• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1309-1314
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• 2007

The assignment of cells to reporting or non-reporting cells is an NP-hard problem having an exponential complexity in the Reporting Cell Location Management (RCLM) system. Frequent location update may result in degradation of quality of service due to interference. Miss on the location of a mobile terminal will necessitate a search operation on the network when a call comes in. The number of reporting cells and which cell must be reporting cell should be determined to balance the registration (location update) and search (paging) operations to minimize the cost of RCLM system. T1is paper compares Max-Min ant system (MMAS), rank-based ant system (RAS) and hybrid method of MMAS and RAS that generally used to solve combinatorial optimization problems. Experimental results demonstrate that hybrid method of MMAS and RAS is an effective and competitive approach in fairly satisfactory results with respect to solution quality and execution time for the optimal design of location management system.

• Journal of Korean Society of Rural Planning
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• v.13 no.4
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• pp.9-22
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• 2007

With the establishment of municipalities, public interest in small towns in Korea has been on the rise. To initiate an effective study and suggest subsequent policies for small towns, it is necessary to analyze and discuss substantive issues based on specific conditions of these small towns. The primary objective of this paper is to categorize small towns into types and to analyze the peculiarities and differences of their internal factors. The focus of this research is to determine the general characteristics of the classified towns and to suggest specific revitalization and specialized studies about them. In the main analysis of this paper, 39 small towns are divided into sets according to urban rank, conditions of location, and size of the population in the central site. Furthermore, distinctions of the divided towns are analyzed using three constituents for urban organization, including populations, activities, and facilities/land. From the research results, it was determined that there is a difference between small town types, according to population, land cost, and urban activities, based upon the urban rank and size of the population in the central site. Therefore, this paper concludes it is necessary to conduct further studies on time series analysis regarding the peculiarity changes of the types, and to complement the variables for future related studies.

• Journal of Information Technology Services
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• v.22 no.1
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• pp.57-74
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• 2023

It has been pointed out as a limitation that the rank of some efficient DMUs(decision making units) cannot be discriminated due to the relativity nature of efficiency measured by DEA(data envelopment analysis), comparing the production structure. Recently, to solve this problem, a DEA-SNA(social network analysis) model that combines SNA techniques with data envelopment analysis has been studied intensively. Several models have been proposed using techniques such as eigenvector centrality, pagerank centrality, and hypertext induced topic selection(HITS) algorithm, but DMUs that cannot be ranked still remain. Moreover, in the process of extracting latent information within the DMU group to build effective network, a problem that violates the basic assumptions of the DEA also arises. This study is meaningful in finding the cause of the limitations by comparing and analyzing the characteristics of the DEA-SNA model proposed so far, and based on this, suggesting the direction and possibility to develop more advanced model. Through the results of this study, it will be enable to further expand the field of research related to DEA.

• The Korean Journal of Emergency Medical Services
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• v.26 no.3
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• pp.21-35
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• 2022

Purpose: The purpose of this study was to investigate the effects of firefighters' job stress and emotional labor on their turnover intention, and analyze the main factors impacting turnover intention in this context. Methods: Based on a descriptive survey study design, we administered a structured questionnaire among 231 firefighters at one fire station in G metropolitan city from November 13 to 27, 2020. Results: Regarding job stress, participants showed differences based on marital status (p<.05), health status (p<.001), total service period (p<.05), and assignment (p<.05). For emotional labor, a significantly higher rate was observed for female than male firefighters (p<.05), with differences also observed in age (p<.001), health status (p<.001), total service period (p<.05), rank (p<.001), and assignment (p<.05). Further, for turnover intention, significant differences were noted with respect to age (p<.001), education (p<.01), health status (p<.001), total service period (p<.01), work unit (p<.05), rank (p<.001), and assignment (p<.05). A significant correlation was found between job stress and emotional labor and turnover intention. Regarding the factors affecting turnover intention, significant differences were noted based on education, rank, job stress, and emotional labor; the explanatory power was 53.9% (F=13.806, p<.001). Conclusion: Tailored support programs must be developed to ease firefighters' job stress and reduce their emotional labor to facilitate effective manpower management and reduce firefighters' turnover intention.

• Journal of the Korean Society for information Management
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• v.16 no.1
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• pp.7-30
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• 1999

This study is to develop effective document ranking algorithms in the P-norm retrieval system which can be implemented to the Boolean retrieval system without major difficulties by using non-statistical term weights based on document structure. Also, it is to enhance the performance by introducing the rank adjustment process which rearranges the ranks of retrieved documents according to the similarity between the top ranked documents and the rest of them. Of the non-statistical term weight algorithms, this study uses field weight and term pair distance weight. In the rank adjustment process, five retrieval experiments were performed, ranging between the case of using one record for the similarity measurement and the case of using first five records. It is proved that non-statistical term weights are highly effective and the rank adjustment process enhance the performance further.

