• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.219-228
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• 2007

End-to-end path setup and maintenance are very important for mobile ad-hoc wireless communications, because of the mobility and the limited battery capacity of the nodes in the networks. the AODV routing protocol is the one of mary proposed protocols. However, there are route failure problem with the Proposed protocols between intermediate nodes due to such mobility and exhausted battery characteristics, and this is because only the shortest hop count is considered for the route setup. If route failure happens. Problem such as the waste of bandwidth and the increment of the energy consumption occur because of the discarding data packets in the intermediate nodes and the path re-setup process required by the source node. In addition, it obviously causes the network lifetime to be shortened. This paper proposes a routing protocol based on the AODV routing protocol that it makes use of the remaining energy, signal strength and SNR of the MAC layer resources to setup a path.

• Radiation Oncology Journal
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• v.35 no.1
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• pp.39-47
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• 2017

Purpose: The purpose of this study was to analyze clinical outcomes from cervical cancer and stratify patients into risk groups for prognostic factors for early-stage disease. Materials and Methods: We retrospectively reviewed patients with stage IB or IIA cervical cancer treated with adjuvant radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) following primary surgery at Samsung Medical Center from 2001 to 2011. Adjuvant RT was added for patients with intermediate-risk factors, and adjuvant CCRT was performed on high-risk patients after surgery. Results: We reviewed 247 patients-149 in the high-risk group and 98 in intermediate-risk group. The median follow-up was 62 months. Loco-regional failure (LRF) alone occurred in 7 patients (2.8%), distant metastasis alone in 37 patients (15.0%) and LRF with DM in 4 patients (1.6%). The 5-year disease-free survival (DFS) and overall survival (OS) rates for both groups were 79.7% and 87.6%, respectively. In the high-risk group, the 5-year DFS and OS probabilities were 72.5% and 81.9%, respectively. Histologic type, pathologic tumor size, and the number of pelvic lymph node (PLN) metastasis were significant prognostic factors for DFS and OS. We suggest a scoring system (0-3) using these prognostic factors to predict poor prognosis in high-risk patients. Using this system, patients with higher scores have higher recurrence and lower survival rates. Conclusion: In the high-risk cervical-cancer group who received primary surgery and adjuvant CCRT, non-squamous type, large tumor size and the number of PLN metastasis were significant prognostic factors, and the number of these factors was associated with survival rates.

• Journal of KIISE:Information Networking
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• v.33 no.6
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• pp.428-437
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• 2006

Wireless ad-hoc routing has been extensively studied and many clever schemes have been proposed over the last several years. One class of ad-hoc routing is geographic routing where each intermediate node independently selects the next hop using the given location information of destination. Geographic routing, which eliminates the overhead of route request packet flooding, is scalable and suitable for large scale ad hoc networks. However, geographic routing may select the long detour paths when there are voids between a source and a destination. In this paper, we propose a novel geographic routing approach called Geographic Landmark Routing(GLR). GLR recursively discovers the intermediate nodes called landmarks and constructs sub-paths that connect the subsequent landmarks. Simulation results on various network topologies show that GLR significantly improves the performance of geographic routing.

• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.213-220
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• 2008

A MANET is an autonomous, infrastructureless system that consists of mobile nodes. In MANET, on-demand routing protocols are usually used because network topology changes frequently. The current approach in case of broken routes is to flag an error and re-initiate route discovery either at the source or at the intermediate node. Repairing these broken links is a costly affair in terms of routing overhead and delay involved. Therefore, this paper propose a NAODV(Neighbor-aware AODV) protocol that stands on the basis of an AODV. It sets up the route rapidly if it operates for setting the route directly by using sequence number of neighbor nodes without re-search the route when the route to destination node is broken. Also, it reduces loss of packets. We use NS-2 for the computer simulation and validate that the proposed scheme is better than general AODV in terms of packet delivery ratio and average end-to-end delay. Also, when the proposed protocol is applied to the large ad-hoc network with multiple nodes, the performance is more efficient.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.561-578
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• 2010

This study proposes a multi-level damage localization strategy to achieve an effective damage detection system for civil infrastructure systems based on wireless sensors. The proposed system is designed for use of distributed computation in a wireless sensor network (WSN). Modal identification is achieved using the frequency-domain decomposition (FDD) method and the peak-picking technique. The ASH (angle-between-string-and-horizon) and AS (axial strain) flexibility-based methods are employed for identifying and localizing damage. Fundamentally, the multi-level damage localization strategy does not activate all of the sensor nodes in the network at once. Instead, relatively few sensors are used to perform coarse-grained damage localization; if damage is detected, only those sensors in the potentially damaged regions are incrementally added to the network to perform finer-grained damage localization. In this way, many nodes are able to remain asleep for part or all of the multi-level interrogations, and thus the total energy cost is reduced considerably. In addition, a novel distributed computing strategy is also proposed to reduce the energy consumed in a sensor node, which distributes modal identification and damage detection tasks across a WSN and only allows small amount of useful intermediate results to be transmitted wirelessly. Computations are first performed on each leaf node independently, and the aggregated information is transmitted to one cluster head in each cluster. A second stage of computations are performed on each cluster head, and the identified operational deflection shapes and natural frequencies are transmitted to the base station of the WSN. The damage indicators are extracted at the base station. The proposed strategy yields a WSN-based SHM system which can effectively and automatically identify and localize damage, and is efficient in energy usage. The proposed strategy is validated using two illustrative numerical simulations and experimental validation is performed using a cantilevered beam.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.504-510
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• 2016

