• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.67-75
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• 2009

The growing need for the mobility supportable networks induces the IP-based mobility management protocols. Though HMIPv6 which manages the micro-mobility of mobile nodes using MAPs suggests an effective method for mobility-support for mobile nodes within the domain that is managed by MAP. There is a problem that traffic may be concentrated on MAPs. In this paper, therefore, we proposed a method that can effectively distribute the traffic which is concentrated on a MAP under phased Mobile IPv6. In our proposed method, two or more MAPs are required and classified as an 'Active MAP' or a 'Passive MAP'. In addition, we defined the state of transition events between Active MAP and Passive MAP and the operations among MAPs for load distribution when an overload condition is occurred at some MAPs by traffic congestion. We compared the performance of our proposed method with its phased Mobile IPv6 to prove the propriety of our proposed method. As a result, we showed that our proposed method can provide an enhanced performance by about 12 percentages in view of packet throughput at the node.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1290-1298
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• 2000

Turbo Code decoder is an iterate decoding technology, which extracts extrinsic information from the bit to be decoded by calculating both forward and backward metrics, and uses the information to the next decoding step Turbo Code shows excellent performance, approaching Shannon Limit at the view of BER, when the size of Interleaver is big and iterate decoding is run enough. But it has the problems which are increased complexity and delay and difficulty of real-time processing due to Interleaver and iterate decoding. In this paper, it is analyzed that MAP(maximum a posteriori) algorithm which is used as one of Turbo Code decoding, and the factor which determines its performance. MAP algorithm proceeds iterate decoding by determining soft decision value through the environment and transition probability between all adjacent bits and received symbols. Therefore, to improve the performance of MAP algorithm, the trust between adjacent received symbols must be ensured. However, MAP algorithm itself, can not do any action for ensuring so the conclusion is that it is needed more algorithm, so to decrease iterate decoding. Consequently, MAP algorithm and Turbo Code performance are analyzed in the nongaussian channel applying Robust equalization technique in order to input more trusted information into MAP algorithm for the received symbols.

• Journal of IKEEE
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• v.4 no.2 s.7
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• pp.257-265
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• 2000

Turbo Code decoder is an iterate decoding technology, which extracts extrinsic information from the bit to be decoded by calculating both forward and backward metrics in each decoding step, and uses the information to the next decoding step. Viterbi decoder, which is for a convolutional code, runs continuous mode, while Turbo Code decoder runs by block unit. There are algorithms used in a decoder : which are MAP(maximum a posteriori) algorithm requiring very complicated calculation and SOVA(soft output Viterbi algorithm) using Viterbi algorithm suggested by Hagenauer, and it is known that the decoding performance of MAP is better. The result of this make experimentation shows that the performance of SOVA, which has half complex algorithm compare to MAP, is almost same as the performance of MAP when the SOVA decoding performance is supplemented with Robust equalization techniques.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.3
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• pp.77-82
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• 2020

Most of the navigation in the vehicle has been developed based on a complex structure of PSF(Physical Storage Format) files, making it difficult to support incremental map updates. DB-based navigation is drawing attention as a next-generation navigation method to solve this problem. In DB-based navigation that supports incremental map updates, data fragmentation due to continuous map data updates can increase data access costs, which can lead to a decrease in search performance. In this paper, as one of the performance enhancement methods of DB-based navigation that supports incremental map updates, data fragmentation prevention techniques were presented and the performance improvement effect was verified through actual implementation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.47-53
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• 2011

To enable the efficient operation of ITS, it is necessary to collect location data for vehicles on the road. In the case of futuristic transportation systems like ubiquitous transportation and smart highway, a method of data collection that is advanced enough to incorporate road lane recognition is required. To meet this requirement, technology based on radio frequency identification (RFID) has been researched. However, RFID may fail to yield accurate location information during high-speed driving because of the time required for communication between the tag and the reader. Moreover, installing tags across all roads necessarily incurs an enormous cost. One cost-saving alternative currently being researched is to utilize GNSS (global navigation satellite system) carrierbased location information where available. For lane recognition using GNSS, a precise digital map for determining vehicle position by lane is needed in addition to the carrier-based GNSS location data. A "precise digital map" is a map containing the location information of each road lane to enable lane recognition. At present, precise digital maps are being created for lane recognition experiments by measuring the lanes in the test area. However, such work is being carried out through comparison with vehicle driving information, without definitions being established for detailed performance specifications. Therefore, this study analyzes the performance requirements of a precise digital map capable of lane recognition based on the accuracy of GNSS location information and the accuracy of the precise digital map. To analyze the performance of the precise digital map, simulations are carried out. The results show that to have high performance of this system, we need under 0.5m accuracy of the precise digital map.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.382-388
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• 1987

In this paper, the performance of Mini MAP architecture is analyzed by simulation method. Token rotation time and waiting time are obtained by simulation. The results of the simulation are compared with these of the analytic model. From these comparisons, it is shown that simulation results are approximately identical to analytic results. Mini MAP architecture has good real time performances in token rotation time and waiting time and can be used to many real time applications.

• ETRI Journal
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• v.26 no.6
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• pp.615-621
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• 2004

Next generation mobile communication system, such as IMT-2000, adopts Turbo codes due to their powerful error correction capability. This paper presents a block-wise maximum a posteriori (MAP) Turbo decoding structure with a low memory requirement. During this research, it has been observed that the training size and block size determine the amount of required memory and bit-error rate (BER) performance of the block-wise MAP decoder, and that comparable BER performance can be obtained with much shorter blocks when the training size is sufficient. Based on this observation, a new decoding structure is proposed and presented in this paper. The proposed block-wise decoder employs a decoding scheme for reducing the memory requirement by setting the training size to be N times the block size. The memory requirement for storing the branch and state metrics can be reduced 30% to 45%, and synthesis results show that the overall memory area can be reduced by 5.27% to 7.29%, when compared to previous MAP decoders. The decoder throughput can be maintained in the proposed scheme without degrading the BER performance.

• School Mathematics
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• v.3 no.1
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• pp.75-99
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• 2001

The purpose of this study is to develop concept map as a tool of performance assessment in mathematics and to conduct feasibility test of the task. I developed and applied a concept map, an assessment tool, in the form of a mathematics performance task for 1st and 2nd year middle school students. I also conducted feasibility test of the task, and at the same time sought ways to guarantee reliability of the assessment procedure. Results of the task assessment can be summarized into the following four points. First, the concept map task was found to be appropriate for an assessment of mathematics in middle school. Second, results of all 10 factors on verification of validity of the content of the task were positive with over 50%. Third reliability of teachers who conducted marking of the four concept map tasks was high, all recording over .871 in correlation number.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.452-454
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• 2015

This paper provides the coding performance comparisons of depth map resolution in 3D video system. In multiview plus depth map system, depth map is used for synthesis view rendering, and affects to synthesis views quality. In the paper, we show the experimental results as depth map resolution in 3D video system, and show performance variation as dilation filter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11B
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• pp.945-952
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• 2006

In hierarchical mobile IPv6 networks, when an inter-domain handover occurs, mobile nodes suffer from excessive signaling traffic and long handover latency, resulting in possible disruption of ongoing connections. Further, the selection of MAP and its load status critically affect the overall system performance. Therefore, we propose a dynamic MAP selection scheme that seeks to distribute load among MAPs as well as reduces inter-domain handovers. Performance is evaluated from not only an analytic model of average signaling cost but also simulation. The analytical and simulation results show that our proposed scheme improves load distributedness and reduces inter-domain handovers and signaling cost compared to another existing IETF based approach.