• 정보보호학회논문지
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• 제22권3호
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• pp.525-536
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• 2012

본 논문에서는 스마트그리드 통신망 보호를 위한 AMI 망 분리와 인증 프레임워크를 제안한다. 기존 AMI 구조에서는 기기들이 직 간접적으로 인터넷과 연계되어 있고, AMI 네트워크에 대한 접근제어 인증을 고려하지 않아 악의적인 목적의 전력망 침투 공격에 취약하다. 또한 AMI 전력망에 존재하는 여러 인증 구간과 AMI 연계장치에 다양한 인증 프로토콜을 수용해야 하는 환경을 고려한 효율적인 인증 프레임워크 연구가 이루어지고 있지 않다. 제안하는 AMI 전력망 분리는 스마트미터를 댁내 기기 및 인터넷과 물리적으로 분리하고, 인증 프레임워크는 네트워크 및 응용레벨 인증을 EAP 기반의 인증 구조 및 절차로 통합한다. 제시된 AMI 전력망 보안대책은 안전하고 효율적이며, 향후 스마트그리드 AMI 구축 설계에 유용하게 활용될 것으로 기대된다.

• 한국산업융합학회 논문집
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• 제7권2호
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• pp.199-205
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• 2004

This paper describes the fault diagnosis method to order to construct CIM in complex system with hierarchical structure similar to human body structure. Complex system is divided into unit, item and component. For diagnosing this hierarchical complex system, it is necessary to implement a special neural network. Fault diagnosis system can forecast faults in a system and decide from the signal information of current machine state. Comparing with other diagnosis system for a single fault, the developed system deals with multiple fault diagnosis, comprising hierarchical neural network (HNN). HNN consists of four level neural network, i.e. first is fault symptom classification and second fault diagnosis for item, third is symptom classification and forth fault diagnosis for component. UNIX IPC is used for implementing HNN with multitasking and message transfer between processes in SUN workstation with X-Windows (Motif). We tested HNN at four units, seven items per unit, seven components per item in a complex system. Each one neural network represents a separate process in UNIX operating system, information exchanging and cooperating between each neural network was done by message queue.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.436-442
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• 2017

A novel method of Skin lesion segmentation based on the combination of Texture and Neural Network is proposed in this paper. This paper combines the textures of different pixels in the skin images in order to increase the performance of lesion segmentation. For segmenting skin lesions, a two-step process is done. First, automatic border detection is performed to separate the lesion from the background skin. This begins by identifying the features that represent the lesion border clearly by the process of Texture analysis. In the second step, the obtained features are given as input towards the Recurrent Echo state neural networks in order to obtain the segmented skin lesion region. The proposed algorithm is trained and tested for 862 skin lesion images in order to evaluate the accuracy of segmentation. Overall accuracy of the proposed method is compared with existing algorithms. An average accuracy of 98.8% for segmenting skin lesion images has been obtained.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.351-356
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• 2006

This study developed an artificial neural network (ANN) to estimate the growth of microorganisms during a fermentation process. The ANN relies solely on the cumulative consumption of alkali and the buffer capacity, which were measured on-line from the on/off control signal and pH values through automatic pH control. The two input variables were monitored on-line from a series of different batch cultivations and used to train the ANN to estimate biomass. The ANN was refined by optimizing the network structure and by adopting various algorithms for its training. The software estimator successfully generated growth profiles that showed good agreement with the measured biomass of separate batch cultures carried out between at 25 and $35^{\circ}C$.

• 제어로봇시스템학회논문지
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• 제8권4호
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• pp.281-287
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• 2002

This paper investigates on the feasibility of fuzzy logic control for networked control systems. In order to evaluate its feasibility, a networked control system for motor speed control is implemented on a Profibus-DP network. The NCS consists of several inde-pendent, but interacting processes running on two separate stations. By using this NCS, the network-induced delay is analyzed to find the cause and effect of the delay. Furthermore, in order to prove the feasibility, the fuzzy logic controller's performance is compared with those of conventional PID controllers. Based on the experimental results, the fuzzy logic controller can be a viable choice far NCS due to its robustness against parameter uncertainty.

