• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.5171-5189
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• 2016

With the popularity of cloud computing, many data owners outsource their graph data to the cloud for cost savings. The cloud server is not fully trusted and always wants to learn the owners' contents. To protect the information hiding, the graph data have to be encrypted before outsourcing to the cloud. The adjacent vertex search is a very common operation, many other operations can be built based on the adjacent vertex search. A boolean adjacent vertex search is an important basic operation, a query user can get the boolean search results. Due to the graph data being encrypted on the cloud server, a boolean adjacent vertex search is a quite difficult task. In this paper, we propose a solution to perform the boolean adjacent vertex search over encrypted graph data in cloud computing (BASG), which maintains the query tokens and search results privacy. We use the Gram-Schmidt algorithm and achieve the boolean expression search in our paper. We formally analyze the security of our scheme, and the query user can handily get the boolean search results by this scheme. The experiment results with a real graph data set demonstrate the efficiency of our scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.816-818
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• 2016

The Industry 4.0 should decide work operation of manufacture facilities by itself. But small and medium sized enterprises(SMEs) still not prepared these work operations. In this paper, we had research that work operation manufacture facilities of a management system of mold life-cycle based on CPS. The management system of mold manages life-cycle using by shot, this information offers users by cloud system. This system will help SMEs products quality improve and business operation more efficiency.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.6
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• pp.375-382
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• 2022

This paper proposes a multi-core cooperative computing structure considering the heterogeneous features of automotive embedded on-chip software. The automotive embedded software has the heterogeneous execution flow properties for various hardware drives. Software developed with a homogeneous execution flow without considering these properties will incur inefficient overhead due to core latency and load. The proposed method was evaluated on an target board on which a automotive MCU (micro-controller unit) with built-in multi-cores was mounted. We demonstrate an overhead reduction when software including common embedded system tasks, such as ADC sampling, DSP operations, and communication interfaces, are implemented in a heterogeneous execution flow. When we used the proposed method, embedded software was able to take advantage of idle states that occur between heterogeneous tasks to make efficient use of the resources on the board. As a result of the experiments, the power consumption of the board decreased by 42.11% compared to the baseline. Furthermore, the time required to process the same amount of sampling data was reduced by 27.09%. Experimental results validate the efficiency of the proposed multi-core cooperative heterogeneous embedded software execution technique.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.9
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• pp.309-316
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• 2022

In 2011, the 4^th industrial revolution officially occurred and developed in most countries. The fourth industrial revolution has given organizations numerous business opportunities, enabling them to optimize their manufacturing processes, cut costs, and thereby improve their operations. The development of enterprises is a decisive factor in increasing national productivity, thereby improving economic growth and per capita income. Therefore, it is necessary to grasp the digital transformation plan and apply science and technology to domestic enterprises and improve the operational efficiency of the economy. Research on small and medium enterprises in Hanoi, Vietnam, which is considered a successful country in economic development and digital transformation and has become a middle-income economy and a highly open economy, the research results suggest that the ability to apply technology in businesses is capable of improving corporate financial performance. The choice of capital structure favoring debt has a negative effect on the financial performance of the enterprise; that is, enterprises in Vietnam should limit the choice of financing investment projects with debt, on the contrary, enterprises should choose to finance with equity. Finally, the study also discusses managerial implications for improving business performance in the context of the rapidly evolving 4.0 technology revolution.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.40-48
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• 2022

An automated material handling system (AMHS) has been emerging as an important factor in the semiconductor wafer manufacturing industry. In general, an automated guided vehicle (AGV) in the Fab's AMHS travels hundreds of miles on guided paths to transport a lot through hundreds of operations. The AMHS aims to transfer wafers while ensuring a short delivery time and high operational reliability. Many linear and analytic approaches have evaluated and improved the performance of the AMHS under a deterministic environment. However, the analytic approaches cannot consider a non-linear, non-convex, and black-box performance measurement of the AMHS owing to the AMHS's complexity and uncertainty. Unexpected vehicle congestion increases the delivery time and deteriorates the Fab's production efficiency. In this study, we propose a Q-Learning based dynamic routing algorithm considering vehicle congestion to reduce the delivery time. The proposed algorithm captures time-variant vehicle traffic and decreases vehicle congestion. Through simulation experiments, we confirm that the proposed algorithm finds an efficient path for the vehicles compared to benchmark algorithms with a reduced mean and decreased standard deviation of the delivery time in the Fab's AMHS.

