• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.302-308
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• 2019

Aircraft data network (ADN) is a data networking for signal transmission among avionic systems in aircraft, and it mostly has been applied MIL-STD-1553B that guarantees high reliability considering its application environments. However, commercial Ethernet has been widely applied for ADN recently, and its range of applications have increased. Ethernet provides high speed of data transmission, however, it could not guarantee quality of service (QoS) so high as MIL-STD-1553B. In this paper, we propose dynamic routing and priority based data transmission schemes in order to improve the QoS of legacy Ethernet. Our propose schemes can be applied to Ethernet switch, and it is able to manage network traffic efficiently, and reduce the time for data transmission. We analyze the packet transmission time for both legacy and proposed schemes in Ethernet environments using simulation, and we show that our proposed scheme can reduce the time for data transmission compare to legacy spanning tree protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.673-685
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• 2002

In this paper, we analyze the pros and cons of the fast power control to the forward link in the environments where mixed traffics of voice and data produce the transmitted/received power difference. We propose the Zone-based power control scheme that can improve the performance of the fast power control scheme in the viewpoint of the resource allocation. The proposed scheme is a mechanism that controls both the power and rate of non-realtime data traffics according to location distribution of the mobile stations. The scheme is based on the conventional fast power control scheme in the CDMA systems, and it adaptively controls the transmission rate of each data traffic. Zone-based rate control of data call brings about somewhat power margin to the call. As a result, the proposed scheme saves the power consumption of portables and reduces the amount of interference. With the proposed scheme, not only be extended the service coverage of high-rate traffic to the entire cell service coverage, but also the QoS of low-rate traffic can keep going through the service time, especially, in the situation that the amount of incoming interference is much larger. The experimental results show that the proposed scheme yields a improved performance compared with the conventional scheme in terms of the power consumption and traffic throughput of portables, especially, with the increasing number of high-rate data traffics.

• The Transactions of the Korea Information Processing Society
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• v.13 no.4
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• pp.157-165
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• 2024

The evolution of the Distributed Denial of Service Attack(DDoS Attack) method has increased the difficulty in the detection process. One of the solutions to overcome the problems caused by the limitations of the existing victim-side detection method was the source-side detection technique. However, there was a problem of performance degradation due to network traffic irregularities. In order to solve this problem, research has been conducted to detect attacks using a collaborative network between several nodes based on artificial intelligence. Existing methods have shown limitations, especially in nonlinear traffic environments with high Burstness and jitter. To overcome this problem, this paper presents a collaborative source-side DDoS attack detection technique introduced with an attention mechanism. The proposed method aggregates detection results from multiple sources and assigns weights to each region, and through this, it is possible to effectively detect overall attacks and attacks in specific few areas. In particular, it shows a high detection rate with a low false positive of about 6% and a high detection rate of up to 4.3% in a nonlinear traffic dataset, and it can also confirm improvement in attack detection problems in a small number of regions compared to methods that showed limitations in the existing nonlinear traffic environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.75-80
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• 2008

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.73-82
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• 2009

The traffic volume of Seoul is extremely high in comparison to other major cities in Korea, and the result has been harmful physical and mental exposure to pollution by Seoulites on a regular basis. The street air pollution is more important than the others, because the air pollution generated by street traffic directly impacts the health of nearby pedestrians. This problem requires urgent attention and resolution. Among the factors creating the air pollution originating from the street, is the configuration of streets, which have emerged as the most significant because it is related to air and pollutant dispersion. Therefore, this study was conducted under the assumption that street form affects the air quality. Study sites were classified by street characteristics, and air quality was analyzed in each class. Then the OSPM (Operational Street Pollution Model) was employed to simulate the relationship between street configuration and air quality of streets within the old city center and new city center in Seoul. After that this study analyzed the correlation between air pollution and the spatial configuration of urban streets (ex. street width, building height, building density, etc.) to determine their contributions to air pollution. The outcome of this study is as follows : First, the result that was derived from the correlation analysis between street configuration and air quality hewed that the air pollution of the street is influenced by the average height of building, width of the roads as well as traffic volume. On the roadside, the concentration level of $NO_2$ is mainly affected by the average height of building and the deviation of building height along the street and CO is affected by street width. The outcome of this study can be used as a basis for more sound urban design policies, and the promotion of desirable street environments for pedestrians.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.81-86
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• 2014

