• Title/Summary/Keyword: nodes

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Dynamic Threshold Method for Isolation of Worm Hole Attack in Wireless Sensor Networks

  • Surinder Singh;Hardeep Singh Saini
    • International Journal of Computer Science & Network Security
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    • v.24 no.5
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    • pp.119-128
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    • 2024
  • The moveable ad hoc networks are untrustworthy and susceptible to any intrusion because of their wireless interaction approach. Therefore the information from these networks can be stolen very easily just by introducing the attacker nodes in the system. The straight route extent is calculated with the help of hop count metric. For this purpose, routing protocols are planned. From a number of attacks, the wormhole attack is considered to be the hazardous one. This intrusion is commenced with the help of couple attacker nodes. These nodes make a channel by placing some sensor nodes between transmitter and receiver. The accessible system regards the wormhole intrusions in the absence of intermediary sensor nodes amid target. This mechanism is significant for the areas where the route distance amid transmitter and receiver is two hops merely. This mechanism is not suitable for those scenarios where multi hops are presented amid transmitter and receiver. In the projected study, a new technique is implemented for the recognition and separation of attacker sensor nodes from the network. The wormhole intrusions are triggered with the help of these attacker nodes in the network. The projected scheme is utilized in NS2 and it is depicted by the reproduction outcomes that the projected scheme shows better performance in comparison with existing approaches.

Structures of hemal nodes and hemolymph nodes in sheep (면양의 혈절과 혈림프절의 구조)

  • Park, Cheol-beom;Seong, Je-kyung;Lee, In-se;Lee, Heungshik S.;Lee, Joon-sup;Yoon, Yeo-sung
    • Korean Journal of Veterinary Research
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    • v.41 no.3
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    • pp.281-285
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    • 2001
  • This study was performed to investigate the gross anatomical features and microscopical structures of the hemal nodes and the hemolymph nodes in the sheep. The hemal nodes and hemolymph nodes were observed mainly in periphery of the thoracic and abdominal aortae of the animals. The size of hemal nodes was generally smaller than that of the hemolymph nodes, and the shape of the both organs was spherical or ovoid. The color of the hemal nodes was red, while that of the hemolymph nodes was grary with red bands. The hemal nodes were surrounded by a relatively thick connective tissue capsule and there were extensive subcapsular sinuses distended by a great number of erythrocytes. Although a few number of lymphatic nodules and small areas of diffuse lymphatic tissues were observed in the parenchyma, no typical cortex and medulla were defined in the hemal node. Small numbers of blood vessels were found at the connective tissue capsule but lymph vessel was not observed microscopically in this organ. The hemolymph nodes were covered by a relatively thick connective tissue capsule and there was a hilus in each node. The parenchyma was divided into cortex and medulla. The cortex was composed of a few numbers of lymphatic nodules and some diffuse lymphatic tissues. The medulla comprised medullary sinuses and cords. Afferent and efferent lymph vessels were observed at the periphery of the capsule adn the hilus, respectively. The subcapsular and medullary sinuses were not extensive but filled with small numbers of erythrocytes. The stroma of hemal node and hemolymph node was composed of reticular cells and fibers, and the capsule and trabecula consisted of collagenous fibers with smooth muscle fibers.

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Differentiation of Malignant and Benign Cervical Lymph Nodes with Color and Pulsed Doppler Ultrasonography (색채 및 펄스 도플러 초음파를 이용한 경부 림프절의 양성과 악성의 감별)

  • Lee Kang-Dae;Lee Bong-Hee;Lee Yun-Woo;Lee Hwan-Ho;Ahn Kyong-Mo;Lee Young-Soo
    • Korean Journal of Head & Neck Oncology
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    • v.17 no.1
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    • pp.19-25
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    • 2001
  • Objectives: The clinical efficacy of the color and pulsed Doppler ultrasound with spectral waveform analysis for differentiation of malignant from benign cervical lymphadenopathy was prospectively evaluated in cervical lymphadenopathy. Materials and Methods: Color and pulsed Doppler ultrasound examination was prospectively performed in 32 cervical lymph nodes in 28 patients. These 10 nodes from 10 patients were malignant and 22 nodes from 18 patients were benign, proved by operation, biopsy, and follow-up examination. Another 12 lymph nodes from 12 normal volunteers were evaluated as control group. The peak systolic velocity (PSV), minimal diastolic velocity (MDV) , and resistive indexes (RI) of arterial flows within the 32 lymph nodes were assessed to differentiate the malignant from benign nodes with pulsed Doppler ultrasonography. The results were qualitified with one-way ANOVA and Bonferroni method of multiple comparison. Results: The mean values of PSV of malignant, benign, and control nodes were 38.2(10.1-134)cm/sec, 23.3(9-38.5) cm/sec and 11.8(6.7-18.1) cm/sec, respectively. The mean values of MDV of them were 0.9(-7.5-10.7)cm/sec, 9.7(2.9-18.6)cm/sec and 6.5(3.7-9.3)cm/sec, respectively. However, there was no statistical significance in differentiation of malignant from benign nodes with PSV and MDV. The mean values of RI of malignant, benign, and control nodes were 0.99(0.80-1.30), 0.59(0.46-0.77) and 0.45(0.38-0.50), respectively. RI value of 0.8 is suggestive value for discrimination of malignant from benign lymphadenopathy during examination of color Doppler ultrasound of cervical lymphadenopathy. Conclusion: Color and pulsed Doppler ultrasound examination with spectral waveform analysis may be quite helpful in the differentiation between benign and malignant alterations of cervical lymph nodes.

