• 한국통신학회논문지
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• 제37권4A호
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• pp.205-213
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• 2012

본 논문에서는 IEEE 802.11 무선 네트워크에서 재밍 (jamming) 공격에 효과적으로 대처할 수 있는 IEEE 802.11h 기반의 채널 도약 기법을 제안한다. IEEE 802.11h의 Dynamic Frequency Selection (DFS)은 현재 사용하는 채널에서 군 레이더와 같은 높은 간섭을 감지할 경우 임의의 채널을 선택하지 않고 전체 채널 측정을 통해 가장 좋은 채널로 도약하는 기법이다. 이러한 기법은 재밍 공격이 발생하는 환경에서는 채널 도약을 위해 모든 채널 측정을 위한 시간이 소요되며 그 시간만큼의 통신 단절이 발생해 네트워크 성능이 저하되는 단점을 가진다. 제안하는 기법에서는 기존의 기법과는 달리 재밍 공격 이전에 도약할 채널을 모든 단말이 알게 함으로써 재머에 대해 즉각적인 대처가 가능하다. 이를 위해 제안하는 기법에서는 비콘 (Beacon)을 통해 도약할 채널을 매번 갱신하며 이것은 이전 비콘 구간마다 전채널 상태 측정을 수행하는 것으로 가능하다. 다양한 환경에서의 모의 실험을 통해 제안 기법이 재머에 즉각적인 대응을 수행함으로써 네트워크 성능 저하를 완화할 수 있음을 확인할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3703-3708
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• 2015

Background: The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of mortality in patients with colorectal, lung, gastric cancer, pancreatic and metastatic renal cell carcinoma. We here evaluated whether preoperative NLR is an independent prognostic factor for non-metastatic renal cell carcinoma (RCC). Materials and Methods: Data from 327 patients who underwent curative or palliative nephrectomy were evaluated retrospectively. In preoperative blood routine examination, neutrophils and lymphocytes were obtained. The predictive value of NLR for non-metastatic RCC was analyzed. Results: The NLR of 327 patients was $2.72{\pm}2.25$. NLR <1.7 and NLR ${\geq}1.7$ were classified as low and high NLR groups, respectively. Chi-square test showed that the preoperative NLR was significantly correlated with the tumor size (P=0.025), but not with the histological subtype (P=0.095)and the pT stage (P=0.283). Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method. Effects of NLR on OS (P=0.007) and DFS (P=0.011) were significant. To evaluate the independent prognostic significance of NLR, multivariate COX regression models were applied and identified increased NLR as an independent prognostic factor for OS (P=0.015), and DFS (P=0.019). Conclusions: Regarding patient survival, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. An elevated blood NLR may be a biomarker of poor OS and DFS in patients with non-metastatic RCC.

• 한국콘텐츠학회논문지
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• 제14권9호
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• pp.350-361
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• 2014

본 연구에서는 15세에서 17세의 청소년들을 대상으로 치과치료에 대한 공포감의 일반적인 경향과 관련변인들에 따라 공포감이 어떻게 차이가 나며, 이들 변인들이 치과치료에 대한 공포감에 영향을 미치는 정도와 인과관계를 밝히고자 하였다. DFS, DBS 및 GFS를 포함한 설문도구와 청소년의 특성에 관한 문항들로 구성된 설문지를 이용하였고, SPSS를 이용하여 단변량 분석을 시행한 후 LISREL 8.12를 사용하여 공변량 구조모형을 분석하였다. DFS (0.957), DBS (0.916) 및 GFS (0.910)의 Cronbach 신뢰도 계수가 모두 0.9이상으로 높게 나타났고, 자신의 치아상태가 건강하지 않다고 생각할수록, 최근 구강 내 동통을 경험했을 경우, 치과치료 시 동통을 강하게 느꼈을 경우, 그리고 치료 시 동통을 자주 경험했을 경우와 치과약속을 어긴적이 있을 경우에 그렇지 않은 경우보다 치과치료에 대한 공포감의 수준이 통계적으로 유의하게 높아지는 추세로 나타났다. 구조방정식 모형의 적합도는 양호하게 나타났으며, 치과치료시 동통정도와 동통 횟수, 치과약속을 어긴 횟수, 치과의사에 대한 불신감 그리고 일반적인 공포감이 치과치료와 관련된 공포감에 정(+)의 직접효과가 있었다.

