• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2587-2605
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• 2022

In order to efficiently detect community structure in complex networks, community detection algorithms can be designed from the perspective of node similarity. However, the appropriate parameters should be chosen to achieve community division, furthermore, these existing algorithms based on the similarity of common neighbors have low discrimination between node pairs. To solve the above problems, a noval community detection algorithm using closeness similarity based on common neighbor node clustering entropy is proposed, shorted as CSCDA. Firstly, to improve detection accuracy, common neighbors and clustering coefficient are combined in the form of entropy, then a new closeness similarity measure is proposed. Through the designed similarity measure, the closeness similar node set of each node can be further accurately identified. Secondly, to reduce the randomness of the community detection result, based on the closeness similar node set, the node leadership is used to determine the most closeness similar first-order neighbor node for merging to create the initial communities. Thirdly, for the difficult problem of parameter selection in existing algorithms, the merging of two levels is used to iteratively detect the final communities with the idea of modularity optimization. Finally, experiments show that the normalized mutual information values are increased by an average of 8.06% and 5.94% on two scales of synthetic networks and real-world networks with real communities, and modularity is increased by an average of 0.80% on the real-world networks without real communities.

• International Journal of Control, Automation, and Systems
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• 제1권4호
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• pp.412-430
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• 2003

In many practical problems in signal processing and control, the signal values are often restricted to belong to a finite number of levels. These questions are generally referred to as "finite alphabet" problems. There are many applications of this class of problems including: on-off control, optimal audio quantization, design of finite impulse response filters having quantized coefficients, equalization of digital communication channels subject to intersymbol interference, and control over networked communication channels. This paper will explain how this diverse class of problems can be formulated as optimization problems having finite alphabet constraints. Methods for solving these problems will be described and it will be shown that a semi-closed form solution exists. Special cases of the result include well known practical algorithms such as optimal noise shaping quantizers in audio signal processing and decision feedback equalizers in digital communication. Associated stability questions will also be addressed and several real world applications will be presented.

• 대한수학교육학회지:수학교육학연구
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• 제11권1호
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• pp.67-87
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• 2001

Variable concept plays a crucial role in understanding not only algebra itself but also school mathematics which is algebra-oriented. It solves as an essential means in applying mathematics to the real world because il enables us to describe varying phenomena in the real world. In this study, we examined some matters related to the learning of variable concept in school mathematics. In Particular, we discussed on the teaching of variable concept in the [7-first] stage of the 7th Mathematics Curriculum. We analysed the textbooks in the [7-first] stage and attempted to explain concretely the contents and teaching methods of variable concept which be taught in school mathematics. After reconsidering the practices on variable concept teaching, we pointed out the problems of formalistic teaching method and then proposed the direction in which variable concept teaching should go.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4557-4572
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• 2020

The Alaska competition provides an opportunity to study the practical problems of real-world steganalysis. Participants are required to solve steganalysis involving various embedding schemes, inconsistency JPEG Quality Factor and various processing pipelines. In this paper, we propose a method to ensemble multiple deep learning steganalyzers. We select SRNet and RESDET as our base models. Then we design a three-layers model ensemble network to fuse these base models and output the final prediction. By separating the three colors channels for base model training and feature replacement strategy instead of simply merging features, the performance of the model ensemble is greatly improved. The proposed method won second place in the Alaska 1 competition in the end.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
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• pp.169-172
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• 2000

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. And the progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of Share collaboration engine and Virtual Architectural Engineering 2000 (VAE2000) system which is our pilot application implemented with Share collaboration engine. And we explain problems presented by our experiments with VAE2000 system. For those problems, we design our new middle-ware system, SHINE(SHared INternet Environment). The SHINE proposes new concepts and approaches for collaboration with 3D objects in a virtual world.