• The Korean Journal of Ecology
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• 제23권2호
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• pp.89-100
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• 2000

On community data. sampled in regular intervals on a long-term basis. artificial neural networks were implemented to extract information on characterizing patterns of community changes. The Adaptive Resonance Theory and Kohonen Network were both utilized in learning benthic macroinvertebrate communities in the Soktae Stream of the Suyong River collected monthly for three years. Initially, by regarding each monthly collection as a separate sample unit, communities were grouped into similar patterns after training with the networks. Subsequently, changes in communities in a sequence of samplings (e.g., two-month, four-month, etc.) were given as input to the networks. After training, it was possible to recognize new data set in line with the sampling procedure. Through the comparative study on benthic macroinvertebrates with these learning processes, patterns of community changes in chironomids diverged while those of the total benthic macro-invertebrates tended to be more stable.

• Journal of Information Technology Applications and Management
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• 제14권2호
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• pp.11-26
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• 2007

In this paper we suggest a context-driven configuration model of virtual businesses to form a business network model consisting of role-based, interaction-centered business partners. The model makes use of the subcontext concept which explicitly represents actors and interactions in virtual business (VB) context. We separate actors who have capacities on tasks in a specific kind of role and actor subcontext which models requirements in specific interaction subcontext. Three kinds of actors are defined in virtual service chains, service user, service provider, and external service supporter. Interaction subcontext models a service exchange process between two actor subcontexts with consideration of context dependencies like task and quality dependencies. Each subcontext may be modeled in the form of a situation network which consists of a finite set of situation nodes and transitions. A specific situation is given in a corresponding context network of actors and interactions. It is illustrated with a simple example.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.637-638
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• 2017

MQTT broker는 트래픽에 따라 네트워크 성능이 저하되어 패킷 손실, 지연 등의 문제가 발생한다. 하지만 MQTT broker는 트래픽 측정을 위한 별도의 인터페이스를 지원하지 않아 네트워크 성능 저하에 대처할 수 없다. 본 논문에서는 MQTT broker의 트래픽 측정을 위한 시스템을 제안한다. 제안하는 시스템은 jnetpcap 라이브러리를 사용하여 MQTT broker로 송수신되는 모든 트래픽을 측정한다.

• 한국통신학회논문지
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• 제37B권10호
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• pp.877-888
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• 2012

네트워크 가상화 기술은 NaaS (Network as a Service) 또는 SDN (Software Defined Network)으로 불리는 서비스 지향 아키텍처를 추구하는 미래인터넷에서 중요하게 다루고 있는 연구 분야이다. 네트워크 가상화는 혁신적인 프로토콜들에 대한 상호 독립적인 시험이 가능한 네트워크 테스트베드 구축 기술로서 미래인터넷 연구에서 중요한 역할을 할 것으로 기대하고 있다. 본 논문에서는 단일 도메인의 중소규모 연구망에서 네트워크 가상화를 통해 사용자가 정의하는 토폴로지와 대역폭을 제공하여 다중 사용자의 서비스 트래픽들을 분리, 관리함을 목적으로 하는 제어프레임워크를 제안한다. 본 프레임워크(VIMS; Virtual network Integrated control and Management System)는 이기종의 가상네트워크 장비 제어평면을 수용함으로써 장비에 변경을 요하지 않고 확장할 수 있는 구조를 지닌다. KOREN (Korea advanced REsearch Network)에 적용, 실현 가능성을 확인하였으며 GENI의 제어프레임워크와 비교를 통해 본 프레임워크와의 차이점과 개선을 위한 향후 연구 방향을 도출한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1817-1836
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• 2020

Network convergence is considered as one of the key solutions to the problem of achieving future high-capacity and reliable communications. This approach overcomes the limitations of separate wireless technologies. Efficient interface selection is one of the most important issues in convergence networks. This paper solves the problem faced by users of selecting the most appropriate interface in the heterogeneous radio-access network (RAN) environment. Our proposed scheme combines a hierarchical evaluation of networks and game theory to solve the network-selection problem. Instead, of considering a fixed weight system while ranking the networks, the proposed scheme considers the service requirements, as well as static and dynamic network attributes. The best network is selected for a particular service request. To establish a hierarchy among the network-evaluation criteria for service requests, an analytical hierarchy process (AHP) is used. To determine the optimum network selection, the network hierarchy is combined with game theory. AHP attains the network hierarchy. The weights of different access networks for a service are calculated. It is performed by combining AHP scores considering user's experienced static network attributes and dynamic radio parameters. This paper provides a strategic game. In this game, the network scores of service requests for various RANs and the user's willingness to pay for these services are used to model a network-versus-user game. The Nash equilibria signify those access networks that are chosen by individual user and result maximum payoff. The examples for the interface selection illustrate the effectiveness of the proposed scheme.