• 전자공학회논문지CI
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• 제44권1호
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• pp.113-121
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• 2007

다수의 노드로 구성된 무선센서네트워크는 Ad-hoc 방식으로 노드간 통신이 이루어지며, 센싱데이터는 베이스노드로 취합되어진 후 Host PC에 의해 처리되어지게 된다. 하지만 Ad-hoc 방식의 네트워크는 잘못된 라우팅 정보를 전달하거나 데이터를 중간에 소실 및 변경시키는 싱크홀 공격에 대해 취약할 수밖에 없다. 이러한 싱크홀 공격은 네트워크의 오버헤드를 가중시키고 전체 네트워크의 배터리 소모를 가속화 시켜 전체 네트워크의 수명을 단축시키고 또한 다른 공격을 적용하기가 용이하므로 싱크홀 공격에 대한 대응방법은 신중하게 고려되어져야 한다. 본 논문은 이러한 싱크홀 공격이 일어났을 때 공격노드와 주변의 공모노드를 검출해 낼 수 있는 Hop-depth 알고리즘을 제안하였다. 제안된 알고리즘은 홉 깊이가 변경되는 공격의심 노드들을 검색한 후 주변의 공모노드의 경로 값을 재계산한 후 실제 공격이 이루어지는 노드를 검출해 낸다. 제안된 알고리즘의 성능평가는 NS2를 사용하여 이루어 졌으며 원 공격노드 검출성공률, 양성오류율 및 음성오류율, 에너지 소비효율 값을 비교분석하였다.

• 대한두개안면성형외과학회지
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• 제18권1호
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• pp.37-43
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• 2017

Background: Skin cancer is the most common type of cancer. Of the 4 million skin lesions excised annually worldwide, approximately 2 million are considered cancerous. In this study, we aimed to describe a regional experience with skin cancers treated by a single senior surgeon and to provide a treatment algorithm. Methods: The medical records of 176 patients with head and neck non-melanocytic skin cancer (NMSC) who were treated by a single surgeon at our institution between January 2010 and May 2016 were retrospectively reviewed, and their data (age, sex, pathological type, tumor location/size, treatment modality) were analyzed. Patients with cutaneous squamous cell carcinoma (cSCC) who were classified as a high-risk group for nodal metastasis underwent sentinel node mapping according to the National Comprehensive Cancer Network guidelines. Results: Among the patients with NMSC who were treated during this period, basal cell carcinoma (BCC; n=102, 57.9%) was the most common pathological type, followed by cSCC (n=66, 37.5%). Most lesions were treated by complete excision, with tumor-free surgical margins determined via frozen section pathology. Thirty-one patients with high-metastasis-risk cSCC underwent sentinel node mapping, and 17 (54.8%) exhibited radiologically positive sentinel nodes. Although these nodes were pathologically negative for metastasis, 2 patients (6.5%) later developed lymph node metastases. Conclusion: In our experience, BCC treatment should comprise wide excision with tumor-free surgical margins and proper reconstruction. In contrast, patients with cSCC should undergo lymphoscintigraphy, as nodal metastases are a possibility. Proper diagnosis and treatment could reduce the undesirably high morbidity and mortality rates.

• Journal of Gastric Cancer
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• 제3권1호
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• pp.33-37
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• 2003

Purpose: Alpha-fetoprotein (AFP) is widely accepted as a useful tumor marker for diagnosis of hepatocellular carcinomas. On rare occasions, however, an abnormal elevation of serum AFP also has been reported in an adenocarcinoma of the gastrointestinal tract. We evaluated the influence of preoperative abnormal elevation of serum AFP (AFP positivity) on the prognosis of resectable gastric cancers. Materials and Methods: 812 gastric cancer patients, who were investigated for serum AFP before their operations and who underwent gastric resections with D2 or more extended lymph node dissection, were enrolled in the study. The survival rates were calculated by using the Kaplan-Meier method and were compared by using the log-rank test. A multivariate analysis was performed using the Cox proportional hazards model. Results: Fifty patients ($6.2\%$) were AFP positive (10.1. 4322.6 ng/ml). The survival rate of the AFP positive group was significantly lower than that of the AFP negative group ( $46.6\%\;vs.\;67.0\%$; P=0.0002). The depth of tumor invasion, the degree of regional lymph node metastasis, distant metastases, the TNM stage, the gross type, differentiation, the extent of gastric resection, and the curability of the surgery also significantly influenced survival. Multivariate analysis revealed that the depth of tumor invasion, the degree of regional lymph node metastasis, the curability of the surgery, and AFP positivity were independent prognostic indicators. Conclusion: Preoperative serum AFP can be used as an independent prognostic factor of resectable gastric cancer.

