• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.99-104
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• 2012

The United States will proceed with the effort to modernize the GPS system, and one of its main content is to provide L5 signal. L5 will be transmitted in a radio band reserved exclusively for aviation safety services. And, L5, in combination with L1, will improve the position accuracy via ionospheric correction and robustness via signal redundancy. However, The acquisition processing time of L5 takes longer than that of L1 as the code length of L5 is 10 times longer than that of L1. To reduce this acquisition processing time, a higher number of correlators in the aquisition module should be used. However, there is a problem that this causes increase in the complexity of the correlator configuration and the computation power. So, in this paper, we propose L5 signal tracking scheme using tracking results in the GPS L1/L5 receiver. The proposed scheme could reduce the hardware complexity as the GPS L5 signal acquisition module is not needed, and provide fast and stable tracking of L5 signal by aiding L1 tracking results such as PRN, the code phase synchronization, and the Doppler frequency. The feasibility of the proposed scheme is demonstrated through simulation results.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.76-84
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• 2013

In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDOA (frequency difference of arrival) measurements, the estimation accuracy can be improved by collecting additional measurements. To achieve this goal, it is required to increase the number of the sensors. However, in electronic warfare environment, a large number of sensors cause the loss of military strength due to high probability of intercept. Also, the additional processes should be considered such as the data link and the clock synchronization between the sensors. Hence, in this paper, the passive localization of a stationary emitter is presented by using the successive TDOA and FDOA measurements from two moving sensors. In this case, since an independent pair of sensors is added in the data set at every instant of measurement, each pair of sensors does not share the common reference sensor. Therefore, the QCLS (quadratic correction least squares) methods cannot be applied, in which all pairs of sensor should include the common reference sensor. For this reason, a Gauss-Newton algorithm is adopted to solve the non-linear least square problem. In addition, to show the performance of the proposed method, we compare the RMSE (root mean square error) of the estimates with CRLB (Cramer-Rao lower bound) and derived the CEP (circular error probable) planes to analyze the expected estimation performance on the 2-dimensional space.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.7
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• pp.421-428
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• 2006

In this paper, the way of remote installation and back-up of 3-tier structure is introduced for efficient utilizing the cluster system resources distributed at several places. Recently, cluster system is constructed as the system of over hundreds nodes under complex network system mixed with public networks and private networks. Therefore, the as installation method suitable for the large scale cluster system and the remote recovery of failure nodes are important. However the previous researches which are based on 2-tier architecture may not provide the efficient cluster installation and image back-up method when the network of cluster system is composed of several private networks and public networks. In this paper, RISE (Remote Installation Service and Environment) based on the 3-tier architecture is proposed to solve this problem. In our approach, the managing node's role is divided into the global master node (GRISE) and the local master node (LRISE) to provide the efficient initial system deployment and remote failure recovery of distributed cluster system under the various network systems. Also, LRISE's availability is ensured under the complex network environments by adopting the auto-synchronization mechanism between GRISE and LRISE. In this work, a 64-node cluster system with gigabit network system is utilized for the experiment. From the experimental result, the system image with 1.86GB data can be obtained in 5 minutes and 53 seconds and the image-based installation of 64-node system can be carried out in 17 minutes and 53 seconds.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.1
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• pp.59-73
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• 2007

Although there exist many middlewares such as Havi, Jini, LonWorks, UPnP, and SLP, new middlewares specialized for diverse information appliances are expected to appear continuously as home networks evolve. In this paper, we examine an integrated architecture for supporting interoperability among heterogeneous middlewares under home network, we also propose and implement a scenario-based user-oriented integrated architecture for efficient home automation which is different from existing methods. HOMI(Homenetwork Middleware for Interoperability) architecture proposed in this paper provides interfaces that assist users with designing and modifying desirable scenarios using a script interpreter language HOMIL(HOMI Language). Different from an existing integrated middleware architecture, HOMI improves efficiency and convenience of interoperation between heterogeneous appliances for home automation allowing users to design and organize scenarios through these interfaces. HOMI classifies interoperation services into time contort, synchronization context, and asynchronization context and helps to execute next services considering contexts when a specific event occurs. Applying modified scenarios immediately to home network environment, HOMI provides users with seamless services without installing new applications, updating the server, or rebooting in order to adopt new scenarios. Lastly, distribution agents into several devices, we solved the overhead problem occurred in a centralized architecture for integrated middleware.

• Information Systems Review
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• v.4 no.2
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• pp.191-208
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• 2002

In the area of new millennium of twenty first century, one of the urgent and critical research issues in commerce area is the regenerating of new business opportunities from the high value added perspectives. With this motivation, in this paper, we create new on-line e-businesses with the speed of lightning their affiliated supply, finance and business communities - which are involved in more and more tightly connected, open trading - we find that we need to deal with hundreds of business collaborative partners, millions of buyers and sellers while we have to face incompatible IT systems. Challenges of new business opportunities linking multi-enterprise data and processes cost effectively, reliably and securely in real time remains an open area in e-business. This challenge we shall describe as the problem of synchronization of multiple enterprise collaborative e-business opportunities (production related), value (finance related), business (operations related) in new business opportunity and infrastructure integrated all together over the off-line and online basis. It brings a new e-commerce opportunities infrastructure into this profitable challenge: by extracting and tracking new business information, new trends in the events of e-business processes. The transformation of the traditional commerce into this type of electronic based commerce can be interpreted as new Cultural Revolution. The revolution will be a new paradigm crossing over the geographical, and organizational zone, restructuring enterprise business process infrastructure.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.17-26
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• 2013

