• 한국산학기술학회논문지
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• 제13권2호
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• pp.648-653
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• 2012

정부는 2008년에서 2012 과학기술 577전략을 발표하고 세계적인 과학 기술력을 가지기 위해 꾸준한 노력을 기울이고 있다. 하지만 공동연구 사업은 총 예산 중 전체 예산의 1.3% 만이 투입되었다. 특히 EU권과의 국제공동연구에 대한 성과는 정부의 노력에 비해 크지 않다. 본 논문에서는 우리나라 기업들이 국제 공동연구 참여전략 방안을 찾는데 연구의 목적을 둔다. 그 중에서 특히 EU권 EUREKA를 중심으로 살펴보았다. 본 논문은 6장으로 구성되어 있다. 제 2장에서는 우리나라 기업들의 국제 공동연구 참여현황을 살펴보았다. 이어서 제 3장은 국제공동연구에 대한 이론적 배경 그리고 제 4장에서는 연구방법 그리고 제 5장에서는 본 논문의 핵심인 EU의 EUREKA 공동연구 참여방안이 제시되었으며 제 6장에서는 결론 및 정책적 제안점을 도출하였다.

• International Journal of Computer Science & Network Security
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• 제22권11호
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• pp.241-247
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• 2022

Ad hoc network is self-organized network powered by battery. The reliability of virtual user identification and channel security are reduced when SNR is low due to limited user energy. In order to solve this problem, a joint virtual user identification and channel security en/decoding method is proposed in this paper. Transmitter-receiver-based virtual user identification code is generated by executing XOR operation between orthogonal address code of transmitter and pseudo random address code of receiver and encrypted by channel security code to acquire orthogonal random security sequence so as to improve channel security. In order to spread spectrum as well as improve transmission efficiency, data packet is divided into 6-bit symbols, each symbol is mapped with an orthogonal random security sequence. Subspace-based method is adopted by receiver to process received signal firstly, and then a judgment model is established to identify virtual users according to the previous processing results. Simulation results indicate that the proposed method obtains 1.6dB E_b/N₀ gains compared with reference methods when miss alarm rate reaches 10^-3.

• International journal of advanced smart convergence
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• 제8권4호
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• pp.154-160
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• 2019

In this paper, we propose the miniaturization size of wearable Range of Motion(ROM) and a system that can be connected with smart devices in real-time to measure the joint movement range dynamically. Currently, the ROM of the joint is directly measured by a person using a goniometer. Conventional methods are different depending on the measurement method and location of the measurement person, which makes it difficult to measure consistently and may cause errors. Also, it is impossible to measure the ROM of joints in real-life situations. Therefore, the wearable sensor is attached to the joint to be measured to develop a miniaturize size ROM device that can measure the range of motion of the joint in real-time. The sensor measured the resistance value changed according to the movement of the joint using a load cell. Also, the sensed analog values were converted to digital values using an Analog to Digital Converter(ADC). The converted amount can be transmitted wireless to the smart device through the wearable sensor node. As a result, the developed device can be measured more consistently than the measurement using the goniometer, communication with IoT-based smart devices, and wearable enables dynamic observation. The developed wearable sensor node will be able to monitor the dynamic state of rehabilitation patients in real-time and improve the rapid change of treatment method and customized treatment.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.332-340
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• 2016

A design optimization is performed for the double-bolted joint in cylindrical composite structures by using a simplified analytical method. This method uses failure criteria for the major failure modes of the bolted composite joint. For the double-bolted joint with a zigzag arrangement, it is necessary to consider an interaction effect between the bolt arrays. This paper proposes another failure mode which is determined by angle and distance between two bolts in different arrays and define a failure criterion for the failure mode. The optimal design for the double-bolted joint is carried out by considering the interactive net-tension failure mode. The genetic algorithm (GA) is adopted to determine the optimized parameters; bolt spacing, edge distance, and stacking sequence of the composite laminate. A purpose of the design optimization is to maximize the burst pressure of the cylindrical structures by ensuring structural integrity. Also, a progressive failure analysis (PFA) is performed to verify the results of the optimal design for the double-bolted joint. In PFA, Hashin 3D failure criterion is used to determine the ply that would fail. A stiffness reduction model is then used to reduce the stiffness of the failed ply for the corresponding failure mode.

• International Journal of Aeronautical and Space Sciences
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• 제18권4호
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• pp.688-696
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• 2017

This paper presents an integrated roll-pitch-yaw autopilot using an equivalent based sliding mode control for skid-to-turn nonlinear time-varying missile system with lumped disturbances in its six-equations of motion. The considered missile model are developed to integrate the model uncertainties, external disturbances, and parameters perturbation as lumped disturbances. Moreover, it considers the coupling effect between channels, the variation of missile velocity and parameters, and the aerodynamics nonlinearity. The presented approach is employed to achieve a good tracking performance with robustness in all missile channels simultaneously during the entire flight envelope without demand of accurate modeling or output derivative to avoid the noise existence in the real missile system. The proposed autopilot consisting of a two-loop structure, controls pitch and yaw accelerations, and stabilizes the roll angle simultaneously. The Closed loop stability is studied. Numerical simulation is provided to evaluate performance of the suggested autopilot and to compare it with an existing autopilot in the literature concerning the robustness against the lumped disturbances, and the aforesaid considerations. Finally, the proposed autopilot is integrated in a six degree of freedom flight simulation model to evaluate it with several target scenarios, and the results are shown.

