• Journal of Digestive Cancer Research
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• 제10권2호
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• pp.99-106
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• 2022

Clinical research ultimately aimed to promptly diagnose and prevent diseases through precise biomarker development. Finding the optimal cut-off point of a regularly measured biomarker can help its interpretation and ultimately help in disease investigation and diagnosis, more specifically in determining the presence of diseases. Therefore, this study aimed to use the characteristics of outcome variables in clinical research to explain how to determine the optimal cutoff point. The outcome variables can be divided into dichotomous, ordinal, and survival types. The optimal cut-off point can be determined by finding points that maximize the Youden index, extended Youden index, and log-rank statistics. This study will enable clinical researchers to accurately determine the optimal cut-off points for regularly measured biomarkers, thereby enabling prompt disease diagnosis for effective treatment.

• 한국통신학회논문지
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• 제32권7C호
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• pp.658-666
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• 2007

일반적으로 기존의 선형 위상을 갖는 저역통과 MAXFLAT FIR 필터 설계 방법들은 폐쇄형 전달함수의 특성으로 인하여 하프 주파수 대역 $(0{\leq}w{\leq}{\pi}/2)$에서 이득 응답을 갖는다. 더욱이 주파수 영역에서 MAXFLAT과 선형 위상 특성에 도달하기 위해 추정 알고리즘을 사용하기 때문에 설계 필터들은 저지대역에서의 리플 에러, 완만한 차단감쇠, 위상 및 그룹지연 그리고 부정확한 차단주파수와 같은 문제점들을 가지고 있다. 본 논문에서는 이러한 문제점들을 해결하기 위하여 제로 위상의 광대역 이득 응답을 갖는 MAXFLAT FIR 저역통과 필터 설계를 위한 새로운 수학적인 폐쇄형 전달함수를 제안하였다. 더욱이, 제안된 폐쇄형 전달함수는 임의의 차단 주파수를 포함한 MAXFLAT 조건들을 이용하여 새롭게 유도한 일반화한 공식들로 쉽게 실현됨이 증명되었다. 따라서 제안방식은 간단하고 빠른 설계에 적합하다. 결론적으로 제안된 설계 기술은 제로 위상과 광대역 이득 응답을 갖는 MAXFLAT FIR 저역통과 필터 실현이 가능하며, 설계된 필터들은 모두 250dB가 넘는 최대 차단 감쇠를 갖는 것을 알 수가 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.891-896
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• 2000

It is necessary to drill new opening in an existing R.C beam either for service ducts and pipes or the determination of in place concrete strength. Therefore, to simulate in this study, 18-R.C beams were fabricated with circular openings. The major parameters considered are the sizes, location of opening and cut-off stirrup. These beams are tested shear failure and capacity under a point loading. The sizes of opening are changed 0.11, 0.2, 0.3 times of beam-depth and the locations of opening are divided into $X_1$ zone, $X_2$ zone, $X_3$zone. Loads are applied up to failure to observe the cracking initiation and propagation, initial diagonal cracking, midspan deflection. As a result, the sizes of opening with 0.11D and 0.2D in R.C beams without cutoff stirrup are profitable in $X_1$ and $X_3$zone. R.C beams with 0.3D and cutoff stirrup are advantageous in $X_3$zone.

• 대한전기학회논문지
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• 제45권1호
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• pp.146-158
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• 1996

The WKB method has been widely used in evaluating of the propagation characteristics of planar waveguides with graded-index profiles. This method, however, yields large errors when a turning point is near or at the discontinuity in the presence of the index discontinuity or index slope discontinuity. Especially, in the case of a truncated-index profile, this phenomenon appears more clearly in the low-order modes and near the cutoff regions. The MWKB method is introduced to reduce these inherent errors of the conventional WKB method. The MWKB method is based on both the linearization of the index profile from an index discontinuity and the introduction of a virtual turning point. It is noticed that the b-v curves obtained by the MWKB method agree well with those of the finite-difference method, and that the phase shift at a turning point depends on both the index profile and its propagation constant. (author). refs., figs.

• 대한의용생체공학회:의공학회지
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• 제12권1호
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• pp.43-48
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• 1991

As the computerized methods and equipments In nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic Images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected Profiles of radioisotope distribution from the Quantitative point of view, and reduced the filter parameters such as cutoff frequency and order of filter which are neces mary to minimize the quantification error using computer-generated phantoms.

• 대한의용생체공학회:의공학회지
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• 제3권1호
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• pp.51-54
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• 1982

As the computerized methods and equipments in nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected profiles of radioisotope distribution from the quantitative point of view, and reduced the filter Parameters such as cutoff frequency and order of filter which are necessary to minimize the quantification error using computer -generated phantoms.

