• Clinical and Experimental Pediatrics
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• 제49권12호
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• pp.1301-1307
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• 2006

목 적 : 신생아기의 청력 소실은 그 빈도가 높으며 조기 발견 및 조기 치료가 예후를 결정하는데 중요하다. 신생아 집중치료실에 입원했던 신생아들은 일반 신생아에 비해 청력 소실의 빈도가 더 높은 것으로 알려지고 있다. 이에 저자들은 신생아 집중치료실에 입원했던 신생아를 대상으로 청력 소실의 발생 빈도와 위험 인자 및 청력 소실의 양상을 조사하기 위해 이 연구를 시행하였다. 방 법 : 2002년 7월부터 2005년 6월까지 3년간 경북대학교병원 신생아 집중치료실에 입원한 환아를 대상으로 ABR 검사를 시행하여 이들의 청력 소실 정도와 이와 관련된 임상 소견을 조사하고 추적 관찰을 시행하였다. 결 과 : 연구 기간 동안 ABR 검사를 받은 환아는 474명으로 총 입원아의 54.0%였고, 검사를 받은 신생아의 13.5%인 64명이 ABR 검사에 이상 소견을 보였다. 이들 64명의 귀 128례의 청력 소실의 양상은 편측 정상이 37례(28.9%)이고 경증, 중등도, 중증 및 초중증 청력 소실이 각각 43례(33.6%), 36례(28.1%), 2례(1.6%) 및 10례(7.8%)로 중증 이상의 청력 소실 빈도는 9.5%였다. 미숙아, 저출생 체중아 및 극소 저출생 체중아, 신생아 가사, 두부 안면 기형 및 amikacin의 15일 이상 사용이 ABR 비정상군에서 유의하게 많았다(P<0.05). 고빌리루빈혈증 환아에서 최고 빌리루빈 수치, 광선치료의 기간과 교환수혈의 시행 여부 모두 ABR 정상군과 비정상군 사이에 유의한 차이를 보이지 않았다. ABR 비정상군 중 15명에서 생후 $8.8{\pm}4.4$개월에 시행한 추적 ABR 검사는 80.0%에서 호전 혹은 정상화되었다. 결 론 : 신생아 집중치료실에 입원했던 신생아는 청력 소실의 위험이 높으므로 이에 대한 체계적이고 효과적인 청력 평가와 관리가 필요하다.

• Journal of Communications and Networks
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• 제11권2호
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• pp.157-165
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• 2009

In this paper, we investigate a dynamic spectrum sharing problem for the centralized uplink cognitive radio networks using orthogonal frequency division multiple access. We formulate a large-scale joint rate and power allocation as an optimization problem under quality of service constraint for secondary users and interference constraint for primary users. We also suggest admission control to nd a feasible solution to the optimization problem. To implement the resource allocation on a large-scale, we introduce a notion of using the conservative factors $\alpha$ and $\beta$ depending on the outage and violation probabilities. Since estimating instantaneous channel gains is costly and requires high complexity, the proposed algorithm pursues a practical and implementation-friendly resource allocation. Simulation results demonstrate that the large-scale joint rate and power allocation incurs a slight loss in system throughput over the instantaneous one, but it achieves lower complexity with less sensitivity to variations in shadowing statistics.

• Steel and Composite Structures
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• 제16권2호
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• pp.135-156
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• 2014

In this research the effect of seismic design level as a practical approach for progressive collapse mitigation and reaching desired structural safety against it in seismically designed concentric braced frame buildings was investigated. It was achieved by performing preliminary and advanced progressive collapse analysis of several split-X braced frame buildings, designed for each seismic zone according to UBC 97 and by applying various Seismic Load Factors (SLFs). The outer frames of such structures were studied for collapse progression while losing one column and connected brace in the first story. Preliminary analysis results showed the necessity of performing advanced element loss analysis, consisting of Vertical Incremental Dynamic Analysis (VIDA) and Performance-Based Analysis (PBA), in order to compute the progressive collapse safety of the structures while increasing SLF for each seismic zone. In addition, by sensitivity analysis it became possible to introduce the equation of structural safety against progressive collapse for concentrically braced frames as a function of SLF for each seismic zone. Finally, the equation of progressive collapse safety as a function of bracing member capacity was presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권6호
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• pp.1627-1648
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• 2012

