• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3584-3602
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• 2022

NFV realizes flexible and rapid software deployment and management of network functions in the cloud network, and provides network services in the form of chained virtual network functions (VNFs). However, using VNFs to provide quality guaranteed services is still a challenge because of the inherent difficulty in intelligently scaling VNFs to handle traffic fluctuations. Most existing works scale VNFs with fixed-capacity instances, that is they take instances of the same size and determine a suitable deployment location without considering the cloud network resource distribution. This paper proposes a traffic forecasted assisted proactive VNF scaling approach, and it adopts the instance capacity adaptive to the node resource. We first model the VNF scaling as integer quadratic programming and then propose a proactive adaptive VNF scaling (PAVS) approach. The approach employs an efficient traffic forecasting method based on LSTM to predict the upcoming traffic demands. With the obtained traffic demands, we design a resource-aware new VNF instance deployment algorithm to scale out under-provisioning VNFs and a redundant VNF instance management mechanism to scale in over-provisioning VNFs. Trace-driven simulation demonstrates that our proposed approach can respond to traffic fluctuation in advance and reduce the total cost significantly.

• 한국컴퓨터정보학회논문지
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• 제18권2호
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• pp.59-68
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• 2013

LTE-Advanced 망에서 핸드오버가 발생하면 멀티미디어 트래픽의 전송이 지연 및 손실에 의하여 영향 받기 때문에, 일관된 QoS를 유지하기 위한 효율적인 자원 관리 방안이 필요하다. 본 논문은 핸드오버 시에 OFDMA 시스템에서 이종 트래픽의 QoS를 보장하기 위한 부하제어 기반의 자원 관리 방안을 제안한다. 이를 통하여 음성, 영상, 데이터 서비스 등 자원할당 요구 사항이 서로 다른 멀티미디어 서비스들의 서비스 연속성을 지원할 수 있다. 핸드오버 실패율과 패킷 손실률을 성능척도로 하여 수행된 시뮬레이션 결과에 의하면 제안된 방안은 기존 방안에 비하여 더 우수한 성능을 가짐이 확인된다.

• 경영과학
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• 제33권3호
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• pp.19-30
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• 2016

This study provides a framework to assess network design under the regime of QoE (Quality of Experience). Our approach is expected to reveal the necessity of developing the QoE measures and applying this notion to network design, particularly in the mobile environment. Furthermore, our model shows the ample potential that both users and network providers are able to attain a win-win case by shifting the focus on network design and service operations from QoS (Quality of Service) to QoE. Since the former considers only relevant technological specifications, it may fail in capturing critical factors surrounding users, such as a context where the corresponding user is working on. For example, according to one study [13], the bit-rate, a widely employed QoS measure, shows inferior performance in provisioning network resources to the MOS (Mean Opinion Score), a representative QoE measure. Our framework develops the idea and construct a prototype to systematically assess network design and operations in terms of QoE. The proposed prototype aims at achieving a higher level of efficiency without severely deteriorating users' satisfaction level. We also provide some simulation results which support our idea. That is, reducing the chance of over-provisioning on the basis of the QoE paradigm results in a great flexibility. It may give price cut for users or postponement of network investment for providers or both. Our simulation results also seem robust irrespective of the forms of the QoS-QoE relationship.

• 한국통신학회논문지
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• 제29권7B호
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• pp.613-627
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• 2004

본 논문은 DiffServ 방식에서 Assured Service를 이용하는 각 사용자 플로간에 수율의 공평성을 향상시키기 위하여 도메인 입구 라우터에서 Aggregate Fairness Marker (AFM)를 제안한다. 각 사용자별 플로의 패킷 표기 방법은 본 논문에서 제안하는 방법인 user flow Three Color Marker (uf-TCM)에 따라서 각각 green 패킷과 yellow 패킷, 그리고 red 패킷으로 구분되어 나온다. yellow 패킷은 uf-TCM에서 손실된 토큰을 소비하는 패킷 및 AFM에서 집합 트래픽에 대한 계약률을 준수하지 못하여 demotion 된 green 패킷에 대한 표기 방법이다. 제안하는 AFM은 플로별 관리 없이 공평한 방법으로 yellow 패킷을 green 패킷으로 promotion 하거나 green 패킷을 yellow 패킷으로 demotion 하여 사용자별 수율의 공평성 및 링크 이용률을 향상시킨다. DiffServ 내부 라우터에서는 yellow 패킷과 red패킷의 패킷 폐기 우선순위를 동일하게 하여 RIO 버퍼 관리 방식을 사용할 수 있게 한다. 성능 평가는 제안하는 AFM과 플로별 관리 없이 수율 공평성 향상을 위해 제안되었던 REDP Marker를 비교하였으며, 시뮬레이션 결과는 본 논문에서 제안하는 방식이 잉여 대역폭이 있는 경우와 최소대역폭이 있는 경우, 그리고 대역폭이 부족한 상황에서 각 사용자 플로간의 수율 공평성 및 링크 이용률 향상에 효과가 있음을 단일 도메인뿐만 아니라 다중 도메인 환경에서도 보인다.

