• Journal of the Korean Institute of Navigation
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• v.24 no.5
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• pp.405-415
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• 2000

DGPS/Radio beacons are currently being planned or installed in many countries. They offer a cost-effective way of distributing differential data to large number of users. These networks are also being deployed in South Korea, Japan, and China. Several DGPS stations among them are operating on the same frequencies. The DGPS signal based on a radio beacon in medium frequency band travels principally as a groundwave over the surface of the earth. The signal may also be received as skywaves at locations beyond about 100 km from the reference station. These skywaves interfere with groundwave signals due to fading. This factor has generally ignored in designing DGPS/Radio beacon systems. A further important factor is to reduce the coverage due to interference from other beacons on the same or adjacent frequencies. The desired signal may fade due to interaction between its skywave and groundwave components. It may degrade the accuracy of the positioning in a complex fashion. This paper estimates the coverage of Far East Asia DGPS stations which are operating on the same frequencies, which is based on the signal protection ratio and interference of the signal strength of the groundwave and skywave.

• Journal of Internet Computing and Services
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• v.7 no.3
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• pp.53-60
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• 2006

As it has been continuously increased the volume of traffic over Internet, it is hard for a network traffic monitoring system to analysis every packet in a real-time manner. While it is increased usage of applications which are dynamically allocated port number such as peer-to-peer(P2P), steaming media, messengers, users want to analyze traffic data generated from them. This high level analysis of each packet needs more processing time. This paper proposes to introduce load shedder for limiting the number of packets. After it determines what application generates a selected packet, the packet is analyzed with a defined application protocol.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.265-270
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• 2019

The technology to locate an individual has enabled various services, its utilization has increased. There were constraints such as the use of separate expensive equipment or the installation of specific devices on a facility, with most of the location technology studies focusing on the accuracy of location verification. These constraints can result in accuracy within a few tens of centimeters, but they are not technology that can be applied to a user's location in real-time in daily life. Therefore, this paper aims to track the locations of smartphones only using the basic components of smartphones. Based on smartphone sensor data, localization accuracy that can be used for verification of the users' locations is aimed at. Accelerometers, Wifi radio maps, and GPS sensor information are utilized to implement it. In forging the radio map, signal maps were built at each vertex based on the graph data structure This approach reduces traditional map-building efforts at the offline phase. Accelerometer data were made to determine the user's moving status, and the collected sensor data were fused using particle filters. Experiments have shown that the average user's location error is about 3.7 meters, which makes it reasonable for providing location-based services in everyday life.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.29-35
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• 1998

In this paper, the proposed audio/video control device for multiple user in the multimedia platform is changed for the better a disadvantage that must get one computer per participant to process a floor mode needed for interactive collaboration in the multimedia based distance education. It also proposed simulator of co-work environment that included multimedia data. This developed to proceed a multimedia distance education efficiently and sharing a computer among multiple users. Therefore, this is resulting in a reduction the cost needed to build a multimedia distance education system as well as totally simplified the organization of system. It also offers compatibility and generality, interfacing with the printer port of standard PC supporting the bi-direction mode.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.165-171
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• 2005

we can define the procedure of Authoring that it makes area cord and the reproduction prevent menu programmed into MPEG II video stream , Audio which is AC-3 audio stream and subtitle under its own category. And it makes process an attribute, an order and an operation, gives the last disk image (DVD). There are various types of Authoring tools in the market so that authoring tools can enable, encourage, and assist users ('authors') in the selection of tools that produce simple title and video production and editing suites. In this paper, we will compare and analyze authoring process in which image and sound are captured into DVD creation with IEEE 1394port with regard to Window system using generally with Desktop PC and the Macintosh of the PC on the system of Windows and OSX.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.145-151
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• 2005

We can define the procedure of Authoring that it makes area cord and the reproduction prevent menu programmed into MPEG II video stream , Audio which is AC-3 audio stream and subtitle under its own category. And it makes process an attribute, an order and an operation, gives the last disk image, Which is DVD(digital versatile disc). There are various process of Authoring tools in the market so that authoring tools can enable, encourage, and assist users ('authors') in the selection of tools that produce simple title, video production and editing suites. In this paper, we will compare and analyze authoring process in which image and sound are authorized into DVD with IEEE 1394port between Window system using generally with Desktop PC and the Macintosh that is based on OSX.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.785-790
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• 2017

Network scanning tools typically use port scans to steal information from network terminals and identify vulnerabilities. In particular, Shodan and Censys use a network scanning tool to gather a wide range of terminal information, store it in their database and provide it to the users. In order to prevent such information gathering, it is required to know the scanning methods of Shodan and Censys. However, the scanning model used by Shodan and Censys is not known exactly. Therefore, this paper estimates scanning models of Shodan and Censys and analyzes the performance of each models.

• Journal of Convergence Society for SMB
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• v.4 no.4
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• pp.13-18
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• 2014

The usage rate of user due to advances in smartphone development is higher than the usage rate to use a PC. However, smartphone usage popularized research to protect sensitive information, such as smart phone users personal information, financial information is a small state. In this paper, we analyzed the various vulnerabilities in smartphone studies to date have been looking into the corresponding port smart consumer dispute resolution methods and criteria for smartphone security attack methods and analysis. In particular, the threat of such a network, malware, Peep attack of the security threats arising from the smartphone they can avoid or mitigate threats to minimize the smartphone security damage is done to the disclosure of personal information, such as direct damage or financial loss the analysis of that method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.103-108
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• 2005

In this article, it has been shown that penises devices such as illumination facilities, heating/cooling systems and security equipment can be controlled even outside premises using UPnP (Universal Plug and Play) applicable to the Internet or cellular phone services. To load UPnP protocol into each device, current manufacturers will be required to port flexible OS (Operating System), that is, Windows or Linux to these premises devices. Furthermore, prospective users want to experience a variety of specific functions based on more standardized and stable network. This study aims to provide application by implementing these functions on the Linux system.

• Journal of the Korean Institute of Navigation
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• v.6 no.2
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• pp.13-33
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• 1982

The NAVSTAR/GPS is a satellite-based navigation system that will provide extremely accurate three-dimensional position and velocity information to users anywhere on or near the earth. This system has been studied primarly for military use and thus the results of studies are seldom obtainable for civilian use up to date. Expecting this system to be opened to civilian use in the future, this paper aims to the collection of basic data of the PN phase modulated communication system adopted in the GPS system by computer simulation. The results of studies are as follows; 1) The PN phase modulation of the speed of 106b/s can be simulated by Fourier summation, the spectrum region which can be restricted is in the region of 0.5-1.5 MHz and spectrum number required is over than 270. 2) By computer simulation, it is verified that optimum r.f filter bandwidth is about 0.3 MHz for the case of $10^6$b/s PN codes phase modulated in 1.575GHz carrier. 3) In case that PN rate to data rate is between 10 and 100, the allowable minimum SNR to demodulate data signal correctly by optimum LPF is about 0.3. It is also verified that the larger the frequency ratio of PN code to the data code, the lower the allowable minimum SNR required.