• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2215-2227
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• 1994

A multicast switch, which can provide a single uniform switching function for vastly different classes of traffic, is crucial for the successful deployment of intergrated broadband networks. In this paper, we study the call blocking probability of heterogeneous circuit emulated traffic in a multicast switch. A previous work on the analysis of homogeneous traffic, where all calls have the same fan-out, show the performance showed that the call blocking probability increases rapidly as fan out increases. We study the performance of heterogeneous traffic, which consists of calls of different fan out, and show the performance gaps between larger fan-out traffic and smaller fan-out traffic are larger than those of homogeneous traffic these results indicate the necessity of efficient resource allocation policies to improve the performance of multicast calls. We conclude the paper introducing several methods to improve the performance of multicast traffic.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.7-14
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• 2015

This paper proposes the development model of the aerodrome traffic control simulator (ATCS) System for the domestic airport. The application of the ATCS is used as a OJT training function for the air traffic controller and research function for a new control procedure. In order to perform those functions, we classified the ATCS in three types such as education, research and integrated management system, and the ATCS types analysed by the working and OJT training condition in domestic airport. Therefore, we proposed the ATCS models such as uniform type, differential type, and center type, and analysed the merits and demerits of the proposed models. Also we looked up ATCS's application in terms of the building and maintenance costs, operational utilization and scalability. So, we proposed the differential type which was suitable for the developing ATCS for the domestic airports.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1387-1394
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• 2005

In this paper, we propose and the call admission control mechanism that can improve the capacity of the wireless system for the non-uniform traffic load distribution based intelligent information in multiple cellular CDMA environment. The number of mobile stations that can be served simultaneously in a base station is limited by the amount of total interference received in CDMA system. Further, the average number of mobile stations in each cell may not be uniformly distributed. In this paper, considering this factors, the call admission control mechanism using the effective bandwidth concept is adapted to improve the system capacity of non-uniform traffic load distribution based intelligent information. Thus, the bandwidth for a new call can be varied dynamically for reducing the blocking rate of new calls and the dropping rate of handoff calls. The suggested call admission control mechanism is experimented through simulation by dynamically assigning the bandwidth to new and handoff calls. The simulation results show that the proposed call admission control mechanism can accommodate more mobile stations than the other methods in multiple cellular CDMA environment.

• Structural Engineering and Mechanics
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• v.47 no.4
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• pp.531-544
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• 2013

Compared with pavement structures of ordinary road sections, pavement structures in the intersection are exposed to more complex traffic characteristics which may exacerbates pavement distresses such as fatigue-cracking, shoving, shear deformation and rutting. Based on a field survey about traffic characteristics in the intersection conducted in Shanghai China, a three dimensional dynamic finite-element model was developed for evaluating the mechanistic responses in the pavement structures under different traffic characteristics, namely uniform speed, acceleration and deceleration. The results from this study indicated that : (1) traffic characteristics have significant effects on the distributions of the maximum principal strain (MPS) and the maximum shear stress (MSS) at the pavement surface; (2) vehicle acceleration or deceleration substantially impact the MPS and MSS at pavement surface and could increase the magnitude of them by 20 percent to 260 percent; (3) in the vertical direction, with the increase of vehicle deceleration rate, the location of the MPS peak value and the MSS peak value changes from the sub-surface layer to the pavement surface.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.129-132
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• 1991

The safe design against fatigue failure becomes more important criterion in highway bridges. The fatigue-safety evaluation is performed for the current bridge code. A reliability model incorporating fatigue damage is formulated and the satety indices are calculated. The present study indicates that the calculated safety indices vary greatly with traffic volumes and loadometer values. A method is proposed to maintain uniform reliability for vafious traffic conditions and loadings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.470-473
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• 2002

Most networks for automation are tuned to an expected traffic at their design stage. During their actual operations, however, the networks experience considerable changes in traffic from time to time. These traffic changes caused by common events like machine failure and production schedule change may adversely affect the network performance and, in turn, the performance of the connected devices. This paper presents communication delay model for Profibus token passing protocol, and introduces TTR selection methods to maintain a uniform level of network performance at all stations under changing network traffic.

• Journal of the Korean Society of Costume
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• v.58 no.7
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• pp.13-30
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• 2008

Visual language is 'a form of communication without text'. Visual language is one of the strongest methods to spread knowledge. Uniforms could be interpreted as a symbolic language that establishes order in this complicated modern society by placing identity and responsibility on each members of various different organizations. In light of the above, the purpose of this research paper will be to analyze police uniforms of U.S.A, Great Britain, Italy, France and Korea as a form of visual language and interpreting them in terms of visual design in order to understand the fundamental ideas behind the designs and the effective applications thereof. Upon analysis of traffic police uniforms of each individual county mentioned above by separating each uniform's distinctive design, pattern, color, material and decoration based on visual factor, three characteristics of authority, dynamic functionality and friendliness were derived from comparing and analyzing each country's distinctive uniform design. The traditional unique role of police in our society was to maintain social order as their nature inherently possesses characteristic of authority and preservation, but has since undergone transition in many countries to appeal to the broader public by incorporating friendliness and dynamic functionality. Analyzing police uniforms in terms of visual linguistic sense requires a much more profound process of understanding beyond simple interpretation of configurative shapes. In conclusion, the true purpose of uniforms is to include and portray images of mankind's desire toward expressing ideas like 'mankind's bias toward existence beyond theirselves and the exercise of force through authority' and materializing such ideas into a physical form.

• Journal of Korean Society of Transportation
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• v.33 no.3
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• pp.223-236
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• 2015

This study dealt with regional characteristics in car insurance for reduction of traffic accidents. The objective was to establish scientifically the verification procedure in the application of regional auto insurance rate. To specify the objective, this study conducts the correlation analysis between factors which are various in each local traffic environment and the loss ratio in automobile insurance. Also, this provides a correlation and a modal in loss ratio, classifying human factors in locality in major cause result from traffic accident. Based on the results, this brings up the problems with applying a uniform criterion for automobile insurance rate although various factors have effect on traffic accidents in locality. Therefore, what stands out most from this study is that a policy on automobile insurance applied to regional factor should be introduced.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.83-91
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• 2017

The Manual on Uniform Traffic Control Devices advises that, "Signs should be placed on the right side of the roadway where they are easily recognized and understood by road users." Guidance is provided on the spacing and prioritization of signs, and in some conditions, additional steps may be needed to ensure that signs are conspicuous. This study proposes a design methodology using ergonomics concepts applied to traffic sign and street name signs. Initially, a literature revision on cognitive ergonomics is performed. Several design methodologies are analyzed and the aspects to be considered in traffic signs are selected.. In this study, problems of traffic signs in Korea were identified through the comparative analysis of domestic and foreign traffic signs and a prototype of ergonomic traffic sign was developed based on the analysis results. And the driver's views on the developed traffic sign were investigated. In addition, based on the results of this study, this study is to provide the necessary foundation for improving traffic signs in order to help the various age groups of drivers to reach their destinations without difficulties when they drive.

• Wind and Structures
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• v.35 no.4
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• pp.269-285
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• 2022

The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in C_Pmax, C_Pmin, and ΔC_P, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.