• Coupled systems mechanics
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• 제3권3호
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• pp.305-318
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• 2014

The study deals with the physical modeling of a typical building frame resting on pile foundation and embedded in cohesive soil mass using complete three-dimensional finite element analysis. Two different pile groups comprising four piles ($2{\times}2$) and nine piles ($3{\times}3$) are considered. Further, three different pile diameters along with the various pile spacings are considered. The elements of the superstructure frame and those of the pile foundation are descretized using twenty-node isoparametric continuum elements. The interface between the pile and pile and soil is idealized using sixteen-node isoparametric surface elements. The current study is an improved version of finite element modeling for the soil elements compared to the one reported in the literature (Chore and Ingle 2008). The soil elements are discretized using eight-, nine- and twelve-node continuum elements. Both the elements of superstructure and substructure (i.e., foundation) including soil are assumed to remain in the elastic state at all the time. The interaction analysis is carried out using sub-structure approach in the parametric study. The total stress analysis is carried out considering the immediate behaviour of the soil. The effect of various parameters of the pile foundation such as spacing in a group and number piles in a group, along with pile diameter, is evaluated on the response of superstructure. The response includes the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase displacement in the range of 58 -152% and increase the absolute maximum positive and negative moments in the column in the range of 14-15% and 26-28%, respectively. The effect of the soil- structure interaction is observed to be significant for the configuration of the pile groups and the soil considered in the present study.

• Journal of Gastric Cancer
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• 제18권1호
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• pp.20-29
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• 2018

Purpose: Pre-operative lymph node (LN) size is a valuable parameter for determining treatment strategy for gastric cancer. However, a correlation between LN size and metastasis has not been established. Materials and Methods: Thirty-six LN-positive (LNP) and matched 36 LN-negative (LNN) patients were included, and pathology slides of the LNs of these patients were reviewed. All the LNs were measured along the long-axis (LA) and short-axis (SA), manually. Results: Average retrieved LNs were $37.3{\pm}19.8$ and $40.5{\pm}11.6$ in the LNN and LNP groups, respectively. In total 2,800 LNs, including 136 metastatic LNs (MLNs) and 2,664 non-metastatic LNs (nMLNs), were evaluated. Mean length was significantly more in MLNs along both, the LA and SA (MLN_LA vs. nMLN_LA: $4.97{\pm}3.84$ vs. $3.37{\pm}2.40mm$, MLN_SA vs. nMLN_SA: $3.86{\pm}3.19$ vs. $2.43{\pm}1.59mm$; P<0.001). However, 92.6% (126/136) and 95.6% (130/136) of MLNs were <10 mm along the LA and SA, respectively. In addition, only 22.2% of the LNP group exhibited an MLN as the largest LN. Conclusions: Pre-operative multi-detector computed tomography has limited ability in estimating the presence of metastasis in LNs because most MLNs are less than 10 mm, and only a small proportion of the LNP group exhibits an MLN as the largest MLN.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2145-2152
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• 2014

Background: The survival rate for oral squamous cell carcinoma (OSCC) has remained generally unchanged in the past three decades, underlining the need for more biomarkers to be developed to aid prognostication and effective management. The prognostic potential of E-cadherin expression in OSCCs has been variable in previous studies while galectin-9 expression has been correlated with improved prognosis in other cancers. The aim of the present study was to investigate the expression of galectin-9 and E-cadherin in OSCC and their potential as prognostic biomarkers. Materials and Methods: E-cadherin and Galectin-9 expression was examined by immunohistochemistry in 32 cases of OSCC of the buccal mucosa (13 with and 19 without lymph node metastasis), as well as 6 samples of reactive lesions and 5 of normal buccal mucosa. Results: The expression of E-cadherin in OSCC was significantly lower than the control tissues but galectin-9 expression was conversely higher. Median E-cadherin HSCOREs between OSCCs positive and negative for nodal metastasis were not significantly different. Mean HSCOREs for galectin-9 in OSCC without lymph node metastasis ($127.7{\pm}81.8$) was higher than OSCC with lymph node metastasis ($97.9{\pm}62.9$) but this difference was not statistically significant. Conclusions: E-cadherin expression is reduced whilst galectin-9 expression is increased in OSCC. However, the present results suggest that E-cadherin and galectin-9 expression may not be useful as prognostic markers for OSCC.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.855-860
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• 2014

Background: The purpose of this study was to assess the relationship between different sonographic features of papillary thyroid carcinoma (PTC) on high-frequency ultrasound and cervical lymph node metastasis (CLNM). Materials and Methods: We enrolled 548 patients who underwent initial surgery for PTC between May 2011 and December 2012 in our hospital at diagnosis. The sonographic features of 513 PTC nodules in 513 eligible patients, who had single PTC nodules in their thyroid glands, were retrospectively investigated. All patients with a suspect malignant nodule (d<0.5cm) among multiple nodules were initially diagnosed by fine-needle aspiration biopsy (FNAB) to ascertain if the suspect nodule was PTC. The final diagnosis of all the thyroid nodules and existence of CLNM were based on postoperative pathology. Patients were divided into two groups: a positive group with CLNM (224 nodules) and a negative group without CLNM (289 nodules). The following factors were investigated: gender, age, echogenicity, echotexture, size, shape, location, margin, contour, calcification morphology, distance between the nodule and pre- or post-border of the thyroid capsule, vascularity and the differences between the two groups. Results: Correlation analysis showed that shorter distances between the nodule and pre- or postborder of thyroid capsule resulted in greater risk of CLNM (Spearman correlation coefficient=-0.22, p<0.0001). The significant factors in multivariate analysis were age<45yrs, larger size (d>1cm), "wider than tall" shape, extrathyroid extension and mixed flow (internal and peripheral) (p<0.05, OR=0.406, 2.093, 0.461, 1.610, 1.322). Conclusions: Significant sonographic features of PTC nodules in preoperative high-frequency ultrasound are crucial for predicting CLNM.

