• Journal of Information Processing Systems
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• 제14권4호
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• pp.926-940
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• 2018

In clustering-based approaches, cluster heads closer to the sink are usually burdened with much more relay traffic and thus, tend to die early. To address this problem, distance-aware clustering approaches, such as energy-efficient unequal clustering (EEUC), that adjust the cluster size according to the distance between the sink and each cluster head have been proposed. However, the network lifetime of such approaches is highly dependent on the distribution of the sensor nodes, because, in randomly distributed sensor networks, the approaches do not guarantee that the cluster energy consumption will be proportional to the cluster size. To address this problem, we propose a novel approach called CACD (Clustering Algorithm Considering node Distribution), which is not only distance-aware but also node density-aware approach. In CACD, clusters are allowed to have limited member nodes, which are determined by the distance between the sink and the cluster head. Simulation results show that CACD is 20%-50% more energy-efficient than previous work under various operational conditions considering the network lifetime.

• 대한두경부종양학회지
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• 제18권1호
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• pp.50-55
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• 2002

Objectives: Thyroid cancer is the most common endocrine malignancy with favorable histologic and prognostic characteristics. Total or near total thyroidectomy has been used as a standard surgical procedure. The aims of this study are to determine the extent of resection of thyroid gland and to find the influencing factors of lymph node metastasis. Materials and Methods: The authors reviewed the records of 194 patients of thyroid cancer surgically treated at Department of General Surgery, Inje University Busan Paik Hospital from January, 1996 to December, 2000. Pathologic classifications, surgical procedures, and lymph node metastasis were analyzed. Results: There were 163 women and 31 men. The age ranged from 12 to 79 years old (mean age 43.2 years). The histological classifications of 194 cases revealed papillary cancer in 171 cases (88.1%), follicular cancer in 17 cases (8.8%), undifferentiated cancer in 3 cases (1.6%), medullary cancer in 2 cases (1.0%) and mixed cancer in 1 case (0.5%). Among the 194 patients, lobectomy was perfomed in 31 patients, subtotal thyroidectomy in 30 patients, near total thyroidectomy in 82 patients and total thyroidectomy in 51 patients. In the subgroup of papillary carcinoma 141 cases with lymph node dissection, lymph node metastasis had no statistical significance according to sex, age and primary tumor size. Conclusions: The mainly performed surgical procedures were total thyroidectomy and near total thyroidectomy. In thyroid cancer surgery, the extent of resection was influenced by age, differentiation and primary tumor size. The lymph node dissection should be decided by lymph node metastasis identified by preoperative radiologic evaluation or intraoperative lymph node findings.

• 대한두경부종양학회지
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• 제7권1호
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• pp.10-16
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• 1991

Elective neck dissection (END), provide proper information on nodal status and stage which are significant prognosticator in head and neck cancers with clinically $N_{(0)}$ neck. But there are many controversies for the extents, methods of surgery, moreover, whether normal lymph nodes, local defencer, have to be removed or not. The authors performed 47 END in 39 patients of head and neck squamous cell carcinoma from 1984 to 1989 and a retrospective study of the cases was conducted. Eighteen percent of nodal metastasis and five percent of extracapsular spread were found in END specimens. We concluded that END provide significant information for the management and evaluation of prognosis in head and neck cancer.

• 대한두경부종양학회지
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• 제10권1호
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• pp.3-6
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• 1994

Neck dissection has become an integral part of the staging and management of head and neck tumors. This paper reports a series of head and neck patients who had pathological findings in their neck dissection specimens, which were unrelated to their primary tumors. In 7 cases, there was unexpected pathology in the cervical lymph nodes which was not related to the primary tumor. Four cases were squamous cell carcinomas and 3 were thyroid carcinomas. In 3 cases of squamous cell carcinomas, there were no evidence of metastatic squamous cell carcinoma in neck dissection specimen; however, the lymph nodes were found to be involved by metastatic papillary carcinoma in one larynx cancer, metastatic adenocarcinoma in the other larynx cancer, tuberculosis in one nasopharynx cancer. In three of neck dissection specimen of carcinoma(two thyroid carcinomas, one laryngeal carcinoma), dual nodal pathology was found: Each of these specimen contained carcinoma with tuberculosis of the lymph nodes in three cases. In one thyroid carcinoma, there was no evidence of metastasis; however, the lymph nodes were found to be involved by tuberculosis. Preoperative assessment did not reveal any findings to alert us to the possibility of a synchronous pathological process in the cervical nodes of this group of 7 patients. In particular, there was no evidence of active pulmonary tuberculosis in the 5 patients with active lymph node disease.

