• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.683-688
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• 2011

The wireless sensor network (WSN) is well known for an enabling technology for the ubiquitous environment such as real-time surveillance system, habitat monitoring, home automation and healthcare applications. However, the WSN featuring wireless communication through air, a resource constraints device and irregular network topology, is threatened by malicious nodes such as eavesdropping, forgery, illegal modification or denial of services. For this reason, security in the WSN is key factor for utilizing the sensor network into the commercial way. There is a series of symmetric cryptography proposed by laboratory or industry for a long time. Among of them, recently proposed HUMMINGBIRD algorithm, motivated by the design of the well-known Enigma machine, is much more suitable to resource constrained devices, including smart card, sensor node and RFID tags in terms of computational complexity and block size. It also provides resistance to the most common attacks such as linear and differential cryptanalysis. In this paper, we implements ultra-lightweight cryptography, HUMMINGBIRD algorithm into the resource constrained device, sensor node as a perfectly customized design of sensor node.

• 전기학회논문지P
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• 제60권3호
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• pp.161-166
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• 2011

In this paper, for analysing the major factors giving the effect to the quality of HD level video on the multicasting service, we tried this test experiment on the College school network similar to the real service network environment. We measure the video quality distortion on the multicasting HD level video according to generating and increasing the broadcasting traffic on the situation that apply the QoS technique to the test network and not apply the QoS technique and then find out the threshold value of network factors giving the effect to the video quality distortion on the multicasting HD level video service. This paper can be used for guaranteeing the constant video quality and reducing the video quality distortion on the multicasting HD level video service.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.373-375
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• 2000

By DC load flow approximation, we analyzed marginal cost that is the important factor of price signal for network congestion management and expressed as a function of load. In network congestion, a large scale electric network is partitioned into subnetwork to provide a effetive price signal through zonal pricing. We propose a new network partition technique using marginal cost sensitivity with a variety of load consumption.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.255-264
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• 2005

In this paper, a practical bushing model is proposed to improve the accuracy of the vehicle dynamic analysis. The results of the rubber bushing are used to develop an empirical bushing model with an artificial neural network. A back propagation algorithm is used to obtain the weighting factor of the neural network. Since the output for a dynamic system depends on the histories of inputs and outputs, Narendra algorithm of 'NARMAX' form is employed to consider these effects. A numerical example is carried out to verify the developed bushing model. Then, a full car dynamic model with artificial neural network bushings is simulated to show the feasibility of the proposed bushing model.

• 지식경영연구
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• 제13권2호
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• pp.1-18
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• 2012

This article describes how attributes of social network contribute to enhance innovativeness of corporation which is considered to be one of the competitive factors in this global market. The study especially focused on employees' formal and informal communication that is expected to play a mediating role between the factors. 211 employees were randomly selected to participate in an online survey. The result has shown that the static correlation exists between social network, communication, and innovativeness. Closeness of social network was the only influencing factor on communication and innovativeness, and had a partial mediated effect between social network and innovativeness. Based on the suggested contribution for HRD intervention, various communication channels should be developed and supported in order to enhance innovation among social networks in organizations.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.110-118
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• 2004

In this paper, a blackbox approach is carried out to model the nonlinear dynamic bushing model. One-axis durability test is performed to describe the mechanical behavior of typical vehicle elastomeric components. The results of the tests are used to develop an empirical bushing model with an artificial neural network. The back propagation algorithm is used to obtain the weighting factor of the neural network. Since the output for a dynamic system depends on the histories of inputs and outputs, Narendra's algorithm of ‘NARMAX’ form is employed in the neural network bushing module. A numerical example is carried out to verify the developed bushing model.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 1997년도 추계학술대회 발표논문집:21세기를 향한 정보통신 기술의 전망
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• pp.147-161
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• 1997

In the future, the performance of B-lSDN offering the multimedia and a various service depends on the performance of switch that is the important factor consisting of network. Bufferless banyan network consisted of MIN(multistage interconnection network) selected for- the fabric of ATM switch and has a limitation of performance because of blocking. Input buffered banyan networks with FIFO(first-in first-out) buffering scheme for the reduction of blocking and the cell bypass queueing theory for the reduction of HOL(head of line) blocking were seperately compared of the performance of switch. Specially input buffered banyan networks were applied monotonic buffering scheme that was proposed. As a result of simulation, Buffered Banyan Network with cell bypass queueing theory showed better performance than FIFO type input buffered Banyan network. Monotonic increase buffering scheme showed better performance than Monotonic decrease buffering scheme.

• 디지털융복합연구
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• 제9권1호
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• pp.25-36
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• 2011

This paper examines user's loyalty to social network sites (SNS) from switching costs (SC) incurred by both technology and social factors. We propose a research model specifying that the perceived values of resources of the factors affect the SC and the SC determine user's loyalty. Empirical results show that technology variables of ease of use and privacy controllability, and social variables such as network size, usefulness of SNS activities, and awareness of network status have significant effect on SC. In particular, ease of use is negatively associated with SC. Since it is shown that in overall the impact of social factors is stronger than that of technology factors, we can interpret that technological superiority itself does not lead to the success of SNS. Contributions of this paper are: 1) application of SC in SNS research from the resource based perspective, which can be used for developing strategies of sustainable SNS, and 2) provision of different perspective toward the variable of ease of use, which has been considered an important factor of technology acceptance.

• 한국시스템다이내믹스연구
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• 제9권1호
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• pp.73-92
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• 2008

Internet portal sites have served customers for more than a decade in Korea. There have been several such sites have survived, succeeded and led the internet industry. What is the source of their competitiveness? We assumed that the network effect, which can vary dynamically, is an important factor; so we tried to build and analyze a system dynamics model on portal sites that represent their advertising business model. This model includes not only the network effect, but also customer's' expectations of the quality of portal sites, which also varies dynamically. As a result of our research, we can state that the network effect is important to stabilize and increase portal sites' quality, market share, income and cash flow. And we know that investment at a level above that which is merely required is necessary to preserve and stabilize their business.

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.30-35
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• 2015

The most important factor within the wireless sensor network is to have effective network usage and increase the lifetime of the individual nodes in order to operate the wireless network more efficiently. Therefore, many routing protocols have been developed. The LEACH protocol presented by Wendi Hein Zelman, especially well known as a simple and efficient clustering based routing protocol. However, because LEACH protocol in an irregular network is the total data throughput efficiency dropped, the stability of the cluster is declined. Therefore, to increase the stability of the cluster head, in this paper, it proposes a stochastic cluster head selection method for improving the LEACH protocol. To this end, it proposes a SH-LEACH (Stochastic Cluster Head Selection Method-LEACH) that it is combined to the HEED and LEACH protocol and the proposed algorithm is verified through the simulation.