• Journal of Gastric Cancer
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• 제19권1호
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• pp.102-110
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• 2019

Purpose: Despite an increased acceptance of laparoscopic gastrectomy (LG) in early gastric cancer (EGC), there is insufficient evidence for its oncological safety in advanced gastric cancer (AGC). This is a prospective phase II clinical trial to evaluate the feasibility of LG with D2 lymph node dissection (LND) in AGC. Materials and Methods: The primary endpoint was set as 3-year disease-free survival (DFS). The eligibility criteria were as follows: 20-80 years of age, cT2N0-cT4aN3, American Society of Anesthesiologists score of 3 or less, and no other malignancy. Patients were enrolled in this single-arm study between November 2008 and May 2012. Exclusion criteria included cT4b or M1, or having final pathologic results as EGC. All patients underwent D2 lymphadenectomy. Three-year DFS rates were estimated by the Kaplan-Meier method. Results: A total of 157 patients were enrolled. The overall local complication rate was 10.2%. Conversion to open surgery occurred in 11 patients (7.0%). The mean follow-up period was $55.0{\pm}20.4months$ (1-81 months). The cumulative 3-year DFS rates were 76.3% for all stages, and 100%, 89.3%, 100%, 88.0%, 71.4%, and 35.3% for stage IB, IIA, IIB, IIIA, IIIB, and IIIC, respectively. Recurrence was observed in 37 patients (23.6%), including hematogenous (n=6), peritoneal (n=13), locoregional (n=1), distant node (n=8), and mixed recurrence (n=9). Conclusions: In addition to being technically feasible for treatment of AGC in terms of morbidity, LG with D2 LND for locally advanced gastric cancer showed acceptable 3-year DFS outcomes.

• 대한두경부종양학회지
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• 제37권1호
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• pp.17-22
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• 2021

Background/Objectives: To evaluate clinical significance of FDG PET-CT for detection of residual cancer cells after curative radiation therapy or chemoradiotherapy for patients with squamous cell carcinoma (SCC) of Head and Neck Materials & Methods: A retrospective analysis of patients with SCC of Head and neck with curative radiotherapy or chemoradiotherpy between June 2011 and Jan. 2019 was performed. Sixty patients were treated with Intensity-modulated radiotherapy (IMRT). The Metabolic responses were evaluated on the post-treatment FDG PET-CT at 12 weeks after curative radiotherapy completion. Results: Median follow up was 51.5 months (3-102). The overall survival (OS), disease free survival (DFS), local control rate (LCR), and Distant metastasis free survival (DMFS) at 5 years were 80.5%, 80.1%, 87.7% and 89.1%. Metabolic CR was found in 43 (71.7%) and partial metabolic response (PR) was noted in 17 (14.6%). Metabolic CR was significantly correlated with OS, DFS, LCR, and DMFS. On multivariate analysis, Metabolic CR remained significant for DFS and LCR. Conclusion: Metabolic CR on post-radiotherapy FDG PET-CT is highly predictive of increased DFS and LCR in patients with head and neck cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권4호
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• pp.192-200
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• 2022

Objectives: This study aimed to analyze the treatment outcomes and to evaluate the clinicopathological prognostic factors of oral tongue cancer. Patients and Methods: We retrospectively analyzed treatment results and prognostic factors in 205 patients with oral tongue squamous cell carcinoma who were admitted to the National Cancer Center, South Korea, between January 2001 and December 2020. The patients were treated with surgery and postoperative, definitive radiotherapy (RT) or chemoradiotherapy (CRT). Results: Eighteen patients (8.8%) were treated with curative RT or CRT, while the rest (91.2%) were treated with surgery with or without postoperative RT or CRT. The median follow-up period was 30 months (range, 0-234 months). The 5-year overall survival (OS) and 5-year disease-free survival (DFS) were 72% and 63%, respectively. Multivariate analysis revealed that a positive neck nodal status (N1, N2-3) was significantly associated with poorer 5-year OS and DFS, while perineural invasion was associated with poorer 5-year DFS. Conclusion: Cervical metastasis and perineural invasion are significant prognostic predictors, and combination treatments are necessary for improving OS and DFS in patients with these factors.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.105-114
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• 2017