• 대한기관식도과학회지
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• 제6권1호
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• pp.80-86
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• 2000

Background : Stomal recurrence that occasionally follows total laryngectomy is associated with very poor prognosis regardless of treatment modality, so it is very important to identify high risk patients to prevent stomal recurrence. Objectives : We attempted to select an optimal management method to prevent stomal recurrence by analyzing risk factors in each patient who was found to have stomal recurrence following total laryngectomy. Materials and Methods : Risk factors in each of eleven patients who had stomal recurrence out of 159 patients who underwent total laryngectomy in the last ten years were analyzed retrospectively. Data were gathered on risk factors such as the presence of subglottic extension, extralaryngeal extension, thyroid gland invasion, lymph node metastasis, timing of tracheotomy, tumor stage, postoperative radiotherapy, and inclusion of the stoma in the radiotherapy field. Results : There were eight cases of subglottic extension, six cases of extralaryngeal invasion, one case of pharyngocutaneous fistula that occurred as a postoperative complication, and one case who was taken completion laryngectomy following conservation surgery. With the exception of one case who was taken tracheotomy prior to total laryngectomy, all tracheotomies were performed intra-operatively after endotracheal intubation. There was no evidence of paratracheal lymph node or prelaryngeal lymph node metastasis on preoperative neck CT scan. There were six cases of T4 tumors, four cases of T3 tumors, and one case of T2 tumor. Salvage surgery was performed following radiotherapy in three cases, and aside from one case who was not taken post-operative radiotherapy, postoperative radiotherapy including the stoma was performed in the remaining seven cases within one month after surgery. Conclusion : Total laryngectomy with wide paratracheal lymph node dissection, thyroidectomy, and tracheotomy should be performed for patients who have high risk factors such as subglottic extension and advanced stage. We believe that tracheotomy should be precede endotracheal intubation. Efforts should be made to prevent stomal recurrence by utilizing postoperative radiotherapy and by minimizing postoperative complications such as infection and fistula.

• 대한두경부종양학회지
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• 제19권2호
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• pp.142-147
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• 2003

Purpose: Accurate evaluation of metastatic cervical lymph nodes plays a decisive role in the treatment and prognosis of patients with squamous cell carcinoma of the head and neck. The purpose of this study is to investigate the usefulness of FDG-PET for diagnosis of cervical metastasis in the head and neck cancer by comparing with the conventional imaging study. Materials and Methods: The subjects on this study were 30 patients (24 males and 6 females, aged 39 to 76, mean 57.1) diagnosed as pathologic-proven squamous cell carcinomas of the head and neck. All patients underwent preoperative FDG-PET, CT(n=27) or MRI (n=3). Their medical records were reviewed retrospectively. Using pathologic reports as a golden standard, the results of FDG-PET were compared with conventional imaging study (CT/MRI) in the evaluation of cervical metastasis. Results: Thirty patients had five different primary sites which were tongue (11), supraglottis (10), glottis (6), hypopharynx (2) and tonsil (1). A total of 40 neck dissections were performed unilaterally in 20 patients and bilaterally in 10 patients. Of these, 16 showed pathologically positive for lymph node metastasis. The sensitivity and specificity of FDG-PET for the diagnosis of cervical metastasis was 75% and 100% respectively, compared with conventional imaging of 56.3% and 95.8%, respectively. The difference of sensitivity was not statistically significant (p=0.453). Of 5 cases with small metastatic node (<1cm), 3 were detected on PET detected correctly but none were detected by CT. Conclusion: FDG-PET was more accurate than conventional imaging study in the diagnosis of metastatic lymph nodes in squamous cell carcinomas of the head and neck, especially detection of small metastatic node. FDG-PET might be useful adjunct to conventional image in the preoperative evaluation of head and neck squamous cell carcinoma.