According to the development of streaming services with P2P and mobile network technologies, researches to enhance the service quality in mobile environment have been proposed. However, streaming services considering high-speed mobile environment and characteristics of heterogenous terminals have been hindered from being provided with the required quality from user because of bandwidth congestion between selfish peers of existing P2P system. It is also prone to long delay and loss in accordance with the repeated traffic amounts because there are no optimized solution for traffic localization. The structure to enhance peer contribution for service differentiation and peer selection with clustering scheme with location information of terminal can satisfy both users and service providers with service quality and efficiency. In this paper, we propose an incentive mechanism and resource distribution scheme with user contribution and traffic cost information based on user location, which make mobile users increase the satisfaction of service quality in LTE environments.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.150-156
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• 2011

Smart Highway is a next generation highway that significantly improves a traffic safety, reduces incidence of traffic accidents, and supports intelligent and convenient driving environments so that drivers can drive at high speeds in safety. In order to implement smart highway, it is required to gather a large amount of data including conditions of a road and the status of vehicles, and other useful data. To provide situation information of highway, it has been gathered traffic information using optical sensors(CCTV, etc.). However, this technique has problems such as the problem of information gathering, lack of accuracy depending on weather conditions and limitation of maintenance. It needs radar system which has not effect on environmental change and algorithm processing technique in order to provide information for a safety driving to driver and car. In this paper, it is used radar with 9.4GHz to test performance of a road surface and developed radar system for detecting test. And we compared and analyzed a performance of data acquired from each radar through computer simulation.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.21-26
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• 2012

As the new requirements for wireless sensor networks are emerging, real-time communications is becoming a major research challenge because resource-constrained sensor nodes are not powerful enough to accommodate the complexity of the protocol. In addition, an efficient energy management scheme has naturally been a concern in wireless sensor networks for a long time. However, the existing schemes are limited to meeting one of these two requirements. To address the two factors together, we propose real-time communications with two approaches, a protocol for satisfied conditions and one for unsatisfied. Under the satisfied requirement, existing real-time protocol is employed. On the other hand, for the unsatisfied requirement, the newly developed scheme replaces the existing scheme by adjusting the transmission range of some surplus nodes. By expanding the transmission range, the end-to-end delay is shortened because the number of intermediate nodes decreases. These nodes conserve their energy for real-time communications by avoiding other activities such as sensing, forwarding, and computing. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic environments.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.69.5-69
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• 2001

Computer simulations are widely used to analyze passenger safety in traffic accidents. ATB(articulated total body) is a computer simulation model developed to predict gross human body response to such dynamic environments as vehicle crashes and pilot ejections. ATB, whose code is open, has high flexibility and application capability that users can easily insert defined modules and functions. ATB is, however, inconvenient as it was coded in FORTRAN and it needs a formatted input file. Moreover, it takes much time to make input files and to modify coding errors. This study aims to increase user friendliness by adding a preprocessor program, WINATB(WiNdow ATB), to the conventional ATB. WINATB programmed in Visual C++ and OpenGL uses ATB IV as a dynamic solver ...

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.483-488
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• 2012

With the fast growing data traffic, the performance of the convergent overlay network environment under the cognitive networking environment is crucial for the implementation of the efficient network structure. In order to achieve high capacity and reliable link quality in wireless communication of the overlay convergent networks with the cognitive networking based on the advanced capability of the mobile terminal, a Distributed Wireless Communication System (DWCS) can provide the capability of ambient-aware dual cell system's operation. This paper has considered virtual cell: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on DWCS network. One is the Active Virtual Cell which exists for user's actual data traffic and the other is the Candidate Virtual Cell which contains a set of candidate antennas to protect user's link quality from performance degradation or interruption. The considered system constructs DVC by using cognitive ability of finding useful virtual signals. Also, for multi-user high-rate data transmission, the DWCS system exploits Space-Time Trellis Codes. The effects of changing environments on the system performance has been investigated thereafter.