• Journal of Wind Energy
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• v.14 no.3
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• pp.100-108
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• 2023

The aim of this study is to develop guidelines for predicting interference between drones and wakes during non-destructive blade inspections in wind power systems. The wake generated by wind towers and blades can affect the stability of drone flights, necessitating the establishment of guidelines to ensure safe and efficient inspections. In order to predict the interference between drones and blades, environmental variables must be considered, including quantification of turbulence intensity in the wake generated by the tower and blades, as well as determining the appropriate distance between the drone and the tower/blades for flight stability. To achieve this, computational fluid dynamics (CFD) analysis was performed using cross-sectional geometries corresponding to the main wind turbine blade and tower span locations. Based on the CFD analysis results, a safe flight path for drones is proposed, which minimizes the risk of collision and interference with towers and blades during maintenance operations of wind power systems. Implementation of the proposed guidelines is expected to enhance the safety and efficiency of maintenance work.

• Smart Structures and Systems
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• v.33 no.5
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• pp.333-347
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• 2024

There has been an increasing interest in the construction of smart buildings that can actively monitor and react to their surroundings. The capacity of these intelligent structures to precisely predict and respond to deflection is a crucial feature that guarantees both their structural soundness and efficiency. Conventional techniques for determining deflection often depend on intricate mathematical models and computational simulations, which may be time- and resource-consuming. Artificial intelligence (AI) algorithms have become a potent tool for anticipating and controlling deflection in intelligent structures in response to these difficulties. The term "deflection-aware smart structures" in this sense refers to constructions that have AI algorithms installed that continually monitor and analyses deflection data in order to proactively detect any problems and take appropriate action. These structures anticipate deflection across a range of operating circumstances and environmental factors by using cutting-edge AI approaches including deep learning, reinforcement learning, and neural networks. AI systems are able to predict real-time deflection with high accuracy by using data from embedded sensors and actuators. This capability enables the systems to identify intricate patterns and linkages. Intelligent buildings have the potential to self-correct in order to reduce deflection and maximize performance. In conclusion, the development of deflection-aware smart structures is a major stride forward for structural engineering and has enormous potential to enhance the performance, safety, and dependability of designed systems in a variety of industries.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1161_1162
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• 2009

The recent environmental protection trend requires more strict energy saving, therefore every transportation system should reduce energy consumption to the minimum value. High-efficiency operation system, energy saving and $CO_2$ emissions shall be addressed as important issue in railway system. These issues are the most essential factors of railway, compared to major public transportation system. Recently, saving energy in the electric railway system has been studied. For such new energy saving, the energy storage system is considered for saving energy. Energy saving is possible by efficient use of regenerated energy. Regenerated energy is recycled amongst vehicles by mean of charge and discharge corresponding to powering and braking of electric vehicle operations. This energy saving contributes to cut $CO_2$ to reduce greenhouse gas emissions. Recycling regenerated energy demonstrate significant effect on peak cut of consumption energy in railway substation. Absorption of excess energy avoids regeneration failure due to high traction voltage. Therefore, the energy storage system is needed to be adopted to use regeneration energy when the vehicle is braking.

• Journal of Korean Library and Information Science Society
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• v.40 no.2
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• pp.47-67
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• 2009

The purpose of this study is to verify the gain and loss of cataloging outsourcing in Korea public libraries. To this end, the following specific research questions are investigated: (1) How much has cataloging outsourcing enhanced the efficiency of cataloging operations? (2) What is an influence of cataloging outsourcing on the quality of catalogs? and finally, (3) Is there any evidence to strengthen core library service by outsourcing cataloging? The data needed for this study were collected from a survey with 3 public libraries which have experienced outsourcing. To make a comparative study, a survey with 3 public libraries against outsourcing are also included.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.10
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• pp.10-17
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• 2001

For high-speed Internet services, considerations on interworking methods are required for interworking between networks with different technologies. lnterworking and structures in interworking point nodes can affect on transfer efficiency. This paper proposes interworking procedures and functions of the edge routers for overhead reduction in MPOA-MPLS networks. The MPLS networks can be based on ATM technology. Therefore, we consider ATM seamless connections for the interworking and compare the proposed method with that without seamless connection. We perform computer simulations to get both of the transfer delays and throughputs for the comparison., we describe required interworking functions and operations in the edge routers.