• Korean Journal of Microbiology
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• v.53 no.4
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• pp.257-264
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• 2017

Pseudomonas veronii MS1 and P. migulae MS2 have several mechanisms of copper resistance and plant growth promoting capability, and also can alleviate abiotic stress in plant by hydrolysis of a precursor of stress ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC deaminase. In 4-week pot test for tomato growth in soil contained 700 mg/kg Cu, inoculation of MS1 and MS2 significantly increased root and shoot lengths, wet weight and dry weight of tomato plants compared to those of uninoculated control. The inoculated tomato plants contained less amounts of proline that can protect plants from abiotic stress, and malondialdehyde, an oxidative stress marker than those of control. ACC synthase genes, ACS4 and ACS6, and ACC oxidase genes, ACO1 and ACO4, both involved in ethylene synthesis, were strongly expressed in Cu stressed tomato, whereas significantly reduced in tomato inoculated with MS1 and MS2. Also, a gene encoding a metal binding protein metallothionein, MT2 showed similar expression pattern with above genes. All these results indicated that these rhizobacteria could confer Cu resistance to tomato plant under Cu stress and allowed a lower level of Cu stress and growth promotion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3512-3528
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• 2016

A network with high mobility nodes or vehicles is vehicular ad hoc Network (VANET). For improvement in communication efficiency of VANET, many techniques have been proposed; one of these techniques is vehicular node clustering. Cluster nodes (CNs) and Cluster Heads (CHs) are elected or selected in the process of clustering. The longer the lifetime of clusters and the lesser the number of CHs attributes to efficient networking in VANETs. In this paper, a novel Clustering algorithm is proposed based on Ant Colony Optimization (ACO) for VANET named ACONET. This algorithm forms optimized clusters to offer robust communication for VANETs. For optimized clustering, parameters of transmission range, direction, speed of the nodes and load balance factor (LBF) are considered. The ACONET is compared empirically with state of the art methods, including Multi-Objective Particle Swarm Optimization (MOPSO) and Comprehensive Learning Particle Swarm Optimization (CLPSO) based clustering techniques. An extensive set of experiments is performed by varying the grid size of the network, the transmission range of nodes, and total number of nodes in network to evaluate the effectiveness of the algorithms in comparison. The results indicate that the ACONET has significantly outperformed the competitors.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.117-123
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• 2008

In this paper, we propose a novel ant colony optimization(ACO)-based application core ma ins method for implementing network-on-chip(NoC)-based systems-on-chip(SoCs). The proposed method efficiently put application cores to a mesh-type NoC satisfying a given design objective, the network latency. Experimental results using a functional circuit including 12 cores show that the proposed algorithm can produce near optimal mapping results within a second.

• Journal of Energy Engineering
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• v.5 no.2
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• pp.203-208
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• 1996

An experimental study was conducted on the natural convection heat transfer with a heat source (heater) in a top-vented cylindrical enclosure. Using an Air Controlled Oxidizer (ACO) for treatment of depleted uranium chips, the heat transfer characteristics of the ACO was studied with various heat generation. Heat flux, Nusselt number, Grashof number and Rayleigh number were obtained and the relation between Nusselt number and Rayleigh number was derived.

• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.568-571
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• 2009

Accessory middle cerebral artery (MCA) is an infrequent vascular anomaly of the brain. Cerebral aneurysms associated with this anomalous artery are also very rare. To our knowledge, there have only been ten previous reports of an aneurysm associated with accessory MCA. The authors present two patients with accessory MCA-related aneurysms. A 38-year-old male and a 59-year-old female both presented with sudden-onset severe headache. In both patients, computed tomography (CT) scan revealed subarachnoid hemorrhage. A subsequent angiogram demonstrated an accessory MCA arising from the anterior cerebral artery (ACA) and a saccular aneurysm at the anterior communicating artery (ACoA) complex associated with an accessory MCA. Surgical clipping allowed for complete exclusion of the aneurysm from the arterial circulation. Based on our review of the ten cases of aneurysms associated with accessory MCA documented in the literature, we suggest that accessory MCA-related aneurysms can be classified according to whether the accessory MCA originates from the proximal A1 segment or from the ACoA complex. We also emphasize the importance of precise interpretation of preoperative angiograms and intraoperative precaution in determining the presence of this anomalous artery prior to temporary clip placement.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.260-263
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• 2009

