• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.7B
• /
• pp.586-594
• /
• 2012

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalization of LBS is the accurate estimating position for mobile object. Focusing on AP's probabilistic position estimation, we develop an AP distribution map and new pattern matching algorithm for position estimation. The developed approaches can strengthen the advantages of Radio fingerprint based Wi-Fi Positioning System, especiall on the algorithms and data handling. Compared on the existing approaches of fingerprint pattern matching algorithm, we achieve the comparable higher performance on both of average error of estimation and deviation of errors. Furthermore all fingerprint data have been harvested from the actual measurement of radio fingerprint of Seoul, Kangnam area. This can approve the practical usefulness of proposed methodology.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.10A
• /
• pp.796-806
• /
• 2009

This paper presents the method of emergency warning system operation based on T-DMB and the design of T-DMB AEAS receiver model. The proposed receiver model compares the geographical location of emergency with the location of DMB transmitting station from T-DMB broadcasting signal and classifies the receiver location into alert region, neighboring region and non-alert region and transmits the emergency alert message according to each region. The geographical location of emergency can be obtained from FIG 5/2 EWS data field for AEAS message and the location of DMB transmitting station can be estimated from either the latitude and the longitude in main identifier and sub identifier in FIG 0/22 data filed for TII(Transmitter Identification Information) or TII distribution database. In our experiment, we implemented the proposed receiver model with display section, storage section, DMB module for receiving broadcasting signal and control section and performed test emergency alert broadcasting using T-DMB signal generator.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.6A
• /
• pp.648-656
• /
• 2007

This paper is about band pass filter, using Ceramics in the condition of center frequency 370Hz at milli-wave. The band pass filter is applied to Broadband Convergence Network, representing WLL(Wireless Local Loop) and LMDS(Local Multi-point Distribution Service). Sticking ceramic between strip line on a dielectric material substrate with which conductor's covers upper and basal surface, One will house the exterior by using structural resonance. In this Non Radiative Microstrip Line Filter structure, based upon simulations, generalized the two formulas finding resonant frequency of 1step ceramic resonator and bandwidth of 4step ceramic resonator. Also, As a result of experiment, using Network Analyzer, about created a experiment of structure based on the simulation result of 4-step ceramic resonator, It showed good characteristic of targeted bandwidth, comparing simulated result of 36.58GHz$\sim$37.650GHz with experimented result of 36.6GHz$\sim$37.65GHz.

• Journal of Electrical Engineering and Technology
• /
• v.5 no.2
• /
• pp.228-238
• /
• 2010

There is an increasing interest in research to help overcome the energy crisis that has been focused on energy storage applications in various parts of power systems. Energy storage systems are good at enhancing the reliability or improving the efficiency of a power system by creating a time gap between the generation and the consumption of power. As a contribution to the various applications of storage devices, this paper describes a novel algorithm that determines the power and storage capacity of selected energy storage devices in order to improve upon railroad system efficiency. The algorithm is also demonstrated by means of simulation studies for the Korean railroad lines now in service. A part of this novel algorithm includes the DC railroad powerflow algorithm that considers the mobility of railroad vehicles, which is necessary because the electric railroad system has a distinct distribution system where the location and power of vehicles are not fixed values. In order to derive a more accurate powerflow result, this algorithm has been designed to consider the rail voltage as well as the feeder voltage for calculating the vehicle voltage. By applying the resultant control scheme, the charging or discharging within a specific voltage boundary, energy savings and a substation voltage stabilization using storage devices are achieved at the same time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.2
• /
• pp.57-63
• /
• 2001

This paper analysed the characteristic of Power consumption at many type of Inverter controlled Elevator. Especially, this paper proposed the standard value of full load currents. For this propose, it was classified by the passenger capacity and manufacture company. As a result, it is found that (i) the value is between -3[A] and 7[A] in case of elevator. That means the full load currents was smaller than the standard value of conventional operation type (ii) the value is between 0.5[kVA] and 3[kVA] in case of Power transformer. That means the transformer capacity was smaller than the standard value of conventional operation type. it was classified by the passenger capacity at inverter controlled elevator in apartment Also, to guarantee the operation stop of inverter controlled elevator, this paper proposed the redundancy method of electrical installations. the redundancy method is (i) 2 line service system and (ii) 2 distribution line system.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.3
• /
• pp.499-505
• /
• 2014

