• International Journal of Korean Welding Society
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• 제1권2호
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• pp.36-44
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• 2001

To get the appropriate welding process variables, mathematical modeling in conjunction with many experiments is necessary to predict the magnitude of weld bead shape. Even though the experimental results are reliable, it has a difficulty in accurately predicting welding process variables for the desired weld bead shape because of nonlinear and complex characteristics of welding processes. The welding condition determined for the desired weld bead shape may cause the weld defect if the welding current/voltage/speed combination is improperly selected. In this study, the $2^{n-1}$ fractional factorial design method and correlation parameter were used to investigate the effect of the welding process variables on the fillet joint shape, and the multiple non-linear regression analysis was used for modeling the gas metal arc welding(GMAW）parameters of the fillet joint. Finally, a fuzzy rule-based method and a neural network method were proposed so that the complexity and non-linearity of arc welding phenomena could be effectively overcome. The performance of the proposed neuro-fuzzy system was evaluated through various experiments. The experimental results showed that the proposed neuro-fuzzy system could effectively check the welding conditions as to whether or not weld defects would occur, and also adjust the welding conditions to avoid these weld defects.

• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.389-395
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• 2012

The problem of spacecraft attitude control is solved using an adaptive neuro-fuzzy inference system (ANFIS). An ANFIS produces a control signal for one of the three axes of a spacecraft's body frame, so in total three ANFISs are constructed for 3-axis attitude control. The fuzzy inference system of the ANFIS is initialized using a subtractive clustering method. The ANFIS is trained by a hybrid learning algorithm using the data obtained from attitude control simulations using state-dependent Riccati equation controller. The training data set for each axis is composed of state errors for 3 axes (roll, pitch, and yaw) and a control signal for one of the 3 axes. The stability region of the ANFIS controller is estimated numerically based on Lyapunov stability theory using a numerical method to calculate Jacobian matrix. To measure the performance of the ANFIS controller, root mean square error and correlation factor are used as performance indicators. The performance is tested on two ANFIS controllers trained in different conditions. The test results show that the performance indicators are proper in the sense that the ANFIS controller with the larger stability region provides better performance according to the performance indicators.

• 한국의류학회지
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• 제41권2호
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• pp.254-265
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• 2017

This study examines the possibility of a neuro-scientific approach to fashion Visual Merchandising (VM), by researching the brain activation of customers about fashion stores in terms of VM. Study subjects were in 20's-30's residing in Busan and ten ordinary person or fashion industry related individuals, it measures the change of cerebral blood flow on positive/negative photo stimulus in terms of VM using a functional Near Infrared Spectroscopy (fNIRS) device, and then compared the brain activation to the difference of the fashion store VM. Photo stimuli utilized in the experiment were selected through a preliminary study in advance. The results of this study are as follows. First, the brain activation was found in all 16 channels of stimulus ranges of fashion store VM regardless of positive/negative stimulus. This means that the VM of fashion store causes changes to the cerebral blood flow of consumers, which implies that consumer behavior can be affected by store VM. It also shows that the brain is more active in negative VM stimulus than positive VM despite slight differences in the subjects. In terms of VM, this suggests that the negative factors of fashion stores have a greater effect on the brains of consumers compared to the positive factors. Second, the reaction of the brain channel is different according to the positive/negative VM stimulus of the fashion store by product group and confirms that positive/negative VM stimulus can be distinguished by brain-reaction for the three product groups except for the underwear group among four product groups (men's wear store, women's wear store, underwear store, and sportswear store). The results indicate that more objective scientific measure and decision-making are possible through neuro-science in the strategic execution of VM. This study verified the possibility for a neuro-scientific approach to fashion VM; therefore, there are expectations for the various activation of interdisciplinary research and subsequent development of VM that utilize neuroscience in fashion marketing.

