• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.755-762
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• 2003

For the route optimization in the MIPv6, MN(Mobile Node) sends CN(Correspondent Node) a binding update message to notify the binding of is HoA(Home Address) with its new CoA(Care-of Address). However, unautenticated binding updates expose the involved MN and CM to various sucurity attacks. Thus, protecting the binding update process becomes of paramount importance in the MIPv6, and several secure binding update protocols, and the performance of packet exchanges and cryptographic operations. Then, we analyze the four typical binding update protocols based on the presented criterions. In addition, we propose some improvement tips for secure binding updates.

• Journal of Internet of Things and Convergence
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• v.10 no.4
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• pp.71-76
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• 2024

The importance of location-based services has been steadily rising, leading to the increased integration of Ultra-Wideband (UWB) technology in mobile devices and vehicles. Conventional UWB-based positioning systems typically determine the distance and direction between devices or track locations by pre-installing UWB anchors in environments like buildings or factories. This paper analyzes the characteristics of a distributed node-based Anchor-less UWB positioning system, measuring its actual ranging period and distance estimation error with varying node numbers and configured ranging periods. Experimental results show that even without anchors or node synchronization, the system achieves an average error of 0.32 meters.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6287-6292
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• 2013

Background: Surgery is the only curative treatment for operable non-small lung cancer (NSCLC) and the importance of adjuvant chemotherapy for stage IB patients is unclear. Herein, we evaluated prognostic factors for survival and factors related with adjuvant treatment decisions for stage I and IIA NSCLC patients without lymph node metastasis. Materials and Methods: We retrospectively analyzed 302 patients who had undergone curative surgery for prognostic factors regarding survival and clinicopathological factors related to adjuvant chemotherapy. Results: Nearly 90% of the patients underwent lobectomy or pneumonectomy with mediastinal lymph node resection. For the others, wedge resection were performed. The patients were diagnosed as stage IA in 35%, IB in 49% and IIA in 17%. Histopathological type (p=0.02), tumor diameter (p=0.01) and stage (p<0.001) were found to be related to adjuvant chemotherapy decisions, while operation type, lypmhovascular invasion (LVI), grade and the presence of recurrence were important factors in predicting overall survival (OS), and operation type, tumor size greater than 4 cm, T stage, LVI, and visceral pleural invasion were related with disease free survival (DFS). Multivariate analysis showed operation type (p<0.001, hazard ratio (HR):1.91) and the presence of recurrence (p<0.001, HR:0.007) were independent prognostic factors for OS, as well visceral pleural invasion (p=0.01, HR:0.57) and LVI (p=0.004, HR:0.57) for DFS. Conclusions: Although adjuvant chemotherapy is standard for early stage lymph node positive NSCLC, it has less clear importance in stage I and IIA patients without lymph node metastasis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.37-46
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• 2007

The authentication in WSN(Wireless Sensor Network) usually means the entity authentication, but owing to the data centric nature of sensor network, much more importance must be put on the authentication(or attestation) for code of sensor nodes. The naive approach to the attestation is for the verifier to compare the previously known memory contents of the target node with the actual memory contents in the target node, but it has a significant drawback. In this paper, we show what the drawback is and propose a countermeasure. This scheme can verify the whole memory space of the target node and provides extremely low probability of malicious code's concealment without depending on accurate timing information unlike SWATT. We provide two modes of this verification method: BS-to-node and node-to-node. The performance estimation in various environments is shown.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.209-216
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• 2013

In traditional social network analysis, the betweenness centrality measure has been heavily used to identify the relative importance of nodes in terms of message delivery. Since the time complexity to calculate the betweenness centrality is very high, however, it is difficult to get it of each node in large-scale social network where there are so many nodes and edges. In this paper, we define a new type of network, called the expanded ego network, which is built only with each node's local information, i.e., neighbor information of the node's neighbor nodes, and also define a new measure, called the expended ego betweenness centrality. Through the intensive experiment with Barab$\acute{a}$si-Albert network model to generate the scale-free networks which most social networks have as their embedded feature, we also show that the nodes' importance rank based on the expanded ego betweenness centrality has high similarity with that based on the traditional betweenness centrality.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1665-1667
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• 2013

Background: Ten to 30% of early breast cancer (EBC) patients develop brain metastasis (BM) during their follow-up. In this study, we aimed to evaluate importance of the lymph node ratio (LNR) in development of BM in EBC cases. Materials and Methods: Ninety patients whom had axillary metastases in lymph nodes at their initial diagnosis and developed BM during 5-year follow-up were detected in 950 EBC patients. LNR values were calculated for all patients and after categorization into 4 molecular sub-types as luminal A, luminal B HER-2 (+), HER-2 overexpressing and basal- like. Comparison was with control group patients who had similar characteristics. Results: In the comparison of all molecular sub-types of LNR, 54.9% and 28.4% values were found in patients with and without BM respectively (p<0.001). In the comparison of the LNR with control groups, a statistically significant differences were found with luminal A with BM (p=0.001), luminal B HER-2 (p=0.001), HER-2 overexpressing (p=0.027) and basal-like groups (p<0.001). In the evaluation of patients with BM, the highest ratio was found in the basal-like group (67.9%) and there was a statistically significant difference between this group and the others (p=0.048). Conclusions: EBC patients developing BM within 5 years follow-up had significantly higher LNRs for all molecular sub-types, especially in the basal-like group. Larger scale studies are now needed for evaluating LNR prognostic importance for EBC regarding BM development.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.407-415
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• 2007

