• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.584-587
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• 1997

In this paper, we present a transmission constraints modeling of carrier relay signal over ATM network. Since teleprotection system, which is used for protecting power transmission lines using telecommunications, has strict transmission delay constraints, it is a important problem to transmit teleprotection signals in future utilities' ATM networks when utilites' communications are integrated. Therefore, we considered the transmission constraints of carrier relay signal over ATM network and the transmission model system.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.221-229
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• 2005

We present a numerical analysis of the optimal group number for minimizing the average paging delay. In the analysis, we consider uniform distributions for location probability conditions and apply M/D/1 queueing model to paging message queues of cells. We also get the lower bounds of group numbers and investigate the minimum transmission capacity under average paging delay constraints. Minimizing the average paging delay is important because it means minimizing the amount of bandwidth used for locating mobile terminals. Therefore, the numerical results of this paper will be very useful in PCS system when designing its signalling capacity due to its simplicity and effectiveness.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.58-58
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• 2000

As many sensors and actuators are used in various automated systems, the application of network system to real-time distributed control is gaining acceptance in many industries. In order to take advantages of the network technique. however, network implementation should be carefully designed to satisfy real-time constraints and to consider network delays. This paper presents the implementation of feedback control system in Profibus-DP. Profibus-DP is a type of fieldbus protocols that are specifically designed to interconnect simple devices with fast I/O data exchange. As feedback control in profibus-DP is implemented, Network delays is found with influence of system performance. We analyze network delays in Profibus-DP into 3 reasons - dead time in Profibus interface, protocol delay, delay by asynchronization. In order to compensate the network delays, we introduce control algorithms with time delay concept. The results show that network delay can be compensated.

• IE interfaces
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• v.13 no.1
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• pp.110-119
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• 2000

Resource-constrained project scheduling is to allocate limited resources to activities to optimize certain objective functions and to determine a start time for each activity in the project such that precedence constraints and resource requirements are satisfied. This study suggests a multi-project scheduling model which can level work loads, make the most of production capacity and restrain the delay of delivery by developing a heuristic algorithm which minimizes the project completion time and maximizes the load rate under resource constraints.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.632-650
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• 2013

The paper considers a spectrum sharing cognitive radio (CR) network coexisting with a primary network under the average interference power constraint. In particular, the secondary user (SU) is assumed to carry delay-sensitive services and thus shall satisfy a given delay quality-of-service (QoS) constraint. The secondary receiver is also assumed to be equipped with multiple antennas to perform maximal ratio combining (MRC) to enhance SU performance. We investigate the effective capacity of the SU with MRC diversity under aforementioned constraints in Nakagami fading environments. Particularly, we derive the optimal power allocation to achieve the maximum effective capacity of the SU, and further derive the effective capacity in closed-form. In addition, we further obtain the closed-form expressions for the effective capacities under three widely used power and rate adaptive transmission schemes, namely, optimal simultaneous power and rate adaptation (opra), truncated channel inversion with fixed rate (tifr) and channel inversion with fixed rate without truncation (cifr). Numerical results supported by simulations are presented to consolidate our studies. The impacts on the effective capacity of various system parameters such as the number of antennas, the average interference power constraint and the delay QoS constraint are investigated in detail. It is shown that MRC diversity can significantly improve the effective capacity of the SU especially for cifr transmission scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.69-76
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• 2011

In this paper, we present the analytic model to quantify the system capacity with delay Quality of Service (QoS) constraints, and analyze the effect of user-multiplexing on the delay QoS performance in multiuser low-power wireless communication systems. For this purpose, we define the degree of multiplexing as the number of scheduled users to be served in a frame, and investigate the effect of degree of multiplexing (DoM) on the trade-off of throughput and delay QoS constraints. Through this analysis, we characterize the optimal DoM maximizing the energy efficiency in low-power communication environments. Finally, through the simulation results, we verify that our approach with its optimal DoM yields substantial capacity gain.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.10a
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• pp.108-111
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• 1983

This paper presents a new method for the optimum capacity assignment in store-and-forward communication networks under a total fixed-capacity constraints. Any two link capacities needed in this method can have the desirable quantites and then other capacities can be obtained from the fixed two link capacities. When the minimum and the maximum capacities that are the quantites of the conventional method are fixed, the total average time delay from the new method is almost the same as that from the conventional method. And when the minimum capacity is fixed, the new method gives smaller average time delay.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.5
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• pp.387-397
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• 1991

This paper presents the design and implementation of a performance-driven logic synthesis system that automatically generates circuits satisfying the given timing and fanout constraints in minimal silicon area. After performing technology independent and dependent optimization, the system identifies and resynthesizes the gates with large loading delay due to excessive fanouts to eliminate the critical path. Experimental results for MCNC benchmark circuits show that proposed system generates the circuits with less delay by up to 20%.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.225-227
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• 2004

A sensor networkis composed of a large number of sensor nodes, which are densely deployed either inside the phenomenon or very close to it. One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, generally irreplaceable, power sources. Therefore, while traditional networks aim to achieve high quality of service (QoS) provisions, sensor network protocols must focus primarily on power conservation. This paper presents the characteristics of energy consuming, average delay in 802.11 MAC, S-MAC that is specifically designed for wireless sensor networks. We analyze the energy consuming state in the 802.11 MAC in the simulation topology nodes, and measure average delay in 802.11 and S-MAC. Energy efficiency is the primary goal in this protocol design. 802.11 MAC is more efficient than S-MAC in the average delay, throughput. However S-MAC is an energy efficient protocol, a tradeoff between energy efficiency and delay.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.132-135
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• 2000

We have been aware fer some time. that it is becoming harder to develop ASIC only, using the vendor wire model for the current top-down/bottom-up process. Because VDSM has a much bigger wired delay than cell delay, it is also difficult to reduce development time, as well as time-to-market, while developing several million gate ASIC's. The same is true for high frequency ASIC's with VDSM (which have larger wire delay versus cell delay). Therefore, a solution called “RTS-GDS”, using physical constraints fur SOC with timing met, is being actively discussed. This paper suggests a methodology for SOC development by utilizing a top down flow via CWLM along with discussing potential problems. This paper also provides a design flow, including physical synthesis, DFT, floor plan and CWLM, all of which are relevant to proper SOC development.