• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.1-23
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• 2005

The shortest-paths problem is a fundamental problem in graph theory and finds diverse applications in various fields. This is why shortest path algorithms have been designed more thoroughly than any other algorithm in graph theory. A large number of optimization problems are mathematically equivalent to the problem of finding shortest paths in a graph. The shortest-path between a pair of vertices is defined as the path with shortest length between the pair of vertices. The shortest path from one vertex to another often gives the best way to route a message between the vertices. This paper presents an $O(n^2)$ time sequential algorithm and an $O(n^2/p+logn)$ time parallel algorithm on EREW PRAM model for solving all pairs shortest paths problem on circular-arc graphs, where p and n represent respectively the number of processors and the number of vertices of the circular-arc graph.

• 복식
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• 제58권10호
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• pp.123-134
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• 2008

The purpose of this study is to examine the postmodern characteristics in global fashion advertising. This analysis of postmodern print campaign strategies will increase the understanding of global fashion consumer and assist in establishing global advertising strategies for domestic fashion brands. 2006 A/W and 2007 S/S magazine campaigns for 190 fashion luxury brands were are collected, which were uploaded on the WGSN website. All advertising campaigns were analyzed in terms of postmodern features by four fashion professionals. As a result, major findings are as follows; First, advertising model stereotype was deconstructed. Besides young celebrities, ad models such as real people and old or childish celebrities were cast. Second, expression technique was deconstructed. Chromatic harmony was broadened to include black and white advertising, additive and subtractive color mixing. Innovative layout techniques such as collage were used. And also narrative structure was deconstructed. Third, diverse issues such as environmental message, globalization, fantasy, feminism, everyday life were expressed as advertisement appeals.

• 한국정보처리학회논문지
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• 제6권11호
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• pp.2954-2964
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• 1999

In this paper, we propose the model to measure and compare the performances of the Linux, PC_Solaris and FreeBSD which are the heterogeneous PC based UNIX kernels connected by network. Using the stop-watch timer with the $mutextrm{s}$ unit, we measure the important performance indices of UNIX kernels which are the primitive and command execution time and disk I/O time. Also we measure the message transfer time using the TCP, UDP and RPC methods to compare the network performance of UNIX kernels. And we compare the performance of NFS for each UNIX kernels. And we display the measured data on internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3911-3924
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• 2016

Compared to the classical cryptography, lattice-based cryptography is more secure, flexible and simple, and it is believed to be secure against quantum computers. In this paper, an efficient signature scheme is proposed from the ring learning with errors (R-LWE), which avoids sampling from discrete Gaussians and has the characteristics of the much simpler description etc. Then, the scheme is implemented in C/C++ and makes a comparison with the RSA signature scheme in detail. Additionally, a linearly homomorphic signature scheme without trapdoor is proposed from the R-LWE assumption. The security of the above two schemes are reducible to the worst-case hardness of shortest vectors on ideal lattices. The security analyses indicate the proposed schemes are unforgeable under chosen message attack model, and the efficiency analyses also show that the above schemes are much more efficient than other correlative signature schemes.

• ETRI Journal
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• 제37권1호
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• pp.186-196
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• 2015

In resource-constrained, low-cost, radio-frequency identification (RFID) sensor-based mobile ad hoc networks (MANETs), ensuring security without performance degradation is a major challenge. This paper introduces a novel combination of steps in lightweight protocol integration to provide a secure network for RFID sensor-based MANETs using error-correcting codes (ECCs). The proposed scheme chooses a quasi-cyclic ECC. Key pairs are generated using the ECC for establishing a secure message communication. Probability analysis shows that code-based identification; key generation; and authentication and trust management schemes protect the network from Sybil, eclipse, and de-synchronization attacks. A lightweight model for the proposed sequence of steps is designed and analyzed using an Alloy analyzer. Results show that selection processes with ten nodes and five subgroup controllers identify attacks in only a few milliseconds. Margrave policy analysis shows that there is no conflict among the roles of network members.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.659-679
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• 2015

Distributed applications are composed of multiple nodes, which exchange information with individual nodes through message passing. Compared with traditional applications, distributed applications have more complex behavior patterns because a large number of interactions and concurrent behaviors exist among their distributed nodes. Thus, it is difficult to detect anomalous behaviors and determine the location and scope of abnormal nodes, and some attacks and misuse cannot be detected. To address this problem, we introduce a method for detecting anomalous behaviors based on process algebra. We specify the architecture of the behavior detection model and the detection algorithm. The anomalous behavior detection and analysis demonstrate that our method is a good discriminator between normal and anomalous behavior characteristics of distributed applications. Performance evaluation shows that the proposed method enhances efficiency without security degradation.

• 산업기술연구
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• 제25권B호
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• pp.221-229
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• 2005

We present a numerical analysis of the optimal group number for minimizing the average paging delay. In the analysis, we consider uniform distributions for location probability conditions and apply M/D/1 queueing model to paging message queues of cells. We also get the lower bounds of group numbers and investigate the minimum transmission capacity under average paging delay constraints. Minimizing the average paging delay is important because it means minimizing the amount of bandwidth used for locating mobile terminals. Therefore, the numerical results of this paper will be very useful in PCS system when designing its signalling capacity due to its simplicity and effectiveness.

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.166-170
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• 2010

To numerically calculate electromagnetic scattering from the electrical-large three-dimensional(3D) objects, the high-frequency approaches have been usually applied, but the accuracy and feasibility of these geometrical and physical optics(GO-PO) approaches, to some extent, are remained to be improved. In this paper, a new framework is developed for calculation of the near-field scattering field of an electrical-large 3D target by using a multilevel fast multipole algorithm(MLFMA) and generation of radar images by using a fast back-projection(FBP) algorithm. The MPI(Message Passing Interface) parallel computing is carried out to multiply the calculation efficiency greatly. Finally, a simple example of perfectly electrical conducting(PEC) patch and a canonical case of Fighting Falcon F-16 are presented.

• 디지털산업정보학회논문지
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• 제5권3호
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• pp.9-18
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• 2009

This paper proposes a Ubiquitous Henhouse Monitoring System (UHMS) that can not only monitor henhouse's conditions and raising environments, but also control the henhouse remotely by using sensor network technology. The system consists of three layers. The physical layer connects sensors with facilities. The middleware layer processes and manages data collected from the physical layer. And the application layer provides the user with the user requested services. The system provides a real-time monitoring service, a facility controlling service, an expert service, a consumer safety service, and a mobile message service via interacting with components of each layer. Finally, a henhouse model is defined and the relevant system components and the application GUIs are implemented.

• Asia pacific journal of information systems
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• 제25권4호
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• pp.805-822
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• 2015

Online communities are an important source of electronic word-of-mouth (e-WOM). However, few studies have examined the use of such messages within the Middle Eastern context. This study focuses on Saudi women as members of an online beauty forum. Previous work suggested a mediating effect of gender, with women being more likely to trust word-of-mouth and follow it up with a purchase. A conceptual model with a theoretical underpinning from existing contributions in literature provides the basis of a coding framework for the message characteristics that influence members' e-WOM adoption. A total of 310 threads and 2200 messages coded into 5725 units were content analyzed to demonstrate cases where e-WOM was adopted and indicate further continuance intention with members returning to the forum. A new category of 'community bonding' was created from the content analysis given the prevalence of emotional aspects in messages. Emotion expressed in messages, often expressed in religious terms, is as influential and important as the cognitive aspects of community bonding.