This study was investigated to find the effects of sowing time on growth and yields of cowpea grown in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (Latitude 35° 04' N, Longitude 126° 54' E) during 2013 and 2014. The intermediate-erect type strains used in this study were Jeonnam1 and Jeonnam2 (Okdang). Sowing time was performed between middle-April and middle-August at intervals of one month. The days from sowing to emergence was significantly higher in the middle-April sowing (12 days) time but there was no significant differences other sowing dates (5 to 3 days). The days from sowing to first flowering were shorter for sowing dates between middle-April and middle-July because sowing time was delayed and then were lengthened again at middle-August sowing; the days were longest at middle-April sowing (around 62 days) and were shortest at middle-July sowing (35 days). The days from first flowering to harvesting were short for the sowing dates between middle-April and middle-July (17 to 15 days) but were relatively long for middle-August sowing date (24 days). Stem length was relatively long for the middle-May and middle-June sowing dates. Peduncle length was relatively long for the middle-April sowing date. Main-stem node number was highest for the middle-July sowing. Branch number per plant was highest in the middle-April sowing. Seed yields were highest for the middle-April sown Jeonnam1 and the Jeonnam2 (Okdang) strains showing, 199 and 211 kg/10a, respectively, and then followed by sowing in middle-July, 191 and 195 kg/10a, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.678-690
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• 2014

The current networks do not disclose information about a management domain due to scalability, manageability and commercial reasons. Therefore, it is very hard to calculate an optimal path to the destination. Also, due to poor information sharing, if an error occurs in the intermediate path, it is very difficult to re-search the path and find the best path. Hence, to manage each domain more efficiently, an architecture with top-level path computation node which can obtain information of separate nodes are highly needed This study aims to investigate a federation of a united network around NRN(National Research Network) that could allow resource sharing between countries and also independent resource management for each country. Considering first the aspects that can be accessed from the perspective of a national research network, ICE(Information Control Element) and GFO(Global Federation Organizer)-based architecture is designed as a top-level path computation element to support traffic engineering and applied to the multi-domain network. Then, the federation for the independent management of resources and resource information sharing among national research networks have been examined.

• Computational Structural Engineering : An International Journal
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• v.1 no.2
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• pp.89-96
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• 2001

A study on the topology optimization of a Hard-Disk-Driver(HDD) actuator arm is presented. The purpose of the present wert is to increase the natural frequency of tole first lateral mode of the HDD actuator arm under the constraint of total moment of inertia, so as to facilitate the position control of the high speed actuator arm. The first lateral mode is an important factor in the position control process. Thus the topology optimization for 2-D model of the HDD actuator arm is considered. A new objective function corresponding to multieigenvalue optimization is suggested to improve the solution of the eigenvalue optimization problem. The material density of the structure is treated as the design variable and the intermediate density is penalized. The effects of different element types and material property functions on the final topology are studied. When the problem is discretized using 8-node element of a uniform density, tole smoothly-varying density field is obtained without checker-board patterns incurred. AS a result of 7he study, an improved design of the HDD actuator arm is suggested. Dynamic characteristics of the suggested design are compared computationally with those of the old design. With the same amount of the moment of inertia, the natural frequency of the first lateral mode of the suggested design is subsequently increased over the existing one.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.804-809
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• 2001

In this paper, a shared channel scheme and routing algorithms are proposed to reduce the number of wavelength channels for the optical WDM multihop networks using the every-other-row-connecting bilayered ShuffleNet scheme. In the shared channel scheme proposed, 2P nodes share the common wavelength channel reducing the number of required channels compare to other ones. By assigning an effective address each node, packets can be routed to the destination nodes through the intermediate nodes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.271-287
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• 2013

We propose a new multipath-based reliable routing protocol on MANETs, Multipath-based Reliable routing protocol with Fast-Recovery of failures (MRFR). For reliable message transmission, MRFR tries to find the most reliable path between a source and a destination considering the end-to-end packet reception reliability of the routes. The established path consists of a primary path that is used to transmit messages, and the secondary paths that are used to recover the path when detecting failures on the primary path. After establishing the path, the source transmits messages through the primary path. If a node detects a link failure during message transmission, it can recover the path locally by switching from the primary to the secondary path. By allowing the intermediate nodes to locally recover the route failure, the proposed protocol can handle the dynamic topological change of the MANETs efficiently. The simulation result using the QualNet simulator shows that the MRFR protocol performs better than other protocols in terms of the end-to-end message delivery ratio and fault-tolerance capability.