• Journal of the Korea Society of Computer and Information
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• v.19 no.7
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• pp.103-111
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• 2014

This paper proposes a modified algorithm that improves on Dijkstra's algorithm by applying it to purely two-way traffic paths, given that a road where bi-directional traffic is made possible shall be considered as an undirected graph. Dijkstra's algorithm is the most generally utilized form of shortest-path search mechanism in GPS navigation system. However, it requires a large amount of memory for execution for it selects the shortest path by calculating distance between the starting node and every other node in a given directed graph. Dijkstra's algorithm, therefore, may occasionally fail to provide real-time information on the shortest path. To rectify the aforementioned shortcomings of Dijkstra's algorithm, the proposed algorithm creates conditions favorable to the undirected graph. It firstly selects the shortest path from all path vertices except for the starting and destination vertices. It later chooses all vertex-outgoing edges that coincide with the shortest path setting edges so as to simultaneously explore various vertices. When tested on 9 different undirected graphs, the proposed algorithm has not only successfully found the shortest path in all, but did so by reducing the time by 60% and requiring less memory.

• The KIPS Transactions:PartA
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• v.11A no.5
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• pp.341-346
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• 2004

Recently A Hyper-Star Graph HS(m, k) has been introduced as a new interconnection network of new topology for parallel processing. Hyper-Star Graph has properties of hypercube and star graph, further improve the network cost of a hypercube with the same number of nodes. In this paper, we show that Hyper-Star Graph HS(m, k) is subgraph of hypercube. And we also show that regular graph, Hyper-Star Graph HS(2n, n) is node-symmetric by introduced mapping algorithm. In addition, we introduce an efficient one-to-all broadcasting scheme - takes 2n-1 times - in Hyper-Star Graph HS(2n, n) based on a spanning tree with minimum height.

• Journal of Korean Society for Quality Management
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• v.26 no.1
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• pp.192-200
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• 1998

The quickest path problem is one of the important things for quality of services in communication networks. It is to find a path to send a given amount of data from the source to the sink with minimum transmission time, where the transmission time is dependent on both the capacities and the traversal times of the arcs in the network. This is found under the networks that the capacity and the lead time of each ring are predetermined. It is general to solve the quickest path problem using shortest path algorithms. The relevant algorithms proposed till now are based on the capacity of rings in distributed environments. When the configuration of networks is changed, there can be two a, pp.oaches to find the quickest paths. The one is to find new quickest paths, and the other is to update the current quickest paths. As one of the algorithms for the latter, the distributed quickest path update algorithm was proposed. This paper aims to propose the distributed algorithm a, pp.icable to find the quickest path, when the configuration of networks is changed, using the quickest path tree update altorithm, and to verify its possibility of a, pp.ication by analyzing the transmission amount of data from one node to another from the theoretical point of view.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.185-195
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• 2013

In this paper, we propose a video summarization technique on a smartphone, based on spatiotemporal saliency. The proposed technique detects scene changes by computing the difference of the color histogram, which is robust to camera and object motion. Then the similarity between adjacent frames, face region, and frame saliency are computed to analyze the spatiotemporal saliency in a video clip. Over-segmented hierarchical tree is created using scene changes and is updated iteratively using mergence and maintenance energies computed during the analysis procedure. In the updated hierarchical tree, segmented frames are extracted by applying a greedy algorithm on the node with high saliency when it satisfies the reduction ratio and the minimum interval requested by the user. Experimental result shows that the proposed method summaries a 2 minute-length video in about 10 seconds on a commercial smartphone. The summarization quality is superior to the commercial video editing software, Muvee.

• International Journal of Computer Science & Network Security
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• v.24 no.8
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• pp.85-104
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• 2024

The DNA (Deoxyribonucleic Acid) database size increases tremendously transmuting from millions to billions in a year. Ergo for storing, probing the DNA database requires efficient lossless compression and encryption algorithm for secure communication. The DNA short pattern repetitions are of paramount characteristics in biological sequences. This algorithm is predicated on probing exact reiterate, substring substitute by corresponding ASCII code and engender a Library file, as a result get cumulating of the data stream. In this technique the data is secured utilizing ASCII value and engendering Library file which acts as a signature. The security of information is the most challenging question with veneration to the communication perspective. The selective encryption method is used for security purpose, this technique is applied on compressed data or in the library file or in both files. The fractional part of a message is encrypted in the selective encryption method keeping the remaining part unchanged, this is very paramount with reference to selective encryption system. The Huffman's algorithm is applied in the output of the first phase reiterate technique, including transmuting the Huffman's tree level position and node position for encryption. The mass demand is the minimum storage requirement and computation cost. Time and space complexity of Repeat algorithm are O(N²) and O(N). Time and space complexity of Huffman algorithm are O(n log n) and O(n log n). The artificial data of equipollent length is additionally tested by this algorithm. This modified Huffman technique reduces the compression rate & ratio. The experimental result shows that only 58% to 100% encryption on actual file is done when above 99% modification is in actual file can be observed and compression rate is 1.97bits/base.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.241-248
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• 2002

With the structure of tilde-area computing system which Is specified by a researching team in Vrije University, Netherlands, lots of researchers and developers have been progressing the studies of global location and interconnection services of distributed objects existing in global sites. Most of them halve focused on binding services of only non-duplicated computational objects existing wide-area computing sites without any consideration of duplication problems. But all of objects existing on the earth rave the duplicated characteristics according to how to categorize their own names or properties. These objects with the same property can define as duplicated computational objects. Up to now, the existing naming or trading mechanism has not supported the binding services of duplicated objects, because of deficiency of independent location service. For this reason, we suggest a new model that can not only manages locations of duplicated objects In wide-area computing environments, but also provide minimum binding time by considering both the optimal selection of one of duplicated objects and load balance among distributed systems. Our model is functionally divided into 2 parts, one part to obtain an unique object handle of duplicated objects with same property as a naming and trading service, and the other to search one or more contact addresses by a node manager using a liven object handle, as a location service For location transparency, these services are independently executing each other. Based on our model, we described structure of wide-area integrated tree and algorithms for searching and updating contact address of distributed object on this tree. finally, we showed a federation structure that can globally bind distributed objects located on different regions from an arbitrary client object.

• Journal of KIISE:Databases
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• v.35 no.5
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• pp.432-446
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• 2008

Queries for tracing tag locations are among the most challenging requirements in RFID based applications, including automated manufacturing, inventory tracking and supply chain management. For efficient query processing, a previous study proposed the index scheme for storing tag objects, based on the moving object index, in 3-dimensional domain with the axes being the tag identifier, the reader identifier, and the time. In a different way of a moving object index, the ranges of coordinates for each domain are quite different so that the distribution of query regions is skewed to the reader identifier domain. Previous indexes for tags, however, do not consider the skewed distribution for query regions. This results in producing many overlaps between index nodes and query regions and then causes the problem of traversing many index nodes. To solve this problem, we propose a new disproportional insertion and split policy of the index for RFID tags which is based on the R*-tree. For efficient insertion of tag data, our method derives the weighted margin for each node by using weights of each axis and margin of nodes. Based the weighted margin, we can choose the subtree and the split method in order to insert tag data with the minimum cost. Proposed insertion method also reduces the cost of region query by reducing overlapped area of query region and MBRs. Our experiments show that the index based on the proposed insertion and split method considerably improves the performance of queries than the index based on the previous methods.