• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.720-725
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• 2008

This paper proposes a system architecture for USN with a service robot to provide more active assisted living services for elderly persons by monitoring their mental and physical well-being with USN environments at home, hospital, or silver town. Sensors embedded in USN are used to detect preventive measures for chronic disease. Logged data are transferred to main controller of a service robot via wireless channel in which the analysis of data is performed. For the purpose of handling emergency situations, it needs real-time processing on gathering variety sensor data, routing algorithms for sensor nodes to a moving sink node and processing of logged data. This paper realized multi-hop sensor network to detect user movements with biometric data transmission and performed algorithms on Xenomai, a real-time embedded Linux. To leverage active sensing, a mobile robot is used of which task was implemented with a priority to process urgent data came from the sink-node. This software architecture is anticipated to integrate sensing, communication and computing with real-time manner. In order to verify the usefulness of a proposed system, the performance of data transferring and processing on a real-time OS with non real-time OS is also evaluated.

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.350-358
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• 2017

Recently, owing to increased interest in low-carbon energy supplies, renewable energy sources such as photovoltaics and wind turbines in distribution networks have received considerable attention for generating clean and unlimited energy. The presence of energy storage systems (ESSs) in the promising field of active distribution networks (ADNs) would have direct impact on power system problems such as encountered in probabilistic distributed generation (DG) model studies. Hence, the optimal procedure is offered herein, in which the simultaneous placement of an ESS, photovoltaic-based DG, and wind turbine-based DG in an ADN is taken into account. The main goal of this paper is to maximize the net present value of the loss reduction benefit by considering the price of electricity for each load state. The proposed framework consists of a scenario tree method for covering the existing uncertainties in the distribution network's load demand as well as DG. The collected results verify the considerable effect of concurrent installation of probabilistic DG models and an ESS in defining the optimum site of DG and the ESS and they demonstrate that the optimum operation of an ESS in the ADN is consequently related to the highest value of the loss reduction benefit in long-term planning as well. The results obtained are encouraging.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.799-808
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• 2002

According to the wide-spread of information transmission system over network, the use of cryptographic system to provide the integrity of transmitted message over network is increasing and the importance of that is emphasized. Because the security of the cryptographic system totally relies on the key, key management is a essential part of cryptographic system. A number of key agreement protocols have been proposed to far, but their rigorous security analysis is still open. In this paper, we analyze the features of Diffie-Hellman based standard key agreement protocols and provide the security analysis of those protocols against several kinds of active attacks.

• Journal of The Korean Astronomical Society
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• v.52 no.2
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• pp.31-40
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• 2019

A long standing problem in the study of Active Galactic Nuclei (AGNs) is that the observed VLBI core is in fact a blending of the actual AGN core (classically defined by the ${\tau}=1$ surface) and the upstream regions of the jet or optically thin flows. This blending may cause some biases in the observables of the core, such as its flux density, size or brightness temperature, which may lead to misleading interpretation of the derived quantities and physics. We study the effects of such blending under the view of the Korean VLBI Network (KVN) for a sample of AGNs at 43 GHz by comparing their observed properties with observations obtained using the Very Large Baseline Array (VLBA). Our results suggest that the observed core sizes are a factor ~ 11 larger than these of VLBA, which is similar to the factor expected by considering the different resolutions of the two facilities. We suggest the use of this factor to consider blending effects in KVN measurements. Other parameters, such as flux density or brightness temperature, seem to possess a more complicated dependence.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.176-184
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• 2011

As modern megalopolises become more complex and huge, convenience and safety of citizens are main components for a welfare state. In order to make safe society, telemetrics technology, which remotely measures the information of target system using electronic devices, is an essential component. In general, telemetrics technology consists of USN (ubiquitous sensor network) based on a wireless network, smart sensor, and SoC (system on chip). In the smart sensor technology, the following two problems should be overcome. Firstly, because it is very difficult for transducer manufacturers to develop smart sensors that support all the existing network protocols, the smart sensor must be independent of the type of networking protocols. Secondly, smart sensors should be modular so that a faulty sensor element can be replaced without replacing healthy communication element. To solve these problems, this paper investigates the feasibility of an IEEE 1451 based ZigBee smart sensor system. More specifically, a smart sensor for large network coverage has been developed using ZigBee for active telemetrics.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.21-26
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• 2008