• 대한한의학방제학회지
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• 제13권1호
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• pp.103-121
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• 2005

Alzheimer's disease(AD) is a geriatric dementia that is widespread in old age. In the near future AD will be the biggest problem in public health service. It has been widely believed that $A{\beta}$ peptide devided from APP causes apoptotic neurotoxicity in AD brain. However, recent evidence suggests that n99 may be an important factor causing neurotoxicity in AD. Mouse Neuro 2A cells expressed with CT99 exhibited remarkable apoptotic cell damage. We invesgated the protective effects of Ikgiansintang water extract(IGA). Findings from our experiment have shown that IGA inhibits the activities of CT99, which has neurotoxicities and apoptotic activities in cell line. In addition treatment of IGA($50{\mu}g/ml$ for 24 hours) partially prevented CT99-induced cytotoxicity in Neuro 2A cells. As the result of this study, In IGA group, the apoptosis in the nervous system is inhibited, the repair against the degerneration of Neuro 2A cells by n99 expression is promoted. Base on these findings, IGA may be beneficial for the treatment of AD.

• Journal of Korean Neurosurgical Society
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• 제66권4호
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• pp.465-475
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• 2023

Objective : Our objective is to analyze the occurrence, clinical course and risk factors for glioma patients with leptomeningeal metastasis (LM) according to different metastasis patterns and clinical variables. Methods : We retrospectively reviewed data from 376 World Health Organization (WHO) grade II-IV adult glioma patients who were treated in the National Cancer Center from 2001 to 2020. Patients who underwent surgery at other institutions, those without initial images or those with pathologically unconfirmed cases were excluded. LM was diagnosed based on magnetic resonance imaging (MRI) findings or cerebrospinal fluid (CSF) cytology. The metastasis pattern was categorized as nodular or linear according to the enhancement pattern. Tumor proximity to the CSF space was classified as involved or separated, whereas location of the tumor was dichotomized as midline, for tumors residing in the thalamus, basal ganglia and brainstem, or lateral, for tumors residing in the cerebral and cerebellar hemispheres. Results : A total of 138 patients were enrolled in the study. A total of 44 patients (38%) were diagnosed with LM during a median follow-up of 9 months (range, 0-60). Among the clinical variables, tumor proximity to CSF space, the location of the tumor and the WHO grade were significant factors for LM development in univariate analysis. In multivariate analysis, the midline location of the tumor and WHO grade IV gliomas were the most significant factor for LM development. The hazard ratio was 2.624 for midline located gliomas (95% confidence interval [CI], 1.384-4.974; p=0.003) and 3.008 for WHO grade IV gliomas (95% CI, 1.379-6.561; p=0.006). Conclusion : Midline location and histological grading are an important factor for LM in glioma patients. The proximity to the CSF circulation pathway is also an important factor for WHO grade IV glioma LM. Patients carrying high risks should be followed up more thoroughly.

• 생물환경조절학회지
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• 제3권1호
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• pp.42-51
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• 1994

대다수 농산물과 마찬가지로 건조표고의 등급판정은 외관특징에 주로 의존한다. 표고 갓의 전후면에 걸친 복잡하고 다양한 외관특징들로 인하여 표고의 등급판정은 임의로 추출한 표고샘플에 대하여 전문가가 수작업으로 판정하고 있으며, 선별작업 역시 전적으로 수작업에 의존하고 있다. 단순한 반복작업으로 보이는 농산물의 등급판정은 사실 시각과 촉각을 위시한 고도의 감각신경계를 통하여 상호 복잡하게 얽혀 들어오는 정보를 지능적으로 처리하는 고기능의 작업이다. 농산물의 경우, 외관특성을 비롯한 물성은 종류별로 그 경계치를 일괄적으로 명확하게 규정할 수 없기 때문에 대개는 오차를 포함한 통계적 접근에 의하여 규정하고 있다. 따라서 농산작업에 있어서는 농산물 물성이 갖는 모호성을 효율적으로 처리할 수 있는 가변적인 작업구조 및 정보처리가 필수적으로 요구된다. 본 연구에서는 인간 뇌의 정보처리 기능을 부분적으로 구현할 수 있는 인공신경회로망을 컴퓨터 시각 시스템에 적용하여 단순 기하도형의 분류 및 표고의 등급판정을 성공적으로 수행하였다. 회로망 입력으로는 컴퓨터시각 시스템을 이용하여 건조표고의 정성적 외관특징을 자동으로 추출한 후 정량화한 특징점 값들을 이용하였다. 신경회로망의 학습은 표본 추출한 등급표고와 이들의 정량적 특징점 값들을 입출력 쌍으로 하여 수행하였다. 학습한 회로망의 등급판정 성능시험은 표본추출한 미지의 표고에 대한 컴퓨터 영상 특징점 값들을 입력하여 수행하였다.