• 무역상무연구
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• 제39권
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• pp.105-142
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• 2008

For many companies, selling in an international market place is the ultimate challenge. One of the greatest problems facing exporters is the increasing insistence by importers that trade be conducted on open account terms. This often means that payment is received many weeks or even months after delivery. Unsurprisingly, many organisations find that giving buyers credit in this way can cause severe cash flow problems. Further problems can arise if the importer delays payment beyond originally agreed terms or makes no payment at all because of financial failure. In particular, many SMEs find it difficult to finance their production cycle, since after goods are delivered most buyers demand 30 to 90 days to pay. Therefore, International factoring for SME has been developing very rapidly in the world trade financing markets. Functions of international factoring as trade financing is a comprehensive financial service that includes credit protection, accounts receivable bookkeeping, collection services and financing. Factoring can be a powerful tool in providing financing to high-risk, informationally opaque sellers. International factoring is very helpful for international exporters to get competitiveness in the world markets. In Korea, a few banks are operating international factoring. But International factoring in Korea could not play a key roll as general trade supporting service. So, This study is to suggest importances of international factoring development for trade development and to investigate real operation situations and problems by way of interviews with operators in banks that are operating international factoring and suggest development strategies for international factoring in Korea.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.787-790
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• 2017

Data quality is the main issue in the classification problems; generally, the presence of noisy instances in the training dataset will not lead to robust classification performance. Such instances may cause the generated decision tree to suffer from over-fitting and its accuracy may decrease. Decision trees are useful, efficient, and commonly used for solving various real world classification problems in data mining. In this paper, we introduce a preprocessing technique to improve the classification accuracy rates of the C4.5 decision tree algorithm. In the proposed preprocessing method, we applied the naive Bayes classifier to remove the noisy instances from the training dataset. We applied our proposed method to a real e-commerce sales dataset to test the performance of the proposed algorithm against the existing C4.5 decision tree classifier. As the experimental results, the proposed method improved the classification accuracy by 8.5% and 14.32% using training dataset and 10-fold crossvalidation, respectively.

• 산업기술연구
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• 제18권
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• pp.139-148
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• 1998

Traditionally, the problems of manufacturing technology and manufacturing management have been treated independently. In this research, we endeavor to integrate the process planning and scheduling activities as an attempt to integrate the two realms. To draw up a plan of process planning and scheduling in real manufacturing environment is not an easy task because available time to plan could be limited and the shop status could change frequently. So we propose an architecture of integrated process planing and scheduling problem within the allowed time even if sheep situations change rather frequently. We argue that we can obtain a better and practical scheduling solution by dynamically changing the processing machines and operations as the shop condition changes. The proposed system takes the initial information for alternative machines and operations represented by an AND/OR graph as its input. Other informational inputs to the system are part order and shop statues. The system then generates new process plan and schedules during permitted time. Experimental results show that the proposed scheme provides a viable solution for real world scheduling problems.

• 디지털산업정보학회논문지
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• 제13권1호
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• pp.113-123
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• 2017

Virtual reality technology is recognized as a next-generation technology and can create realistic environments like the real world and reproduce sensory experiences. And it is a cutting-edge technology that allows humans to experience the same real-world experience in a virtual world by computing the five senses with computers. Also Virtual reality is a technology that has the advantage of experiencing reality in cyberspace and is applied to content such as movies and games. However, many users who use virtual reality can feel cybersickness. And it especially in virtual reality games. This is an important issue for the virtual reality game industry to be resolved. Main symptoms of cyberscickness include dizziness, headache, and vomiting. Existing motion sickness and symptoms are similar, but the cause of cybersickness is different from traditional sickness. Therefore, this study uses virtual reality games and data from various organizations to determine the causes of cybersickness. Also, it intends to contribute to the development of the virtual reality game industry by presenting methods to supplement these problems.

• 한국수학사학회지
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• 제37권3호
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• pp.59-75
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• 2024

This study aims to analyze Joseon mathematical knowledge and its application to real world. The mathematical knowledge refers to measuring the area of plane figures, known as square-shaped land(方田). Its application is land surveys(量田) conducted for taxation purposes. Specifically, this study analyzes the correlation between the related contents in representative mathematical books of the Joseon Dynasty, such as MuksaJipsanbub (17th century), Guiljib (18th century), and SanhakIbmun (18th century), and the shapes and areas of plane figures presented in GwangmuYangan (20th century). The analysis reveals both differences and similarities in the measured area between mathematical books and real world land surveys. While most results of the land survey align with the results obtained from mathematical methods, differences arise due to variations in real measurement of lengths and given conditions in the problems. Additionally, various aspects such as the focus on rectangles in land surveys, the proportionality and relativity of lengths, types of approximation, composed shapes, the purpose of problem solving, and reasoning of unspecified shapes or measures are discussed.