• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.169-173
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• 2014

Nobody has yet been able to determine the optimal solution conclusively whether NP-complete problems are in fact solvable in polynomial time. Gu$\acute{e}$ret et al. tries to obtain the optimal solution using linear programming with $O(m^4)$ time complexity for barge loading problem a kind of bin packing problem that is classified as nondeterministic polynomial time (NP)-complete problem. On the other hand, this paper suggests the loading rule of profit priority rank algorithm with O(m log m) time complexity. This paper decides the profit priority rank firstly. Then, we obtain the initial loading result using the rule of loading the good has profit priority order. Finally, we balance the loading and capability of barge swap the goods of unloading in previously loading in case of under loading. As a result of experiments, this algorithm reduces the $O(m^4)$ of linear programming to O(m log m) time complexity for NP-complete barge loading problem.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.82-89
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• 2000

This study analyzes the cell loss probability of an ATM multiplexer with real time and non-real time bursty traffics. It is assumed that an ATM multiplexer with loss priority control for the analysis. The loss priority control uses the CLP Reld of cell header. For easy analysis and less computation. the multiplexed traffic of the ATM multiplexer was modeled by the MMDP. The ATM multiplexer is simulated by the MMDP/MMDP/l/K queueing system. From the above results, The connection admission of an ATM multiplexer with loss priority control is determined by the cell loss probability with low priority as well as the size of threshold buffer. Therefore, to increase the statistical multiplexing gain it will be good to utilize the loss priority control in order.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1770-1780
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• 1997

Our problem is improvement of image quality because it is inevitable cell loss of image data when traffic congestion occurs. If cells are discarded indiscriminately in transmission of MPEG video data, it occurs severe degradation in quality of service(QOS). In this paper, to solve this problem, we propose two method. The first, we analyze the traffic characteristics of an MPEG encoder and generate high priority and low priority data stream. During network congestion, only the least low priority cells are dropped, and this ensures that the high priority cells are successfully transmitted, which, in turn, guarantees satisfactory QoS. In this case, the prioritization scheme for the encoder assigns components of the data stream to each priority level based on the value of a parameter ${\beta}$. The second, Number of high priority cells are increased when value of ${\beta}$ is large. It occurs the loss of high priority cell in the congestion. To prevent it, this paper is regulated to data stream rate as buffer occupancy with UPC controller. Therefore, encoder's bandwidth can be calculated renegotiation of the encoder and networks. In this paper, the encoder's bandwidth requirements are characterized by a usage parameter control (UPC) set consisting of peak rate, burstness, and sustained rate. An adaptive encoder rate control algorithm at the Networks Interface Card(NIC) computes the necessary UPC parameter to maintain the user specified quality of service. Simulation results are given for a rate-controlled VBR video encoder operating through an ATM network interface which supports dynamic UPC. These results show that dynamic bandwidth renegotiation of prioritized data stream could provided bandwidth saving and significant quality gains which guarantee high priority data stream.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.59-66
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• 2008

This paper presents a spectrum sharing and allocation problem in multiple network operators(NOs). Most of previous works as to dynamic spectrum allocation(DSA) schemes have presented the DSA gain achieved by utilizing the time or regional variations in traffic demand between multi-network operators(NOs). In this paper, we introduce the functionalities required for the entities related with the spectrum sharing and allocation and propose a spectrum allocation algorithm while considering the long-term priority(or fairness) between NOs, the prioritybetween multiple class services, and the urgent bandwidth request. It was shown that the proposed algorithm with priorities between multiple class services could sustain better satisfaction ratio(SR) than the fixed allocation schemes or one without priority under different traffic patterns. Therefore, we conclude that the proposed DSA with priorities between multiple class services and network operators could provide the fairness between service classes of network operators and effective negotiation procedure for urgent bandwidth request by users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.354-363
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• 1994

This paper describes the method that voice traffic is served efficiently in BISDN. Voice is divided into talkspurt and silent period, and it is possible to transmit olny talksurt by the speech activity detection. This paper described the voice traffic control algorithm in the ATM network where cell discarding method is applied to the embedded ADPCM voice data. For traffic control, the cell discarding was used over low priority cells when it overflows the queue threshold. To estimate the efficiency of traffic control algorithm, the computer simuation was performed with cell loss probability, queue length and mean delay as performance parameters. The embedded ADPCM voice coding and cell disscarding resulted in improving the voice cell traffic efficiency and the dynamic control over network congestion.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.1-8
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• 2007

