• KIPS Transactions on Computer and Communication Systems
• /
• v.9 no.11
• /
• pp.256-264
• /
• 2020

Industrial Wireless Sensor Networks (IWSNs) is exploited to achieve various objectives such as improving productivity and reducing cost in the diversity of industrial application, and it has requirements such as low-delay and high reliability packet transmission. To accomplish the requirement, the network manager performs graph construction and resource allocation about network topology, and determines the transmission cycle and path of each node in advance. However, this network management scheme cannot treat mobile devices that cause continuous topology changes because graph reconstruction and resource reallocation should be performed as network topology changes. That is, despite the growing need of mobile devices in many industries, existing scheme cannot adequately respond to path failure caused by movement of mobile device and packet loss in the process of path recovery. To solve this problem, a network management scheme is required to prevent packet loss caused by mobile devices. Thus, we analyse the location and movement cycle of mobile devices over time using machine learning for predicting the mobility pattern. In the proposed scheme, the network manager could prevent the problems caused by mobile devices through performing graph construction and resource allocation for the predicted network topology based on the movement pattern. Performance evaluation results show a prediction rate of about 86% compared with actual movement pattern, and a higher packet delivery ratio and a lower resource share compared to existing scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.6
• /
• pp.1-10
• /
• 2009

In a network-based approach such as Proxy Mobile IPv6 (PMIPv6), the serving network controls the mobility management on behalf of a Mobile Node (MN), thereby eliminating a MN from any mobility-related signaling. Although PMIPv6 is being standardized by the IETF NetLMM WG, PMIPv6 still suffers from a lengthy handover latency and the on-the-fly packet loss during a handover. Therefore, this paper presents an enhanced fast handover scheme for PMIPv6. The proposed handover scheme uses the Neighbor Discovery message of IPv6 to reduce the handover latency and packet buffering at the Mobile Access Gateway (MAG) to avoid the on-the-fly packet loss during a handover. In addition, it uses an additional packet buffering at the Local Mobility Anchor (LMA) to solve the packet ordering problem. We evaluate the performance of the proposed handover scheme using both analytical model and simulation. The numerical analysis shows that the proposed scheme has a relatively shorter handover latency. Simulation results demonstrate that the proposed scheme could avoid the on-the-fly packet loss and ensure the packet sequence.

• Journal of Food Hygiene and Safety
• /
• v.33 no.1
• /
• pp.23-30
• /
• 2018

The purpose of this research was to introduce network analysis method for analyzing pesticide residues in incongruity commercial agricultural commodities. Based on the "results in pesticide residues on incongruity commercial agricultural commodities" on "Guidelines for food safety management 2017", we used centrality analysis for pesticide residues via degree, closeness and betweenness centrality measurement. In case of degree centrality result, chlorpyrifos and diazinon were the most highly "connected node" in pesticide network. For the closeness centrality result, the most pesticides showed the similar closeness trend except for 19 species of pesticides. Fludioxonil and chlorpyrifos are recognized as the "bridge" of pesticides network with their high betweenness centrality. The results of network analysis show the "relation" data, which could not represent through out the conventional statistical analysis, among the pesticide residues. We hope that the network analysis method will be appropriate and precise tool for analyzing pesticide residues via elaboration and optimization.

• Journal of KIISE:Information Networking
• /
• v.34 no.1
• /
• pp.1-15
• /
• 2007

Increase in the wireless mobile network users brings the issue of mobility management into the Virtual Private Network (VPN) services. We propose a provider edge (PE)-based provider provisioned mobile VPN mechanism, which enables efficient communication between a mobile VPN user and one or more correspondents located in different VPN sites. The proposed mechanism not only reduces the IPSec tunnel overhead at the mobile user node to the minimum, but also enables the traffic to be delivered through optimized paths among the (mobile) VPN users without incurring significant extra IPSec tunnel overhead regardless of the user's locations. The proposed architecture and protocols are based on the BGP/MPLS VPN technology that is defined in RFC24547. A service provider platform entity named PPVPN Network Server (PNS) is defined in order to extend the BGP/MPLS VPN service to the mobile users. Compared to the user- and CE-based mobile VPN mechanisms, the proposed mechanism requires less overhead with respect to the IPSec tunnel management. The simulation results also show that it outperforms the existing mobile VPN mechanisms with respect to the handoff latency and/or the end-to-end packet delay.