• Journal of Korean Neurosurgical Society
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• 제58권1호
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• pp.1-8
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• 2015

Treatment of Leptomeningeal carcinomatosis (LMC) from solid cancers has not advanced noticeably since the introduction of intra-cerebrospinal fluid (CSF) chemotherapy in the 1970's. The marginal survival benefit and difficulty of intrathecal chemotherapy injection has hindered its wide spread use. Even after the introduction of intraventricular chemotherapy with Ommaya reservoir, frequent development of CSF flow disturbance, manifested as increased intracranial pressure (ICP), made injected drug to be distributed unevenly and thus, the therapy became ineffective. Systemic chemotherapy for LMC has been limited as effective CSF concentration can hardly be achieved except high dose methotrexate (MTX) intravenous administration. However, the introduction of small molecular weight target inhibitors for primary cancer treatment has changed the old concept of 'blood-brain barrier' as the ultimate barrier to systemically administered drugs. Conventional oral administration achieves an effective concentration at the nanomolar level. Furthermore, many studies report that a combined treatment of target inhibitor and intra-CSF chemotherapy significantly prolongs patient survival. Ventriculolumbar perfusion (VLP) chemotherapy has sought to increase drug delivery to the subarachnoid CSF space even in patients with disturbed CSF flow. Recently authors performed phase 1 and 2 clinical trial of VLP chemotherapy with MTX, and 3/4th of patients with increased ICP got controlled ICP and the survival was prolonged. Further trials are required with newly available drugs for CSF chemotherapy. Additionally, new LMC biologic/pharmacodynamic markers for early diagnosis and monitoring of the treatment response are to be identified with the help of advanced molecular biology techniques.

• 응용통계연구
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• 제29권6호
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• pp.1129-1145
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• 2016

뇌기능 연결성 문제는 뇌의 신경역학적 현상과 밀접한 관련이 있다는 의미에서 뇌과학에서 주요 연구주제이다. 본 논문에서는 기능적 자기공명영상(fMRI)자료를 뇌활동에 대한 반응 자료의 주요 형태로써 선택하였는데, 이 fMRI자료는 높은 해상도 때문에 뇌과학 연구에서 선호되는 자료 형태이다. 뇌활동에 대한 생리학적 반응을 측정해서 자료로 사용한다는 전제하에서 뇌의 기능적 연결성을 분석하는 방법들을 고찰하였다. 여기서의 전제란 상태공간 및 측정 모형을 다룬다는것을 의미하는데, 여기서 상태공간 모형은 뇌신경역학을 표현한다고 가정한다. 뇌기능 영상자료의 분석은 무엇을 측정하였느냐에 따라서 분석방법과 그 해석이 조금씩 달라진다. 실제 fMRI자료를 고차원 자기회귀모형을 적용해서 분석한 결과를 논문에 포함하였는데, 이 결과를 통해서 서로 다른 도형문제를 푸는데 서로 다른 뇌신경 역학관계가 요구된다는 것을 엿볼 수 있었다.

• 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.