In this paper, we evaluate a performance on a resource allocation algorithm for prioritized data services in CDMA networks supporting real-time and non-real-time data services. The weighted aggregate data throughput is used to characterize the performance of the prioritized data service. Our prioritized data service is implemented so that the weighted aggregate data throughput is maximized via efficient power and spreading gain allocation. Numerical experiments are performed to evaluate a suboptimal resource allocation algorithm for typical parameters.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.204-206
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• 2006

구조개편 이후로 수요관리 프로그램에 매년 막대한 재원이 투자되고 있으나, 수요관리 프로그램별 포트폴리오 구성에 대한 연구가 이루어져 오지 않았다. 지금까지의 수요관리 목표량은 과거 보급실적이나 전년도 실적을 근거로 단순히 추정하는 수준이며, 수요관리 프로그램 유형별, 세부프로그램별 보급 우선순위가 체계적으로 정해져 있지 않다. 본 논문에서는 효율개선 프로그램의 고효율기기에 대한 수요관리 목표량을 운영상의 경제적인 이득을 얻을 수 있는 관점에서 해석하여 수요 관리 목표량을 선정한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.394-396
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• 2003

본 논문에서는 메시지 패싱 시스템에서의 태스크 스케줄링에 대해 다룬다. 병렬/분산 시스템의 어플리케이션의 태스크에 대한 적절한 스케줄링이 이루어지지 않는 경우, 정렬/분산 처리를 이용한 이득을 기대하기는 어렵기 때문에 이 주제에 대한 연구는 컴퓨터 아키텍처의 발달과 함께 지속되고 있으며, 많은 연구들이 태스크 스케줄링에 대한 다양한 기법들을 제안하고 있다. 하지만 통신비용을 데이터를 소모하는 한쪽의 테스크에만 부과하는 기존 기법들을 메시지 패싱 시스템에 적용하기는 부족한 면이 있다. 본 논문에서는 기존 연구의 모델과 메시지 패싱 시스템에서 통신비용이 통신과 관계된 모든 노드에서 발생함을 고려하여 리스트 스케줄링 기법에 기초한 개선된 우선순위 함수와 새로운 프로세서 선택 기준을 제안한다. 이들 두 가지 제안을 적용한 태스크 스케줄링 기법은 메시징 패싱 시스템에서 통신비용이 누적되는 특징으로 발생하는 비효율적인 스케줄링을 개선한다.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.159-163
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• 2006

본 연구는 국제환경규제에 따라 폐자동차의 재활용율 향상을 위한 재활용 부품 우선순위를 도출하고, 폐시트 등 부품 재활용에 의한 환경성을 평가하기 위하여 폐차 해체시스템 전과정평가를 수행하였다. 연구결과 차피의 고철을 재활용 할 경우에는 지구온난화와 오존층파괴에 큰 환경이득을 얻을 수 있으나 폐시트를 폴리올 원료로 재활용할 경우에는 많은 자원의 사용으로 오히려 소각으로 인한 환경부하보다 지구온난화와 오존층파괴, 광화학산화물생성 등의 부하를 증가시키는 것으로 나타났다. 그러나 폐차의 95% 이상을 재활용 및 회수하기 위해서는 분해시간 및 시장성, 기술현황 등을 종합하여 고려하여야 하며 재활용이 곤란한 유리와 같은 다른 부품과 함께 시트의 물질재활용도 반드시 포함되어야 될 것으로 사료된다. 처리와 재활용에 따른 환경성을 비교한 결과 재활용이 필요한 부품은 시트와 유리가 가장 시급하며, 배터리, 혼합플라스틱도 재활용시 환경친화적 공정개발이 필요한 것으로 도출되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.662-668
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• 2013

Mobile communication systems have been adopting link adaptive transmission schemes such as adaptive modulation and coding (AMC) and hybrid-ARQ (HARQ). Incremental redundancy (IR) HARQ scheme is known to be highly efficient in terms of throughput and power consumption and can be a good solution for mobile communication systems. In this paper, we propose an IR-HARQ scheme based on dual-diagonal parity-type block LDPC codes in which we define a transmission priority of coded bits and propose the sub-packet construction rule. We present the throughput performance of IR-HARQ with various modulation and coding and multi-antenna modes. Consequently, the proposed scheme provides the improvement of system throughput by elaborate link adaptation with CQI information.