We propose an adaptive method for detecting plagiarized pairs from a large set of source code. This method is adaptive in that it uses an adaptive algorithm and it provides an adaptive threshold for determining plagiarism. Conventional algorithms are based on greedy string tiling or on local alignments of two code strings. However, most of them are not adaptive; they do not consider the characteristics of the program set, thereby causing a problem for a program set in which all the programs are inherently similar. We propose adaptive local alignment-a variant of local alignment that uses an adaptive similarity matrix. Each entry of this matrix is the logarithm of the probabilities of the keywords based on their frequency in a given program set. We also propose an adaptive threshold based on the local outlier factor (LOF), which represents the likelihood of an entity being an outlier. Experimental results indicate that our method is more sensitive than JPlag, which uses greedy string tiling for detecting plagiarism-suspected code pairs. Further, the adaptive threshold based on the LOF is shown to be effective, and the detection performance shows high sensitivity with negligible loss of specificity, compared with that using a fixed threshold.

• Corrosion Science and Technology
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• 제3권4호
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• pp.166-171
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• 2004

Recent developments in Bridge Management Systems (BMS) and in Life-Cycle Cost (LCC) of bridges, have raised the need for evaluation procedure of future condition (Deterioration) of a bridge. Predicting future deterioration is not an easy task due to limited past data to extrapolate from and also due to difficulty in measuring actual deterioration such as section loss of steel on an actual steel bridge. Also, increase in live load and reduction of resistance are random variables, thus a probabilistic approach should be adopted for determining the future deterioration. Due to difficulties in evaluation of future deterioration on steel bridges, accepting uncertainties within a reasonable error, a deterministic procedure using bridge condition rating can be a useful tool for projection of future condition of bridges to identify repair and maintenance needs. The object of this paper is to determine applicability of evaluating deterioration of steel bridge components based on Bridge condition ratings. Bridge condition ratings of bridge components show wide variation for bridges of same age and does not directly correlate well with the age of the bridge and/or deterioration of the bridge. High uncertainty can be reduced by breaking down the rating and by sensitivity analysis. From refined condition rating data, generalized deterioration profile of structures based on age can be derived. Examples are shown for sample bridges in USA. Approximately, 3,000 short to medium span steel bridges were listed in the inventory database. Results show wide variation of rating factors but by subdividing the Bridge condition ratings for various categories general deterioration profiles of steel bridges can be determined.

• 산업공학
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• 제18권2호
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• pp.136-147
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• 2005

This paper introduces a simulation study regarding the operation of the Painted Body Storage (PBS) in an automobile factory. In the paint shop of the factory, same colored bodies are grouped together in order to increase the effectiveness of process, for example decrease the loss of cleaning the painting-gun when the color of body changes from one to another. However the production of automobiles in the assembly shop is a typical example of the mixed model assembly production. Therefore PBS locates between the paint shop and the assembly shop for control the input sequence of bodies to the assembly shop, and it enables to meet the smoothing requirement of assembly sequence. There are highly restricted constraints on the assembly sequence in a assembly shop. Those are spacing restriction and smoothing restriction. If such restrictions are violated, conveyor-stop or utility work will be necessary. Thus the major objective of PBS is to control the assembly sequence in a way to meet the two restrictions. In this paper a case study of PBS in an automotive factory is introduced. The storage/retrieval algorithms are suggested and the proposed system is verified using simulation models. Sensitivity analysis for operating factors is also conducted.

