• Title/Summary/Keyword: Traffic Loads

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An Enhanced LPI Control Mechanism in Energy Efficient Ethernet (에너지 효율적인 이더넷에서 개선된 LPI 제어 메커니즘)

  • Lee, Sung-Keun;Jang, Yong-Jae;Yoo, Nam-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.5
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    • pp.983-989
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    • 2012
  • IEEE 802.3az LPI mechanism allows an Ethernet link to reduce power consumption by entering a low-power sleeping mode and letting some components being powered off when there is no data to be transmitted through the link. However, if small amount of packets are being sent periodically, such a mechanism can not obtain energy efficiency due to a high overhead caused by excessive mode transitions. In this paper, we propose an enhanced LPI mechanism which can perform state transition adaptively based on the traffic characteristics on transport layer and network status. This simulation result shows that proposed mechanism improves energy efficiency than LPI mechanism with respect to energy consumption rate for various traffic loads.

Adaptive Load Balancing Algorithms for Overlay Multimedia Network (오버레이 네트워크에서 멀티미디어 서비스를 위한 적응적인 부하균형 기법)

  • Kim, Sung-Wook;Kim, Sung-Chun
    • Journal of KIISE:Information Networking
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    • v.34 no.4
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    • pp.239-245
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    • 2007
  • New multimedia services over the cellular/WLAN overlay networks require different Quality of Service (QoS). In the cellular/WLAN overlay structure, the main issue of load balancing is to balance the available bandwidth among different networks. In this paper, we propose a new online network management scheme. Our proposed scheme is designed to improve bandwidth utilization by balancing the traffic load between the cellular network and WLANs. Simulation results indicate the superior performance of our proposed framework to strike the appropriate performance balance between contradictory QoS requirements under widely varying diverse traffic loads.

Development of Monitoring Site Selection Criteria of the Korean Soil Quality Monitoring Network to Meet its Purposes (토양측정망 운영목적에 따른 토양측정망 지점 선정 방안 연구)

  • Jeong, Seung-Woo
    • Journal of Soil and Groundwater Environment
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    • v.18 no.2
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    • pp.19-26
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    • 2013
  • This study developed the classification of National Soil Quality Monitoring Network (NSQM) and its site selection criteria to meet the recently established purposes of the NSQM. The NSQM were suggested by this study to classify into the six-purposes site groups from the current classification of land uses. The six purposes site groups were 1) intensive observation sites, 2) contaminant loading sites, 3) human activity sites, 4) background sites, 5) river soil sites, and 6) sites near the groundwater quality monitoring wells. Furthermore, this study developed the site selection criteria of NSQM utilizing the accumulated NSQM data, road traffic data, chemical emission data, census, soil information, and the literature related to soil quality variation due to contaminant loads. For selecting suitable sites for NSQM, this study used road traffic, chemical emission, the distance from the contaminant sources, and population information as specific criteria. The suggested site classification and criteria were appled for the current 100 NSQM sites for evaluation. Forty sites were met to the criteria suggested by this study, but sixty sites were not met to the criteria. However, some of the sixty sites also included the obscure sites that their addresses were not apparent to find them.

Adaptive Overlay Network Management Algorithms for QoS sensitive Multimedia Services (멀티미디어 서비스의 품질 보장을 위한 오버레이 네트워크 관리 기법에 대한 연구)

  • Kim, Sung-Wook;Kim, Sung-Chun
    • The KIPS Transactions:PartC
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    • v.14C no.1 s.111
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    • pp.81-86
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    • 2007
  • New multimedia services over the cellular/WLAN overlay networks require different Quality of Service (QoS). Therefore, efficient network management system is necessary in order to provide QoS sensitive multimedia services while enhancing network performance. In this paper, we propose a new online network management scheme that implements bandwidth reservation, congestion and transmission control strategies. Our online approach to network management exhibits dynamic adaptability, flexibility, and responsiveness to the current traffic conditions in multimedia overlay networks. Simulation results indicate the superior performance of our proposed scheme to strike the appropriate performance balance between contradictory QoS requirements under widely varying diverse traffic loads.

Optimization Model for Location Management in WCDMA Networks (WCDMA 네트워크에서의 일치관리 최적화 모형)

  • Chung, Yong-Joo
    • Korean Management Science Review
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    • v.26 no.3
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    • pp.23-35
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    • 2009
  • This study deals with the location management in WCDMA (Wideband Code Division Multiple Access) networks. The new location management method is the one of the many techniques used to provide the packet switched (PS) services effectively in WCDMA networks. WCDMA introduces RA (routing area) for the PS services in addition to LA (location area) for the circuit switched (CS) services. WCDMA system also adopts the cooperative paging and the combined area update which are to decrease signaling traffic using the PS network resources for the CS services. Considering the characteristics of the WCDMA networks, this study formulate into the mathematical programming problem for the location management. Rather than the existing researches which consider the single MSC/SGSN networks, we deal with the multi MSC/SGSN networks, where both MSC area and SGSN area should be determined as well. Fairness between traffic loads of MSC/SGSN and the system cost incurred to MSC/SGSN are also incorporated into our model, which make the model more realistic. We propose greedy algorithms for the problems, which consists of the merger of two neighboring areas and the movement of an area. Extensive experiment has been done based on the realistic problem examples. Followed by the analysis of parameter effect on the final solutions and the quality of final solutions obtained by our greedy algorithms. Our proposed model and analysis result can be used to determine WCDMA system areas and to predict the system performance measures by the determination.

