이는 없었으며, 편평세포암과 선암의 세부 군 분석에서도 생존의 차이는 없었다. 결 론: 수술로 절제한 제 1기 비소세포폐암 조직에서 면역조직화학 염색으로 평가한 p53 과발현은 조직형, 병기 및 흡연력과 관련이 있었고, 다변량 분석에서 조직형만이 p53 과발현과 관련된 독립적 인자였다. 하지만, p53 과발현과 환자의 생존과는 관련이 없었다.

• 대한골관절종양학회지
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• 제19권1호
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• pp.9-13
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• 2013

목적: 연골육종의 종양학적 결과와 무병생존율에 영향을 주는 요인들에 대하여 분석하고자 하였다. 대상 및 방법: 1993년부터 연골육종을 진단 받고 생검술 또는 수술적 치료를 시행 받은 환자 중 설정한 최소 추시기간인 18개월 이전에 사망한 4명을 포함하여 총 48명을 대상으로 하였다. 종양학적 결과를 평가하고 조직학적 등급, 병기, 위치, 용적, 내원시 연령, 수술 절제연, 수술적 치료 방법을 변수로 하여 무병생존율에 미치는 영향에 대하여 후향적 연구를 시행하였다. 추시 기간은 평균 43.8개월(1-196개월)이었다. 결과: 평균 43.8개월 추시상 무병생존율은 77.1%였으며 질병으로 인한 사망 7예(14.6%), 유병 생존 4예(8.3%)였다. 5년 및 10년 무병생존율은 각각 64%와 58%였다. 조직학적 악성도와 외과적 병기, 내원시 연령이 유의한 차이를 나타냈으며, 사지골의 저 악성도 연골육종에서는 광범위 소파술을 시행한 9예 모두에서 무병생존과 우수한 기능적 결과를 보였다. 결론: 연골육종의 무병생존율은 조직학적 악성도와 외과적 병기 및 내원 시의 연령과 관련이 있는 것으로 나타났다. 국소 재발과 원격 전이의 유무 또한 무병생존율과 유의한 상관성을 보였다. 사지골의 저악성도 연골육종에서는 광범위 소파술이 광범위 절제술에 비해 생존율에 영향을 미치지 않으면서 기능소실 및 합병증을 피할 수 있는 효과적인 치료법으로 생각된다.

• 한국임상보건과학회지
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• 제2권1호
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• pp.1-16
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• 2014