• Korean Journal of Head & Neck Oncology
• /
• v.17 no.2
• /
• pp.205-209
• /
• 2001

Purpose: Most cases of primary hyperparathyroidism are due to parathyroid adenoma or parathyroid hyperplasia. Parathyroid carcinoma is a very rare cause of hyperparathyroidism. Although the diagnosis of parathyroid carcinoma is usually established by pathologic criteria especially of vascular or capsular invasion, some clinical and biochemical features differentiate it from benign forms of hyperparathyroidism. We under-took a retrospective study in 6 patients with parathyroid carcinoma, with the aim of conveying experience from management for this rare cause of hyperparathyroidism. Methods: Clinical symptoms, biochemical laboratory, radiologic, and intraoperative findings, local recurrence and distant metastasis were analyzed in 6 patients diagnosed pathologically as a parathyroid carcinoma after operation from 1992 to 2001. Results: Mean age was 50.2 years (33.0-60.0 years) and male to female ratio was 1:1. Neck mass was found in 5 patients, multiple bone pain in 3 patients and renal stone in 1 patient. One case has suffered from chronic renal failure for 19 years. Although preoperative laboratory evaluations showed the aspects of hyperparathyroidism in all cases, mean serum calcium level was 11.2mg/dl(10.5-12.1mg/dl), slightly elevated. Laboratory values after surgery were within the normal range in 5 cases. However, in one case with chronic renal failure, serum PTH levels, serially checked, were above the normal range. Any of imaging methods failed to suggest a parathyroid carcinoma preoperatively. Parathyroid adenoma was suspected in 3 cases, thyroid cancer in the other cases before surgery. The extent of resection was radical resection of parathyroid lesion with more than unilateral thyroid lobectomy and central compartment neck node dissection and in 2 cases, the resection of recurrent laryngeal nerve or strap muscles was added. During follow-up period, any local or systemic recurrence were not evident in all the cases. Conclusion: Although parathyroid carcinoma is a rare disease and its preoperative diagnosis, in our experience, could not easily be made, the understanding of characteristic clinical and biochemical feature could help diagnosis at first surgery. Radical resection without remaining residual tumor is most important for the management of the parathyroid cancer.

• Journal of KIISE:Information Networking
• /
• v.37 no.1
• /
• pp.72-83
• /
• 2010

Group communication in a wireless mesh network is complicated due to dynamic intermediate mesh points, access control for communications between different administrative domains, and the absence of a centralized network controller. Especially, many-to-many multicasting in a dynamic mesh network can be modeled by a decentralized framework where several subgroup managers control their members independently and coordinate the inter-subgroup communication. In this study, we propose a topology-matching decentralized group key management scheme that allows service providers to update and deliver their group keys to valid members even if the members are located in other network domains. The group keys of multicast services are delivered in a distributed manner using the identity-based encryption scheme. Identity-based encryption facilitates the dynamic changes of the intermediate relaying nodes as well as the group members efficiently. The analysis result indicates that the proposed scheme has the advantages of low rekeying cost and storage overhead for a member and a data relaying node in many-to-many multicast environment. The proposed scheme is best suited to the settings of a large-scale dynamic mesh network where there is no central network controller and lots of service providers control the access to their group communications independently.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.2
• /
• pp.283-294
• /
• 1996

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit control devices located in common manufacturing zone and operated by connecting them. This paper introduces deign and test operation of cell system for the management of multivendor PLC by applying to wall paper process based on the manufacturing standardization of CIM. The analysis of designed multivendor PLC group is performed by selecting the parameters such as variation of data packet size and node number of PLC ladder logic program and variation by analyzing the corresponding variation values of token rotation time and waiting time for the system operation. For the method of the analysis,the equation is considering the overhead such as indicated packet service time and transmission safety margin for PLC network connection in M/G/1 queue model,and it is applied to the cell system and PLC group manage-ment for operation .Through the experiment,it is found that the realtime processing is possible with expanded and better result than the resuit obtained by Jayasumana.Browaka with PLC scan time considered,response lower limit of 10-20 msec. data packet size not more than 50 bytes.and the number of nodes less than 40.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.1
• /
• pp.108-113
• /
• 2012

