• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.204-216
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• 2010

Since Sensor nodes around a fixed sink have huge concentrated network traffic, the battery consumption of them is increased extremely. Therefore the lifetime of sensor networks is limited because of huge battery consumption. To address this problem, a mobile sink has been studied for load distribution among sensor nodes. Since a mobile sink changes its location in sensor networks continuously, the mobile sink has time limits to communicate with each sensor node and unstable signal strength from each sensor node. Therefore, a fair and stable data collection method between a mobile sink and sensor nodes is necessary in this environment. When some sensor nodes are not able to send data to the mobile sink, a real-time application in sensor networks cannot be provided. In this paper, the new scheduling method, FQMS (Fair Queuing for Mobile Sink), is proposed for fair and stable data collection for mobile sinks in sensor networks. The FQMS guarantees balanced data collecting between sensor nodes for a mobile sink. In out experiments, the FQMS receives more packets from sensor nodes than legacy scheduling methods and provides fair data collection, because moving speed of a mobile sink, distance between a mobile sink and sensor nodes and the number of sensor nodes are considered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.226-231
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• 2016

Binomial trees are used to price barrier options. Since barrier options are path dependent, option values of each node are calculated from binomial trees using backward induction. We use generalized Catalan numbers to determine the number of cases not reaching a barrier. We will generalize Catalan numbers by imposing upper and lower bounds. Reaching a barrier in binomial trees is determined by the difference between the number of up states and down states. If we count the cases that the differences between the up states and down states remain in a specific range, the probability of not reaching a barrier is obtained at a final node of the tree. With probabilities and option values at the final nodes of the tree, option prices are computable by discounting the expected option value at expiry. Without calculating option values in the middle nodes of binomial trees, option prices are computable only with final option values. We can obtain a probability distribution of exercising an option at expiry. Generalized Catalan numbers are expected to be applicable in many other areas.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.49-58
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• 2007

Hierarchical Mobile IPv6 (HMIPv6) has been proposed by Internet Engineering Task Force (IETF) to compensate for such problems as handover latency and signaling overhead in employing Mobile IPv6 (MIPv6). HMIPv6 supports micro-mobility within a domain and introduces a new entity, namely mobility anchor point (MAP) as a local home agent. However, HMIPv6 causes load concentration at a particular MAP and longer handover latency when inter-domain handover occurs. In order to solve such problems, this paper establishes a virtual domain (VD) of a higher layer MAP and proposes a MAP changing algorithm in which the routing path changes between mobile node (MN) and correspondent node(CN) according to the mobile position and the direction of the MN before inter-domain handover occurs. The proposed algorithm not only enables complete handover binding-update of the on-link care of address (LCoA) only when inter-domain handover occurs, but concentrated load of a particular MAP is distributed as well. This is because the MNs registered with higher layer MAP and lower layer MAP coexist in the VD. We simulate the performance of the proposed algorithm and compare with HMIPv6.

• Research in Plant Disease
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• v.10 no.1
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• pp.34-38
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• 2004

The damage of plant growth and alteration of cellular tissues of barley infected by Barley yellow mosaic virus (BaYMV) was explored. The infected plots significantly damaged in all of measured factors by the disease. In severely diseased plant, the viral infection affected on plant growth like as shorten culm length about 25cm, 36％ constrained ratio, comparing to healthy. The yield decreased over 70％ in diseased plots by fewer numbers of spike and kernel per square meter and spike, respectively. BaYMV constructed typical inclusion body like a pinwheel type inside barley leaves, and the infection affected on cellular elongation or growth not cell division in examined three parts as stem, neck of panicle and node, related to dwarfness of infected barley. The stem tissues were most severely affected on cell growth as restrained epidermis cell length in diameter and vascular bundle size. In neck of panicle tissues, distribution and size of tissues of fiber and cortex parts, respectively, showed differences between healthy and infected plants. In node part, healthy plant showed bigger tissue size as 1.5 times than infected plant. Theses results suggest that BaYMV infection could affect on the cell growth not cell division, and which resulted shorten culm length in plant growth and decreased yield, finally.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3333-3338
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• 2015