According to the increasing use of smart devices such as smart phones and tablets, the service that targets mobile office, finance and e-government for convenience of usage and productivity has emerged significantly. As a result, important information is treated with the smart devices and also, the malicious activity that targets smart devices is increasing steadily. In particular, the damage case by harmful sites, malware distribution sites and phishing sites that targets smart devices has occurred steadily and it has emerged as a social issue. In the case of smart devices, the Android platform is occupied the 90% in Korea, 2013 therefore the method of device block level is required to resolve the social issues of smart devices. In this paper, we propose a method that can be effectively blocked when you try to access an illegal site to Web browser on the Android platform and develop the application and also analyze the wrong site block function.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.28 no.4
• /
• pp.975-985
• /
• 2018

ICN architecture, one of future Internet technologies, proposes that content request packets toward a content source can be responded by several distributed nodes. So, ICN can solve network congestion which is happened around content sources and provide a seamless content distribution service regardless of the network and system statuses of content sources. Especially, CCN implements content caching functionality in network nodes so that such intermediated network nodes can themselves respond to content requests. However, when receiving content from distributed nodes, users receiving content cannot authenticate the nodes providing the content. So CCN is vulnerable to various attacks such as an impersonation attack, a data pollution attack, and so on. This paper first describes CCN content authentication and its weakness. Then it proposes an improved content authentication scheme based on a blockchain and evaluates the performance of the proposed scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.75-81
• /
• 2005

The GNUnet in P2P system have solved an anonymous(publisher, storer, demander); a service of condition equal for peer. The GNUnet for an anonymous has separated a file and dispersed to the network. But, the 1Kbyte block size of the GNUnet is a creation of many additional block. I and R block has created with indirect point of D block The waste of I and R block appeared to 4% of the original file and the additional network traffic for the block transmission. To resolve the problems, this paper proposes an new scheme of file splitting distribution using P2P networks with the new GNUnet protocol, The GNUnet support minimization of the additional block and for a network traffic. It proposed an efficiency improvement of encording block and routing algorithm.

• Journal of Navigation and Port Research
• /
• v.35 no.5
• /
• pp.387-392
• /
• 2011

The value of Photovoltaic as an independent power supply is small, but the city's carbon emissions reduction and for the reduction of fossil fuel use distributed power is the power source to a very high value. However, according to the weather conditions for solar power generation by power fluctuations because of the size distribution to be effective, the big swing for effectively controlling real-time monitoring should be made. But that depends on solar power generation solar radiation forecasts from the National Weather Service does not need to predict it, and this study, the diffuse sky radiation in the history of the solar radiation in the darkness of the clouds, thick and weather forecasts can be inferred from the atmospheric transmittance to announce this value is calculated to represent each weather forecast solar radiation and solar radiation predicted by substituting the expression And the measured solar radiation and CRM (Cloud Cover Radiation Model) technique with an expression of Kasten and Czeplak irradiation when compared to the calculated predictions were verified.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1619-1624
• /
• 2008

Recently, In order to provide ubiquitous service, we develop each middleware and interface for sensors networks, RFID(Radio Frequency IDentification) and GPS(Global Positioning System). We use GPS for the location-based services, RFID for identifying the distribution logistics services, sensor networks for collecting the context data such as temperature, humidity, barometric pressure. Recently, there is increasing the need of integrated interface for using these sensor elements complexly in agriculture and livestock, construction, medical applications and, etc. This paper developments a integrated common interface for supporting efficiently process of sensing data using RFID, GPS and sensor network. This interface have the filtering function, parsing function, queuing function, interface management function, access function and, etc. We present the integrated frame structure combined with the collected context data in GPS, RFID and sensor networks and, support the open interface for providing complex ubiquitous application systems. Therefore, this interface will be efficiently used the system using RFID, GPS and sensor network, and supported many ubiquitous application services.