Internal carotid artery (ICA) trapping can be used for treating intracranial giant aneurysm, blood blister-like aneurysms and ICA rupture during the surgery. We present a novel ICA trapping technique which can be used with insufficient collaterals flow via anterior communicating artery (AcoA) and posterior communicating artery (PcoA). A patient was admitted with severe headache and the cerebral angiography demonstrated a typical blood blister-like aneurysm at the contralateral side of PcoA. For trapping the aneurysm, the first clip was placed at the ICA just proximal to the aneurysm whereas the distal clip was placed obliquely proximal to the origin of the PcoA to preserve blood flow from the PcoA to the distal ICA. The patient was completely recovered with good collaterals filling to the right ICA territories via AcoA and PcoA. This technique may be an effective treatment option for trapping the aneurysm, especially when the PcoA preservation is mandatory.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.88-90
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• 2010

Retroperitoneal hematoma (RH) due to radiologic intervention for an intracranial lesion is relatively rare, difficult to diagnose, and can be lifethreatening. We report a case of RH that developed in a patient on anticoagulant therapy following endovascular coiling of a ruptured anterior communicating artery (AcoA) aneurysm. An 82-year-old man presented with a 12-day history of headache. Computed tomography (CT) on admission demonstrated slight subarachnoid hemorrhage, and left carotid angiography revealed an AcoA aneurysm. The next day, the aneurysm was occluded with coils via the femoral approach under general anesthesia. The patient received a bolus of 5,000 units of heparin immediately following the procedure, and an infusion rate of 10,000 units/day was initiated. The patient gradually became hypotensive 25 hours after coiling. Abdominal CT showed a huge, high-density soft-tissue mass filling the right side of the retroperitoneum space. The patient eventually died of multiple organ failure five days after coiling. RH after interventional radiology for neurological disease is relatively rare and can be difficult to diagnose if consciousness is disturbed. This case demonstrates the importance of performing routine physical examinations, sequentially measuring the hematocrit and closely monitoring systemic blood pressures following interventional radiologic procedures in patients with abnormal mental status.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3496-3514
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• 2015

One of the challenging tasks in Mobile Ad hoc Network is to discover precise optimal routing solution due to the infrastructure-less dynamic behavior of wireless mobile nodes. Ant Colony Optimization, a swarm Intelligence technique, inspired by the foraging behaviour of ants in colonies was used in the past research works to compute the optimal path. In this paper, we propose a Recurrent Ant Colony Optimization (RECACO) that executes the actual Ant Colony Optimization iteratively based on recurrent value in order to obtain an optimal path convergence. Each iteration involves three steps: Pheromone tracking, Pheromone renewal and Node selection based on the residual energy in the mobile nodes. The novelty of our approach is the inclusion of new pheromone updating strategy in both online step-by-step pheromone renewal mode and online delayed pheromone renewal mode with the use of newly proposed metric named ELD (Energy Load Delay) based on energy, Load balancing and end-to-end delay metrics to measure the performance. RECACO is implemented using network simulator NS2.34. The implementation results show that the proposed algorithm outperforms the existing algorithms like AODV, ACO, LBE-ARAMA in terms of Energy, Delay, Packet Delivery Ratio and Network life time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4661-4676
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• 2014

In Wireless Mesh Networks (WMN), an authentication technique can be compromised due to the distributed network architecture, the broadcast nature of the wireless medium and dynamic network topology. Several vulnerabilities exist in different protocols for WMNs. Hence, in this paper, we propose trust based authentication and key establishment for secure routing in WMN. Initially, a trust model is designed based on Ant Colony Optimization (ACO) to exchange the trust information among the nodes. The routing table is utilized to select the destination nodes, for which the link information is updated and the route verification is performed. Based on the trust model, mutual authentication is applied. When a node moves from one operator to another for accessing the router, inter-authentication will be performed. When a node moves within the operator for accessing the router, then intra-authentication will be performed. During authentication, keys are established using identity based cryptography technique. By simulation results, we show that the proposed technique enhances the packet delivery ratio and resilience with reduced drop and overhead.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.7-13
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• 2008

This paper suggests a Path-planning algorithm for mobile agents. While there are a lot of studies on the path-planning for mobile agents, mathematical modeling of complex environment which constrained by spatio-temporally is very difficult and it is impossible to obtain the optimal solutions. In this paper, an optimal path-planning algorithm based on the graphic technique is presented. The working environment is divided into two areas, the one is free movable area and the other is not permissible area in which there exist obstacles and spatio-temporally constrained, and an optimal solution is obtained by using a new algorithm which is based on the well known ACO algorithm.