• The KSFM Journal of Fluid Machinery
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• v.14 no.3
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• pp.59-64
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• 2011

Wind turbine frame will be required to be longer, lighter, more reliable and more consistent. Therefore it is necessary to lose weight of the wind turbine hub. Light-weight Design of a wind turbine is required to be at least 20 years. Therefore, this paper investigates the development for wind turbine rotor hub using design of topology optimization. The model is a pitch regulated wind turbine with three rotor blades where the main frame is made of nodular iron. For optimization, calculating stresses based on displacements and based on these data to carry out a verification of static and fatigue strength carried out. For this verification, two kind of analysis is used. One is static analysis and the other is fatigue analysis. Then the rotor hub of wind turbine frame is optimized using topology method.

• IE interfaces
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• v.25 no.1
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• pp.13-20
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• 2012

Recently, the collaboration among small and medium-sized enterprises(SMEs) has been recognized as an effective competitive tool. As several systems have been developed to boost the collaboration, it is necessary to analyze the effectiveness of the systems in terms of their contribution to enhance operational performance of SMEs through objective and quantitative validation. In particular, the analysis for SMEs rather than large-scaled enterprises has not received much attention due to lack of relevant information and difficulty of collecting data. This paper presents a framework for analyzing the effectiveness of the collaboration support system, called i-manufacturing hub, which has been implemented by Korean government. Identification of influential factors to the effectiveness of collaboration hub, and constructing necessary hypotheses are proposed. To overcome the difficulty in data collection only by means of surveys through subjective questionnaires, we exploit system log data that are generated while SMEs use the system. As an initial phase to analyze the effectiveness through hypothesis validation, we discuss several interesting observations and challenges in the direction of enhancing collaboration among SMEs for better operational performance improvement and more participation in the collaboration hub.

• International Commerce and Information Review
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• v.14 no.3
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• pp.209-227
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• 2012

Northeast Asia where is an epicenter of the global financial crisis's conquest is traditional imbalanced region of oil production and consumption. In recent years, the region has been suffered by the shortage of oil storage and transportation facilities due to surging oil trading and necessity in strategic reserves. Therefore, since independent petroleum logistics with the storage facilities and oil trading hub is required to form efficient oil market in this region. In this study, we analyzed the efficiency of refinery facilities by country that is of importance in being a logistics hub in Northeast Asia by employing non-static and dynamic efficiency analysis, which are a part of DEA(Data Envelopment Analysis) and then policy implications have been drawn. The result illustrates Korea's is the highest country in terms of efficiency of oil refining facilities in Northeast Asia. It implies that Korea has strong position to be the oil hub in Northeast Asia.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.379-390
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• 2022

While the construction industry is striving to make changes suitable for the 4th industrial revolution era through the introduction of 4th industrial revolution technologies, such change is progressing more slowly than in other industries. Nevertheless, the recent digitization and digital transformation of the construction industry can provide a new paradigm to address and innovate the chronic problems faced by the construction industry. Therefore, in this study, a case study using a data hub and API for use of the data hub, which is essential for digitalization and digital transformation, was conducted, and the efficiency and feasibility of using the data hub and API were considered. When the API system was introduced, it was found that the average budget savings per person was about 23%, and the costbenefit ratio was about 4.4 times higher, indicating that the feasibility of the project was very high. The results and framework of this study can serve as fundamental research data for related research, and provide a worthy case study to promote the introduction of related technologies. This will ultimately contribute to digitalization and digital transformation for smartization of the construction industry.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.61-68
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• 2015

For a recent most companies to make efficient business management, we are using a groupware service of integrated information system of the entire group. Groupware service integrates the cooperation in excellent synergy and duplicates has been business functions of the business, through the improvement of multi-purpose business processing capacity, there is an advantage of reduced operating costs. However, if the parent company and subsidiary, or to handle common tasks such information agency, which may cause differences in the format of the data passed in the case of a need to provide a document. Therefore, in this paper, in order to solve the heterogeneity problem in data between groups, the data system of the hub base of the cloud is provided. The proposed system is intended to improve the groupware environment including the interoperability of integrated standardized environmental data sharing service.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.161-168
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• 2024

As the size of big data models grows, distributed training is emerging as an essential element for large-scale machine learning tasks. In this paper, we propose ParamHub for distributed data training. During the training process, this agent utilizes the provided data to adjust various conditions of the model's parameters, such as the model structure, learning algorithm, hyperparameters, and bias, aiming to minimize the error between the model's predictions and the actual values. Furthermore, it operates autonomously, collecting and updating data in a distributed environment, thereby reducing the burden of load balancing that occurs in a centralized system. And Through communication between agents, resource management and learning processes can be coordinated, enabling efficient management of distributed data and resources. This approach enhances the scalability and stability of distributed machine learning systems while providing flexibility to be applied in various learning environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.89-97
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• 2024

