• 한국수자원학회논문집
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• 제44권7호
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• pp.537-551
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• 2011

본 연구에서는 앞선 연구를 통해 선정된 최적 입력 자료 조합을 이용하여 한강수계의 왕숙천과 금강유역의 갑천에 대한 Takagi-Sugeno 퍼지기법과 신경망을 연계한 뉴로-퍼지 홍수예측 모형을 구축하였다. 구축된 뉴로-퍼지 홍수예측 모형을 한강수계의 왕숙천과 금강유역의 갑천에 적용하여 30분, 60분, 90분, 120분, 150분, 180분의 선행시간에 대해 각각 홍수예측을 수행하였다. 선행시간별 예측수위를 관측수위와 비교한 결과 안정되고 정확도 높은 홍수예측을 하는 것을 확인할 수 있었다. 추가적으로 정량적 평가를 위해 평균제곱근 오차(Root Mean Square Error)와 같은 통계지표를 산정하여 모형의 적용성을 검증하였다. 검증 결과 모든 통계지표에서 큰 오차 없이 성공적으로 홍수예측이 모의됨을 확인할 수 있었다. 본 연구결과는 향후 중소하천에서 충분한 선행시간을 확보한 정확도 높은 홍수정보시스템의 구축에 활용할 수 있을 것으로 판단된다.

• Investigative Magnetic Resonance Imaging
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• 제24권2호
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• pp.76-84
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• 2020

Background: Determination of inter-method differences between clinically available volumetry methods are essential for the clinical application of brain volumetry in a wider context. Purpose: The purpose of this study was to examine the inter-method reliability and differences between the Siemens morphometry (SM) software and the NeuroQuant (NQ) software. Materials and Methods: MR images of 86 subjects with subjective or objective cognitive impairment were included in this retrospective study. For this study, 3D T1 volume images were obtained in all subjects using a 3T MR scanner (Skyra 3T, Siemens). Volumetric analysis of the 3D T1 volume images was performed using SM and NQ. To analyze the inter-method difference, correlation, and reliability, we used the paired t-test, Bland-Altman plot, Pearson's correlation coefficient, intraclass correlation coefficient (ICC), and effect size (ES) using the MedCalc and SPSS software. Results: SM and NQ showed excellent reliability for cortical gray matter, cerebral white matter, and cerebrospinal fluid; and good reliability for intracranial volume, whole brain volume, both thalami, and both hippocampi. In contrast, poor reliability was observed for both basal ganglia including the caudate nucleus, putamen, and pallidum. Paired comparison revealed that while the mean volume of the right hippocampus was not different between the two software, the mean difference in the left hippocampus volume between the two methods was 0.17 ml (P < 0.001). The other brain regions showed significant differences in terms of measured volumes between the two software. Conclusion: SM and NQ provided good-to-excellent reliability in evaluating most brain structures, except for the basal ganglia in patients with cognitive impairment. Researchers and clinicians should be aware of the potential differences in the measured volumes when using these two different software interchangeably.

• 한국지능시스템학회논문지
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• 제27권2호
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• pp.113-118
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• 2017

선박 충돌 사고를 예방하기 위해 충돌위험도를 미리 추정하여 알려주는 다양한 연구들이 꾸준히 소개되고 있고, 일부 항해장비에 적용되고 있다. 하지만, 충돌위험을 미리 알려주었을 때, 실제 운항자는 충분히 피항 가능한 상황인데 위험성을 알린다고 판단하여 위험 경고를 무시하거나 장비의 알람 기능을 꺼놓는 경우도 많은 것으로 알려져 있다. 선박 충돌 위험 예측이 운항자들에게 좀 더 유용해지기 위해서는 실제 선박들의 습관화된 충돌 회피 동작을 고려할 필요가 있다. 이 연구는 선박에서의 충돌 회피 조치가 어떻게 이루어지고 있는지 조우 유형별로 분석하고 이력을 관리하기 위한 시스템을 제안한다. 특히, 충돌회피를 위한 초기대응에 대한 적절성을 판단하는 핵심 모듈을 뉴로-퍼지 기반 추론 형태로 상세히 설계하고 테스트함으로써 제안하는 시스템의 타당성을 보인다.

