• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.772-783
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• 2005

In this paper, we propose an effective multicasting protocol in wireless ad-hoc networks. Conventional wired and wireless network multicast protocols do not perform well in wireless ad hoc networks because they were designed without consideration of ad hoc environments such as node mobility, limited bandwidth, high error probability. To solve this problem, some multicasting protocols for ad hoc network have been proposed in the literature. However, these protocols can not provide high packet delivery ratio, low control packet overhead and low expended bandwidth at the same time. Therefore, in this paper, we propose RTMA that improves multicasting performance in wireless ad hoc networks. RTMA calculates its current region from its position information by using GPS in order to make tree among the multicast group nodes in the same region. The proposed region-based tree method is for high packet delivery ratio, low control packet overhead when many senders send data packets. RTMA makes a reliable tree by using speed information to fill a gap of the weak points of the tree structure. When searching the routing path, RTMA selects the reliable path excluding high speed nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.160-171
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• 2011

The one of the core technologies for ubiquitous computing is WSN. WSN detects the information from the environment around them based on the information perceived from the human and all things and manages the information by connecting to the network in realtime. In this environment, the existing research provides the mechanism that most of sensor nodes in the target area can set the transmission path using RGF. However, unrelated to the target area will be responsible for the energy consumption of nodes that are the problem. In this paper, we propose EEDCP protocol. It is designed to collect data from the specific region on sinks in WSN. EEDCP is the protocol that sets the transmission path for collection data inside the target area in WSN. And this paper is shown that the proposed scheme is more efficient in the energy efficiency and the occurrence rate of isolated nodes by comparison with the previous studies through simulation.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.207-212
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• 2015

The sensor network that is component of the Internet of Things require a lot of research to select the best route to send information to the anchor node, to collect a number of environment and cost efficient for communication between the sensor life. On the sensor network in one of the components of IOT's environment, sensor nodes are an extension device with low power low capacity. For routing method for data transmission between the sensor nodes, the connection between the anchor and the node must be accurate with in adjacent areas relatively. Localization CA (Centroid Algorithm) is often used although an error frequently occurs. In this paper, we propose a range-free localization method between sensor nodes based on the Radical Line in order to solve this problem.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.281-291
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• 2021

The Islamic jurisprudential legal system represents an essential component of the Islamic religion, that governs many aspects of Muslims' daily lives. This creates many questions that require interpretations by qualified specialists, or Muftis according to the main sources of legislation in Islam. The Islamic jurisprudence is usually classified into branches, according to which the questions can be categorized and classified. Such categorization has many applications in automated question-answering systems, and in manual systems in routing the questions to a specialized Mufti to answer specific topics. In this work we tackle the problem of automatic categorisation of Islamic jurisprudential legal questions using deep learning techniques. In this paper, we build a hierarchical deep learning model that first extracts the question text features at two levels: word and sentence representation, followed by a text classifier that acts upon the question representation. To evaluate our model, we build and release the largest publicly available dataset of Islamic questions and answers, along with their topics, for 52 topic categories. We evaluate different state-of-the art deep learning models, both for word and sentence embeddings, comparing recurrent and transformer-based techniques, and performing extensive ablation studies to show the effect of each model choice. Our hierarchical model is based on pre-trained models, taking advantage of the recent advancement of transfer learning techniques, focused on Arabic language.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.839-846
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• 1994

This paper presents a simultaneous solution algorithm for one-dimensional unsteady flow routing through a dendritic channel system. This simulations solution algorithm is based on the double-sweep method and utilizes separate recursion equations for continuity, momentum and energy equations for each of the individual components of a dendritic channel system. Through separate recursion equations for each of the components. the new algorithm converts a dendritic channel network problem into a single-channel problem. The new algorithm is utilized in conjunction with a linearized unsteady flow model using full dynamic flow equations. The required computer storage for the coefficient matrix of the whole system is reduced significantly from the $2N{\times}2N$ matrix to a $2N{\times}4$ matrix, where N is the number of cross sections used in the computation of flow variables in a dendritic channel system. The algorithm presented in this paper provides an efficient and accurate modeling of unsteady flow events through a dendritic channel system.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3952-3963
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• 2000

This paper considers the WRA(Wavelength and Houting Assignment) problem on all-optical tree networks using WDM(Wavelength Division Multiplexing). Each link between a pair of request nodes on all optical networks is assigned different wavelengths because of technical constraint. On the basis of this, we give an polynomial time algorithm to assign wavelengths to the all patbs of a arbitrary tree network using divide and conquer method. The time complexity of this algorithm is O(Q. R), in which Q is the request nodes for all to'all communication in a tree topology and U is the maximum number of wavelength. Also we implemented our algorithm using C in Pentium II 233MHz and analyzed performance results.

• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.99-107
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• 2000

Path-based assignment(PBA) is valuable to dynamic traffic control and routing in integrated ITS framework. As one of widely studied PBA a1gorithms, Gradient Projection(GP) a1gorithm typically fields rapid convergence to a neighborhood of an optimal solution. But once it comes near a solution, it tends to slow down. To overcome this problem, we develop more efficient path-based assignment algorithm by combining Conjugate Gradient method with GP algorithm. It determines more accurate moving direction near a solution in order to gain a significant advantage in speed of convergence. Also this algorithm is applied to the Sioux-Falls network and verified its efficiency. Then we demonstrate that this type of method is very useful in improving speed of convergence in the case of user equilibrium problem.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.78-89
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• 2013

This paper proposes a high-throughput and multi-mode quasi-cyclic (QC) low-density parity-check (LDPC) decoder based on a fully parallel structure. The proposed QC-LDPC decoder employs the fully parallel structure to provide very high throughput. The high interconnection complexity, which is the general problem in the fully parallel structure, is solved by using a broadcasting-based sum-product algorithm and proposing a low-complexity cyclic shift network. The high complexity problem, which is caused by using a large amount of check node processors and variable node processors, is solved by proposing a combined check and variable node processor (CCVP). The proposed QC-LDPC decoder can support the multi-mode decoding by proposing a routing-based interconnection network, the flexible CCVP and the flexible cyclic shift network. The proposed QC-LDPC decoder is operated at 100 MHz clock frequency. The proposed QC-LDPC decoder supports multi-mode decoding and provides 8.1 Gbps throughput for a (1944, 1620) QC-LDPC code.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.1
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• pp.23-34
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• 2022

With the development of network technology, the application area has also been diversified, and protocols for various purposes have been developed and the amount of traffic has exploded. Therefore, it is difficult for the network administrator to meet the stability and security standards of the network with the existing traditional switching and routing methods. Software Defined Networking (SDN) is a new networking paradigm proposed to solve this problem. SDN enables efficient network management by programming network operations. This has the advantage that network administrators can flexibly respond to various types of attacks. In this paper, we design a threat level management module, an attack detection module, a packet statistics module, and a flow rule generator that collects attack information through the controller and switch, which are components of SDN, and detects attacks based on these attributes of SDN. It proposes a method to block denial of service attacks (DoS) of advanced attackers by programming and applying honeypot. In the proposed system, the attack packet can be quickly delivered to the honeypot according to the modifiable flow rule, and the honeypot that received the attack packets analyzed the intelligent attack pattern based on this. According to the analysis results, the attack detection module and the threat level management module are adjusted to respond to intelligent attacks. The performance and feasibility of the proposed system was shown by actually implementing the proposed system, performing intelligent attacks with various attack patterns and attack levels, and checking the attack detection rate compared to the existing system.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.627-634
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• 2006

Overlay network eliminates the need to change the application-layer tree when the underlying network changes and enables the overlay network to survive in environments where nonmember nodes do not support multicast functionality. An overlay protocol monitors group dynamics, while underlying unicast protocols track network dynamics, resulting in more stable protocol operation and low control overhead even in a highly dynamic environment. But, if overlay multicast protocols does not know the location information of node, this makes it very difficult to build an efficient multicasting tree. So, we propose a Hierarchical Overlay Multicast Architecture (HOMA) with the location information. Because proposed architecture makes static region-based dynamic group by multicast members, it is 2-tired overlay multicasts of application layer that higher layer forms overlay multicast network between members that represent group, and support multicast between multicast members belonging to region at lower layer. This use GPS, take advantage of geographical region, and realizes a region-sensitive higher layer overlay multicast tree which is impervious to the movements of nodes. The simulation results show that our approach solves the efficiency problem effectively.