본 연구는 유방암 환자를 출산력과 연령으로 그룹화한 후 비만에 따른 생존율과 무병생존율을 비교분석하여, 비만 여부가 유방암 환자의 예후와 어떤 관련성이 있는지 알아보고자 하였다. 본 연구의 조사대상은 2006년부터 2008년까지 3년 동안 서울 일개 종합병원에 유방암으로 내원한 4181명의 환자였으며 2015년 5월 30일까지 생존여부와 재발여부를 추적 조사한 후향적 코호트 연구이다. 연구결과 전체 환자에 대해 출산경험이 없는 환자군이 출산경험이 있는 환자군보다 생존율이 낮았고(p=.000), 나이가 40세 미만인 환자군이 40세 이상인 환자군보다 생존율(p=.003)과 무병생존율(p=.000)이 낮았으나, 비만 여부에 따른 생존율과 무병생존율의 차이는 없었다. 그러나 출산력이나 연령을 기준으로 대상자를 그룹화한 후 분석한 결과 비만이 생존율과 무병생존율에 영향을 미치는 하위집단이 확인되었다. 출산력을 기준으로 분류한 환자군에 대해, 출산력이 있는 환자군 내에서 비만 환자의 생존율(p=.001)이나 무병생존율(p=.005)이 비비만 환자보다 낮았다. 연령을 기준으로 분류한 환자군에 대해서도, 나이가 40세 이상인 환자군 내에서 비만 환자의 생존율(p=.005)이나 무병생존율(p=.014)이 비비만 환자보다 낮았다. 연구대상자를 출산력이 있으면서 동시에 연령이 40세 이상인 환자들로 한정한 환자군 내에서도 비만 환자의 생존율(p=.000)이나 무병생존율(p=.003)이 비비만 환자보다 낮은 것으로 나타났다. 결론적으로 유방암 환자 전체에 대해서는 비만이 생존율과 무병생존율에 영향을 미치지 않았으나 출산력과 연령을 기준으로 그룹화한 후 하위집단 내에서 비교했을 때는 비만과 예후와의 관련성을 확인할 수 있었다. 이는 기존 연구들에서 구체적으로 확인하기 힘들었던 내용이므로 비만이 예후에 영향을 미치는 것으로 확인된 유방암 환자 하위집단에 대해 적절한 간호중재 방안이 마련되어야겠다.

• 한국통신학회논문지
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• 제38C권12호
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• pp.1207-1215
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• 2013

이 논문에서는 장애물이 존재하는 환경에서 적외선 센서를 가진 다수의 감시 로봇이 획득한 정보를 융합하여 분산되어있는 표적의 위치 좌표를 추정하는 기법을 제안한다. 방위각(azimuth)과 표적을 대응시키는 방법으로는 장애물이 존재하지 않는 경우에서 제안되었던 깊이-우선(depth-first) 트리 탐색(tree search) 기법을 바탕으로, 우회경로 탐색, 중간 단계 탐색 종료, 하위 단계 부분 탐색, 결정기준 보완 등을 추가함으로써 트리 탐색을 확장한 새로운 기법을 제시하였다. 방위각과 표적이 대응된 후에는 하나의 표적을 가리키는 방위각들에 최소 제곱 오차(least square error) 알고리듬을 적용하여 최적 교점을 구함으로써 표적의 위치 좌표를 추정한다. 제안한 위치 추정 기법의 좌표 추정 성능과 복잡도를 모의실험으로 제시하고 분석한다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8101-8105
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• 2014

Background: Although mucinous adenocarcinoma has been recognized for a long time, whether it is associated with a poorer prognosis in colorectal cancer patients is still controversial. Many studies put emphasis on mucinous adenocarcinoma containing mucin component ${\geq}50%$. Only a few studies have analyzed cases with a mucin component <50%. Objectives: This study aimed to analyze the prognostic value of different mucin component proportions in patients with stage III rectal cancer. Materials and Methods: Clinical, pathological and follow-up data of 136 patients with the stage III rectal cancer were collected. Every variable was analyzed by univariate analysis, then multivariate analysis and survival analysis were further performed. Results: Univariate analysis showed pathologic T stage, lymphovascular invasion, and histological subtype were statistically significant for DFS. Pathologic T stage was significant for OS. Histological subtype and lymphovascular invasion were independent prognostic factors in multivariate analysis for DFS, and histological subtype was the only independent prognostic factor for OS. Survival curves showed the survival time of mucinous adenocarcinoma (MUC) was shorter than non-MUC (adenocarcinomas with a mucin component <50% and without mucin component). Conclusions: Histological subtype (tumor with different mucin component) was an independent prognostic factor for both DFS and OS. Patients with MUC had a worse prognosis than their non-MUC counterparts with stage III rectal carcinoma.

• Journal of Pharmaceutical Investigation
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• 제41권4호
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• pp.211-215
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• 2011

The aim of this study was to develop a stable enteric coated diclofenac sodium (DFS) tablets using Aqua-Polish E without using a subcoat. DFS uncoated tablets were manufactured through the non direct compression process. AquaPolish E white aqueous coating dispersion was used as enteric coating material. This film forming polymer is a mixture of selected polymethacrylic/ethylacrylate copolymers. The stability of the obtained enteric coated tablets was evaluated according to ICH guidelines. No signs of disintegration or cracking was observed when they placed in 0.1N HCl solution (pH1.2), but they were completely disintegrated within 10 minutes when they placed in buffered solution at pH6.8. Dissolution test was also conducted by placing tablets in 0.1 N HCl for 2 hours and then 1 hour in phosphate buffer at pH 6.8. Less than 0.9 % of drug was released in the acidic phase and up to 97% in the basic medium. These findings suggest that aqueous enteric coating with AquaPolish E system is an easy and economical approach for preparing stable DFS enteric coat without the use of a subcoating layer.