• 대한두경부종양학회지
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• 제32권2호
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• pp.1-4
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• 2016

Background and Objectives: National cancer center institute reports that male patients of papillary thyroid carcinoma (PTC) are annually increasing. This study aimed to analyze the features of the male patients with PTC. Materials and Method: We retrospectively reviewed and analyzed clinical records of 170 patients who were treated for PTC in male patients between 2000 and 2010. Clinical features, size, pathologic type, extrathyroidal extension, recurrence, multiplicity, extent of surgery, and lymph node metastasis were retrospectively evaluated.Univariate and multivariate analyses of various clinical factors were performed. Results: Total 4145 patients received surgery for papillary thyroid carcinoma. The number of male patients was 170 (4.1%) among them. Of170 male patients, only 16(9.4%) patients underwent the recurrence of PTC. The size of tumor, central neck node metastasis, lateral neck node metastasis, extrathyroidal extension and RAI ablation therapy were associated with recurrence(p< 0.05) in univariate analysis. However, only the extrathyroidal extension [p=0.03, Odds ratio=3.58(95% CI. 1.09~14.24)] was related to the recurrence in multivariate analysis. Conclusion: Re-estimation of clinical features in male PTC patients should be concerned. The recurrence of PTC in male patients was 16(9.4%) and nearly same as the other studies. The extrathyroidal extension was revealed as an associated factor for the recurrence. Evaluation of regional or distant metastasis should be considered in patients with the extrathyroidal extension in male PTC patients during long-term follow-up.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.612-615
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• 2012

무선 센서 네트워크는 제한된 에너지를 사용하기 때문에 에너지 효율성을 증가시키는 것이 매우 중요하다. 일반적인 무선 센서 네트워크에서 특정 지역에 무작위로 배포된 센서노드는 배포 방법 및 환경에 영향을 받아 불균형하게 분포되어 센서 노드 밀집 지역이 발생되며 이는 네트워크의 전체적 수명을 단축시키는 단점이 된다. 따라서 본 논문에서는 센서 노드 밀집 지역에 클러스터 헤드를 추가적으로 선출하여 무선 센서 네트워크의 수명을 연장시키는 알고리즘을 제안한다. 클러스터링의 대표적인 LEACH(Low Energy Adaptive Clustering Hierarchy) 클러스터링을 이용하여 네트워크를 구성하였을 때와 제안한 알고리즘을 이용하여 네트워크를 구성하였을 때 본 논문에서 제안한 알고리즘을 이용한 네트워크가 전체적으로 균등한 에너지를 유지하고 있음을 알 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1773-1795
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• 2020

Unmanned aerial vehicles (UAVs) network are a very vibrant research area nowadays. They have many military and civil applications. Limited bandwidth, the high mobility and secure communication of micro UAVs represent their three main problems. In this paper, we try to address these problems by means of secure clustering, and a security clustering algorithm based on integrated trust value for UAVs network is proposed. First, an improved the k-means++ algorithm is presented to determine the optimal number of clusters by the network bandwidth parameter, which ensures the optimal use of network bandwidth. Second, we considered variables representing the link expiration time to improve node clustering, and used the integrated trust value to rapidly detect malicious nodes and establish a head list. Node clustering reduce impact of high mobility and head list enhance the security of clustering algorithm. Finally, combined the remaining energy ratio, relative mobility, and the relative degrees of the nodes to select the best cluster head. The results of a simulation showed that the proposed clustering algorithm incurred a smaller computational load and higher network security.

• 대한두경부종양학회지
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• 제34권1호
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• pp.49-53
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• 2018

Primary non-Hodgkin's lymphoma (NHL) rarely involves the parotid gland and its incidence is only 1.7% to 3.1% of all salivary gland neoplasms. The mucosa associated lymphoid tissue (MALT) is the most common subtype of NHL, followed by follicular lymphoma (FL) and diffuse large B cell lymphoma (DLBCL). However, two distinct types of lymphomas occurring synchronously in the parotid gland and cervical lymph node have not been reported earlier. A 72-year-old man with rubbery-hard and fixed mass on the left parotid area came to our clinic. We performed the left total parotidectomy with ipsilateral excision of lymph node (level II), and he was finally diagnosed as DLBCL in parotid gland and FL in upper neck. It is presumed that the DLBCL appeared to be a transformation from FL. We report the unique and rare disease entity with brief literature review.