• 핵의학기술
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• 제16권2호
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• pp.99-105
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• 2012

Purpose : This study is designed to compare two parameters reflecting $^{18}F$-FDG uptake, SUV and radioactivity, for diagnosis of thyroid cancer in dual time $^{18}F$-FDG PET/CT imaging and to find which parameter is more useful to decide whether the tumor is malignant or not. Materials and Methods : We performed retrospective study for 40 patients. All patients are diagnosed as primary thyroid cancer and examined $^{18}F$-FDG PET/CT. First, we got the dispersion of scattering beam of neck and lung apex to set a background and compared each dispersion, mean value, standard deviation of maxSUV and radioactivity. Also, mean maxSUV, ${\Delta}maxSUV$, ${\Delta}maxBq$/ml(%) and radioactivity between groups according to lesion's size based on biopsy are compared with independent-sample t-test. Results : the values that were from maxSUV and radioactivity measurement technique were compensated and calculated to practical values for mean comparison and patients were divided to two groups based on tumor size, Group1 ($size{\leq}1$ cm, n=21), Group2 (size>1 cm, n=19) for accurate comparison. In Group1, maxSUV (semi-quantitative analysis) was increased from $5.64{\pm}5.85$ (1.89~17.84) at first image to $5.90{\pm}5.01$ (1.95~18.22) at second image and radioactivity (Bq/ml) (quantitative analysis) showed similar increase from $5.93{\pm}6.38$ (2.50~16.75) at first image to $6.01{\pm}5.25$ (2.66~16.58) at second image. In Group2, TFmaxSUV was $10.54{\pm}14.36$ (2.54~33.89) in true first image, TSmaxSUV was $9.85{\pm}12.88$ (2.62~26.20) in true second image separately. The maxSUV showed a significant difference in the mean comparison between the two groups (p=0.035) But, mean radioactivity (Bq/ml) was $5.93{\pm}6.38$ (4.81~40.99) in true first image, $6.01{\pm}5.25$ (4.51~36.93) in true second image and didn't show a significant difference statistically (p=0.126) Conclusion : In diagnosis of thyroid tumor, SUV and radioactivity depending on $^{18}F$-FDG uptake showed high similarity with coefficient of determination (R2=0.939) and malignant evaluation results using dual time also showed similar aspect. Radioactivity for evaluation of malignant tumor didn't show better specificity or sensitivity than maxSUV.

• 한국측량학회지
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• 제40권4호
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• pp.251-260
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• 2022

소나무 재선충 피해나무는 줄어들고 있으나, 피해 지역은 전국으로 확대되고 있다. 최근에 딥러닝 기술이 발전하면서 소나무재선충 고사목 탐지 연구에 적용이 빠르게 시도되고 있다. 본 연구의 목적은 딥러닝 학습데이터의 효과적인 취득과 정확한 참값을 확보하고, 학습을 통해 U-Net 모델의 탐지능력을 보다 향상시키기 위함이다. 이러한 목적달성을 위해 단계별 딥러닝 알고리즘을 적용한 필터링 방법을 이용하여 딥러닝 모델의 불명확한 분석 근거를 최소화하고, 효율적인 분석 및 판단을 할 수 있도록 하였다. 분석결과 U-Net알고리즘을 이용한 소나무재선충 고사목 탐지 및 성능향상에 있어 기간별로 분석한 참값을 이용한 U-Net 모델이 기존에 제공하였던 참값을 이용한 U-Net 모델보다 재현율(Recall)은 -0.5%p, 정밀도(Precision)은 7.6%p, F-1 score는 4.1%p로 분석되었다. 향후 다양한 필터링 기법을 적용하여 재선충 탐지 정밀도를 높일 수 있는 가능성이 있을 것으로 판단되며, 드론 정사영상과 인공지능을 이용한 드론 예찰방법이 소나무재선충 방제 사업에 활용 가능할 것으로 판단된다.