• Investigative Magnetic Resonance Imaging
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• v.20 no.4
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• pp.215-223
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• 2016

Purpose: The management of metal-induced field inhomogeneities is one of the major concerns of distortion-free magnetic resonance images near metallic implants. The recently proposed method called "Slice Encoding for Metal Artifact Correction (SEMAC)" is an effective spin echo pulse sequence of magnetic resonance imaging (MRI) near metallic implants. However, as SEMAC uses the noisy resolved data elements, SEMAC images can have a major problem for improving the signal-to-noise ratio (SNR) without compromising the correction of metal artifacts. To address that issue, this paper presents a novel reconstruction technique for providing an improvement of the SNR in SEMAC images without sacrificing the correction of metal artifacts. Materials and Methods: Low-rank approximation in each coil image is first performed to suppress the noise in the slice direction, because the signal is highly correlated between SEMAC-encoded slices. Secondly, SEMAC images are reconstructed by the best linear unbiased estimator (BLUE), also known as Gauss-Markov or weighted least squares. Noise levels and correlation in the receiver channels are considered for the sake of SNR optimization. To this end, since distorted excitation profiles are sparse, $l_1$ minimization performs well in recovering the sparse distorted excitation profiles and the sparse modeling of our approach offers excellent correction of metal-induced distortions. Results: Three images reconstructed using SEMAC, SEMAC with the conventional two-step noise reduction, and the proposed image denoising for metal MRI exploiting sparsity and low rank approximation algorithm were compared. The proposed algorithm outperformed two methods and produced 119% SNR better than SEMAC and 89% SNR better than SEMAC with the conventional two-step noise reduction. Conclusion: We successfully demonstrated that the proposed, novel algorithm for SEMAC, if compared with conventional de-noising methods, substantially improves SNR and reduces artifacts.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.1-9
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• 2024

Multivariate Quadratic (MQ)-based digital signature schemes have advantages such as ease of implementation and small signature sizes, making them promising candidates for post-quantum cryptography. To enhance the efficiency of such MQ-based digital signature schemes, utilizing sparse matrices have been proposed, including HiMQ, which has been standardized by Korean Telecommunications Technology Association standard. However, HiMQ shares a similar key structure with Rainbow, which is a representative MQ-based digital signature scheme and was broken by the MinRank attack proposed in 2022. While HiMQ was standardized by a TTA and recommended parameters were provided, these parameters were based on cryptanalysis as of 2020, without considering recent attacks. In this paper, we examine attacks applicable to MQ-based digital signatures, specifically targeting HiMQ, and perform a security analysis. The most effective attack against HiMQ is the combined attack, an improved version of the MinRank attack proposed in 2022, and none of the three recommended parameters satisfy the desired security strength. Furthermore, HiMQ-128 and HiMQ-160 do not meet the minimum security strength requirement of 128-bit security level.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.1
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• pp.47-55
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• 2000

In this paper, a vision-based roadway detection algorithm for an automated vehicle control system, based on roadway sign information on roads, is proposed. First, in order to detect roadway signs, the color scene image is enhanced under hue-invariance. Fuzzy logic is employed to simplify the enhanced color image into a binary image and the binary image is morphologically filtered. Then, an effective algorithm of locating signs based on binary rank order transform (BROT) is utilized to extract signs from the image. This algorithm performs better than those previously presented. Finally, the inner shapes of roadway signs with curving roadway direction information are recognized by neural networks. Experimental results show that the new detection algorithm is simple and robust, and performs well on real sign detection. The results also show that the neural networks used can exactly recognize the inner shapes of signs even for very noisy shapes.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.653-661
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• 2012

The purpose of this research is to analyze teacher's lesson language pattern based on robot class. For this research as an analytical tool AF (Advanced Flanders) was utilized. Actually ClassReport ver 1.0 computer program was used in the process of input data. From the results of the Flanders index, The major instruction sequences were 4-8-3 in elementary school and 4-8 in middle school. The teacher's remarks in robot class in the elementary school rank 'instruction', 'question'. And In the middle school rank 'instruction' and 'positive advice' are very high ratio, but 'indication' is low ratio. The teacher constantly teach and ask question ratio in the middle school was higher than elementary school. But a tendency for non-indication was low ratio in the middle school than elementary school. These results could provide effective cues and information on how to to improve instruction.

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.444-451
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• 1998

The cost-effective reduction of occupational radiation exposure (ORE) dose at a nuclear power plant could not be achieved without going through an extensive analysis of accumulated ORE dose data of existing plants. It is necessary to identify what are high ORE jobs for ALARA implementation. In this study, the Rank Sum Method (RSM) is used in identifying high ORE jobs. As a case study, the database of ORE-related maintenance and repair jobs for Kori Units 3 and 4 is used for assessment, and top twenty high ORE jobs are identified. The results are also verified and validated using the Friedman test, and RSM is found to be a very efficient way of analyzing the data.