• 한국ITS학회 논문지
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• 제16권6호
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• pp.67-78
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• 2017

교통혼잡비용은 매해 증가하며, 교통혼잡비용의 63.8%에 해당되는 도심부 교통혼잡에 대한 대책 마련이 시급한 상태이다. 최근 빅데이터, 인공지능 등 4차 산업혁명을 선도하는 기술들의 발전으로 교통부문의 정보화에도 많은 변화가 초래되고 있다. 이러한 신개념 기술을 활용하여 소통상황 예측정보를 제공함으로써 교통혼잡비용을 저감할 수 있을 것으로 기대된다. 이에 본 연구에서는 순환 인공 신경망(RNN)을 활용하여 반복 및 비반복 정체 예측 모형을 개발하고자 하였다. 제안 모형은 실시간 소통정보, 이력정보, 유고상황정보 등을 활용하여 현재를 기점으로 15분 간격의 1시간 이후 소통 상황을 예측하는 모형이다. 33개 링크로 구성된 서울시 논현로에 대해 2개의 은닉층으로 구성된 RNN 모형을 구축하였다. 총 30개 모형을 계량활용변화역전파 알고리즘으로 학습하여, 이 중 평균오차제곱이 0.0834인 모형을 최적 모형으로 선정하였다. 모형 검증 결과 25개 링크에 대해 유의성 높은 예측을 하였다. 모형의 예측력을 열지도를 통해 검토한 결과 반복 정체뿐 아니라 비반복 정체까지 예측할 수 있는 것을 확인할 수 있었다. 따라서 실제 도로 상에서의 교통혼잡 예측을 위한 모형으로 활용할 수 있을 것이라 기대된다.

• 대한수학회보
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• 제53권4호
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• pp.985-1004
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• 2016

We consider the MAP/PH/c/K queue in which blocked customers retry to get service and servers may take vacations. The time interval between retrials and vacation times are of phase type (PH) distributions. Using the method of mean drift, a sufficient condition of ergodicity is provided. A condition for the system to be unstable is also given by the stochastic comparison method.

• 대한수학회보
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• 제57권4호
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• pp.1033-1048
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• 2020

We synthesize the recent work done on conditionally defined Lucas and Fibonacci numbers, tying together various definitions and results generalizing the linear recurrence relation. Allowing for any initial conditions, we determine the generating function and a Binet-like formula for the general sequence, in both the positive and negative directions, as well as relations among various sequence pairs. We also determine conditions for periodicity of these sequences and graph some recurrent figures in Python.

• East Asian mathematical journal
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• 제26권3호
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• pp.351-363
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• 2010

We introduce a special class of real recurrent polynomials $f_m$$($m{\geq}1$) of degree m+1, with positive roots $s_m$, which are decreasing as m increases. The first root $s_1$, as well as the last one denoted by $s_{\infty}$ are expressed in closed form, and enclose all $s_m$ (m > 1). This technique is also used to find weaker than before [6] sufficient convergence conditions for some popular iterative processes converging to solutions of equations.

• BMB Reports
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• 제51권1호
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• pp.1-2
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• 2018

Positive selection on a new beneficial mutation generates a characteristic pattern of DNA sequence polymorphism when it reaches an intermediate allele frequency. On genome sequences of African Drosophila melanogaster, we detected such signatures of selection at 37 candidate loci and identified "sweeping haplotypes (SHs)" that are increasing or have increased rapidly in frequency due to hitchhiking. Based on geographic distribution of SH frequencies, we could infer whether selective sweeps occurred starting from de novo beneficial mutants under simple constant selective pressure. Single SHs were identified at more than half of loci. However, at many other loci, we observed multiple independent SHs, implying soft selective sweeps due to a high beneficial mutation rate or parallel evolution across space. Interestingly, SH frequencies were intermediate across multiple populations at about a quarter of the loci despite relatively low migration rates inferred between African populations. This invokes a certain form of frequency-dependent selection such as heterozygote advantage. At one locus, we observed a complex pattern of multiple independent that was compatible with recurrent frequency-dependent positive selection on new variants. In conclusion, genomic patterns of positive selection are very diverse, with equal contributions of hard and soft sweeps and a surprisingly large proportion of frequency-dependent selection in D. melanogaster populations.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7627-7632
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• 2015

Background: The present study was conducted to evaluate the technical feasibility, safety and adequacy of surgical margins with salvage transoral robotic surgery (TORS) for recurrent or residual head and neck squamous cell carcinoma patients. Materials and Methods: Thirty patients who underwent salvage TORS using the 'DaVinci' robot were enrolled in the study and data related to their surgical time, complications and functional outcome were recorded. Results: The feasibility of salvage TORS in our study was observed to be 100%. Positive margins were encountered in only 6.7% of patients. Mean blood loss was 23.3 ml with no patient requiring blood transfusion. Postoperative complications in the form of primary haemorrhage requiring active surgical intervention occurred in 13.3%. Oral feeding could be started as early as the 3rd postoperative day in a few patients, with nasogastric tubes being removed on the 12th postoperative day. Long term gastrostomy tube dependency was seen in 10% cases. Median survival of patients was 19 months. Conclusions: Salvage TORS is a safe, effective and feasible option in the management of treatment failure cases. It offers an alternative surgical approach with unexpected benefits in terms of tracheostomy tube use, Ryle's tube and gastrostomy dependence.