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Security Design for Efficient Detection of Misbehavior Node in MANET (MANET에서 비정상 노드를 효율적으로 탐지하기 위한 보안 설계)

  • Hwang, Yoon-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.3B
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    • pp.408-420
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    • 2010
  • On a Mobile Ad hoc NETwork(MANET), it is difficult to detect and prevent misbehaviors nodes existing between end nodes, as communication between remote nodes is made through multiple hop routes due to lack of a fixed networked structure. Therefore, to maintain MANET's performance and security, a technique to identify misbehaving middle nodes and nodes that are compromise by such nodes is required. However, previously proposed techniques assumed that nodes comprising MANET are in a friendly and cooperative relationship, and suggested only methods to identify misbehaving nodes. When these methods are applied to a larger-scale MANET, large overhead is induced. As such, this paper suggests a system model called Secure Cluster-based MANET(SecCBM) to provide secure communication between components aperANET and to ensure eed. As such, this pand managems suapemisbehavior nodes. SecCBM consists apetwo stages. The first is the preventis pstage, whereemisbehavior nodes are identified when rANET is comprised by using a cluster-based hierarchical control structure through dynamic authentication. The second is the post-preventis pstage, whereemisbehavior nodes created during the course apecommunication amongst nodes comprising the network are dh, thed by using FC and MN tables. Through this, MANET's communication safety and efficiency were improved and the proposed method was confirmed to be suitable for MANET through simulation performance evaluation.

Hierarchical Priority Trie for Efficient Packet Classification (효율적인 패킷 분류를 위한 계층 우선순위 트라이)

  • Chu, Ha-Neul;Lim, Hye-Sook
    • Proceedings of the IEEK Conference
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    • 2007.07a
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    • pp.15-16
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    • 2007
  • In order to provide value-added services, next generation routers should perform packet classification for each incoming packet at wire-speed. In this paper, we proposed hierarchical priority trio (Hptrie) for packet classification. The proposed scheme improves the search performance and the memory requirement by replacing empty internal nodes in ordinary hierarchical trio with priority nodes which are the nodes including the highest priority rule among sub-trie nodes.

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Minimum Deficiency Ordering with the Clique Storage Structure (클릭저장구조에서 최소 부족수 순서화의 효율화)

  • Seol, Tong-Ryeol;Park, Chan-Kyoo;Park, Soon-Dal
    • Journal of Korean Institute of Industrial Engineers
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    • v.24 no.3
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    • pp.407-416
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    • 1998
  • For fast Cholesky factorization, it is most important to reduce the number of nonzero elements by ordering methods. Generally, the minimum deficiency ordering produces less nonzero elements, but it is very slow. We propose an efficient implementation method. The minimum deficiency ordering requires much computations related to adjacent nodes. But, we reduce those computations by using indistinguishable nodes, the clique storage structures, and the explicit storage structures to compute deficiencies.

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Clinicopathologic Features Predicting Involvement of Nonsentinel Axillary Lymph Nodes in Iranian Women with Breast Cancer

  • Moosavi, Seyed Alireza;Abdirad, Afshin;Omranipour, Ramesh;Hadji, Maryam;Razavi, Amirnader Emami;Najafi, Massoome
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7049-7054
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    • 2014
  • Background: Almost half of the breast cancer patients with positive sentinel lymph nodes have no additional disease in the remaining axillary lymph nodes. This group of patients do not benefit from complete axillary lymph node dissection. This study was designed to assess the clinicopathologic factors that predict non-sentinel lymph node metastasis in Iranian breast cancer patients with positive sentinel lymph nodes. Materials and Methods: The records of patients who underwent sentinel lymph node biopsy, between 2003 and 2012, were reviewed. Patients with at least one positive sentinel lymph node who underwent completion axillary lymph node dissection were enrolled in the present study. Demographic and clinicopathologic characteristics including age, primary tumor size, histological and nuclear grade, lymphovascular invasion, perineural invasion, extracapsular invasion, and number of harvested lymph nodes, were evaluated. Results: The data of 167 patients were analyzed. A total of 92 (55.1%) had non-sentinel lymph node metastasis. Univariate analysis of data revealed that age, primary tumor size, histological grade, lymphovascular invasion, perineural invasion, extracapsular invasion, and the number of positive sentinel lymph nodes to the total number of harvested sentinel lymph nodes ratio, were associated with non-sentinel lymph node metastasis. After logistic regression analysis, age (OR=0.13; 95% CI, 0.02-0.8), primary tumor size (OR=7.7; 95% CI, 1.4-42.2), lymphovascular invasion (OR=19.4; 95% CI, 1.4-268.6), extracapsular invasion (OR=13.3; 95% CI, 2.3-76), and the number of positive sentinel lymph nodes to the total number of harvested sentinel lymph nodes ratio (OR=20.2; 95% CI, 3.4-121.9), were significantly associated with non-sentinel lymph node metastasis. Conclusions: According to this study, age, primary tumor size, lymphovascular invasion, extracapsular invasion, and the ratio of positive sentinel lymph nodes to the total number of harvested sentinel lymph nodes, were found to be independent predictors of non-sentinel lymph node metastasis.