Performance Analysis of Large CDMA Random Access Systems with Retransmission Diversity over Fading Channels

  • Yu, Kai;Sun, Yi;Fan, Pingzhi;Lei, Xianfu;Shu, Lei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.4 no.4
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    • pp.509-528
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    • 2010
  • The random access systems, with retransmission diversity (RD) employment, over large random spreading code division multiple access (CDMA) channel subject to fading is investigated, under the assumption of infinite number of users and infinite spreading gain with their ratio converging to a constant. The low bound of the signal to interference and noise ratio (SINR) is shown to converge almost surely to a constant. The throughput, spectrum efficiency and energy efficiency in the dominating systems are obtained. The analytical results are confirmed by simulations. We find that in high traffic loads the throughput with fading is higher than that without. When the energy efficiency increases, the spectrum efficiency tends to two contrary values due to SNR increases or decreases. For the ordinary stable systems, the stability region is shown to shrink as the traffic increases and enlarge with RD employment.

Study on Reorganization of the Functional Hierarchy of Arterial Road in CBD : Seomyeon Area in Pusan Metropolitan City (도심부 도로 기능별 위계 재편에 관한 연구 : 부산광역시 서면 도심을 중심으로)

  • Roh, You-Jin;Ko, sang-sun;Bae, sang-hoon
    • International Journal of Highway Engineering
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    • v.19 no.6
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    • pp.155-164
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    • 2017
  • PURPOSES : Owing to the growth of income and socio-economic levels, demands from road users have diversified. Accordingly, new road policies are being actively sought. The metropolitan city government of Busan has been focused on constructing and expanding roads to accommodate the increasing traffic demand. Given the increase in functional characteristics, we need to re-evaluate the hierarchy and function of roads, and specifically remodel the road planning and operations that fit into their functions. METHODS : First, this study focuses on introducing the minimum condition required to redefine the hierarchy of the roads. Second, the authors propose a new model that identifies the impact level of road hierarchy adopting discriminated analysis technique. RESULTS : Authors suggest that we redefine the hierarchy of roads in the central business distinct in Busan, and specifically the arterial roads in Busan, namely, Joonang-daero and Gaya-ro. These roads need to be reequipped with cross walks, a lower speed limit, and exclusive bus lanes to improve their accessibility. CONCLUSIONS : The authors found that the sub-arterial and collector roads have been subjected to excessive loads, owing to inappropriate functions being assigned to the main arterial road. Moreover, given that through traffic is concentrated on the sub-arterial and collector roads, over-speeding and other safety issues are consequently created.

Effect of Bracket and H-beam Members on the Sungsoo Grand Bridge (브라켓 및 H-빔 부재가 성수대교 붕괴에 미친 영향)

  • 조효남;임종권;안중산
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.422-430
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    • 1998
  • This paper presents the results of a major parametric study on the collapse cause of the Sungsoo Grand Bridge, a Gerber-type continuous truss bridge, which had collapsed just at the 15th year since opening to traffic. Among the various collapse causes such as poor design, poor welding, poor maintenance, and heavy traffic loads, this study focuses on the collapse cause assessment incorporating the effects of braket and H-beam members right below the expansion joint of the suspended truss. A local FEM analysis using fine shell elements is carrided out for the more precise estimation of stress range of the vertical pin-connected hanger whose fatigue fracture triggered the collapse of the bridge. Both the conventional S-N approach and the Ang-Munse's fatigue reliability method are used for the evaluation of the fatigue life and fatigue failure probability for the assessment based on all the available results of various field and labolatory tests. From these observations, It may be affirmatively stated that the effects of bracket and H-beam members accelerated the fatigue failure, and thus should be regarded as one of major causes that triggered the bridge collapse

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Study on Bridge Dynamic Responses under Vehicle Loads (차량하중에 의한 교량의 동적응답특성 분석)

  • 김상효;박흥석;윤성호
    • Computational Structural Engineering
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    • v.10 no.4
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    • pp.337-347
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    • 1997
  • The dynamic responses of highway bridges are varying depending on the features of either traveling vehicles or bridges. In this study, the probabilistic characteristics of dynamic amplification factors of highway bridges due to traveling heavy vehicles have been examined through analytical simulation processes. The truck with tandem axle and tractor with semitrailer are selected as the representative heavy vehicles, which are modeled with three dimensional 7-DOF and 12-DOF models, respectively. The analytical results have been compared with the experimental results of dynamic loading tests and the validity of the analytical models has been examined. Parametric studies on the means and extreme values of amplification factors have been performed with various traffic conditions such as vehicle types, vehicle weights, surface profiles, number of loading vehicles, loading positions, etc.

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Congestion effect on maximum dynamic stresses of bridges

  • Samanipour, Kianoosh;Vafai, Hassan
    • Structural Engineering and Mechanics
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    • v.55 no.1
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    • pp.111-135
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    • 2015
  • Bridge behavior under passing traffic loads has been studied for the past 50 years. This paper presents how to model congestion on bridges and how the maximum dynamic stress of bridges change during the passing of moving vehicles. Most current research is based on mid-span dynamic effects due to traffic load and most bridge codes define a factor called the dynamic load allowance (DLA), which is applied to the maximum static moment under static loading. This paper presents an algorithm to solve the governing equation of the bridge as well as the equations of motions of two real European trucks with different speeds, simultaneously. It will be shown, considering congestion in eight case studies, the maximum dynamic stress and how far from the mid-span it occurs during the passing of one or two trucks with different speeds. The congestion effect on the maximum dynamic stress of bridges can make a significant difference in the magnitude. By finite difference method, it will be shown that where vehicle speeds are considerably higher, for example in the case of railway bridges which have more than one railway line or in the case of multiple lane highway bridges where congestion is probable, current designing codes may predict dynamic stresses lower than actual stresses; therefore, the consequences of a full length analysis must be used to design safe bridges.