• TTA Journal
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• s.134
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• pp.24-29
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• 2011

지난 1990년대에는 월드와이드웹 (WWW)이 화투였고, 2000년대에는 모바일 인터넷이 화두였다면, 2010년대는 모든 사물이 네트워크에 연결되는 Internet of Things(이하 IoT)의 세상이 될 것으로 전망되고 있다. 지난 2005년에 발간된 ITU 보고서에 따르면, IoT가 식별자(부착하는 사물)와 센서 및 무선 센서 네크워크(감지하는 사물), 임베디드 시스템(생각하는 사물), 나노공학(수축하는 사물) 분야의 기술 발전을 통하여 감각뿐 아니라 지능적 형태로 전 세계의 모든 사물 및 객체가 상호 연결될 것이라 주장하며, 이에 대한 준비와 대비가 필요하다고 언급한 바 있다. 또한, 본 보고서는 IoT 실현을 위한 가장 중요한 도전으로 표준화와 협력, 프라이버시, 사회 도덕적 이슈에 대한 철저한 대응이 될 것이라 직시한 바 있다. 이제 우리가 살아가는 세상은 또 다른 새로운 변화에 직면하고 있는 것이다. 현재 전 세계에는 15억 대의 PC와 10억 대의 휴대폰이 인터넷에 연결되어 있으며, 향후 2020년까지 약 500억 대에서 1,000억 대의 장치가 인터넷에 접속하는 IoT 세상으로 전환될 것으로 예측하고 있다. 더욱이, M2M 통신뿐만 아니라 객체 사이 통신까지 포함한다면 인터넷에 연결되는 잠재적 객체의 수는 100조 개에 달할 것이라고 한다. 최근 우리나라에서도 사물지능통신이란 용어가 자주 회자되고 있다. 사물지능통신을 광의의 의미에서 해석하면 IoT로 일컬을 수 있을 것이며, 다만, 협의의 의미로 해석한다면, M2M 통신을 지칭하는 것이 맞는 해석이라고 생각된다. 이에 본 특집에서는 사물지능통신 기술에 대한 현황 및 정책, 앞으로의 서비스 전망, 나아가 표준화 추진 동향 등에 대해 살펴보고 앞으로 다가올 미래 디지털 ICT 사회 변화를 조명해 보고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.64-73
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• 2000

Since so many potentials of services, applications, marketing and regulation, it is difficult to decide the fair pricing scheme of network services. However, these considerations are not particular to the operation of a communications network, which is closely related to technological constraints for QoS guarantee. In this paper, the power spectral analysis of MPEG video based on the P-MMBBP model is discussed in the manner of the QoS degradation to the packet delay. As a consequence of the QoS-degradation, a new fair-pricing scheme with the discount factor is proposed. As a result, the proposed scheme shows good characteristics to guarantee the fairness of the charging in the Internet wide-area network.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.2062-2069
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• 2001

It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure, a method is presented in this paper which uses synthetic artificial intelligent technique, that is, Adaptive-Network-based Fuzzy Inference System(ANFIS) solved via hybrid learning algorithm(the back-propagation gradient descent and the least-squares method) are used to learn the input(the location and depth of a crack)-output(the structural eigenfrequencies) relation of the structural system. With this ANFIS and a continuous evolutionary algorithm(CEA), it is possible to formulate the inverse problem. CEAs based on genetic algorithms work efficiently for continuous search space optimization problems like a parameter identification problem. With this ANFIS, CEAs are used to identify the crack location and depth minimizing the difference from the measured frequencies. We have tried this new idea on a simple beam structure and the results are promising.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.519-524
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• 2001

In this paper, power flow characteristics of a hydromechanical transmission(HMT) are investigated using network analysis. The HMT used in this study consist of a hydrostatic unit(HSU), planetary gear sets, clutches and brakes providing forward 4 speeds and backward 2 speeds. Since the HMT power flows showing a closed loop and the HSU efficiency varies depending on the pressure and speed, a systematic approach is required to analyze the power transmission characteristics of the HMT. In order to analyze the closed loop power flow and the HSU power loss which changes depending on the pressure and speed, network model is constructed for each speed range. In addition, an algorithm is proposed to calculate an accurate HSU loss corresponding to the experimental results. It is found from the network analysis that the torque and speed of each transmission element including the HSU can be obtained as well as direction of the power flow by the proposed algorithm. It is expected that the network analysis can be used in the design of relatively complicated transmission system such as HMT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6105-6110
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• 2012

Smart devices have made our daily life more intelligent and provided convenient life styles in which advanced interface and high speed LTE enable us to have proliferation of empirical Apps. This research has analyzed and evaluated Unstructured data from the users who experienced 'Hair Style Magic Mirror App' by focusing on emotional information. Further this study suggests some directions that the application development industry should take in the near future. The findings through Chi-Square analysis indicate that the application has not affected the overall satisfaction of the consumers; consumers received higher satisfaction in paid version of applications than free versions. Emotional Information analysis shows that users value the practicality of each application the most. Thus, the application developers should focus on practicality and sensitivity side corresponding to the demand of consumers.