• Journal of Chest Surgery
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• 제46권1호
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• pp.49-55
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• 2013

Background: The aim of this study was to determine the survival rate of patients with non-small cell lung cancer (NSCLC) who were preoperatively diagnosed with a negative N2 lymph node, but postoperatively confirmed as a positive N2 node based on a pathological evaluation. Materials and Methods: The hospital records of 248 patients from 1994 to 2009 with resected primary NSCLC who were preoperatively diagnosed with negative N2 lymph node, were retrospectively reviewed. Of these, after surgery, there were 148 (59.7%) patients with pathological N0, 54 (21.8%) with pathological N1 and 46 (18.5%) with pathological N2. Results: The median follow-up period was 24 months (range, 1 to 132 months). The 5-year disease free survival rates were 60% in pN0, 44% in pN1, and 29% in pN2. The 5-year overall survival rates were 63.1% in pN0, 51.9% in pN1, and 33.5% in pN2. There were no statistically significant differences between pN1 and pN2 (p=0.326 and p=0.106, respectively). Thirty-three (71.7%) of the 46 pN2 patients had single-zone metastasis, and 13 patients (28.3%) had multiple-zone metastases over the two nodal zone metastasis. There were no statistical differences in the 5-year disease free survival rate and the 5-year overall survival rates between the two groups. Conclusion: The 5-year disease free survival and the overall survival rate of the patients with unsuspected N2 disease were statistically similar with that of the patients with pathological N1 disease. There was no statistically significant difference between the patients with a single-zone metastasis and a multiple zone metastasis.

• The Korean Journal of Physiology
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• 제21권1호
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• pp.1-12
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• 1987

There is evidence that the effect of extracellular $Ca^{2+}$ on heart rate is temperature-dependent: at $38^{\circ}C$ excess $Ca^{2+}$ induces positive chronotropic response, whereas at $30^{\circ}C$ there is no significant chronotropic effect of $Ca^{2+}$. The cause of this temperature-dependency, however, remains still unclear. Therefore, this study was undertaken to investigate the chronotropic effect of external $Ca^{2+}$ at different temperature in the isolated rabbit atria and in the small strips of SA node cut perpendicularly to crista terminalis. In the isolated atria, the $Ca^{2+}$ effect was temperature-dependent: at $35^{\circ}C$ excess $Ca^{2+}$ evoked positive chronotropic response, while at $30^{\circ}C$ there was no significant changes in sinus rate. On the contrary, in the small SA strips external $Ca^{2+}$ induced negative chronotropic effect. At $35^{\circ}C$ changes in $Ca^{2+}$ concentration from 2 to 4, 6, and 10 mM decreased the sinus rate by $2.7{\pm}1.6%$, $11.2{\pm}3.7%$ and $23.2{\pm}8.1%$ respectively. Lowering the temperature to $30^{\circ}C$, the negative chronotropic effect of $Ca^{2+}$ became greater. With intracellular microelectrodes transmembrane potential was recorded in the small SA strips at $30^{\circ}C$, $35^{\circ}C$ and $38^{\circ}C$. As temperature increased from 30 to $38^{\circ}C$, sinus rate was accelerated by $13/min/^{\circ}C$, $APD_{50}$(action ptential duration from peak to 50% repolarization) decreased by $5\;msec/^{\circ}C$, and amplitude of action potential was slightly decreased. With an increase in $Ca^{2+}$ concentrations from 0.5 to 6 mM, overshoot increased and MDP decreased. These $Ca^{2+}$ effects on the overshoot and MDP of action potentials were not altered by temperature. But the $Ca^{2+}$ effects on the rates of diastolic depolarization, systolic depolarization and repolarization were modified by temperature. Discrpancy of the chronotropic effects of $Ca^{2+}$ between isolated atria and small SA strips was discussed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권2호
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• pp.151-156
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• 2006

술전 경부 임파절 평가의 정확성은 신체검사와 방사선학적 소견 모두에서 정확성의 한계를 보였으며, 정확성을 보다 높이기 위해서는 임상의사와 방사선의사간에 의견 교환이 중요하다고 사료된다. 그리고 필요에 따라서는 초음파 촬영, 세침 흡인세포검사(FNAC) 등의 보조적인 임파절 평가 방법을 이용하는 것도 전체 정진율을 높일 수 있을 것이다. 또한 구강암의 원발 부위가 고위험군인 경우에는 가음성도 비율이 높고, 방사선학적 검사에서 전체 정진율이 낮은 결과를 보이는 것으로 볼때, 지금까지 알려진대로 예방적 경부 곽청술을 보다 적극적으로 고려하는 것이 필요하다고 사료된다.