• ETRI Journal
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• v.35 no.6
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• pp.1068-1074
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• 2013

This paper proposes an additional forward error correction (FEC) layer to compensate for the defectiveness inherent in the conventional FEC layer in the Long Term Evolution specifications. The proposed additional layer is called a graceful degradation (GD)-FEC layer and maintains desirable service quality even under burst data loss conditions of a few seconds. This paper also proposes a non-delayed decoding (NDD)-GD-FEC layer that is inherent in the decoding process. Computer simulations and device-based tests show a better loss recovery performance with a negligible increase in CPU utilization and occupied memory size.

• ETRI Journal
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• v.16 no.1
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• pp.59-72
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• 1994

In this paper, a new N-way hybrid power combiner for improving the graceful degradation performance has been proposed. The proposed combiner has been configured with two dummy transmission lines per each section, where each dummy transmission line has a different characteristic impedance, of the standard combiner. Under this proposed configuration, a detailed theoretical analysis has been performed to show the general function of a power combiner. When any M amplifiers among N identical amplifiers are suffering the failure mode in a power combining circuit or system, the graceful degradation performance has been improved due to the separation of a transmission line and an internal resistor in every failed section from the proposed combiner by simultaneously operating two shorting devices. Simulation results for all the items which can be measured from all the items which can be measured from the proposed combiner with an eight-way configuration have been presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.853-862
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• 2019

In this paper, we designed a 4.5kW X-band SSPA transmitter to replace the TWTA search radar transmitter with low MTBF and high maintenance cost. The transmitter is designed for the performance of over 520W average transmission output and 4.0kW maximum transmission output. In particular, by implementing a graceful degradation, it is designed to maintain better performance than conventional TWTA transmitter up to 40% (13 assembly modules) failure level of 200W power amplifier assembly. Through an experiment on the effective range of X-band, the performance of proposed transmitter verified the values of the maximum transmission output 6.1kW, spurious output 69.16dBc, RF pulse rising time 15.2ns and RF pulse falling time 16.3ns. The experiment confirmed the change of output power according to the graceful degradation due to fault injection.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.7
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• pp.325-331
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• 2001

A dynamic anti-windup method for state delayed control systems with input saturation is considered. Under the assumption that a linear controller has been designed for a state delayed control system based on the existing design technique which shows desirable nominal performance, an additional compensator is incorporated to provide a graceful performance degradation despite of input saturation. By regarding the difference of the controller states in the absence and presence of input saturation as an objective function, the dynamic compensator which minimizes it is determined explicitly. The proposed dynamic compensator is the closed form of plant and controller parameters. The proposed method not only provides graceful performance degradation, but it also guarantees the total stability of resulting systems. An illustrative example is provided to show the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.6
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• pp.6-9
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• 1977

A general purpose language is defined and a computer architecture suitable for this language is proposed. The proposed architecture utilities the microprogramming technique. The significant features of the proposed architecture are the reduction of the overhead in micro-module swapping and graceful degradation of the execution upon detection of the micro.module fault in the time-sharing environment.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.296-298
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• 1998

본 논문의 폭주적인(bursty) 트래픽을 생성하는 스트리밍에서 사용자가 요구하는 최소 품질 (Quality of Service)의 보장 및 공정한 대역폭 활용을위하여 개선된 대역폭 적응 기법을 제안한다. LAN상의 서버/클라이언트 유니캐스트 환경에서 수행된 시뮬레이션은 제안한 기법에 의한 전송율의 패턴이 네트워크의 일시적인 혼잡에 의한 영향이 적고 안정하며 대역폭을 공유하는 기타 커넥션들에게 공정하도록 대역폭을 활용함을 보여준다. 제안한 대역폭 적응 기법에 사용한 윈도우 기반 전송율 추정은 윈도우 크기에 따라 스트리밍 어플리케이션의 graceful degradation과 대역폭 활용의 trade-off을 갖고 있지만 세션 중 윈도우 크기를 상황에 따라 동적으로 변화시킴으로 요구사항을 충족하도록 응용될 수 있다.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.371-376
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• 2001

Since continuous media such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms cold be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm based on the stride scheduler is a scheduling algorithm considered the time constraint of the continuous media. The stride schedulers, which are designed to general tasks, guarantee the fairness of resource allocation and predictability. The key concept of RRPSSA is a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness which is a strong point of the stride schedulers, and does not show graceful degradation of performance under overloaded situation. This paper proposes a new modified algorithm, namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and it reduces the scheduling violations up to 70% by maintaining the fair resource allocation. The number of context switching is 8% less than RRPSSA and the overall performance is increased.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.626-632
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• 2017

This paper describes a high power amplifier combining eight low power amplifiers using a radial power combiner with low insertion loss. The radial power combiner is a non-resonant type combiner with 8 input ports and is implemented by microstrip transmission line. The combiner characteristics designed at operating frequency of 1.045 GHz have an insertion loss of 0.7 dB and a return loss of more than 12 dB. Also, the low power amplifier used was designed with AFT27S010NT1 transistor and designed to satisfy the same gain, phase and constant output characteristic at operating frequency. The high power amplifier, which combiners the radial power combiner and the drive amplifier of 8 W output by driving low power amplifiers obtained the output characteristic of 33 W at operating frequency of 1.045 GHz. Also, the change of the output characteristic of the amplifier using the radial combiner was graceful degradation when the low power amplifier failed one by one.

• Journal of Internet Computing and Services
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• v.3 no.2
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• pp.15-26
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• 2002

Since multimedia data such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms could net be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm is a scheduling algorithm considered the time constraint of the multimedia data. This scheduling algorithm uses a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness, and does not show graceful degradation of performance under overloaded situation, This paper proposes a new modified algorithm. namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency, Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and the reduction in the number of context switching, Furthermore, a new evaluation method is proposed which can evaluate the flexibility of scheduling algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.1-7
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• 2002

Since multimedia data such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms could not be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm is a scheduling algorithm considered the time constraint of the multimedia data. This scheduling algorithm uses a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness, and does not show graceful degradation of performance under overloaded situation. This paper proposes a new modified algorithm, namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and the reduction in the number of context switching. Furthermore, a new evaluation method is proposed which can evaluate the flexibility of scheduling algorithm.