ISO/IEC 29157 originally developed in the Republic of Korea and is based on commercially available PicoCast v1.0. ISO/IEC JTC1 SC6 was registered by the international standard on May 2010. A single platform for a variety of applications and media formats to support development objectives were. ISO/IEC 29157 based wireless networks, ie, Pico-net to master node periodically transmit sync signal is synchronized to the number of slave nodes have the communications structure. Pico-net also supports a variety of network topologies and direct communication between nodes(single-hop communication) and QoS is guaranteed. But Pico-net network structure has the following problems. Loss of communication problems due to mobile nodes, resulting in limitations of node mobility and wireless network operation range of conventional wireless networks operating range less than 1/4 was reduced to the problem. In this paper, a possible solution to the problems mentioned is proposed, using multi-hop communication technology and sync signal transmission technology between nodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.485-489
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• 2002

The concepts from OOP have been integrated in a concurrency, leading to the emergence of concurrent OOP. Concurrency of concurrent OOP and various model technique of OOP language are integrated had been proposed. Concurrent programming and OOP technique unite that can gain various kinds advantage to develop concurrency application program. There have been a number of models proposed for integrating concurrency and OOP However, concurrency and inheritance are two paradigms which are difficult to combine in a suitable manner. The inheritance anomaly is the conclicted phenomena, which occurs only when concurrency is integrated with inheritance. The inheritance anoay is referred to as the serious difficulty in integrating inheritance and concurrency in a simple and efficient manner within a concurrent OOP. Concurrency and inheritance with integrated that Drop reusability of object remarkably and require re-justice of code that is inherited in subclass. So concurrency and inheritance with integrated Collision that happen between two special qualitys or Interference phenomenon is inheritance anomaly. Effect of inheritance anomaly minimum Much study findings announced about access method to improve code reusability. Wish to approach in paper that is division by synchronization code and method code to solve interference problem between and concurrency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1150-1158
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• 2011

More than 100 Mbps rate is needed in the UBcN for a subscriber to receive broadband traffics with multi-channel like UDTV or 3DTV. Although the optical fiber is recently deployed for the FTTH, the UTP is the most widely used medium and will be used in UBcN age. Network providers may consider the 1000BASE-T or the vectorized VDSL if they adopts the UTP in the place where does not have optical fibers. But UTP should be expanded because 1000BASE-T and vectorized UTP needs 4 and 3 pairs cable, respectively while residential region has not exceeding 2 pair UTP cable. To solve the problem, we propose a 500BASE-T technology using 2 pairs UTP in this paper. The technology introduces a rate adaptation sublayer and a SERDES sublayer above and under the PCS, respectively. The rate adaptation sublayer is compatible for the GMII. Also, if we modify the SERDES sublayer, the technology can easily obtain 250BASE-T with 2 pairs UTP. We implement such functions with FPGA and analog board and verify the function of rate adaptation and symbol vector synchronization, and effective transmission rate by experiments. In particular, we show that link efficiency is increased by enable control in the rate adaptation sublayer.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.139-147
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• 2009

The gravity data collected and reserved in Korea is seriously biased in its distribution. That is, only the west-southern part of the peninsula including Chungcheong and Jeonla area has dense distribution while only a part is covered in Gyoungsang area. Especially, the low density of the gravity data in mountainous area basically limits the accuracy of the gravimetric geoid in Korea. As one of the solution to overcome the problem, an airborne gravity survey were conducted from Dec. 2008 $\sim$ Jan. 2009. In this study, free-air gravity anomaly derived from the airborne gravity data which has consistent quality are presented. The data processing for the airborne gravity is composed of several corrections of errors such as errors from gravity measurement, errors from flight dynamics, errors from GPS, and errors from time synchronization. We presented detailed explanations on the data processing with the final cross-over results. The free-air anomaly from airborne gravity finally shows the cross-over accuracy of 2.21mGal which reflects the precision of each track is 1.56mGal. It is expected that the result from this study will play a role as input data in precision geoid determination with ground and ship-borne gravity data after appropriate fusion process.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.1017-1023
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• 2013

Datacommunications transmit the source codes that are coded in information devices, such as computer to the transmission line by means of the line coded signal. AMI method is applied to the line coding method to transmit the signal for long distance. The disadvantage of the AMI method is to loss the bit synchronization when consecutive binary bit '0' over 4ea is coming into line coder. The scrambling technique is used to overcome the problem. The HDB-3 scrambling method is used in Korea standard which standard in ITU-T. When the HDB-3 technology is used. the method should convert the consecutive bit '0' over 4ea to certain bits format. As a result, when there are many such kind of '0' bit stream in source codes, data transmission efficiency will be decreased to treat in line coder, etc. This paper is directed to study the Roman character code system in $KS{\times}1001$, Korea standard for information exchange code in datacommunication systems. Based on the study result, this paper proposed the maximum optimized Roman character code system. In the study, Character coding rule for $4{\times}4$bits and the statistical data for roman character using frequency were considered to simulate. The paper shows the result that when the proposed new roman character coding system is applied to use, the data transmission efficiency could be increased to about 134% compared to existing code system.