• Composites Research
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• 제17권5호
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• pp.25-38
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• 2004

본 연구에서는 라드와 기지의 강성행렬의 중첩을 통해서 임의의 방향에서 공간적으로 보강된 복합재(SRC)의 강성을 예측하였다. 예측치를 실험과 비교하기 위하여 SRC의 물성치를 측정하였다. 라드방향에서는 강성행렬의 중첩을 통해서 예측된 물성치가 실험치와 일치하였고, 라드에서 벗어난 방향에서는 연성행렬의 중첩을 통해서 예측된 물성치가 실험치와 비교적 일치하였다. 이런 이유로 강성행렬과 연성행렬의 중첩을 공간적으로 조합한 물성치 조화함수를 이용하여, SRC의 모든 방향에서 물성치를 예측하였다. 이러한 물성치 조화함수를 이용한 결과, 예측치와 실험치가 라드방향과 라드에서 벗어난 방향 모두에서 일치하였다

• 음성과학
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• 제10권1호
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• pp.95-105
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• 2003

This paper describes a new parameter for voice activity detection which serves as a front-end part for automatic speech recognition systems. The new parameter called run-ratio is derived from the runs test statistic which is used in the statistical test for randomness of a given sequence. The run-ratio parameter has the property that the values of the parameter for the random sequence are about 1. To apply the run-ratio parameter into the voice activity detection method, it is assumed that the samples of an inputted audio signal should be converted to binary sequences of positive and negative values. Then, the silence region in the audio signal can be regarded as random sequences so that their values of the run-ratio would be about 1. The run-ratio for the voiced region has far lower values than 1 and for fricative sounds higher values than 1. Therefore, the parameter can discriminate speech signals from the background sounds by using the newly derived run-ratio parameter. The proposed voice activity detector outperformed the conventional energy-based detector in the sense of error mean and variance, small deviation from true speech boundaries, and low chance of missing real utterances

• Kyungpook Mathematical Journal
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• 제61권4호
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• pp.745-763
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• 2021

For a value s ∈ ℂ∪ {∞}, two meromorphic functions f and g are said to share the value s, CM, (or IM), provided that f(z)-s and g(z)-s have the same set of zeros, counting multiplicities, (respectively, ignoring multiplicities). We say that a meromorphic function f shares s ∈ Ŝ partially with a meromorphic function g if E(s, f) ⊆ E(s, g). It is easy to see that "partially shared values CM" are more general than "shared values CM". With the help of partially shared values, in this paper, we prove some uniqueness results between a non-constant meromorphic function and its generalized differences or shifts. We exhibit some examples to show that the result of Charak et al. [8] is not true for k = 2 or k = 3. We find some gaps in proof of the result of Lin et al. [24]. We not only correct these resuts, but also generalize them in a more convenient way. We give a number of examples to validate certain claims of the main results of this paper and also to show that some of conditions are sharp. Finally, we pose some open questions for further investigation.

• 보건행정학회지
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• 제17권3호
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• pp.1-25
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• 2007

Relative value scales introduced in 2001 remarkably improved health insurance fee schedule, but current relative value scales have many problems. In the beginning the government intended to introduce 'resource based relative value scales(RBRVSs)' like USA, but political adjustment of RBRVS studied in 19.17 weakened the relationship between relative value scale and resource consumption. So unbalance of health insurance fees are existing till now. Also relative value was not divided to physician work and practice expense, and malpractice fee was not divided separately. To correct the unbalance of current relative value scales, the refinement project of health insurance relative value scales started in 2003. The project team divided relative value scales into three components, which are physician work, practice expense, malpractice fee. Physician work was studied by professional organizations like Korean medical association. To develop the practice expense relative value, project team organized clinical practice expert panels(CPEPs) composed of physicians, nurses, and medical technicians. CPEPs constructed direct expense data like labor costs, material costs, equipment costs about each medical procedures. The practice expense relative values of medical procedures were developed by the allocation of the institution level direct & indirect costs according to CPEPs direct costs. Institution level direct & indirect costs were collected in 21 hospitals, 98 medical clinics, 53 dental clinics, 78 oriental clinics, and 46 pharmacies. The malpractice fee relative values were developed through the survey of malpractice related costs of hospitals, clinics, pharmacies. Putting together three components of relative values in one scale, the final relative values were made. The final relative values were calculated under budget neutrality by medical departments, that is, total relative value score of a department was same before and after the revision. but malpractice fee relative value scores were added to total scores of relative values. So total score of a department was increased by the malpractice fee relative value score of that department This project failed in making 'resource based' relative value scales in the true sense of the word, because the total relative value scores of medical departments were fixed. However the project team constructed the objective basis of relative value scale like physician's work, direct practice expense, malpractice fee. So step by step making process of the basis, the fixation of total scores by the departments will be resolved and the resource based relative value scale will be introduced in true sense.

