• 핵의학기술
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• 제16권1호
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• pp.86-90
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• 2012

Rb-82를 이용한 PET 검사는 심근 관류의 임상적 평가에 중요한 역할을 한다고 알려져 있다. 그러나 PET/CT의 dead time 때문에 count value와 방사능농도 사이의 직선성이 유지되지 않는다면 데이터를 획득할 때 좌심실 입력 함수가 과대평가되어 심근관류가 과대평가될 수 있다. 본 연구에서는 리스트 모드에서 획득한 PET data에서 방사능농도에 따른 count value의 직선성을 평가하였다. Biograph 40 True Point PET/CT를 이용하여 직경 12 cm, 길이 10.5 cm의 cylindrical phantom에 F-18 333 MBq과 물 800 mL를 채우고 7반감기동안 10min frame/bed로 리스트 모드를 이용하여 획득하였다. Raw data는 OSEM (order: 4, subsets: 8)과 FBP (Gaussian filter FWHM 5 mm) 알고리즘을 이용하여 재구성하였다. Sinogram 정보에서 prompt counts, net true counts, random counts를 측정하였다. 재구성 된 phantom 영상에 ROI를 설정하여 총 계수와 background를 측정하고 background correction을 사용하여 count value를 측정하여 직선성을 평가하였다. 리스트 모드를 이용하여 sinogram에서 측정된 prompt counts는 방사능농도에 비례하여 증가하였다. 낮은 방사능농도에서 net true counts와 random counts는 방사능농도에 따라 증가하였다. 높은 방사능농도에서는 net true counts의 증가율이 점차 감소되었고, 반면에 random counts의 증가율은 증가하였다. 그리고 OSEM과 FBP 알고리즘으로 재구성된 영상에서 측정한 count value의 차이는 없었고 방사능농도에 비례하여 count value가 증가하고 직선성이 유지되었다. Biograph 40 True Point PET/CT scanner는 재구성된 영상에서 낮은 방사능농도뿐만 아니라 높은 방사능농도(~416.25 kBq/mL)에서도 측정 된 count value와 방사능농도 사이의 직선성이 유지되는 것을 보여주었다. 따라서 실험에서 사용한 PET/CT scanner는 Rb-82, N-13, O-15, F-18을 이용한 heart dynamic PET study에서데이터의 정량적 분석에 유용할 것으로 판단된다.

• 한국콘텐츠학회논문지
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• 제11권10호
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• pp.19-29
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• 2011

블로그는 사용자에게 자신의 의견을 표현하고 다른 사람들의 의견을 수렴할 수 있는 자유로운 의사표현 네트워크를 제공한다. 어떤 글은 사회적, 정치적 이슈를 몰고 다니기도 하며 또 어떤 글은 사용자의 관심을 끌지 못하고 지나가기도 한다. 글이 작성된 초기에 향후 얼마나 인기를 얻을지 예측한다는 것은 글의 저자, 블로거, 광고회사 그리고 웹호스팅 모두에게 흥미로울 것이다. 인기를 예측하기 위한 다양한 연구들이 진행되어 왔지만 대부분의 연구들이 사용자간의 상호연관성에 기반하고 있고 정확한 값으로 표현하는데 높은 에러율을 발생하고 있다. 본 논문에서는 블로그에 글이 작성된 초기에 향후 글의 인기를 예측하기 위해 조회수를 사용하여 글의 인기를 4타입(explosion, hot, warm, cold)의 가상 온도로 예측하는 방법을 제안한다. 먼저 글의 포화시점을 정의하고, 초기 조회수와 포화시점 조회수의 관계를 통해 포화시점 조회수를 예측하는 모델링 공식을 유도하였다. 예측된 포화시점 조회수를 이용하여 글의 인기를 4타입의 가상 온도로 표현하였다. 초기 관찰기간에 따라 예측 정확률이 결정되고 있다. 실험결과 30분 이후부터 MAPE(Mean Absolute Percentage Error)가 30%이하로 낮아졌지만, explosive 타입의 경우 초기 조회수로 예측하기 힘들었다. explosive를 제외한 hot, warm, cold 타입에서는 30분후부터 86%이상의 평균 예측 정확률을 보여주며, 70분후부터는 90%이상의 평균 예측 정확률을 보여주고 있었다.

• Journal of information and communication convergence engineering
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• 제9권2호
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• pp.172-176
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• 2011

In the Gen-2 Q-algorithm, the values of weight C, which is the parameter for incrementing or decrementing the slot-count size, are not optimized in the standard. However, the standard suggests that the reader uses small values of C when the slot-count is large and larger values of C when the slot-count is small. In this case, if the reader selects an inappropriate weight, there are a lot of empty or collided slots. As a result, the performance will be declined because the frame size does not converge to the optimal point quickly during the query round. In this paper, we propose a scheme to select the weight based on the slot-count size of current query round. Through various computer simulations, it is demonstrated that the proposed scheme achieves more stable performances than Gen-2 Q-algorithm.

