• International Journal of Computer Science & Network Security
• /
• v.21 no.11
• /
• pp.312-320
• /
• 2021

Increase in computational cost and exhaustive search can lead to more complexity and computational energy. Thus, there is need for effective and efficient scheme to reduce the complexity to achieve optimal energy utilization. This will improve the energy efficiency and enhance the proficiency in terms of the resources needed to achieve convergence. This paper primarily focuses on the development of hybrid swarm intelligence scheme for reducing the computational complexity in binary optimization. In order to reduce the complexity, both artificial bee colony (ABC) and particle swarm optimization (PSO) have been employed to effectively minimize the exhaustive search and increase convergence. First, a new approach using ABC and PSO has been proposed and developed to solve the binary optimization problem. Second, the scout for good quality food sources is accomplished through the deployment of PSO in order to optimally search and explore the best source. Extensive experimental simulations conducted have demonstrate that the proposed scheme outperforms the ABC approaches for reducing complexity and energy consumption in terms of convergence, search and error minimization performance measures.

• Journal of Industrial Technology
• /
• v.27 no.B
• /
• pp.37-42
• /
• 2007

A mobile ad hoc network (MANET) is a kind of wireless ad hoc network. It is a self-configuring network of mobile nodes connected by wireless links. Infostation is a lower cost and low power system that provides very high bit rate with limited coverage. In this study, we propose search and rescue system that combines MANET of climbers with Infostations. A climber shares location information of climbers with other climbers while climbing, and delivers the information to Infostations. This system is an intermittent network due to the mobility of nodes. From the system, we can track the locations of missing climbers. Ultimately, proposed system achieves low cost and reduces memory requirement using Infestations. We also analyze the performance of the proposed system by simulation. From the performance analysis results, we expect that the proposed system will be very useful to early detect climbers' locations in emergency situations in Korea mountain areas.

• Journal of Advanced Navigation Technology
• /
• v.21 no.5
• /
• pp.443-449
• /
• 2017

Swarm of low-cost UAVs for search mission has benefit in the sense of rapid search compared to use of single high-end UAV. As the number of UAVs forming swarm increases, not only the time for the mission planning increases, but also the system to operate UAVs has excessive burden. This paper addresses a decentralized area search algorithm adequate for multiple UAVs which takes advantages of flexibility, robustness, and simplicity. To down the cost, it is assumed that each UAV has limited ability: close-communication, basic calculation, and limited memory. In close-communication, heath conditions and search information are shared. And collision avoidance and consensus of next search direction are then done. To increase weight on un-searched area and to provide overlapped search, the score function is introduced. Performance and operational characteristics of the proposed search algorithm and mission planning logic are verified via numerical simulations.

• The Journal of Information Systems
• /
• v.19 no.3
• /
• pp.35-58
• /
• 2010

Portal sites have been providing diverse services to attract new users and retain existing customers. Recently, they also added new services and increased quality of the services they provide to secure more customers. It is, however, not clear how people actually react to such activities. We wanted to understand the mechanism associated with users' continued usage intention of current Portal site. We assumed search, e-mail, information, community, e-commerce services as key services provided by most Portal sites and considered valuable by many customers. The quality of these services may directly affect users' continued usage intention. However, we can also assume that attractive alternatives and switching cost may have some influence on users' continued usage intention. Therefore, in this study, key variables pertaining to the quality of key services provided by Portal sites, attractive alternatives, and switching cost were examined to explain the dynamics of users' continued usage intention. An empirical study based on 891 survey responses showed the importance of the quality of key services for users' continued usage intention. Switching cost also demonstrated strong association with users' continued usage intention. However, attractive alternatives did not show a significant association with users' continued usage intention. We also found that the variable attractive alternatives moderated the relationship between the quality of search service and users' continued usage intention and the relationship between the quality of information service and users' continued usage intention. On the other hand, the variable switching cost showed a moderating effect on the relationship between the quality of e-mail service and users' continued usage intention and the relationship between the quality of community service and users' continued usage intention. This study implies that Portal sites need to make efforts not only to improve the quality of key services but also to consider attractiveness of other Portal sites' services and switching cost to secure more customers.