• 정보과학회 논문지
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• 제44권3호
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• pp.223-231
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• 2017

본 논문에서는 최근 광범위하게 사용되고 있는 멀티 코어 환경에서의 모바일 장치의 성능에 대하여 연구하였다. 이전에 연구되어왔던 멀티 코어의 성능에 대한 분석은, 대부분 데스크톱 PC에서의 분석이었고, heterogeneous 멀티 코어에 대한 분석방법이 충분하지 않았다. 이러한 문제점을 보완하고자 homogeneous 멀티 코어의 분석 방법을 응용한 heterogeneous 멀티 코어 환경에서 성능을 분석하는 방법을 제안하였다. 본 연구에서는 이를 분석하는 데 있어서 작업의 할당에는 Size Interval Task Allocation (SITA) 기법을 사용하였고, 코어에서의 처리 방법은 Shortest Remaining Processing Time (SRPT) 기법을 사용하였다. 이 중 SITA 기법에서 가장 중요한 분석인 cutoff point에 대한 새로운 계산 방법을 제안하였고, 이를 체류 시간을 계산하는 데 사용함으로써 계산의 용이성과 정확성을 높였다. 또한, ESESC 시뮬레이터에서의 측정을 통해 분석값과 측정값에 큰 차이가 없음을 확인하였다.

• 대한한방내과학회지
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• 제26권3호
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• pp.615-625
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• 2005

Objectives : Poststroke depression is a frequent and specific entity that impaires the rehabilliation and functional recovery of patients with hemiplegia. The author evaluated the effect of Banhahubak-tang(Banxiahoupotang) in patients with poststroke depression. Methods : 38 patients suffering from poststroke depression(determined by Diagnostic and Statistical Manual of Mental Disorders, revised. 3rd edition. and Beck Depression Inventory[BDI] cutoff $point{\geqq}10$) in Kyunghee Oriental hospital were randomized into two groups; treatment group(n=19) and control group(n=19). The treatment group was prescribed with Banhahubak-tang(Banxiahoupotang) three times a day fur a week. Control troop was prescribed with other herbal medicines used for stroke Patients three times a day for a week. Patients were evaluated by use of BDI scale, Modified Barthel Index, Depression of Ki score, Yin syndrome score, and Yang syndrome score. Among 38 patients, 24 patients got BDI scores above 21, which is the cut-off score for depression in Korean. The same procedures and assessments described above were applied. Results : Treatment group did not significantly improve compared with control group. Results yielded only slight significance (P=0.086). Especially. patients with poststroke depression as yin syndrome improved more significantly on BDI than those classified as yang syndrome. When BDI cutoff point for depression was defined as being ${\geq}\;21$, treatment group did not significantly improve compared with control group(P=0.114). However, patients with poststroke depression classified as yin syndrome were also significantly improved on BDI than those classified as yang syndrome. Conclusions : This study suggests that Banhahubak-tang(Banxiahoupotang) is significantly effective in patients with poststroke depression classified as yin syndrome.

• 융합정보논문지
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• 제10권11호
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• pp.148-155
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• 2020

본 연구는 한국어판 피츠버그 수면의 질 지수(PSQI-K) 도구의 신뢰도와 타당도를 검증하고 수면장애군의 최적 절단점을 탐색하기 위한 목적으로 수행되었다. 초기 성인 64명을 대상으로 PSQI-K와 Fitbit charge 3^TM을 이용하여 주관적 수면의 질과 수면양상을 측정하였다. 도구의 신뢰도는 Cronbach's alpha coefficient 계수로, 도구의 타당도는 요인분석 및 PSQI-K 점수와 Fitbit tracker 간의 Spearman's rho 상관계수로 분석하였다. 연구결과, PSQI-K 점수의 Cronbach's alpha coefficient는 0.69였고, PSQI-K와 Fitbit tracker의 각 지표값과의 correlation은 0.67 이상으로 유의하였다. 수면장애군 구분을 위한 절단점은 ≥6일 때 민감도 0.93, 특이도 0.84로 가장 적합하였다. PSQI-K는 초기 성인의 수면장애군을 스크리닝함에 있어서 신뢰도와 타당도가 양호한 도구임이 확인되었다.

• Journal of Yeungnam Medical Science
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• 제36권3호
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• pp.241-248
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• 2019

Background: Heatstroke is one of the most serious heat-related illnesses. However, establishing public policies to prevent heatstroke remains a challenge. This study aimed to investigate the most relevant climate elements and their warning criteria to prevent outdoor heatstroke (OHS). Methods: We investigated heatstroke patients from five major hospitals in Daegu metropolitan city, Korea, from June 1 to August 31, 2011 to 2016. We also collected the corresponding regional climate data from Korea Meteorological Administration. We analyzed the relationship between the climate elements and OHS occurrence by logistic regression. Results: Of 70 patients who had heatstroke, 45 (64.3%) experienced it while outdoors. Considering all climate elements, only mean heat index (MHI) was related with OHS occurrence (p=0.019). Therefore, the higher the MHI, the higher the risk for OHS (adjusted odds ratio, 1.824; 95% confidence interval, 1.102-3.017). The most suitable cutoff point for MHI by Youden's index was $30.0^{\circ}C$ (sensitivity, 77.4%; specificity, 73.7%). Conclusion: Among the climate elements, MHI was significantly associated with OHS occurrence. The optimal MHI cutoff point for OHS prevention was $30.0^{\circ}C$.