Background: This study was conducted to analyze positron emission tomography (PET) / computed tomography (CT) and magnetic resonance imaging (MRI) performance with oropharyngeal non-Hodgkin's lymphoma (ONHL).Materials and Methods: The complete image data of 30 ONHL cases were analyzed, all patients were performed PET / CT and MRI examination before the treatment, with the time interval of these two inspections not exceeding 14 days. The distribution, morphology, MRI signal characteristics, enhancement feature, standardized uptake value (SUV) max value and lymph node metastasis way of the lesions were analyzed. Results: Among the 30 cases, 23 cases were derived from the B-cell (76.7%), 5 cases were derived from the peripheral T cells (16.7%) and 2 cases were derived from the NK/T cells (6.7%). 19 cases exhibited the palatine tonsil involvement (63.3%). As for the lesion appearance, 10 cases appeared as mass, 8 cases were the diffused type and 12 cases were the mixed type. 25 cases exhibited the SUVmax value of PET / CT primary lesions as 11 or more (83.3%). MRI showed that all patients exhibited various degrees of parapharyngeal side-compressed narrowing, but MRI still exhibited the high-signal fat, and the oropharyngeal mucosa was intact. 25 cases were associated with the neck lymph node metastasis, among who 22 cases had no necrosis in the metastatic lymph nodes, while the rest 3 cases exhibited the central necrosis in the metastatic lymph nodes. Conclusions: PET / CT and MRI have important value in diagnosing and determining the lesion extent of ONHL.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.803-807
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• 2012

For patients with neck and upper thoracic esophageal carcinoma, it is difficult to control lymph node metastases with conventional dose therapy. In this study, we assessed the feasibility of simplified intensity-modulated radiotherapy (sIMRT) and concurrent chemotherapy for 44 patients and boosted high-dose to metastatic lymph nodes. Three radiation treatment volumes were defined: PGTVnd, with which 68.1Gy was delivered in high dose group (hsIMRT group), and 60Gy in the conventional dose group (csIMRT group); PTV1, featuring 63.9Gy in the hsIMRT group and 60Gy in the csIMRT group; PTV2, with 54Gy given to both groups. The sIMRT plan included 5 equi-angular coplanar beams. All patients received the cisplatin and 5-FU regimen concurrently with radiotherapy. The treatment was completed within six weeks and one case with grade three acute bronchitis was observed in hsIMRT group. For esophageal lesions, 80% complete response (CR) and 20% partial response (PR) rates were found in the hsIMRT group, and 79.2% CR, with 20.8% PR, in the csIMRT group; for lymph node lesions, 75% CR and 25% PR rates were observed in the hsIMRT group, with 45.8% and 37.5% respectively in the csIMRT group (P<0.05). The differences in 1-, 2- and 3-year relapse-free survival rates were all statistically significant (P<0.05). The major toxicity observed in both groups was Grade I~II leucopenia. sIMRT can generate a desirable dose distribution in treatment of neck and upper thoracic esophageal carcinoma with a better short-term efficacy. Boosted high dosing to metastatic lymph nodes can increase the relapse-free survival rate.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.167-179
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• 2005

In hierarchical Mobile IPv4 Networks the highest FA(Foreign Agent) may experience serious congestion and delay since the highest FA plays a role of CoA(Care of Address) for all mobile nodes in the domain, In this paper, we propose mechanism called 'HRFA(Hierarchical Root Foreign Agent)', which distributes the load imposed on the highest FA. In the proposed HRFA scheme, multiple HRFAs are selected to provide the similar service that is provided by the highest FA. According to which entity determines HRFAs, HRFA scheme is categorized into 'Active' and 'Passive' approaches. HRFA scheme is further categorized into 'All MN(Mobile Node)s' and 'New MNs' approaches, depending on which mobile nodes are assigned to a newly elected HRFA. Through a course of simulations, we investigate the performance of 4 possible combinations of HRFA schemes. We also compare the performance of the proposed HRFA schemes with the LMSP(Local Multicast Service Provider) scheme, which is a scheme to distribute the load of FA for multicast service in hierarchical wireless network domain. The simulation results show that the Passive & New MN approach performs best with respect to both the overhead and the load balancing.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.32-40
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• 2006

