• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.5
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• pp.615-620
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• 2005

Sensor networks are usually composed of tens or thousands of tiny devices with limited resources. Because of their limited resources, there will often be some faulty nodes within the network. As nodes in some certain regions rely on each other to route the information gathered by different sensors to a base station (sink), the network should be able to detect a non-operational node in order to determine new paths for routing the information. Failure detection, which identifies the faulty nodes, is rather necessary in sensor networks and a very important research issue. The detection of a non-operational node can be performed using Consensus Algorithm with the purpose of achieving agreement about a node which is supposed to be faulty (non-operational). In this work, we discuss the application of a Consensus Algorithm to sensor node called 'mote'. Our experimental results show that it works efficiently for identifying faulty nodes in sensor networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1799-1805
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• 2007

Wireless Ad-hoc networks may contain nodes of various types of which many can have limited power capabilities. A failure of a node due to energy exhaustion may impact the performance of the whole network hence, energy must be conserved. In this paper, we propose a Delay and Energy-Aware Routing (DEAR) algorithm a multiple metric path cost routing algorithm which considers not only the energy consumed by the node during transmission and reception but as well as the residual energy of the node and the delay incurred during route discovery. Based on our results, DEAR algorithm performs well and maximizes network lifetime by routing flows to nodes with sufficient energy such that the energy consumption is balanced among nodes in proportion to their energy reserves.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3369-3385
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• 2019

There are various research challenges in vehicular ad hoc networks (VANETs) that need to be focused until an extensive deployment of it becomes conceivable. Design and development of a scalable routing algorithm for VANETs is one of the critical issue due to frequent path disruptions caused by the vehicle's mobility. This study aims to provide a novel road-aware routing protocol for vehicular networks named as Two-level hierarchical Hybrid Road-Aware (THERA) routing for vehicular ad hoc networks. The proposed protocol is designed explicitly for inter-vehicle communication. In THERA, roads are distributed into non-overlapping road segments to reduce the routing overhead. Unlike other protocols, discovery process does not flood the network with packet broadcasts. Instead, THERA uses the concept of Gateway Vehicles (GV) for the discovery process. In addition, a route between source and destination is flexible to changing topology, as THERA only requires road segment ID and destination ID for the communication. Furthermore, Road-Aware routing reduces the traffic congestion, bypasses the single point of failure, and facilitates the network management. Finally yet importantly, this paper also proposes a probabilistical model to estimate a path duration for each road segment using the highway mobility model. The flexibility of the proposed protocol is evaluated by performing extensive simulations in NS3. We have used SUMO simulator to generate real time vehicular traffic on the roads of Gangnam, South Korea. Comparative analysis of the results confirm that routing overhead for maintaining the network topology is smaller than few previously proposed routing algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4606-4623
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• 2019

Nowadays modern cities develop in a very rapid speed. Buildings become larger than ever and the interior structures of the buildings are even more complex. This drives a high demand for precise and accurate indoor navigation systems. Although the existing commercially available 2D indoor navigation system can help users quickly find the best path to their destination, it does not intuitively guide users to their destination. In contrast, an indoor navigation system combined with augmented reality technology can efficiently guide the user to the destination in real time. Such practical applications still have various problems like position accuracy, position drift, and calculation delay, which causes errors in the navigation route and result in navigation failure. During the navigation process, the large computation load and frequent correction of the displayed paths can be a huge burden for the terminal device. Therefore, the navigation algorithm and navigation logic need to be improved in the practical applications. This paper proposes an improved navigation algorithm and navigation logic to solve the problems, creating a more accurate and effective augmented reality indoor navigation system.

• Coupled systems mechanics
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• v.12 no.6
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• pp.503-517
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• 2023

Standard Digital Volume Correlation (DVC) approaches are based on pattern matching between two reconstructed volumes acquired at different stages. Such frameworks are limited by the number of scans (due to acquisition duration), and time-dependent phenomena can generally not be captured. Projection-based Digital Volume Correlation (P-DVC) measures displacement fields from series of 2D radiographs acquired at different angles and loadings, thus resulting in richer temporal sampling (compared to standard DVC). The sought displacement field is decomposed over a basis of separated variables, namely, temporal and spatial modes. This study utilizes an alternative route in which spatial modes are con-structed via scan-wise DVC, and thus only the temporal amplitudes are sought via P-DVC. This meth-od is applied to a glass fiber mat reinforced polymer specimen containing a machined notch, subjected to in-situ cyclic tension, and imaged via X-Ray Computed Tomography. Different temporal interpolations are exploited. It is shown that utilizing only one DVC displacement field (as spatial mode) was sufficient to properly capture the complex kinematics up to specimen failure.

• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.533-546
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• 2008

The efficacy of bovine immune sera to correct the calves with failure of passive transfer(FPT) was evaluated. Immune sera were produced from 14 one-year-old Holstein cattle which were inoculated commercial combined viral vaccine, administered by the challenge of some main enteric or respiratory viruses, aseptically filtered and stored at $4^{\circ}C$ before used. After the treatment of bovine immune sera, Mean transfer factor($mg/d{\ell}$, of IgG administered/kg of body weight) was $5.46{\pm}2.74,\;11.17{\pm}1.27,\;1.40{\pm}0.21$ in K-IP, H-IP and K-IV group, respectively. The corrective effect of bovine immune sera to FPT calf without any clinical signs showed that intravenous route was more effective than intraperitoneal administration(P<0.01). FPT calves with severe signs were not effective response to the immunotherapy used and consequently died within 10 days after the treatment. Ten percentage of controls appeared the clinical signs including diarrhea. On the contrary, there were not any clinical signs in K-IP and H-IV group. There was significant increase of the neutralizing titer against bovine viral diarrhea virus and bovine coronavirus as well as of cell population including CD2, CD4, and monocyte in K-IP and H-IV group after the immunotherapy(P<0.05). Also, K-IP and H-IV group showed the successful correction to FPT within one week after the immunotherapy, but controls had kept the FPT two-four weeks even after the same treatment. Consequently, the results were suggesting that the bovine immune sera could be used the corrective tool to young calves with FPT.

• Journal of The Korean Society of Clinical Toxicology
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• v.5 no.1
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• pp.36-42
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• 2007

Purpose: To assess the epidemiology and the clinical features of Glufosinate herbicide in Korea. Methods: Data was prospectively collected during 1 year since August 2005 from 38 hospital in Korea. We analyzed the epidemiologic characters and clinical manifestations of Glufosinate poisoning. In addition, the characteristics of patients with severe central nervous system toxicity were separately analyzed to find poor prognosis relating factors. Results: During study periods, there were 715 persons of poisoning of herbicides and insecticides. 6.3% (45 persons) of the agricultural chemicals poisoning had Glufosinate poisoning. There were 36 cases of suicide attempts and 7 cases of accidental exposure, The major of poisoning route was oral ingestion (44 cases). 28.9 % of the study patients had not toxic symptoms. The most common symptoms were gastrointestinal symptoms relating surfactant irritation. 67.7% of central nervous symptoms occurred lately. 10 persons showed severe central nervous system toxicity. 4 persons of them showed poor outcomes (1 death, 3 hopeless discharged). Complications of respiratory failure and renal failure related with poor outcome. Conclusion: Majority of patients ingested Glufosinate for suicide attempt. 22.2% of patients with Glufosinate poisoning showed delayed serious central nervous system toxicity. Early supportive care of altered mentality may prevent late respiratory complications and improve the outcomes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.1
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• pp.51-56
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• 1983

The recent work on symptomatology and therapy of essential fatty acid (EFA) deficience has been reviewed. EFA deficiency is due to an absence of dietary linoleic acid which cannot be synthesized endogenously in man. The diagnosis of EFA deficiency is based on clinical features such as the appearance of scaly skin rash, sparse hair growth or failure to thrive, which occur late in the course of EFA deficiency and biochemical features occurring within two weeks of fat-free diet. The amount of linoleic acid required to prevent EFA deficiency varies with age of the patient and route of fat administration.

• Journal of Internet Computing and Services
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• v.8 no.5
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• pp.133-140
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• 2007

Currently, as the requirement for high quality Internet access from anywhere at anytime is consistently increasing, the interconnection of pure ad hoc networks to fixed IP networks becomes increasingly important. Such integrated network, referred to as hybrid ad hoc networks, can be extended to many applications, including Sensor Networks, Home Networks, Telematics, and so on. We focus on some data communication problems of hybrid ad hoc networks, such as broadcasting and routing. In particular. power failure of mobile terminals is the most important factor since it affects the overall network lifetime. We propose an energy-efficient routing protocol based on clustering for hybrid ad hoc networks. By applying the index-based data broadcasting and selective tuning methods, the infra system performs the major operations related to clustering and routing on behalf of ad hoc nodes. The proposed scheme reduces power consumption as well as the cost of path discovery and maintenance, and the delay required to configure the route.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1019-1023
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• 2000

Objective : Endoscopic third ventriculostomy is gaining popularity as a minimally invasive surgical option for certain types of hydrocephalus as an alternative to shunting. The authors have tried to fenestrate down to the subdural space passing through the prepontine cistern to lessen or avoid the chance of redoing due to healing. Materials and Method : A 48-year-old male patient with several years of intractable headache was presented. Magnetic Resonance Image(MRI) of the brain revealed marked ventricular dilatation with stenotic cerebral aqueduct. A 2.3mm flexible steerable endoscope($Neuroview^{(R)}$) was introduced via precoronal route and accessed to the third ventricular floor. Using 3-French Fogarty balloon catheter, thin third ventricular floor and the arachnoid membrane of the prepontine cistern were fenestrated, so called "double fenestration". To confirm the fenestration, subdural compa-rtment of the left abducens nerve was identified during the procedure. Forceful pulsating flow through the orifice convinced the patency of the opening. Results : The patient was discharged on the third postoperative day without any postoperative complications. The postoperative follow-up MRI of the brain, at second and sixth months, clearly demonstrated the flow void through the third ventricular floor. Conclusions : Endoscopic third ventriculostomy was successfully performed on an adult hydrocephalus patient with aqueduct stenosis. The third ventricular floor and arachnoid membrane of the prepontine cistern were fenestrated to achieve double fenestration to minimize the chance for failure. The details of this procedure and results are described.