An Improved Time Synchronization Algorithm in Sensor Networks (Sensor Network에서의 개선된 망동기화 알고리즘)

  • Jang, Woo-Hyuk;Kwon, Young-Mi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.9
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    • pp.13-19
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    • 2008
  • Time synchronization of nodes in sensor network synchronizes sensor nodes to one time clock. This is very essential in sensor networks so that the information collected and reported from the sensor nodes becomes meaningful. If sensor nodes are not synchronized, disaster report with time information can be wrong analyzed and this may lead to big calamity. With the limitation of battery and computing power, time synchronization algorithm imported in sensor nodes has to be as simple as it doesn't need big complexity, nor generates many synchronization messages. To reduce the synchronization error, hop count should be kept small between reference node to initiate synchronization and sensor nodes to be synchronized. Therefore, multiple reference nodes are used instead of single reference node. The use of multiple reference nodes introduce the requirement of synchronization among reference nodes in the network. Several algorithms have been proposed till now, but the synchronization among reference nodes are not well considered. This paper proposes improved time synchronization for sensor networks by synchronizing multiple reference nodes inside the network. Through simulation, we validated the effects of new algorithm.

Is Level V Dissection Necessary for Low-risk Patients with Papillary Thyroid Cancer Metastasis in Lateral Neck Levels II, III, and IV

  • Yu, Wen-Bin;Tao, Song-Yun;Zhang, Nai-Song
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.9
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    • pp.4619-4622
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    • 2012
  • Whether it is beneficial to dissect level V in papillary thyroid cancer (PTC) patients with positive lateral neck lymph nodes at levels II-IV is still controversial, especially for low risk cases. In this study, we reviewed the medical records of 47 patients who underwent 47 ipsilateral selective lateral neck dissections (levels II-IV) for previously untreated papillary thyroid carcinomas between October 2006 and October 2008 to assist in establishing the optimal strategy for lateral neck dissection in low risk PTC patients with clinically negative level V nodes. All 47 patients were confirmed to have positive lymph nodes pathologically. Seventeen (36.12%), 36 (76.6%), and 34 (72.34%) patients had positive lymph nodes in levels II, III, and IV, respectively. The mean number of pathologically positive lymph nodes was 1.7 in level II, 2.9 in level III, 2.8 in level IV. No death and distant metastasis were recorded during follow up period. Just 2 patients exhibited recurrence to lymph nodes, and only one showed nodal recurrence in ipsilateral level V, who had positive lymph nodes in all of levels II, III, and IV at initial neck surgery. In conclusion, for PTC low risk patients with clinically negative lymph nodes in level V, non-performance of level V dissection would still achieve good survival results as traditional modified radical neck dissection, with a "wait and see" strategy to be recommended.

A Community-Based Influence Measuring Scheme in Delay-Tolerant Networks (지연 감내 네트워크에서 커뮤니티 기반 영향력 측정 기법)

  • Kim, Chan-Myung;Kim, Yong-Hwan;Han, Youn-Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.1
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    • pp.87-96
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    • 2013
  • Influence propagation is an important research issue in social networks. Influence propagation means that the status or the disposition of nodes get changed by new idea, information and gossip propagated by other nodes. Influenced nodes also make other nodes influenced across the network. The influence propagation problem based on 'word of mouth' referral is to find most influential nodes set in networks to maximize influence. In this paper, we study the influence measuring and finding most influential nodes set in Delay-Tolerant Networks. It is difficult to measure exact influential power in Delay-Tolerant networks where network topology is not stable due to the nodal mobility. In this paper, we propose a distributed scheme that each node constructs $k$-clique community structure and estimates local influential power in Delay-Tolerant Networks. Simulation results show that the influential nodes information estimated by proposed scheme is in agreement with a global view of influential nodes information.