• 무역상무연구
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• 제14권
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• pp.323-348
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• 2000

Facing the current difficulties of fisheries industry nationally and internationally, economic cooperations between South and North Korea are needed urgently. Applying the process of economic integration to fisheries sector of separated nation, cooperation processes are divided as follows; (1) indirect and direct fisheries trade, (2) reciprocal use of fishing grounds, (3) joint venture in fisheries sector, (4) free movement of production factors and common fisheries policy. Here, fisheries trade falls under economic interchange stage. Reciprocal use of fishing ground and fisheries joint venture come in economic cooperation stage. Finally. free factor movement and common fisheries policy are related with economic integration stage. This paper investigates the schemes for fisheries cooperation between South and North Korea in preparation for a unified Korea, focusing on fisheries trade. The paper is composed of 5 chapters. Chapter 2 discusses structure and characteristics of North Korea trade, and trade situation between South and North Korea. Then, the present condition of North Korea fisheries industry and fisheries trade trend between South and North Korea are presented in chapter 3. Next, chapter 4 tackles the most common problems encountered in fisheries trade between South and North Korea, and the devices and schemes to raise fisheries trade between South and North Korea. Finally, chapter 5 summarizes and concludes the research results.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제1권1호
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• pp.29-34
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• 2001

This paper is devoted to investigating direct adaptive neural control of nonlinear systems with uncertain or unknown dynamic models. In the direct adaptive neural networks control area, theoretical issues of the existing backpropagation-based adaptive neural networks control schemes. The major contribution is proposing the variable index control approach, which is of great significance in the control field, and applying it to derive new stable robust adaptive neural network control schemes. This new schemes possess inherent robustness to system model uncertainty, which is not required to satisfy any matching condition. To demonstrate the feasibility of the proposed leaning algorithms and direct adaptive neural networks control schemes, intensive computer simulations were conducted based on the flexible joint robot systems and functions.

• International Journal of Railway
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• 제3권1호
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• pp.1-6
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• 2010

The steel plate-girder bridges with concrete gravity piers have possibilities of overturning by lateral inertial force which can be reproduced by sudden earthquake attack. This paper explores an overturning mechanism of existing concrete gravity pier onto the sandy soil in the event of lateral push-over load by in-situ experimental observation. The in-situ push-over experiment for pier with earth anchors between spread footing and rock beds exhibits a reasonable enhancement of ductility against overturning. In unanchored system, a flexural crack at cold joint of concrete pier is not developed because of the over-turning of the pier. This leads a global instability (rotation) of pier-footing system with relatively low stresses in pier itself. While a lateral load is persistently increased in anchored system, the successive flexural cracking failure at cold joint is observed even after the local shear failure of soil due to redistribution of stress equilibrium between soil and pier structure as long as a tensile action of anchor cable is active.

• International journal of advanced smart convergence
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• 제11권2호
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• pp.13-21
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• 2022

In this paper, we propose a learning based joint demosaicing and super-resolution framework which uses only the mosaiced color filter array(CFA) image as the input. As the proposed method works only on the mosaicied CFA image itself, there is no need for a large dataset. Based on our framework, we proposed two different structures, where the first structure uses one deep image prior network, while the second uses two. Experimental results show that even though we use only the CFA image as the training image, the proposed method can result in better visual quality than other bilinear interpolation combined demosaicing methods, and therefore, opens up a new research area for joint demosaicing and super-resolution on raw images.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.519-527
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• 2005

Recently, weight reduction of vehicles has been of great interest and consequently the use of low-density materials in the automotive industry is increasing every year. However, the substitution of one material for another is not simple because it accompanies several problems, for example, weakness in the strength and stiffness and difficulty in the joining. To overcome these problems, the structure of the automobile redesigned totoally. Aluminum spaceframe is rapidly being adopted as a body structure for accommodating lightness, stiffness and strength requirement. In aluminum spaceframe manufacturing, it is often required to join aluminum tube. However, there are few suitable methods for joining aluminum tube, so that much interest has been focused on testing suitable joining methods. Joining by electromagnetic forming (EMF) can be useful method in joining aluminum tube, which offers some advantages compared with the conventional joining methods. In this paper, joining by EMF was investigated as a pre-study for applying an automotive spaceframe. Finite element simulations and strength tests were performed to analyze the influence of geometric parameters on joint strength. Based on these results, configurations of axial joint and torque joint were suggested and guidelines for designing EMF joint were established.