Purpose. For a more efficient hospital management, this study aims to provide basic data so that the hospital management and staff in charge of hospital administration may systematically classify and collect hospital information, by analyzing the ordinary characters of an upper-level general hospital system and its common-type balance sheet, common-type profit and loss statement and financial ratio. Methods. By using information about an upper-level general hospital in C Province, provided by Alio(www.alio.go.kr), a public organization information provision site, Health Insurance Review & Assessment Service(www.hira.or.kr) and Ministry of Health and Welfare(www.mw.go.kr), this study analyzed 3 year's data from 2010 to 2012 and provided basic data by analyzing the ordinary characters of an upper-level general hospital system, and its common-type balance sheet, common-type profit and loss statement and financial ratio. Results. After analyzing the ordinary characters, common-type balance sheet, common-type proft and loss statement and financial ration of this general hospital, based on the 2010 to 2012 data, this study came to the following conclusions. Firstly, out of all the 1,069 hospital staff, there were 272 doctors working for 24 medical departments, out of whom the majority was 33 physicians. Most of the nurses were third-class ones, and about 2,000 outpatients and 600 inpatients on average were treated per day. Secondly, as a result of analyzing the common-type balance sheet, this study discovered that intangible assets out of fixed assets accounted for 41%, the majority, out of which usable and profitable donation asset buildings were of great importance, and the liquid assets increased more in 2012 than 2011. In the financial structure, the ratio of liquid liabilities was over 50% out of all the liabilities in 2012, and the ratio of purchase payables was high as well. The ratio of fixed liabilities reached up to 40%, out of which the retirement benefit appropriation fund was quite high. The capital was over 80%, but the surplus was in a deficit state. Compared to the capital, the ratio of total liabilities was about 90%, which indicates the financial structure of this general hospital was vulnerable. Thirdly, as a result of analyzing the common-type profit and loss statement, this study found out that the medical profits from inpatients were higher than profits from outpatients. The material cost was related to the medical quality of this general hospital, and it was as high as 30% out of the total costs and was about 45% of the labor cost. This general hospital showed 10% in the ratio of non-medical profits, and it seemed because of government subsidies. The ratios of medical profits and current net income were gradually changing for the better in 2012, compared to 2011. Lastly, as a result of analyzing the financial ratio, it was found that the liquidity ratio kept decreasing, from 110.7% in 2010 and 102.0% in 2011 to 77.2% in 2012. Besides, it was analyzed that the liquidity ratio and the net working capital ratio greatly decreased, while the quick ratio and the liquid ratio kept decreasing. Conclusions. 1. It is necessary to take the risk management into more consideration, and particularly, it is needed to differentiate and manage the levels of risk in detail. 2. By considering the fact that investments into hospital infrastructures were mostly based on liabilities, it is needed to deal with the scale of losses when evaluating risks. 3. By reflecting the character that investments into hospital infrastructures were based on liabilities, it is necessary to consider the ratio of ordinary profits as well as the ratio of operating profits to sales, and it is also important to consider sales productivity factors, such as the sales amount per a sickbed, by comparing them with other hospitals. As for limitations of this study, there may be some problems in terms of data interpretation because of the lack of information about the number of inpatients and the number of outpatients per year, which are needed for the break-even point analysis. Besides, to suggest a direction for the improvement of hospital management through analyses, non-financial factors should be reflected, such as the trend of economy, medical policies, and politic backgrounds. However, this study only focused on the common-type balance sheet, common-type profit and loss statement and financial ratio, so this study is actually limited to generalizing all the factors by analyzing public data only.

• Asia pacific journal of information systems
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• 제19권2호
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• pp.195-221
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• 2009

According to an industry report, a large number of organizations have invested in Organizational Information System(OIS) in the past few years. Several research results indicate that successful investments in OIS lead to productivity enhancement, while failed ones result in undesirable consequences such as financial losses and dissatisfaction among employees. In spite of huge investments, however, many organizations have failed in achieving the hoped-for returns from OIS. Thus, understanding user acceptance, adoption, and usage of new IS(Information Systems) is an important issue for IS practitioners. Indeed, study of the user acceptance of new information system has been one of the most important research topics in the contemporary IS literature. Several theoretical models are tested to examine 'user acceptance' and 'usage behavior' in IS context. While many research models incorporate 'ease of use' or 'usefulness' as important factors in explaining user acceptance, Technology Acceptance Model(TAM) has been one of the most widely applied models in user acceptance and usage behavior. Even in recent IS studies that employ theories of innovation diffusion in the area of IS implementation, a major focus has been on the user's perception of information technologies. In this research, we study 'voluntariness' as an important factor in IS acceptance by users. Voluntariness is defined as "the degree to which the use of the innovation is perceived as being voluntary, or of free will" When examining the diffusion of accepting OIS, a thoughtful consideration should be given to 'perceived voluntariness.' Current article has following research questions: 1) What models are appropriate to explain the success of OIS? and 2) How does the 'voluntariness' affect the success of OIS? In order to answer these questions, a research model is proposed to describe the detailed nature of association among three independent variables (IT usage level, task interdependency, and organizational support), a mediating variable (IS usage), a dependent variable (perceived performance), and a moderating variable(perceived voluntariness). The central claim of this article is that organizations hardly realize expected returns from OIS investments unless perceived voluntariness is effectively managed after operating OIS. As an example of OIS in this study we have selected the Intranet of Republic of Korea Air Force (ROKAF). ROKAF has implemented the Intranet in an attempt to improve communication and coordination within the organization. To test our research model and hypotheses, survey questionnaires were first sent out to 400 Intranet users. With the assistance of ROKAF, Intranet users were initially identified among its members, and subjects were randomly drawn from the pool. 377 survey responses were finally returned. The unit of measurement and analysis in this research is a personal level. Path analysis based on structural equation modeling was used to test research hypotheses. Construct validity represents accordance between the theoretical base concept of constructs and its measurement items. Tests for the reliability and discriminant validity are accepted, thus verifying our survey instrument. In this research, we have proposed a conceptual framework to highlight the importance of perceived voluntariness after organization deploys OIS. The results of our analysis present several key finding. First, all three independent variables (IT usage level, task interdependency, and organizational support) have significant effects on IS usage, which will eventually improve performance. Thus, IS usage plays a mediating role between antecedent variables (IT usage level. task interdependency, and organizational support) and performance improvement. Second, the effect of the task dependency was the highest for IS usage among the three antecedent variables. This is highly plausible since one of the Intranet's major capabilities is to facilitate communication among members within an organization. Accordingly, we conclude that the higher the task dependency, the higher Intranet usage. The effect of user's IT usage level was the second, while the effect of the organizational support was the third. Finally, the perceived voluntariness plays a pivotal role in enhancing perceived performance in personal level after launching the Intranet. Relationships among investigated variables were significantly different between groups with a high level and a low level of voluntariness. The impact of the Intranet usage on the performance was greater in the higher level voluntariness group than in the lower one. For the lower level voluntariness group, the user's IT usage had the highest effect on the Intranet usage among the three antecedent variables. In short, our study suggests that the higher the perceived voluntariness is the more IS usage will be. Perceived voluntariness was found to have a moderating effect on the relationships among user IT usage level, task interdependency, IS usage, and perceived performance, supporting all the hypotheses on the moderating effect. Most of all, user IT usage level has the strongest influence on IS usage, indicating that users with superior IT usage are more likely to enjoy a high level of perceived performance.