In parallel cluster computing systems, the efficiency of communication between computing nodes is one of important factors that decide overall system performance. Accordingly, many researchers have studied on high-performance inter-node communication. The recently launched multi-core processor, however. increases the importance of intra-node communication as well because the more the number of cores in a node, the more the number of parallel processes running in the same node. Though there have been studies on intra-node communications, these have limited considerations on the state-of-the-art systems. In this paper, we propose a Linux kernel module that minimizes the number of data copy by exploiting the memory mapping mechanism for high-performance intra-node communication. The proposed kernel module supports the Linux kernel version 2.6. The performance measurements over a multi-core system present that the proposed kernel module can achieve lower latency up to 62% and higher throughput up to 144% than an existing kernel module approach. In addition, the measurements reveal that the performance of intra-node communication can vary significantly based on whether the cores that run the communication processes are belong to the same processor package (i.e., sharing the L2 cache).

• Radiation Oncology Journal
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• v.37 no.1
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• pp.51-59
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• 2019

Purpose: We evaluated failure pattern and treatment outcomes of observational approach on regional lymph node (LN) in cutaneous melanoma of extremities and sought to find clinico-pathologic factors related to LN metastases. Material and Methods: We retrospectively reviewed 73 patients with cutaneous melanoma of extremities between 2005 and 2016. If preoperative 18-F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) findings were non-specific for regional LNs, surgical resection of primary tumors with adequate margins was performed without sentinel lymph node biopsy (SLNB) and/or complete lymph node dissection (CLND), irrespective of tumor thickness or size. In patients with suspicious or positive findings on PET/CT or CT, SLNB followed by CLND or CLND was performed at the discretion of the surgeon. We defined LN dissection (LND) as SLNB and/or CLND. Results: With a median follow-up of 38 months (range, 6 to 138 months), the dominant pattern of failure was regional failure (17 of total 23 events, 74%) in the observation group (n = 56). Pathologic LN metastases were significant factor for poor regional failure-free survival (hazard ration [HR] = 3.21; 95% confidence interval [CI], 1.03-10.33; p = 0.044) and overall survival (HR = 3.62; 95% CI, 1.02-12.94; p = 0.047) in multivariate analysis. In subgroup analysis for cN0 patients according to the preoperative PET/CT findings, LND group showed the better trend of LRFFS (log rank test, p = 0.192) and RFFS (p = 0.310), although which is not statistically significant. Conclusion: Observational approach on regional LNs on the basis of the PET/CT in patients with cutaneous melanoma of extremities showed the dominant regional failure pattern compared to upfront LND approach. To reveal regional lymph node status, SLND for cN0 patients may of importance in managing cutaneous melanoma patients.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1077-1093
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• 2013

This paper proposes a new network coordinator node design to select the most suitable wireless technology for WBANs by using fuzzy logic. Its goal is to select a wireless communication technology available considering the user/application requirements and network conditions. A WBAN is composed of a set of sensors placed in, on, or around human body, which monitors the human body functions and the surrounding environment. In an effort to send sensor readings from human body to medical center or a station, a WBAN needs to stay connected to a local or a wide area network by using various wireless communication technologies. Nowadays, several wireless networking technologies may be utilized in WLANs and/or WANs each of which is capable of sending WBAN sensor readings to the desired destination. Therefore, choosing the best serving wireless communications technology has critical importance to provide quality of service support and cost efficient connections for WBAN users. In this work, we have developed, modeled, and simulated some networking scenarios utilizing our fuzzy logic-based NCN by using OPNET and MATLAB. Besides, we have compared our proposed fuzzy logic based algorithm with widely used RSSI-based AP selection algorithm. The results obtained from the simulations show that the proposed approach provides appropriate outcomes for both the WBAN users and the overall network.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.4
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• pp.107-121
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• 2015

Diffusion of innovation is the process in which an innovation is communicated through certain channels over time among the members of a social system. The literatures have emphasized the importance of interpersonal network influences on individuals in convincing them to adopt innovations and thereby promoting its diffusion. In particular, the behavior of opinion leaders who lead in influencing others' opinion is important in determining the rate of adoption of innovation in a system. Centrality has been recognized as a good indicator that quantifies a node's influences on others in a given network. However, recent studies have questioned its relevance on various different types of diffusion processes. In this regard, this study aims at examining the effect of a node exhibiting high centrality on expediting diffusion of innovations. In particular, we considered the situation where two innovations compete with each other to be adopted by potential adopters who are personally connected with each other. In order to analyze this competitive diffusion process, we developed a simulation model and conducted regression analyses on the outcomes of the simulations performed. The results suggest that the effect of a node with high centrality can be substantially reduced depending upon the type of a network structure or the adoption thresholds of potential adopters in a network.