It is very important to establish a pairwise key securely in wireless sensor networks. Because sensor networks consist of devices with weak physical security, they are likely to be compromised by an attacker. However, some approaches using key pre-distribution and other approaches using one hop local keys are known to be very vulnerable to threats caused by compromised nodes, even a small number. This paper proposes a scheme where each node establishes three hop local keys and employs them for a later pairwise key establishment. When any two nodes agree a pairwise key, all nodes on the route between two nodes contribute to the agreement of the pairwise key. Here, the initial three hop local keys are employed for encrypting a secret key delivered from a node to other nodes. Therefore, the proposed scheme bothers attackers to compromise much more nodes than the scheme using one hop local keys only. The simulation results have proven that the proposed scheme provides better performance and higher security than the scheme using one hop local keys in terms of message exchange, the number of encryption and decryption, and pairwise key exposure rate.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.627-643
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• 1995

The resistance to fracture of the restored tooth may be influenced by many factors, among these are the cavity dimension and the physical properties of the restorative material. The placement of direct composite resin restorations has generally been found to have a strengthening effect on the prepared teeth. It is the purpose of this investigation to study the relationship between the cavity isthmus and the fracture resistance of a tooth in composite resin restorations. In this study, MO cavity was prepared on the maxillary left first molar and then filled with composite resin. Three dimentional model with 3049 nodes and 2450 8-node blick elements was made by the serial photographic method and isthmus (1/4, 1/3, 1/2 and 2/3 of intercusplal distance between mesiobuccal cusp tip and mesiolingual cusp tip) was varied. Two types of model(B and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall and R model was left unfilled. A load of 1500N was applied vertically on the node from the lingual slope of the mesiobuccal cusp. The results were as follows : 1. There was a significant decrease of stress resulting in increase of fracture resistance in B model when compared with R model. 2. When it comes to stress distribution, the stress was concentrated in the facio-gingival line angle and the buccal side of the distal margin of the cavity in both Band R model. 3. With the increase of the isthmus width, the stress decreased in the area of the facio-gingival line angle, and increased in the area of facio-gingival line angle as well as the buccal side of the distal margin of the cavity in B model. In R model, the stress increased both in the area of facio-gingival line angle and the buccal side of the distal margin of the cavity, therefore the possibility of crack increased. 4. As the width of cavity increased, in B model, the direction of crack moved from horizontal to vertical on the facio-gingival line angle and the facio-pulpal line angle. In R model, the direction of the crack was horizontal on the facio-gingival line angle and moved from horizontal to the $45^{\circ}$ direction on the facio-pulpal line angle.

• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1246-1257
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• 2021

Purpose To assess the predictive factors and describe the imaging features of mediastinal lymph node (MLN) metastases in patients with head and neck cancer. Materials and Methods We compared the clinical features and disease characteristics (sex, age, site of primary tumor, histologic type, history of prior treatments, TNM stages, and metastasis in cervical LNs) of patients with head and neck cancers between the MLN metastasis and no MLN metastasis groups. We also evaluated the chest CT (distribution and maximum dimension of the largest LN) and PET/CT (maximum standardized uptake value) features of MLN metastases based on the MLN classification. Results Of the 470 patients with head and neck cancer, 55 (11.7%) had MLN metastasis, involving 150 mediastinal stations. Hypopharynx cancer, recurrent tumor, T4 stage, N2/N3 stages, and M1 stage were found to be significant predicting factors for MLN metastasis. The most common location of MLN metastasis was ipsilateral station 2 (upper paratracheal LNs, 36.4%), followed by ipsilateral station 11 (interlobar LNs, 27.3%) and ipsilateral station 10 (hilar LNs, 25.5%). Conclusion Metastasis to MLNs should be considered in patients with head and neck cancer, especially in cases that are associated with a hypopharyngeal cancer, recurrent tumor, and high TNM stages.