Routing paths are mightily important for the network security in WSNs. To maintain such routing paths, sustained path re-selection and path management are needed. Region segmentation based path selection method (RSPSM) provides a path selection method that a sensor network is divided into several subregions, so that the regional path selection and path management are available. Therefore, RSPSM can reduce energy consumption when the path re-selection process is executed. However, it is hard to guarantee optimized secure routing path at all times since the information using the path re-selection process is limited in scope. In this paper, we propose partial path selection method in each subregion using preselected partial paths made by RSPSM for routing path optimization in SEF based sensor networks. In the proposed method, the base station collects the information of the all partial paths from every subregion and then, evaluates all the candidates that can be the optimized routing path for each node using a evaluation function. After the evaluation process is done, the result is sent to each super DN using the global routing path information (GPI) message. Thus, each super DN provides the optimized secure routing paths using the GPI. We show the effectiveness of the proposed method via the simulation results. We expect that our method can be useful for the improvement of RSPSM.

• Korean Journal of Head & Neck Oncology
• /
• v.14 no.1
• /
• pp.54-60
• /
• 1998

Objectives: We'd like to give help in diagnosis and treatment of children's thyoid tumor through our clinical experiences and reference consideration. Materials and Methods: The authors report their experiences with 33 cases of thyroid tumor in patients younger than 16 years of age who were treated at Presbyterian Medical Center from 1979 to 1995. Results: 1) Girls were more predominant than boys by a ratio of 5.6:1. The peak incidence was in the 15 years old of age. 2) The final diagnosis in the 33 patients were thyroid carcinoma in 12 cases, nodular goiter in 6 cases, adenoma in 6 cases, Graves disease in 4 cases, Hasimoto's disease in 4 cases and cyst in 1 case. 3) All of 12 patients with thyroid cancer had nodular tumor. 4) In 5 of 6 patients with palpable cervical lymphadenopathy, the final diagnosis was thyroid carcinoma. 5) Delayed diagnosis arose in 6 of 12 thyroid carcinomas which were treated for long periods as benign disease. 6) The surgical procedures were total thyroidectomy in 3 cases, subtotal thyroidectomy in 13 cases and thyroid lobectomy in 17 cases. 7) 11 of 12 patients with thyroid carcinoma had subtotal or total thyroidectomy with lymphnode dissection and only one had lobectomy. 8) The overall rate of postoperative complication was 3%(1 of 33 patient). 9) Postoperative $^{131}I$ therapy was done in 7 case because of recurrence and distant metastasis in six and severe local invasion in one. 10) In thyroid cancer, the metastatic rate of lymph node at initial surgery was 81%(9/11) and rate of recurrence was 50%(6/12). 11) Patients with thyroid carcinoma were followed up for a mean of 12 years but only one died as a result of thyroid carcinoma 3.5 years later. Conclusion: The authors suggest that thyroid tumors in childhood should receive the benifit of joint management by endocrine pediatrician and experianced surgeons with an agreed protocol of diagnosis and management. We, also, recommend aggressive surgical and $^{131}I$ treatment as the most effective regimen for children with thyroid carcinoma.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.5
• /
• pp.468-473
• /
• 2001

Castleman's disease or angiofollicular lymph node hyperplasia, is a rare lymphoproliferative disorder. It may be appear as a local or generalized tumor-like condition, usually in chest or abdomen and may involve both lymph nodes and non-nodal tissues. Castleman's disease is an unusal entity which may at times mimic malignancy but is entirely benign in nature. It is topical as it has been noted to occur with AIDS and Kaposi's sarcoma. Careful interpretation of radiogram may help to distinguish Castleman's disease from other tumor condition, such as lymphoma, neurogenic tumor, or even angiofibroma, etc. But exact diagnosis must be made on the basis of histologic confirmation. In addition to histologic features, clinical distinction between the localized and multicentric form is important in selecting appropriate management. Surgical excision of an localized mass is the first choice of treatment. Partial resection, radiotherapy or observation alone may avoid the need for exessively aggressive therapy. Patients with multicentric disease don't benefit by surgical management because of systemic manifestation and rapid deterioration. Thus, antineoplastic agents and steroids may offer an alternative form of therapy. We report a case of female patient with Castleman's disease in oral and maxillofacial region, treated by surgical excision with good results.