• 대한핵의학회지
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• 제35권2호
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• pp.100-112
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• 2001

목적: 본 연구의 목적은 NEMA 프로토콜에 따라서 GE $Advance^{TM}$ PET 시스템의 성능을 평가하고 그러한 시스템이 나타낼 수 있는 능력과 한계점을 명확히 이해하는데 있다. 대상 및 방법: 성능평가는 $^{18}FDG$ 선상선윈 및 점선원 그리고 NEMA 팬텀을 사용하여 횡축방향 공간분해능, 축방향 공간분해능, 산란분획, 민감도, 계수율손실, 계수율보정, 산란보정, 균일도보정, 감쇠보정을 대상으로 하였다. 횡축방향 공간분해능과 축방향 공간분해능, 산란분획에서는 선상선원 및 점선원을 사용하여 각각 NEMA 프로토콜에 따라 정해진 위치로 이동시키면서 측정하였고, 산란분획 및 나머지 성능평가 검사에서는 직경 20 cm의 PMMA 재질의 팬텀을 이용하여 측정하였다. 결과: 표준영상 획득 모드에서 시행한 본 성능평가의 결과를 고민감도 모드 및 고분해능 모드에 대하여 얻었다. 고민감도 모드에서 동경방향으로 측정된 횡축방향 공간분해능은 스캐너 시야중심에서 4.8 mm, 20 cm에서 7.03 mm로 감소했으며 축방향 공간분해능은 스캐너 시야중심에서 평균 3.98 mm, 20 cm에서 6.71 mm로 감소하였다. 산란분획은 고민감도 모드에서 평균 9.87%였고, 민감도 측정의 결과는 고민감도 모드, 시스템 전체에 대해서 참동시계수율 $225.8kcps/{\mu}Ci/cc$를 얻었고 계수율손실 측정은 50%의 불응시간을 가지는 방사능 농도가 $4.6{\mu}Ci/cc$였으며 이때의 계수율은 427 kcps였다. 계수율 보정의 오차는 고민감도 모드, $4.60{\mu}Ci/cc$에서 최소 1.49%, 최대 3.83%였고, 산란보정의 오차는 고민감도 모드에서 평균 -0.95%였으며 균일도보정 측정은 영상면들 간의 비균일도가 최소 -1.25%, 최대 1.74%였고 변이계수는 0.74%였다. 감쇠보정의 오차는 공기에서 5.68%, 물 0.04%, 테플론 -6.51%를 얻었다. 결론: NEMA 프로토콜에 근거하여 본 연구에서 실시한 표준 성능 평가 검사는 모두 제조사의 시험지침서에 부합하였다. 결론적으로, 이는 본 GE $Advance^{TM}$ PET 시스템이 임상에의 적용에 적합함을 보여주었다.