• 대한영상의학회지
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• 제84권5호
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• pp.999-1008
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• 2023

발생률이 높고, 예후는 좋지만 재발을 잘하는 경향이 있는 갑상선암에서도 전통적인 치료법은 수술이다. 하지만, 2000년대 초반부터, 간암, 폐암, 신장암에서와 마찬가지로 고주파 절제술이 원발 갑상선암 및 재발 갑상선암에 적용되기 시작했다. 원발암에서는 1 cm 이하 크기의 미세유두암 저위험군에서 수술 불가능한 경우에 대한 많은 연구가 이뤄져 왔고, 1 cm보다 더 크고 4 cm 이하의 다양한 군에 대해서도 일부 연구가 시행되었으며, 전반적으로 모두 양호한 결과를 보고하였다. 재발암에 대해서도 주로는 국소 경부 재발암에 고주파 절제술이 시행되었으며, 일부 폐, 뼈 등의 원격 전이에 대해서도 시도되었고, 전반적으로 양호한 결과가 보고되었다. 최근 들어, 한국, 미국, 유럽 등 각지에서 갑상선암의 고주파 절제술에 대해 옹호하는 움직임이 있다. 하지만, 미국 국립 종합 암 네트워크(National Comprehensive Cancer Network) 등의 중립적인 임상지침에는 고주파 절제술이 아직 인정되지는 않은 상태이다. 지금까지의 노력들과 미래의 연구를 바탕으로 향후 가까운 미래에 갑상선암의 치료에 있어 고주파 절제술이 적절한 자리매김을 할 것으로 전망한다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6783-6787
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• 2015

Background: Despite consistent pharmacogenetic effects of CYP2D6 on tamoxifen exposure, there is considerable controversy regarding the validity of CYP2D6 as a predictor of tamoxifen outcome. Understanding the current state of evidence in this area and its limitations is important for the care of patients who require endocrine therapy for breast cancer. Materials and Methods: A total of 101 patients with breast cancer who received tamoxifen therapy for at least 3 years, were genotyped for common alleles of the CYP2D6 gene by nested-PCR and restriction fragment length polymorphism PCR. Patients were classified as extensive or poor metabolizers (PM) based on CYP2D6*4 alleles in 3 different groups according to the menopause, Her2-neu status, and stage 3. Results: The mean age of the patients with the disease recurrence was $50.8{\pm}6.4$ and in non recurrent patients was $48.2{\pm}6.8$. In this study 63.3% (n=64) patients were extensive metabolizers and 36.6% (n=37) were poor metabolizers. Sixty four of the 101 patients (63.3%) were Her2-neu positive. For tamoxifen-treated patients, no statistically significant difference in rate of recurrence observed between CYP2D6 metabolic variants in stage 3 and post-menopausal patients. However, there was a significant association between CYP2D6 genotype and recurrence in tamoxifen-treated Her2-neu positive patients. Compared with other women with breast cancer, those with Her2-neu positive breast cancer and extensive metabolizer alleles had a decreased likelihood of recurrence. Conclusions: This study for the first time demonstrated significant effects of CYP2D6 extensive metabolizer alleles on risk of recurrence in Her2-neu positive breast cancer patients receiving adjuvant tamoxifen therapy. Therefore, CYP2D6 metabolism, as measured by genetic variation, can be a predictor of breast cancer outcome in Her2-neu positive women receiving tamoxifen.

• Journal of Chest Surgery
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• 제28권9호
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• pp.822-828
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• 1995

This paper reports 15 native valve endocarditis cases had surgical operation in the past 10 years at the department of Cardiovascular and Thoracic Surgery, Chonbuk National University Hospital. In this study, 10 cases out of 15 were in class I or II by the New York Heart Association functional classification. None of the cases had a history of taking addictive drugs. Five cases were congenital heart disease, three cases were rheumatic heart disease and two cases were degenerative heart disease. Thus 10 cases had the underlying disease. All cases had antibiotics treatment for 3 to 6 weeks before operation. In the culture test, only four cases were positive in the blood culture and one case was positive in the excised valve culture. Organisms on blood and valve culture were Streptococcus epidermis, Streptococcus viridans, Staphylococcus aureus and Staphylococcus epidermidis. In the 10 cases without ventricular septal defect, the aortic valve was involved in four, mitral in four, both in two and involved valves in the 5 cases with ventricular septal defect were tricuspid in three, pulmonic in two. Eight cases had operation because they showed moderate congestive heart failure due to valvular insufficiency and vegetation with or without embolism. Seven cases had operation because they showed persistent or progressive congestive heart failure and/or uncontrolled infection. Five cases with ventricular septal defect underwent the closure of ventricular septal defect, vegetectomy and leaflet excision of the affected valves without valve replacement. In the cases without ventricular septal defect, the affected valves were replaced with St. Jude mechanical prosthesis. Postoperative complications were recurrent endocarditis in two, embolism in one, allergic vasculitis in two, spleen rupture in one and postpericardiotomy syndrome in one. At the first postoperative day, one case died of cerebral embolism. At the 11th postoperative month, one case died of recurrent endocarditis and paravalvular leakage in spite of a couple of aortic valve replacement. In the survived cases[13 cases in this study , all cases but one became class I or II by the New York Heart Association functional classification.

• 대한한방내과학회지
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• 제42권5호
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• pp.820-832
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• 2021

Objectives: This study examined the case of a patient with ROS1-positive recurrent non-small-cell lung cancer treated with crizotinib and traditional Korean medicine. Methods: The patient was treated with crizotinib from January 20 2021 to May 22 2021, together with Haedogyangpye-tang and Haengso-tang. The tumor size was measured using computed tomography (CT), and adverse events were evaluated according to the National Cancer Institute's Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0. Results: After four months of combined treatment, the sizes of the lymph nodes in the porta hepatis, hepatoduodenal, retrocrural, aortocaval, and para-aortic areas had decreased, and no lymph nodes larger than 1 cm in diameter were observed. The side effects of chemotherapy also improved. Conclusions: This case study suggests that traditional Korean medicine may alleviate the side effects of chemotherapy, improve quality of life, and complement chemotherapy itself.