• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.254-259
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• 2001

There are advantages in the installation of dual subsea pipelines over two separate single lines. In many case it can reduce the cost for trench, back-filling and installation. However the installation of dual pipelines often requires technical challenges. Dual Pipelines should be placed to be stable to external loading not only during the installation but also in the design life. Dual pipelines in trench can reduce the influence of external forces. To investigate applied forces as slope changes, number of experiments are conducted with PIV (Particle Image Velocimetry) in a circulating water channel. Numerical approaches are also made to compare with experimental results. The velocity fields around dual pipelines in trench are investigated and analysed. Comparison of both results show similar pattern of flow around dual pipelines. it is proved that the trench slope affects the pipeline stability significantly. The results can be applied in the stability design of dual pipelines in trench section. The complex flow patterns can be referenced effectively linked in the understanding of fluid around circular bodies in trench.

• Journal of Ship and Ocean Technology
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• 제6권2호
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• pp.12-22
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• 2002

Offshore pipelines play an important role in the transportation of gas, oil, water and oil products. It is common to have a group of pipelines in the oil and gas field. To reduce the installation cost and time, dual pipelines are designed. There are great advantages in the installation of dual pipelines over two separate single lines. It can greatly reduce the cost for trench, back-filling and installation. However the installation of dual pipelines often requires technical challenges. Pipelines should be placed to be stable against external loadings during installation and design life period. Dual pipelines in trench can reduce the influence of external forces. To investigate the flow patterns and forces as trench depth and slope changes, number of experiments are conducted with PIV(Particle Image Velocimetry) equipment in a Circulating Water Channel. Numerical approaches to simulate experimental conditions are also made to compare with experimental results. The velocity fields around dual pipelines in trench are investigated and analysed. Comparison of both results show similar patterns of flow around pipelines. It is proved that the trench depth contributes significantly on hydrodynamic stability. The trench slope also affects the pipeline stability. The results can be applied in the stability design of dual pipelines in trench section. The complex flow patterns can be effectively linked in the understanding of fluid motions around multi-circular bodies in trench.

• 전기학회논문지
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• 제59권12호
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• pp.2268-2272
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• 2010

This letter presents that a rectenna can utilize more stable wireless power by using a new design dual band/dual polarization microstrip patch antenna and 2 stage voltage multiplier at 2.4 GHz band and 3.1 GHz band. The proposed antenna is a new microstrip patch antenna design to make impedance matching possible by using slotted capacitive coupling between the patch and $50\Omega$ feed line on a ground plane. Its advantage is that the size of the rectenna can be reduced by using $50\Omega$ feed line on the ground plane, which can be used efficiently. The dual band/dual polarization microstrip patch antenna shows circular polarization at 2.4 GHz band and linear polarization at 3.1 GHz band. Under -10 dB return loss, The dual band/dual polarization microstrip patch antenna obtains 340 MHz bandwidth as 2.23~2.57 GHz and 375 MHz bandwidth as 2.95~3.325 GHz. Also, 2 Stage Voltage multiplier is possible to operate at 2.4 GHz band and 3.1 GHz band. The designed retenna can usually obtain wireless power at both 3.1 GHz band, and 2.4 GHz band applications such as Wi-Fi, Bluetooth, Wireless LAN, etc. So more stable wireless power can be utilized at the same time.

• 로봇학회논문지
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• 제17권2호
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• pp.164-171
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• 2022

Recently, interest of a dual arm robot which can replace humans is increasing in order to improve the working environment and solve the labor shortage. Various studies related with design and analysis of dual-arm robots have been conducted because dual arm robots can have various kinematic configurations according to the objective task. It is necessary to evaluate the work performance according to various kinematic structures of the dual arm robot to maximize its effectiveness. In the paper, the performance analysis is studied according to the shoulder configuration and the wrist configuration of the dual-arm robot by using main performance indices such as manipulability, condition number, and minimum singular value by assigning proper weight values to each objective motion. Performance analysis for the robotic assembly process is effectively carried out for each representative dual arm robot configuration.