• 한국산림과학회지
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• 제83권3호
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• pp.280-285
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• 1994

인공산성우(人工酸性雨)(pH2.0, 3.0, 4.0, 5.6)의 투수(透水)($100ml{\times}12$회(回))매험(賣驗)에 의(依)한 우리나라 주요(主要) 삼림토양(森林土壤)(갈색삼림토양(褐色森林土壤)(B), 암적색삼림토양(暗赤色森林土壤)(D R), 회갈색삼림토양(灰褐色森林土壤)(GrB), 적황색삼림토양(赤黃色森林土壤)(R Y), 화산회삼림토양(火山灰森林土壤)(Va))별(別) 치환성(置換性) 염기(鹽基)의 용탈변화(溶脫變化)와 그에 따른 영향(影響)을 분석검토(分析檢討)한 결과(結果) 다음과 같은 결론(結論)을 얻었다. 1. 토양(土壤) 침출액중(侵出液中)의 용출(溶出) Ca 농도(農度)는 각(各) 공시토양(供試土壤) 공(共)히 pH2.0 처리(處理)에서 가장 높았으며 처리(處理) pH 값이 낮아질수록 용탈농도(溶脫農度)는 급격(急激)히 증가(增加)하였다. 또 암적색(暗赤色) 삼림토양(森林土壤)에서는 pH2.0 처리(處理)를 제외(除外)하고는 큰 변화(變化)가 없었다. 2. Mg의 용탈(溶脫) 양상(樣相)은 pH 처리간(處理間)에 완만(緩慢)한 감소(減少) 경향(傾向)을 보였다. K 용탈변화(溶脫變化)는 처리(處理) 초기(初期)부터 처리(處理) 회수(回數)가 증가(增加)할수록 점차(漸次) 감소(減少)하는 경향(傾向)을 보였으며 인공산성우(人工酸性雨)의 pH가 낮을수록 K의 용탈(溶脫)은 점차(漸次) 증가(增加)하였고, 공시토양간(供試土壤間)의 차이(差異)는 적게 나타났다. Na의 용탈(溶脫)은 Mg과 비슷한 경향(傾向)을 보였는데, pH 처리간(處理間)에는 큰 차이(差異)가 없었으며, 암적색(暗赤色) 삼림토양(森林土壤)에서 가장 큰 용탈량(溶脫量)을 나타냈다. 그리고, 적황색(赤黃色) 산림토양(山林土壤)에서는 치환성(置換性) 염기중(鹽基中) Na의 용탈(溶脫)이 가장 많았다. 3. 토양(土壤) 침출액(侵出液)의 각종(各種) 치환성(置換性) 염기(鹽基) 농도(農度)는 공시토양간(供試土壤間)에 다소(多少)의 차이(差異)를 나타냈으나 이들 공(共)히 pH2 처리(處理)에서 가장 높았고 pH가 높아짐에 따라 점차(漸次) 감소(減少)하여 pH5.6의 경우(境遇)에 있어서 가장 낮게 나타났다. 그리고 각(各) 공시토양(供試土壤) 중 치환성(置換性) 염기(鹽基)에 의(依)한 수소이온 소비능력(消費能力)이 가장 큰 삼림토양(森林土壤)은 암적색(暗赤色) 삼림토양(森林土壤)이었고, 그 다음이 화산회(火山灰) 삼림토양(森林土壤), 적황색(赤黃色) 삼림토양(森林土壤), 회갈색(灰褐色) 삼림토양(森林土壤), 갈색(褐色) 삼림토양(森林土壤)의 순(順)이었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권9호
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• pp.1320-1328
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• 2013