• 대한기계학회논문집A
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• 제34권11호
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• pp.1567-1573
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• 2010

레이저 프린터에 의해 만들어진 인쇄물 및 활자는 토너 박막과 종이 사이의 계면력에 따라 그 품질과 신뢰성이 크게 좌우된다. 현재 토너 박막의 계면력을 측정하기 위한 방법은 peel-off test로써 이는 토너 박막의 표면 특성, 테이프의 점착특성, 그리고 실험을 수행하는 작업자의 성향과 같은 여러 복합인자들에 따라 측정되는 계면력 특성이 변한다는 문제를 가지고 있다. 따라서 본 연구에서는 peel-off test에서 측정된 계면력에 영향을 미치는 주요인자에 따른 토너 박막의 계면력과 박리 정도의 기여도를 다구찌 실험계획법을 사용하여 알아보았다. 그 결과, 토너 박막의 계면력은 주요인자들의 수준이 커질수록 그 영향력이 크게 증가하지만 토너 박막의 박리 정도는 그렇지 않았다. 또한, 본 연구의 주요인자들에 대한 조건에서 가장 큰 기여도를 가지는 인자는 시편의 이송속도로 나타났다.

• Advances in nano research
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• 제16권4호
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• pp.375-394
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• 2024

The extensive utilization of concrete has given rise to environmental concerns, specifically concerning the depletion of river sand. To address this issue, waste deposits can provide manufactured-sand (MS) as a substitute for river sand. The objective of this study is to explore the application of machine learning techniques to facilitate the production of manufactured-sand concrete (MSC) containing stone nano-powder through estimating the splitting tensile strength (STS) containing compressive strength of cement (CSC), tensile strength of cement (TSC), curing age (CA), maximum size of the crushed stone (Dmax), stone nano-powder content (SNC), fineness modulus of sand (FMS), water to cement ratio (W/C), sand ratio (SR), and slump (S). To achieve this goal, a total of 310 data points, encompassing nine influential factors affecting the mechanical properties of MSC, are collected through laboratory tests. Subsequently, the gathered dataset is divided into two subsets, one for training and the other for testing; comprising 90% (280 samples) and 10% (30 samples) of the total data, respectively. By employing the generated dataset, novel models were developed for evaluating the STS of MSC in relation to the nine input features. The analysis results revealed significant correlations between the CSC and the curing age CA with STS. Moreover, when delving into sensitivity analysis using an empirical model, it becomes apparent that parameters such as the FMS and the W/C exert minimal influence on the STS. We employed various loss functions to gauge the effectiveness and precision of our methodologies. Impressively, the outcomes of our devised models exhibited commendable accuracy and reliability, with all models displaying an R-squared value surpassing 0.75 and loss function values approaching insignificance. To further refine the estimation of STS for engineering endeavors, we also developed a user-friendly graphical interface for our machine learning models. These proposed models present a practical alternative to laborious, expensive, and complex laboratory techniques, thereby simplifying the production of mortar specimens.

• 대한화장품학회지
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• 제43권4호
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• pp.297-307
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• 2017

피부 특성은 다양한 내부 또는 외부 요인의 영향을 받는다. 이 연구는 아시아 여성들의 피부 특성을 조사 및 비교하기 위해 수행되었다. 우리는 7개국(말레이시아, 인도네시아, 베트남, 태국, 인도, 중국 및 한국)에서 1,500명의 아시아인의 피부 물리적 변수 및 지역 간 차이를 평가하였다. 경피 수분 손실, pH, 피부 수분, 피지함량, 피부 민감도, 탄력, 눈가 주름 및 피부 밝기의 값을 측정하였다. 인도 여성들은 다른 국가들의 여성들보다 피부 수분량, 피지량 및 민감도 점수가 낮게 나타났고, 더 어두운 피부색을 갖는 것으로 조사되었다. 또한, 모든 부위의 피부 표면 pH는 7개국 중 가장 높게 나타났다. 베트남인은 가장 낮은 수치의 피부 표면 pH 값을 보였다. 한국인과 중국인은 일반적으로 탄력성이 높고 적은 눈가 주름을 가진 것으로 나타났다. 피부 수분과 경피 수분손실량은 민감도와 양의 상관 관계가 있었으며, 주름과 민감도 간에는 음의 상관 관계가 있었다. 본 연구 결과는 해당 지역이나 지역과 관련된 명확한 추세는 없었다. 피부 물리적 매개 변수는 지역적 차이에 대한 이해와 함께 다양한 요인(피부 관리 습관, 라이프스타일 및 개인 민감도)에 대한 연구도 함께 진행되어야 할 것이다.

• 한국수정란이식학회지
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• 제6권2호
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• pp.1-17
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• 1991

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.