• 전력전자학회논문지
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• 제9권1호
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• pp.50-57
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• 2004

일반적으로 두 대의 전동기를 독립적으로 동시에 구동하려면 2개의 독립적인 제어용 프로세서를 사용해 각각의 전력회로를 구동해야 한다. 본 논문에서는 CAN 네트워크를 이용해 한 개의 제어기만으로 두 대의 인버터 전력회로를 동시에 제어할 수 있는 단일 프로세서에 의한 복수 인버터 제어기법을 제안했다. 이 시스템은 두 대의 전동기를 한 개의 프로세서를 사용해 제어하기 때문에 두 대의 전동기를 연동하여 운전할 경우에도 별도의 인터페이스 장치나 새로운 프로세서의 추가 없이 소프트웨어적으로 간단히 구현할 수 있다. 제안된 시스템을 구현하고 실험을 통해 그 타당성을 입증해 보였다.

• 전기학회논문지
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• 제62권8호
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• pp.1108-1114
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• 2013

This paper presents a new winding topology for MW class offshore wind generator having modular and dual 3-phase. Based on proposed simplified relationship between magnetic flux and phase current in the air gap, several new windings for modular and dual 3-phase are made. In case of one inverter operation or faulty operation, the proposed model can have balanced 3-phase induced voltage whereas the conventional generator with modular winding has unbalanced induced voltage, which can be important issue in offshore generator. The model was applied into 6MW prototype machine with dual 3-phase. Using finite element analysis, induced voltage, inductance were investigated. The results show that the proposed modular winding can be applicable to dual inverter system with electrically balanced voltage.

• 한국멀티미디어학회논문지
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• 제25권9호
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• pp.1291-1306
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• 2022

The dual image-based reversible data hiding scheme embeds secret data into two images to increase the embedding capacity of secret data. The dual image-based reversible data hiding scheme can transmit a lot of secret data. Therefore, various schemes have been proposed until recently. In 2021, Chen and Hong proposed a dual image-based reversible data hiding scheme that embeds a large amount of secret data using a reference matrix, secret data, and bit values. However, in this paper, more secret data can be embedded than Chen and Hong's scheme. To achieve this goal, the proposed scheme generates polynomials and shared values using secret sharing scheme, and embeds secret data using reference matrix and septenary number, and random value. Experimental results show that the proposed scheme can transmit more secret data to the receiver while maintaining the image quality similar to other dual image-based reversible data hiding schemes.

• 로봇학회논문지
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• 제11권4호
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• pp.235-241
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• 2016

Dual arm manipulators have been developed for the entertainment purpose such as humanoid type or the industrial application such as automatic assembly. Nowadays, there are some issues for applying the dual arm robot system into the various fields. Especially, robots can substitute human and perform the dangerous activity such as search and rescue in the battle field or disaster. In the paper, the dual arm manipulator which can be adapted to the rescue robot with the mobile platform was developed. The kinematic design was proposed for the rescue activity and the required specification was determined through the kinematic analysis and the dynamic analysis in the various conditions. The proposed dual arm manipulator was manufactured based on the vibration analysis result and its performance was proved by the experiment.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.753-759
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• 2009

As many systems depend on electronics in an intelligent vehicle, concern for fault tolerance is growing rapidly. For example, a car with its braking controlled by electronics and no mechanical linkage from brake pedal to calipers of front tires(brake-by-wire system) should be fault tolerant because a failure can come without any warning and its effect is devastating. In general, fault tolerance is usually designed by placing redundant components that duplicate the functions of the original module. In this way a fault can be isolated, and safe operation is guaranteed by replacing the faulty module with its redundant and normal module within a predefined interval. In order to make in-vehicle network fault tolerant, this paper presents the concept and design methodology of an IEEE 1451 based dual CAN module. In addition, feasibility of the dual CAN network was evaluated by implementing the dual CAN module.

• 대한수학회보
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• 제46권5호
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• pp.967-978
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• 2009

In this work, we give some characterizations of rectifying curves in dual Lorentzian space. Also, we show that rectifying dual Lorentzian curves can be stated by the aid of dual unit spherical curves.