It was already realized at a current technological level of home network systems that the systems recognizes a user's simple order and carry out the order in the ubiquitous computing environment. However home is not a simple environment consisting into a large number of family members, so various order and situation would be needed accordingly. From now on we need to reach the technological level to infer that how is the user's behavior patterns and what kinds of service is the fittest to user who belong to the ubiquitous computing environment by using the result of the context interpreter. In this regards, active inferred-model needs to be suggested upgrading user's command into one step more higher level than the simple one adapting diversified feature. This study would like to suggest this active model recognizing context, which is user's environmental information applying basic network and inferring Context-based Service that user wants through the recognized result This study proposes a new method that can infer the user's desire in ubiquitous computing environment. First of all, we define a context as user's information of ubiquitous computing environment situation that user belongs to and we classify the context into 4W1H(Where, Who, When, What) formats. We construct Bayesian network and put the factor of context use as Bayesian network nodes. As a result, we can infer the user's behavior pattern and most proper service for user in the intelligent space from the probabilistic result of Bayesian network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.630-638
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• 2005

As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1211-1218
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• 2010

OSPF is the optimized routing protocol in wired network and considered as a tactical routing protocol in wireless tactical communication network. However because it is designed basically based on wired environment, it runs inadequately in wireless tactical environment: noise and jamming signal. So, we proposed new OSPF cost function to develop active routing protocol in wireless tactical communication network. In redefined cost function, there are four parameters that are relative transmission speed, link weight, router utilization, link average BER(Bit Error Rate). These parameters reflect wireless tactical characters. Also, we remodel the option field in Hello packet. It can help user to periodically check the link state. From the simulation result, it is shown that proposed OSPF is better than OSPF in jamming situation and has accumulative delay gain with dispersion of traffic load in entire network.

• Herbal Formula Science
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• v.32 no.1
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• pp.11-28
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• 2024

Objectives : GunRyeong-Tang(GRT) is a traditional herbal prescription that combines Oryeongsan and Sagunja-tang. This study employed network analysis methods on the components of GRT and target genes related to diabetes complications to predict the improvement effects of GRT on diabetes complications. Methods : The collection of active compounds of GRT and related target genes involved the utilization of public databases and the PubChem database. We selected diabetes complication-related genes using GeneCards and confirmed their correlation through comparative analysis with the target genes of GRT. We constructed a network using Cytoscape 3.9.1 and conducted topological analysis. To predict the mechanism, we performed functional enrichment analysis based on Gene Ontology (GO) biological processes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Results : Through network analysis, 234 active compounds and 1361 related genes were collected from GRT. A total of 9,136 genes related to diabetes complications were collected, and 1,039 target genes overlapping with the components of GRT were identified. The core genes of this network were TP53, INS, AKT1, ALB, and EGFR. In addition, GRT significantly reduced the H9c2 cell size and the expression of myocardial hypertrophy biomarkers (ANP, BNP), which were increased by high glucose (HG). Conclusions : Through this study, we were able to predict the activity and mechanism of action of GRT on diabetes and diabetic complications, and confirmed the potential of GRT as a treatment for diabetes complications through the effect of GRT on improving myocardial hypertrophy for diabetic cardiomyopathy.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.105-106
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• 2013

This paper proposes a new topology with active switched-capacitor and switched-inductor impedance network, which can obtain a high boost factor with small shoot-through time. The proposed topology uses an active switched capacitor and switched-inductor impedance network in order to couple the main circuit and input dc source for boosting the output voltage. The proposed topology contains all advantages of the classical Z-source inverter. Comparing with other topologies, the proposed topology uses lesser component and the voltage boost inversion ability significantly increases. The theoretical analysis, pulse width modulation control strategies, and a comparison with classical ZSI have been given in this paper. Both simulation and experimental results will be presented to verify the advantages of the proposed topology.