Three experiments were conducted to evaluate the ME value, standardized ileal digestibility (SID) of amino acids (AA) of fish meal, and the effects of single cell protein (Prosin and Protide) replacing fish meal in diet on growth performance, nutrient digestibility and intestinal morphology in weaned piglets. In Exp. 1, twenty-four barrows with initial BW of $30.8{\times}2.6kg$ were allotted to one of four dietary treatments. Diet 1 contained corn as the only energy source. The other three diets replaced 20% of the corn in diet 1 with one of the three protein feeds (fish meal, Prosin and Protide), and the DE and ME contents were determined by difference. In Exp. 2, eight barrows (initial BW of $25.6{\pm}3.2kg$) were fitted with ileal T-cannulas and allotted to a replicated $4{\times}4$ Latin square design. Three cornstarch-based diets were formulated using each of the protein feeds as the sole source of AA. A nitrogen-free diet was also formulated to measure endogenous losses of AA. In Exp. 3, one hundred and eighty piglets (initial BW of $7.95{\pm}1.59kg$) weaned at $28{\times}2d$ were blocked by weight and assigned to one of five treatments for a 28-d growth performance study, each treatment was fed to six pens with six pigs (three barrows and three gilts) per pen. The five treatments consisted of the control group (CON), which was a corn-soybean meal diet containing 5% fish meal, and the other four treatments, which replaced a set amount of fish meal with either Prosin (2.5% or 5%) or Protide (2.5% or 5%). The diets were formulated to provide same nutrient levels. The results showed that on a DM basis, both of the DE and ME contents were lower in Prosin and Protide than that of fish meal (p<0.05). The SID of CP and all essential AA were greater in fish meal than in Prosin and Protide (p<0.05). The pigs fed CON diet had greater weight gain and lower feed conversion rate (FCR) than pigs fed 5% Prosin and 5% Protide diets (p<0.05). The digestibility of CP was greater in pigs fed CON, 2.5% Prosin and 2.5% Protide diets than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). Villus height in jejunum and ileum, and villus height to crypt depth ratio in the jejunum were higher (p<0.05) in pigs fed CON, 2.5% Prosin and 2.5% Protide diets compared with the 5% Prosin and 5% Protide diets. Pigs fed CON diet had greater villus height to crypt depth ratio in the ileum than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). In conclusion, although Prosin and Protide contained lower ME content and SID of AA than fish meal, Prosin and Protide replacing 50% of fish meal in diet with identical nutrient levels could obtain similar performance, nutrient digestibility and intestinal morphology in weaned pigs.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.46-46
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• 2011

Severe sediment erosion during floods occur disaster and economic losses, but general sediment erosion is basic mechanism to move sediment from upstream to downstream river. In addition, it is important process to change river form. Check dam, which is constructed in mountain stream, play a vital role such as control of sudden debris flow, but it has negative aspects to river ecosystem. Now a day, check dam of open type is an alternative plan to recover river biological diversity and ecosystem through sediment transport while maintaining the function of disaster control. The purpose of this paper is to verify sediment erosion progress of river bottom and bank as first step for river restoration after dam slit by cross-sectional shear stress and critical shear stress. Study area is upstream reach of slit check dam in mountain stream, named Wasada, in Japan. The check dam was slit with two passages in August, 2010. The transects were surveyed for four upstream cross-sections, 7.4 m, 34 m, 86 m, and 150 m distance from dam in October 2010. Sediment size was surveyed at river bottom and bank. Sediment of cobble size was found at the wetted bottom, and small size particles of sand to medium gravel composed river bank. Discharge was $2.5\;m^3/s$ and bottom slope was 0.027 m/m. Excess shear stress (${\tau}_{ex}$) was calculated for hydraulic erosion by subtracting the values of critical shear stress (${\tau}_{c}$) from the value of shear stress (${\tau}$) at river bottom and bank (${\tau}_{ex}=\tau-{\tau}_c$). Shear stress of river bottom (${\tau}_{bottom}$) was calculated using the cross-sectional shear stress, and bank shear stress (${\tau}_{bank}$) was calculated from the method of Flintham and Carling (1988). $${\tau}_{bank}={\tau}^*SF_{bank}((B+P_{bed})/(2^*P_{bank}))$$ where $SF_{bank}=1.77(P_{bed}/p_{bank}+1.5)^{-1.4}$, B is the water surface width, $P_{bed}$ and $P_{bank}$ are wetted parameter of the bed and bank. Estimated values for ${\tau}_{bottom}$ for a flow of $2.5\;m^3/s$ were lower as 25.0 (7.5 m cross-section), 25.7 (34 m), 21.3 (86 m) and 19.8 (150 m), in N/$m^2$, than critical shear stress (${\tau}_c=62.1\;N/m^2$) with cobble of 64 mm. The values were insufficient to erode cobble sediment. In contrast, even if the values of ${\tau}_{bank}$ were lower than the values for ${\tau}_{bottom}$ as 18.7 (7.5 m), 19.3 (34 m), 16.1 (86 m) and 14.7 (150 m), in N/$m^2$, excess shear stresses were calculated at the three cross-sections of 7.5 m, 34 m, and 86 m distances compare with ${\tau}_c$ is 15.5 N/$m^2$ of 16mm gravel. Bank shear stresses were sufficient for erosion of the medium gravel to sand. Therefore there is potential to erode lateral bank than downward erosion in a flow of $2.5\;m^3/s$. Undercutting of the wetted bank can causes bank scour or collapse, therefore this channel has potential to become wider at the same time. This research is about a potential of sediment erosion, and the result could not verify with real data. Therefore it need next step for verification. In addition an erosion mechanism for river restoration is not simple because discharge distribution is variable by snow-melting or rainy season, and a function for disaster control will recover by big precipitation event. Therefore it needs to consider the relationship between continuous discharge change and sediment erosion.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• 대한토목학회논문집
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• 제35권3호
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• pp.679-690
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• 2015