• International Journal of Control, Automation, and Systems
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• 제2권3호
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• pp.263-278
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• 2004

This paper reviews dynamic programming (DP), surveys approximate solution methods for it, and considers their applicability to process control problems. Reinforcement Learning (RL) and Neuro-Dynamic Programming (NDP), which can be viewed as approximate DP techniques, are already established techniques for solving difficult multi-stage decision problems in the fields of operations research, computer science, and robotics. Owing to the significant disparity of problem formulations and objective, however, the algorithms and techniques available from these fields are not directly applicable to process control problems, and reformulations based on accurate understanding of these techniques are needed. We categorize the currently available approximate solution techniques fur dynamic programming and identify those most suitable for process control problems. Several open issues are also identified and discussed.

• 전자공학회논문지B
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• 제30B권6호
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• pp.86-92
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• 1993

In this paper, we present a VLSI chip design of Multi-layer Bidirectionsl Associative Memory with good error-correction performance. The MBAM neural chip utilizes inner product implementation schems with binary storage and analog calculation.. Multi-layer can be constructed by direct cascading of these chips, and the number of neurons is expandable by parallel connection of these chips. We made proto-type chips and interface board to test the expansion. Currently the Chip has 32 input nodes, 32 output nodes, and can store up to 48 patterns, 32x48x2 SRAMs are included in the chip.

• Advances in Computational Design
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• 제8권2호
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• pp.147-177
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• 2023

Elliptical concrete-filled steel tubular (CFST) column is widely used in modern structures for both aesthetical appeal and structural performance benefits. The ultimate axial load is a critical factor for designing the elliptical CFST short columns. However, there are complications of geometric and material interactions, which make a difficulty in determining a simple model for predicting the ultimate axial load of elliptical CFST short columns. This study aims to propose an efficient adaptive neuro-fuzzy inference system (ANFIS) model for predicting the ultimate axial load of elliptical CFST short columns. In the proposed method, the ANFIS model is used to establish a relationship between the ultimate axial load and geometric and material properties of elliptical CFST short columns. Accordingly, a total of 188 experimental and simulation datasets of elliptical CFST short columns are used to develop the ANFIS models. The performance of the proposed ANFIS model is compared with that of existing design formulas. The results show that the proposed ANFIS model is more accurate than existing empirical and theoretical formulas. Finally, an explicit formula and a Graphical User Interface (GUI) tool are developed to apply the proposed ANFIS model for practical use.

• 정신신체의학
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• 제16권1호
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• pp.52-58
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• 2008

연구목적 : 항우울제는 정신과 의사뿐만 아니라 많은 비정신과 의사들에 의해 처방 되어지는 정신과 약물이다. 하지만 항우울제에 대해 부정적인 인식이 높은 게 현실이다. 따라서 본 연구는 대학병원 외래를 방문한 일반 환자군들을 대상으로 항우울제에 대한 전반적인 인식과 태도를 알아봄으로써, 항우울제 및 정신과 약물에 대한 사회적 편견 및 오해를 줄여 나가고, 지역사회 정신건강 발전에 도움이 되는 기초 자료로 삼고자 연구를 시행하였다. 방법 : 일 지역 대학병원에 내원한 내과계열 및 외과계열 외래 환자들 200명을 대상으로 정신과 전공의 2인 및 수련의가 외래 대기실에서 환자들을 면담하여 연구 목적을 설명하고, 항우울제에 대한 인식과 태도에 대해 평가하기 위하여 12문항으로 고안한 자가 보고형 설문지를 사용하였다. 결과 : 1) 내과 및 외과 계열 환자들 모두에서 항우울제에 대한 부정적인 인식이 매우 높았다. 2) 외과계열 외래 환자들이 내과 계열 환자들보다 항우울제 약물이 몸에 해롭다고 생각하는 비율이 더 높았다. 3) 항우울제 복용 경험이 없는 환자들이 항우울제에 대해서 부정적인 인식과 태도를 갖고 있었다. 4) 항우울제 복용 거부 이유로는 약물 부작용에 대한 두려움이 높았다. 결론 : 항우울제의 처방시 일반인들의 항우울제에 대한 부정적인 인식을 이해하고, 항우울제에 대해 근거있고 객관적인 사실을 설명하는 적극적인 노력이 더욱 필요하다.