• IE interfaces
• /
• v.15 no.4
• /
• pp.338-348
• /
• 2002

In this paper, we present a restricted tabu search(RTS) algorithm that schedules jobs on identical parallel machines in order to minimize the maximum lateness of jobs. Jobs have release times and due dates. Also, sequence-dependent setup times exist between jobs. The RTS algorithm consists of two main parts. The first part is the MATCS(Modified Apparent Tardiness Cost with Setups) rule that provides an efficient initial schedule for the RTS. The second part is a search heuristic that employs a restricted neighborhood generation scheme with the elimination of non-efficient job moves in finding the best neighborhood schedule. The search heuristic reduces the tabu search effort greatly while obtaining the final schedules of good quality. The experimental results show that the proposed algorithm gives better solutions quickly than the existing heuristic algorithms such as the RHP(Rolling Horizon Procedure) heuristic, the basic tabu search, and simulated annealing.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.521-523
• /
• 2006

This paper proposes an algorithm and its data structure to support real-time full-text search for the streamed or broadcasted multimedia data containing real-time stenograph text. Since the traditional indexing method used at information retrieval area uses the linguistic information, there is a heavy cost. Therefore, we propose the algorithm and its data structure based on suffix array, which is a simple data structure and has low space complexity. Suffix array is useful frequently to search for huge text. However, subtitle text of multimedia data is to get longer by time. Therefore, suffix array must be reconstructed because subtitle text is continually changed. We propose the data structure called prefix array and search algorithm using it.

• Journal of Communications and Networks
• /
• v.4 no.3
• /
• pp.246-255
• /
• 2002

Constrained minimum Steiner tree (CMST) problem is a key issue in multicast routing with quality of service (QoS) support. Bounded shortest path algorithm (BSMA) has been recognized as one of the best algorithms for the CMST problem due to its excellent cost performance. This algorithm starts with a minimumdelay tree, and then iteratively uses a
-shortest-path (KSP) algorithm to search for a better path to replace a “superedge” in the existing tree, and consequently reduces the cost of the tree. The major drawback of BSMA is its high time complexity because of the use of the KSP algorithm. For this reason, we investigate in this paper the possibility of more efficient implementations of BSMA by using different methods to locate the target path for replacing a superedge. Our experimental results indicate that our methods can significantly reduce the time complexity of BSMA without deteriorating the cost performance.

• Journal of Information Processing Systems
• /
• v.10 no.4
• /
• pp.628-645
• /
• 2014

In past few years, distributed hash table (DHT)-based P2P systems have been proven to be a promising way to manage decentralized index information and provide efficient lookup services. However, the skewness of users' preferences regarding keywords contained in a multi-keyword query causes a query load imbalance that combines both routing and response load. This imbalance means long file retrieval latency that negatively influences the overall system performance. Although index replication has a great potential for alleviating this problem, existing schemes did not explicitly address it or incurred high cost. To overcome this issue, we propose, in this paper, an integrated solution that consists of three replication schemes to alleviate query load imbalance while minimizing the cost. The first scheme is an active index replication that is used in order to decrease routing load in the system and to distribute response load of an index among peers that store replicas of the index. The second scheme is a proactive pointer replication that places location information of each index to a predetermined number of peers for reducing maintenance cost between the index and its replicas. The third scheme is a passive index replication that guarantees the maximum query load of peers. The result of simulations indicates that the proposed schemes can help alleviate the query load imbalance of peers. Moreover, it was found by comparison that our schemes are more cost-effective on placing replicas than PCache and EAD.

• The KIPS Transactions:PartD
• /
• v.18D no.4
• /
• pp.225-236
• /
• 2011

Various applications of LBS (Location Based Services) are being developed to provide the customized service depending on user's location with progress of wireless communication technology and miniaturization of personalized device. To effectively process an amount of vehicles' location data, LBS requires the techniques such as vehicle observation, data communication, data insertion and search, and user query processing. In this paper, we propose the historical location index, GIP-FB (Group Insertion tree with Flexible Buffer Node) and the flexible buffer node technique to adjust the cost of data insertion and search. the designed GIP+ based index employs the buffer node and the projection storage to cut the cost of insertion and search. Besides, it adjusts the cost of insertion and search by changing the number of line segments of the buffer node with user defined time interval. In the experiment, the buffer node size influences the performance of GIP-FB by changing the number of non-leaf node of the index. the proposed flexible buffer node is used to adjust the performance of the historical location index depending on the applications of LBS.

• Journal of the Korean Society for information Management
• /
• v.26 no.1
• /
• pp.185-214
• /
• 2009

The purpose of this study is aimed to clarify the usefulness of meta search system using Open API of library online catalog by constructing OPAC-based search system using Open API of library online catalog and meta search system using Open API of library online catalog, and comparing the usability of the two experimental search systems. As for usability, on the whole, it was higher in meta search system using Open API of library online catalog than OPAC-based search system using Open API of library online catalog, and there was statistically significant difference. Therefore, if libraries share and use enriched content which is provided through Open API for book search, which is opened by Internet bookstores, search engines and Web portals, it is expected that it will be helpful in enhancing bibliographic data, expanding subject access point, empowering subject search ability, extending meta search service, improving book availability, and reducing catalog cost.