• Journal of Animal Science and Technology
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• 제49권6호
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• pp.737-744
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• 2007

수입 옥수수들의 TME가를 구하고 진정 아미노산 이용율(TAAA) 그리고 여타 진정 영양소 이용율을 측정하기 위하여 57주령 된 Hy-Line rooster 24수를 대사 케이지에 수용하고 미국산 (USA), 아르헨티나산(ARG), 중국산(CHN), 중국산‐premium(CHNP) 등 원산지별로 5수씩 공시하였고 내인성 에너지가와 아미노산을 측정하기 위해 4수를 절식구로 두어 총 4회에 걸쳐 4주 간격을 두고 대사시험을 실시하였다. 얻어진 TME값은 In vitro 방법에 의해 측정한 MEn, ME 그리고 MEpc와의 상관계수를 구하였다. 풍건물(as fed) 기준으로 한 TME 값에 있어서 USA구가 3,745로 ARG구 3,555 그리고 CHNP구 3,517 보다 유의하게(P<0.01) 높았고 CHN구 3,671kcal/kg와는 유의한 차가 없었다. 건물(DM) 기준 TME 값은 USA구가 4,144로 CHN구 4,060와 CHNP구 4,008과는 유의한 차가 없었으나 ARG구 4,001kcal/kg 보다는 유의하게(P<0.05) 높았다. 옥수수의 phenylalanine, histidine 그리고 arginine의 TAAA는 수입 옥수수간에 유의한 차이가 있었는데 USA가 가장 높았다. 그러나 전체 아미노산의 TAAA에 있어서는 유의차가 없었으나 USA 옥수수가 89.4%로 다른 원산지 옥수수들인 ARG 89.3%, CHN 89.1%, CHNP 86.5% 보다 다소 높았다. 영양소 이용률에 있어서 NFE 이용율은 USA, ARG 그리고 CHN 옥수수가 CHNP 옥수수 보다 유의하게(P<0.05) 높았으며 조단백, 조지방, 조섬유 및 조회분의 이용율에는 시료간에 유의한 차가 없었다. TME가와 In vitro 방법에 의해 측정된 MEn가 사이의 상관계수는 0.91로 P<0.1이었으나 TME가와 ME가 그리고 TME가와 MEpc가 사이에서의 상관계수는 각각 0.90과 0.83으로 P>0.1이었다. 결론적으로 미국산 옥수수가 TME값과 아미노산 이용율이 가장 높았고 중국산 premium corn은 중국산 regular corn과 비교했을 때 유의한 차이가 없었다. In vitro 방법으로 옥수수의 TME가를 추정할 경우 MEn값 산출 공식을 이용하는 것이 적합하다고 사료된다.

• Journal of applied mathematics & informatics
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• 제2권2호
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• pp.13-20
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• 1995

The goal of this paper is to show that the linear approxi-mation in evaluation of functions may be effectively replaced by the ex-ponential approximation formulas obtained by numerical quadratures and in the instance the relative errors can be estimated without know-ing the true values.

• 대한수학회지
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• 제33권2호
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• pp.235-247
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• 1996

Many numerical computations in science and engineering can only be solved approximately since the available infomation is partial. For instance, for problems defined ona space of functions, information about f is typically provided by few function values, $N(f) = [f(x_1), f(x_2), \ldots, f(x_n)]$. Knwing N(f), the solution is approximated by a numerical method. The error between the true and the approximate solutions can be reduced by acquiring more information. However, this increases the cost. Hence there is a trade-off between the error and the cost.

• 한국경영과학회지
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• 제14권1호
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• pp.119-130
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• 1989

This paper presents average travel time models automated warehousing system where the stacker crane transports only one pallet at a time with the tchebychev travel, I/O point is located at the cornor of the rack, and items are stored by the class-based storage assignment rule. In this study, the racks are treated as the continuous rectangle in time and a statistical approach was used to develop the models. In order to test the proposed models, average travel times determined by the models are compared with the true values for various rack shapes.