• Journal of Korean Neurosurgical Society
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• 제50권5호
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• pp.426-433
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• 2011

Objective : The Histoculture Drug Response Assay (HDRA), which measures chemosensitivity using minced tumor tissue on drug-soaked gelfoam, has been expected to overcome the limitations of in vitro chemosensitivity test in part. We analyzed interim results of HDRA in malignant gliomas to see if the test can deserve further clinical trials. Methods : Thirty-three patients with malignant gliomas were operated and their tumor samples were examined for the chemosensitivity to 10 chosen drugs by HDRA. The most sensitive chemotherapy regimen among those pre-established was chosen based on the number of sensitive drugs or total inhibition rate (IR) of the regimen. The response was evaluated by 3 month magnetic resonance image. Results : Among 13 patients who underwent total resection of the tumor, 12 showed no evidence of disease and one patient revealed progression. The response rate in 20 patients with residual tumors was 55% (3 complete and 8 partial responses). HDRA sensitivity at the cut-off value of more than one sensitive drug in the applied regimen showed a sensitivity of 100%, specificity of 60% and predictability of 70%. Another cut-off value of >80% of total IR revealed a sensitivity of 100%, specificity of 69%, and predictability of 80%. For 12 newly diagnosed glioblastoma patients, median progression-free survival of the HDRA sensitive group was 21 months, while that of the non-sensitive group was 6 months ($p$=0.07). Conclusion : HDRA for malignant glioma was inferred as a feasible method to predict the chemotherapy response. We are encouraged to launch phase 2 clinical trial with chemosensitivity on HDRA.

• Journal of Korean Neurosurgical Society
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• 제64권4호
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• pp.631-643
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• 2021

Objective : Here, we evaluated whether cerebrospinal fluid (CSF) profiles and their changes after intraventricular chemotherapy for leptomeningeal carcinomatosis (LMC) could predict the treatment response or be prognostic for patient overall survival (OS) along with clinical factors. Methods : Paired 1) pretreatment lumbar, 2) pretreatment ventricular, and 3) posttreatment ventricular samples and their CSF profiles were collected retrospectively from 148 LMC patients who received Ommaya reservoir installation and intraventricular chemotherapy. CSF profile changes were assessed by calculating the differences between posttreatment and pretreatment samples from the same ventricular compartment. CSF cell counts were further differentiated into total and other based on clinical laboratory reports. Results : For the treatment response, a decreased CSF 'total' cell count tended to be associated with a 'controlled' increase in intracranial pressure (ICP) (p=0.059), but other profile changes were not associated with either the control of increased ICP or the cytology response. Among the pretreatment CSF profiles, lumbar protein level and ventricular cell count were significantly correlated with OS in univariable analysis, but they were not significant in multi-variable analysis. Among CSF profile changes, a decrease in 'other' cell count showed worse OS than 'no change' or increased groups (p=0.001). The cytological response was significant for OS, but the hazard ratio of partial remission was paradoxically higher than that of 'no response'. Conclusion : A decrease in other cell count of CSF after intraventricular chemotherapy was associated with poor OS in LMC patients. We suggest that more specific CSF biomarkers of cancer cell origin are needed.

• Journal of Korean Neurosurgical Society
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• 제67권4호
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• pp.467-476
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• 2024

Objective : To evaluate the usefulness of a cranial implantable chemoport, the H-port, as an alternative to the Ommaya reservoir for intraventricular chemotherapy/cerebrospinal fluid (CSF) access in patients with leptomeningeal metastasis (LM). Methods : One hundred fifty-two consecutive patients with a diagnosis of LM and who underwent H-port installation between 2015 and 2021 were evaluated. Adverse events associated with installation and intraventricular chemotherapy, and the rate of increased intracranial pressure (ICP) control via the port were evaluated for safety and efficacy. These indices were compared with published data of Ommaya (n=89), from our institution. Results : Time-to-install and installation-related complications of intracranial hemorrhage (n=2) and catheter malposition (n=5) were not significantly different between the two groups. Intraventricular chemotherapy-related complications of CSF leakage occurred more frequently in the Ommaya than in the H-port group (13/89 vs. 3/152, respectively, p<0.001). Intracranial hemorrhage during chemotherapy occurred only in the Ommaya group (n=4). The CSF infection rate was not statistically different between groups (14/152 vs. 12/89, respectively). The ICP control rate according to reservoir type revealed a significantly higher ICP control rate with the H-port (40/67), compared with the Ommaya result (12/58, p<0.001). Analyzing the ICP control rate based on the CSF drainage method, continuous extraventricular drainage (implemented only with the H-port), found a significantly higher ICP control rate than with intermittent CSF drainage (33/40 vs. 6/56, respectively, p<0.0001). Conclusion : The H-port for intraventricular chemotherapy in patients with LM was superior for ICP control; it had equal or lower complication rates than the Ommaya reservoir.