• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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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.

• 산업기술연구
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• 제25권B호
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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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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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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.

• 산업공학
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• 제13권1호
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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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• 제7권4호
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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.

• 대한전자공학회논문지TC
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• 제48권4호
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• pp.69-76
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• 2011

본 논문은 지연 QoS (delay Quality of Service)에 대한 제약이 주어졌을 때의 시스템 용량을 정량화 할 수 있는 분석모델을 제시하고, 이를 바탕으로 다중사용자 저전력 무선통신 시스템에서 사용자 다중화가 지연 QoS에 미치는 영향을 분석하였다. 이를 위해, 한 프레임에서 스케줄 되는 사용자 수를 다중화도 (degree of multiplexing)이라 정의하고, 다중화도가 지연 서비스 품질과 시스템 용량 간의 관계에 미치는 영향을 분석하였다. 또한, 저전력 통신환경에서 에너지 효율성을 고려할 때 최적의 다중화도가 어떻게 변화하는지를 확인하였다. 마지막으로 모의실험을 통하여, 최적의 다중화도를 이용할 때 상당한 성능이득을 얻을 수 있음을 확인하였다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1983년도 추계학술발표회논문집
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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.

• 전자공학회논문지A
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• 제28A권5호
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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%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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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.