• Tunnel and Underground Space
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• v.25 no.5
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• pp.450-461
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• 2015

Extensive numerical experiments have been carried out to investigate effect of block size and fracture geometry on hydraulic characteristics of fractured rock masses based on connected pipe flow in DFN systems. Using two fracture sets, a total of 72 2-D fracture configurations were generated with different combinations of fracture size distribution and deterministic fracture density. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity for each generated fracture network system were calculated using the 2-D equivalent pipe network method. There exist significant effects of block size, orientation, density and size of fractures in a fractured rock mass on its hydraulic behavior. We have been further verified that it is more difficult to reach the REV size for the fluid flow network with decreasing intersection angle of two fracture sets, fracture plane density and fracture size distribution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2367-2372
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• 2015

One of various low-density parity-check(LDPC) codes that has been adopted in many communication standards due to its error correction ability is a quasi-cyclic LDPC(QC-LDPC) code, which leads to comparable decoder complexity. One of the main blocks in the QC-LCDC code decoder is a multi-size circular shifter(MSCS) that can perform various size rotation. The MSCS can be implemented with many structures, one of which is based on Banes network. The Benes network structure can perform the normal MSCS operation efficiently, but it cannot use the properties coming from specifications like rotation sizes. This paper proposesd a scheme where the Benes network structure can use the rotation size property with the modification of the control signal generation. The proposed scheme is applied to the MSCS of IEEE 802.16e WiMAX QC-LDPC decoder to reduce the number of MUXes and the critical path delay.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.743-746
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• 2000

In this paper we propose a new network called Dynamic network for symmetric block ciphers. Dynamic cipher has the property that the key-size, the number of round, and the plaintext-size are scalable simultaneously We present the method for designing secure Dynamic cipher against meet-in-the-middle attack and linear cryptanalysis. Also, we show that the differential cryptanalysis to Dynamic cipher is hard.

• International Journal of Computer Science & Network Security
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• v.22 no.7
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• pp.157-164
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• 2022

The proposed privacy preserving scheme has identified the drawbacks of existing schemes in Vehicular Networks. This prototype enhances the number of nodes by decreasing the cluster size. This algorithm is integrated with the whale optimization algorithm and Block Chain Technology. A set of results are done through the NS-2 simulator in the direction to check the effectiveness of proposed algorithm. The proposed method shows better results than with the existing techniques in terms of Delay, Drop, Delivery ratio, Overhead, throughout under the denial of attack.

• Korean Journal of Social Welfare
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• v.61 no.4
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• pp.61-84
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• 2009

This study is to analyze the nature of mentoring network of single mothers with dependent children and to show the mentoring network effect on mentoring function and empowerment applying social network approach. 439 single mothers with dependent children in Busan and Gyeongsangnam-do have been surveyed about mentoring network properties. The results are 1. The mentoring relationships between single mothers have been shown in various size and relationship characters. The out-degree of Their network is low, the range is narrow, and the tie-strength is weak. 2. When the effect of mentoring network characteristics on mentoring function has been analyzed, in career functions, the range of network and the strength of relationships are represented as significant variables among the mentoring network characteristics, in psychosocial functions, the size of network and the strength of relationships are shown as significant variables, and the inverted-U-shaped relationship according to the size of network has not been revealed. In role modeling function only the size of network is represented as a significant variable. 3. The direct effect of mentoring network of single mothers with dependent children has not been much on empowerment and the career related function among mentoring functions has been revealed as the variable, which affect on empowerment. Based on these results the suggestions and implementations are mentioned in this paper.

• Proceedings of the KWS Conference
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• 1993.05a
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• pp.115-119
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• 1993

Many qualitive analyses of sampled process variables have been attempted to predict nugget size in resistance spot welding process. In this paper, dynamic resistance and electrode movement signal which is a good indicative of the nugget size was examined by introducing an artificial neural network estimator. An artificial neural feedforward network with back-propagation of error was applied for the estimation of the nugget size. To assess the advantage of this method. results have been compared with conventional regression method.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.656-666
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• 2014

In delay tolerant networks (DTNs), delay is inevitable; thus, making better use of buffer space to maximize the packet delivery rate is more important than delay reduction. In DTNs, epidemic routing is a well-known routing protocol. However, epidemic routing is very sensitive to buffer size. Once the buffer size in nodes is insufficient, the performance of epidemic routing will be drastically reduced. In this paper, we propose a buffer scheme to optimize the performance of epidemic routing on the basis of the Lagrangian and dual problem models. By using the proposed optimal buffer scheme, the packet delivery rate in epidemic routing is considerably improved. Our simulation results show that epidemic routing with the proposed optimal buffer scheme outperforms the original epidemic routing in terms of packet delivery rate and average end-to-end delay. It is worth noting that the improved epidemic routing needs much less buffer size compared to that of the original epidemic routing for ensuring the same packet delivery rate. In particular, even though the buffer size is very small (e.g., 50), the packet delivery rate in epidemic routing with the proposed optimal buffer scheme is still 95.8%, which can satisfy general communication demand.

• Asia pacific journal of information systems
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• v.10 no.2
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• pp.97-123
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• 2000

This paper proposes a model for assessing enterprise network maturity. We define maturity in terms of the institutional and member support for the network(organizational maturity) and its technical sophistication(technological maturity), and examine their relationships. We build several hypotheses about the relationships between the maturity types and between the maturity of the network and various organizational factors including industry, size, and performance of the enterprise. We test the hypotheses using data collected from a questionnaire survey with Korean firms. The results show that there is a positive correlation between organizational and technological maturity. It is also found that investment in the network infrastructure has a positive influence on the organizational efficiency. However, it is found that industry type does not affect network utilization, but size does, suggesting that large firms utilize network infrastructure more than small ones do. We also identify various relationships among performance, satisfaction level and the maturity of the enterprise networks. Finally, we provide an overview on the current technological state of the Korean enterprise networks.

• Journal of the Korea Society for Simulation
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• v.14 no.3
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• pp.67-77
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• 2005

Logistics network of the enterprise is defined to determine the optimal node and link considering the production, inventory and transportation based on the demand forecasting. This study consider the optimal logistics network of A painter company which maintain the existing transportation network and plan to relocate its plants and build new distribution centers. For this, we design possible alternative scenarios and install the simulation models for analysis of each scenario. The result of simulation will help the proper logistic network and determining the size of distribution center further.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.1
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• pp.28-36
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• 2010

Hardware implementation methods for Artificial Neural Network (ANN) have been researched for a long time to achieve high performance. We have proposed a Network on Chip (NoC) for ANN, and this architecture can reduce communication load and increase performance when an implemented ANN is small. In this paper, a multiple NoC models are proposed for ANN, which can implement both a small size ANN and a large size one. The simulation result shows that the proposed multiple NoC models can reduce communication load, increase system performance of connection-per-second (CPS), and reduce system running time compared with the existing hardware ANN. Furthermore, this architecture is reconfigurable and reparable. It can be used to implement different applications of ANN.