The problem of the spokes puzzle(SP), which connects the spokes(edges) required by the wheel axis (hub, vertex) without intersection to form a network in which all the hubs are connected, can be said to be a wasteland of research. For this problem, there is no algorithm that presents a brute-force search or branch-and-bound method that takes exponential time. This paper proposes an algorithm to plot a lattice graph with cross-diagonal lines of m×n for a given SP and to pruning(delete) the surplus edges(spokes). The proposed algorithm is a simple way to select an edge of a hub whose number of edges matches the hub requirement and delete the edge crossing it. If there is no hub with an edge that meets the hub requirement, a strategy was adopted to preferentially delete(pruning) the edge of the hub with the maximum amount of spare. As a result of applying the proposed algorithm to 20 benchmarking experimental data, it was shown that a solution that minimizes the number of trials and errors can be obtained for all problems.

• Journal of Distribution Science
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• v.11 no.6
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• pp.31-40
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• 2013

Purpose - The Northeast Asian Logistic Hub strategy was established to create a national competitive advantage in northeast Asia. Countries in this region are competing fiercely to become the central base distribution port as the volume of container shipping continues to increase due to the northeast Asian (especially Chinese) economic growth. The primary method by which shippers are improving their customer service and distribution is enhancing profits by minimizing call ports on the key route through strategic affiliations and the use of large vessels. Each nation is planning large-scale investments in the construction of sea ports that can accommodate large vessels. This paper proposes ways by which the logistical strategies of domestic corporations can keep pace with changes in government policy concerning the Northeast Asian Business Hub policy. It examines the logistics system in the Northeast Asian region, analyzes the government's Northeast Asian Business Hub policy, and suggests logistical strategies for domestic corporations through an analysis based on a questionnaire designed to grasp domestic firms' needs and goals. Research design, data and methodology - The purpose of this study is to determine how shipping companies establish partnerships with third-party logistics providers and draws out the implications of the results. The survey methods used were personal interviews and questionnaires distributed to a sample population through e-mail, fax, mail, and telephone. A total of 600 questionnaires were distributed, of which 165 were returned. Among these, ten were excluded due to insufficient content; ultimately, 155 were used for the sample. The statistical data collection process was analyzed through data coating and a statistical package program. Results - This study argues that greater flexibility in policies, administration, and systems will be needed to significantly improve established business practices. In this dissertation, we primarily identify that in order to become a center of northeast Asian logistics, Korea must adopt a new paradigm and abandon the existing systems that are based on the economic and social systems that have stemmed from bureaucracy, inflexibility, chauvinism, and equalitarianism. Flexible policies, administration, and systems will be necessary to improve business practices. Domestic corporations must establish a strategic logistics hub and related network while simultaneously pursuing value-added logistics businesses by increasing their manpower and building a logistics information system. This will strengthen their competitive edge and lead to system improvements. Conclusions - Domestic corporations must adopt a new paradigm and use more reasonable business laws, systems, and policies that are based on market-driven flexibility and transparency. Moreover, social norms and regulations should be established to help ensure political and social security. Korea must also develop a culture of tolerance for foreign companies. Finally, the paradigm defining the policy governing the development of the capital city and its satellite cities in this context must be changed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1250-1260
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• 2014

In this paper, a novel resource scheduling, which is used for hub network based long distance airborne tactical communication, is proposed. Recently, some countries of the world has concentrated on developing data rate and networking performance of CDL, striving to keep pace with modern warfare, which is changed into NCW. And our government has also developed the next generation high capacity CDL. In hub network, a typical communication structure of CDL, hybrid FDMA/TDMA can be considered to exchange high rate data among multiple UAVs simultaneously, within limited bandwidth. However, due to different RTT and traffic size of UAV, idle time resource and unnecessary packet transmission delay can occur. And these losses can reduce entire efficiency of hub network in long distance communication. Therefore, in this paper, we propose RTT and data traffic size based UAV scheduling, which selects time/frequency resource of UAVs by using iterative sorting algorithm. The simulation results verified that the proposed scheme improves data rate and packet delay performance in low complexity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6D
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• pp.917-926
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• 2006

Transportation Economies of scale are the essential properties of hub networks. One critical property of the hub network design problem is to quantify cost savings which stem from economies of scale, the costs of operating hub facilities and opportunity costs associated with delays stemming from consolidation of traffic flows. Due to the NP-complete property of the hub location problem, however, most previous researchers have focused on the development of heuristic algorithms for approximate solutions. The purpose of this paper is to develop a hub network design model considering transportation economies of scale from the consolidation of traffic flows. The model is designed to consider the uniqueness of hub networks and to determine several cost components. The heuristic algorithms for the developed model are suggested and the results of the model are compared with recently published studies using real data. Results of the analysis show that the proposed model reflects transportation economies of scale due to consolidation of flows. This study can form not only the theoretical basis of an effective and rational hub network design but contribute to the assessment of existing and planned logistics systems.