교통사고 피해를 최소화하기 위해서는 차량과 도로 체계에 대한 공학적인 개선을 통하여 교통사고 원인을 제거해야 한다. 일반적으로 안정성과 효율성이 부족한 도로는 교통사고가 지속적으로 발생할 가능성이 크고 이를 개선하는데 막대한 사회적 비용과 시간이 소요되며, 부적절한 환경 요인으로 발생한 교통사고는 국가적으로 큰 피해를 발생시키게 된다. 따라서 본 연구는 최근 인공지능 분야 중 활발히 연구 중인 역전파 알고리즘(Back-Propagation Algorithm : BPA)을 이용하여 신호교차로를 대상으로 최적의 교통안전 평가기법을 제시하고자 하였다. 본 연구는 광주광역시내 교통혼잡과 교통사고가 빈번하게 발생하고 있는 신호교차로 지점을 대상으로, BPA를 이용하여 보다 신뢰성 높은 교통안전 평가 모형을 개발하고자 다음과 같은 일련의 방법으로 연구를 수행하였다. 첫째, 신호교차로 교통사고와 교통상충간의 순위상관분석을 실시하여 교통사고 순위와 교통상충 순위가 통계적으로 유의함을 확인하였다. 이는 교통상충이 신호교차로 교통안전 평가 변수로 사용될 수 있음에 따라 설명변수로 입력되고 교통사고가 종속변수인 선형회귀모형을 개발하는데 이용하였다. 둘째, 신호교차로의 교통량과 진입 진출 차로수 차이 등을 교통사고의 설명변수로 간주하여 다중회귀분석을 통해 교통사고 예측모형을 개발하였다. 셋째, 교통량과 도로 기하구조 요소를 모형의 설명변수로 설정하고 교통상충을 종속변수로 하여 BPA를 이용한 최적의 교통안전 평가 모형을 개발하였다. 마지막으로, 교통사고 실측값, 다중회귀모형, BPA에 의한 교통사고 예측값을 평균제곱근오차 방법으로 모형의 적합도 비교 분석을 하였다. 본 연구의 결과, BPA에 의해 도출된 교통사고 예측값과 교통사고 실측값 사이의 평균제곱오차는 3.89로 계산되어 BPA가 다중회귀 모형보다 상대적으로 교통안전 평가능력이 우수한 것으로 나타나 실제 신호교차로 교통안전도를 평가하는데 효과적으로 활용될 수 있을 것으로 판단되고 추후, 교통안전정책 수립시 실질적인 도움이 될 것으로 기대된다.