• Journal of Internet Computing and Services
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• v.18 no.6
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• pp.65-73
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• 2017

Congestion occurring at wireless sensor networks(WSNs) causes packet delay and packet drop, which directly affects overall QoS(Quality of Service) parameters of network. Network congestion is critical when important data is to be transmitted through network. Thus, it is significantly important to effectively control the congestion. In this paper, new mechanism to guarantee reliable transmission for the important data is proposed by considering the importance of packet, configuring packet priority and utilizing the settings in routing process. Using this mechanism, network condition can be maintained without congestion in a way of making packet routed through various routes. Additionally, congestion control using packet service time, packet inter-arrival time and buffer utilization enables to reduce packet delay and prevent packet drop. Performance for the proposed mechanism was evaluated by simulation. The simulation results indicate that the proposed mechanism results to reduction of packet delay and produces positive influence in terms of packet loss rate and network lifetime. It implies that the proposed mechanism contributes to maintaining the network condition to be efficient.

• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.11-20
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• 2004

Proportional Fair (PF) share policy has been adopted as a downlink scheduling scheme in CDMA2000 l×EV-DO standard. Although It offers optimal performance in aggregate throughput conditioned on equal time share among users, it cannot provide a bandwidth guarantee and a strict delay bound. which is essential requirements of real-time (RT) applications. In this study, we propose a new scheduling policy that provides quality-of-service (QoS) guarantees to a variety of traffic types demanding diverse service requirements. In our policy data traffic is categorized Into three classes, depending on sensitivity of Its performance to delay or throughput. And the primary components of our policy, namely, Proportional Fair (PF), Weighted Fair Queuing (WFQ), and delay-based prioritized scheme are intelligently combined to satisfy QoS requirements of each traffic type. In our policy all the traffic categories run on the PF policy as a basis. However the level of emphasis on each of those ingredient policies is changed in an adaptive manner by taking into account the channel conditions and QoS requirements. Such flexibility of our proposed policy leads to offering QoS guarantees effectively and. at the same time, maximizing the throughput. Simulations are used to verify the performance of the proposed scheduling policy. Experimental results show that our proposal can provide guaranteed throughput and maximum delay bound more efficiently compared to other policies.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.9
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• pp.19-28
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• 2010

The GTS(Guaranteed Time Slot) of the IEEE 802.15.4 standard, which is the contention free access mechanism, is used for low-latency applications or applications requiring specific data bandwidth. But it has some problems such as delay of service due to FIFS(First In First Service) scheduling. In this paper, we proposes a weight based GTS allocation scheme for fair queuing in IEEE 802.15.4 LR-WPAN. The proposed scheme uses a weight that formed by how much more weight we give to the recent history than to the older history for a new GTS allocation. This scheme reduces service delay time and also guarantees transmission simultaneously within a limited time. The results of the performance analysis shows that our approach improves the performance as compared to the native explicit allocation mechanism defined in the IEEE 802.15.4 standard.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.45-50
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• 2011

In this paper, the encoding time delay of FH/TDD(Frequency Hopping/Time Division Duplex) based Motion JPEG image compression CODEC is analyzed for radio video transmissions of multi-camera systems in a vehicle. And, Synchronized connection of minimum channel collision is designed with synchronized shift and access according to channel status for Motion JPEG based FH/TDD multiple access.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.1-9
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• 2020

Many cryptographic and error control coding algorithms rely on finite field GF(2m) arithmetic. Hardware implementation of these algorithms needs an efficient realization of finite field arithmetic operations. Finite field multiplication is complicated among the basic operations, and it is employed in field exponentiation and division operations. Various algorithms and architectures are proposed in the literature for hardware implementation of finite field multiplication to achieve a reduction in area and delay. In this paper, a low area and delay efficient semi-systolic multiplier over finite fields GF(2m) using the modified Montgomery modular multiplication (MMM) is presented. The least significant bit (LSB)-first multiplication and two-level parallel computing scheme are considered to improve the cell delay, latency, and area-time (AT) complexity. The proposed method has the features of regularity, modularity, and unidirectional data flow and offers a considerable improvement in AT complexity compared with related multipliers. The proposed multiplier can be used as a kernel circuit for exponentiation/division and multiplication.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.78-87
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• 1996

in urban cross-roads with dense buildings, receiving power and delay spread were computed when doing these, we were able to develope codes to be executed in a very fast time by combining image method and algorithm for propagation paths compairing with ray launching technique. And receiving power and delay spread could be viewed in 3-dimensional picture by virtue of computing electric fields in arbitrary receiving point. For numerical computation, receiving power of wide and anrrow band and delay spread were computed, and extension method of ray numbers was facilitated for handling infinite number of rays.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1098-1100
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• 2002

Inter-RNC(radio network controller) and inter-BSC(base station center) hard handovers involve rerouting. Thus additional delay time for the new bearer setup and reroute determination should be considered. For theses kinds of handovers we propose a new scheme and coined it as ICHP(Inter-Cluster Handover Prediction). When a call approaches a boundary cell of a cluster, ICHP prepares for the handover by performing resource reservations and reroute computation in advance. Performance analysis shows that ICHP provides faster handover and that it lowers the blocking probability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.10
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• pp.4025-4041
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• 2020

Mobile edge computing (MEC) is capable of providing services to smart devices nearby through radio access networks and thus improving service experience of users. In this paper, an offloading strategy for the joint optimization of computing and communication resources in multi-user and multi-MEC overlapping scene was proposed. In addition, under the condition that wireless transmission resources and MEC computing resources were limited and task completion delay was within the maximum tolerance time, the optimization problem of minimizing energy consumption of all users was created, which was then further divided into two subproblems, i.e. offloading strategy and resource allocation. These two subproblems were then solved by the game theory and Lagrangian function to obtain the optimal task offloading strategy and resource allocation plan, and the Nash equilibrium of user offloading strategy games and convex optimization of resource allocation were proved. The simulation results showed that the proposed algorithm could effectively reduce the energy consumption of users.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.815-820
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• 2001

This paper presents a distributed mobile architecture aimed to support the mobility of mobile station. The proposed architecture considers three significant objects；mobile station (MS), mobile agent (MA) which logically represents mobile station in the wireline network, and trace agent (TA) to represent application server (AS) providing application service to mobile station. The mobile agent is made closely coupled with the mobile station while the trace agent is made closely coupled with the application server. During the handoff process, a flow control mechanism is considered to correct packet loss and out-of-sequence packets problem. The result of analytic additional time delay due to handoff processing is presented and simulation was performed to check the additional time delay as well as the correctness of handoff algorithm.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.1-22
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• 2011

In this paper, a Lotka-Volterra model with time delays is considered. A set of sufficient conditions for the existence of Hopf bifurcation are obtained via analyzing the associated characteristic transcendental equation. Some explicit formulae for determining the stability and the direction of the Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by applying the normal form method and center manifold theory. Finally, the main results are illustrated by some numerical simulations.