• 응용통계연구
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• 제26권4호
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• pp.569-579
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• 2013

단일 분자에서 발생한 발광의 세기 변화를 분석하는 문제는 단분자 분광학에서 반드시 필요하다. 본 연구에서는 카드뮴셀레나이드/황화아연의 중심-껍질 구조를 갖는 양자점에 대한 단분자 분광학 데이터에 대해 Poisson count data로서 베이지안 접근으로 모수에 대한 공액 감마분포와 변화점 개수에 대한 절단포아송 분포로 사전분포를 주고 다중변화점을 추정하였다.

• 대한수학회지
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• 제42권6호
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• pp.1205-1213
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• 2005

Applying a fixed point theorem for compact admissible maps due to Gorniewicz, we prove that under certain conditions each count ably condensing admissible maps in Frechet spaces has a positive eigenvalue. This result has many consequences, including the well-known theorem of Krasnoselskii.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.889-893
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• 2003

Immunomodulatory and therapeutic potential of Enrofloxacin was studied in bovine sub clinical mastitis (SCM). The therapeutic efficacy was adjudged by Somatic cell count and Total bacterial count of the milk, whereas, the immuno modulatory potential of the drug was assessed by measuring myeloperoxidase (MPO) and acid phosphates (ACP) enzyme level in the milk leukocytes. Forty-five cows were divided into three equal groups. Gr I consisting 15 cows served as healthy control, whereas, 30 cows (SCM), Gr II and Gr III, selected on the basis of California Mastitis Test (CMT) positive reaction. Gr II cows received 150 mg of Enrofloxacin, once a day for three days and Gr.III received sterile 5 ml PBS (pH 7.4) for 7days, both the treatment were given by intramammary route. The observation was made up to 30 days post-treatment (PT). The CMT of the healthy milk was negative (0), whereas, it ranged between 1 point score and 2 point score in SCM. The Somatic cell count (SCC) and Total bacterial count (TBC) decreased significantly (p<0.05) on day 3 PT in GrII cows in Enrofloxacin treated group, however, such changes were insignificant in PBS treated group. Traces of MPO and ACP enzyme were found in the healthy milk. The mean ACP level enhanced by 70% on day 3 PT in GrII and only 18.7% in Gr. III cows. The mean MPO level enhanced to 32% in Gr. II and 18 % in Gr. III cows on day 3 PT. Concomitant use of Enrofloxacin in SCM at sub optimal dose was found to reduce the bacterial load by increasing the bactericidal enzyme level in the milk polymorphonuclear cells (PMNs) in bovine SCM, which indicates its immunomodulatory potential in mastitis.

• 디지털산업정보학회논문지
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• 제7권2호
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• pp.115-125
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• 2011

An accurate estimation of software development size is an important factor in calculating reasonable cost of project development and determining its success. In this study, we propose estimation models, using function point based on the functional correlation between software, with empirical data. Three models($FP_{est}(I)$, $FP_{est}(II)$, $FP_{est}(III)$) are developed with correlation and regression analysis. The validity of the models is evaluated by the significance test by comparing values of Mean Magnitude of Relative Error (MMRE) and predictions of each model at level n%. Model $FP_{est}(III)$ proved to be superior to other models such as IFPC(Indicative Function Point Count), EFPC(Estimated Function Point Count), EPFS(Early Prediction of Function Size), $FP_{est}(I)$, and $FP_{est}(II)$. As a result, the accuracy of the model appears to be very high to determine the usefulness of the model to finally overcome weakness of other estimation models. The model can be efficiently used to estimate project development size including software size or manpower allocation.

• 한국IT서비스학회지
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• 제3권1호
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• pp.5-20
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• 2004

It has been known generally that investment in the extending ability to use the IT applications have further enhanced the productivity of effects of IT on firms by reducing costs, increasing returns, and increasing the speed of operations, etc. Notwithstanding this fact, it was very complex and difficult to evaluate concretely the effect of informatization of firm. SMEs(Small- & Medium-sized Enterprises) in particular. In this study, I point out the weakness of SMEs and analyze the effects of informatization through the count data model. For this analysis, I separate the effects into two part, such as organizational effect and personal effect. It comes to conclusion that organizational effect is larger than personal effect and the ability to practical use of IT systems is most efficient item related with informatization level. Since it will be important to cencentrate on raising this ability for heightening the competitiveness of SMEs.

• 한국생산제조학회지
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• 제5권3호
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• pp.22-30
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• 1996

In order to compensate for out-of-straightness of shafts, an automatic straightening process composed of an automatic measuring module, an automatic control unit and operating softwares was developed with a hydraulic press. The out-of-sraightness of each shaft was measured automatically in the measuring stage. An optimal pressure point was determined to minimize TIR value of the shaft according to press count of 3-points bending process. In the geometric adaptive control procedure, punch stroke and springback of the shaft were predicted by an observer using on-line measured values of press force and deflection amount I each press count. An automatic straightening machine was realized with the measuring module, the GAC module, PLD, IBM-PC and the operating software on the hydraulic press. the validity of the proposed straightening process was confirmed through a series of experiments with cam shafts.

• 대한수학회지
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• 제43권1호
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• pp.1-9
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• 2006

Based on the Schauder fixed point theorem, we give a Leray-Schauder type fixed point theorem for countably condensing mappings in a more general setting and apply it to obtain eigenvalue results on condensing mappings in a simple proof. Moreover, we present a generalization of Sadovskii's fixed point theorem for count ably condensing self-mappings due to S. J. Daher.