• 정보처리학회논문지C
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• 제10C권4호
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• pp.447-454
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• 2003

광 버스트 교환(OBS : Optical Burst Switching)은 광 지연선(FDL: Fiber Delay Line) 사용의 감소와 차세대 전광 네트워크에서의 광 스위칭 패러다임을 실현하기 위해 제안되고 있다. OBS는 버스트를 시분할 다중화함으로써 파장 라우팅보다 대역폭의 효율성을 제공하고 코어 네트워크에 대한 확장성을 제공한다. 최근, 광 버스트 교환망에서 어떻게 QoS(Quality of Service)를 제공할 것인가가 이슈가 되고 있다. 본 논문에서는 혼잡 발생시 우회 라우팅(deflection routing) 경로로 우선순위 0, 1, 2의 버스트를 우회시켜 QoS를 제공하는 우회 라우팅 방법에 대해 제안한다. 제안된 방법의 큰 장점은 QoS를 간단히 제공할 수 있다는 것이고, 이는 QoS 보장 알고리즘으로부터 제공된다. 또한, 제안한 QoS 제공방식은 각 코어 라우터에서 광 지연선의 사용을 최소로 하면서 트래픽을 공평하게 분배함으로써 효율적인 네트워크를 구현하게 한다. 제안 QoS 제공 방식의 우선순위 0, 1, 2 버스트의 QoS 보장과 효율적인 네트워크 사용에 대하여 OPNET을 사용한 컴퓨터 시뮬레이션을 이용하여 평가하였다. 이에 따른 결과로써, 높은 우선 순위 버스트의 종단간 지연은 향상되었으며, 또한 효율적인 네트워크 이용이 확인되었다.

• Journal of Ecology and Environment
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• 제30권4호
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• pp.315-318
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• 2007

Cooperative or non-territorial permanently social spiders are believed to have evolved from species showing subsocial maternal care. The transition from subsocial to cooperative social groups probably involved a transition from an outbreeding breeding system to one with inbreeding. Nepotistic recognition among siblings should facilitate the evolution of social cooperation through avoidance of inbreeding and maintenance of mutual tolerance between siblings. We conducted experiments to determine whether a mechanism for sibling recognition is present in the subsocial spider, Coelotes terrestris which displays extended maternal care in the form of food provisioning. The numbers of surviving individuals within unfed groups were observed and compared between non-sibling groups of ten spiderlings and groups of ten siblings. The number of survivors differed significantly between groups, with consistently fewer spiderlings surviving in the non-sibling groups than the sibling groups over the study period. This result suggests that sibling recognition and nepotism do occur in this subsocial species. The nepotism involved in the maternal social organization of the Coelotes might be an example of a preadaptation facilitating the evolution of permanent social life.

• 한국경영과학회지
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• 제18권2호
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• pp.157-173
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• 1993

Reliability growth modeling can be a requirement when bidding on large military hardware systems. Under current reliability warranty legislature, the reliability growth model can be later translated into necessary reliability performance which must be demonstrated over an extended period of usage. In this paper the modeling situation is concerned with determining the number of spares needed to support a projected reliability growth both at the fightine and in a depot inventory. The model differs from existing models for logistics planning in that we allow for the phenomena of reliability growth. The model can also be used to determine central depot staffing requirements based upon a specified system utilization.

• ETRI Journal
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• 제32권1호
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• pp.22-32
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• 2010

The pervasive game environments have activated explosive growth of the Internet over recent decades. Thus, understanding Internet traffic characteristics and precise classification have become important issues in network management, resource provisioning, and game application development. Naturally, much attention has been given to analyzing and modeling game traffic. Little research, however, has been undertaken on the classification of game traffic. In this paper, we perform an interpretive traffic analysis of popular game applications at the transport layer and propose a new classification method based on a simple decision tree, called an alternative decision tree (ADT), which utilizes the statistical traffic characteristics of game applications. Experimental results show that ADT precisely classifies game traffic from other application traffic types with limited traffic features and a small number of packets, while maintaining low complexity by utilizing a simple decision tree.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.57-60
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• 2004

Next generation wireless network is evolving toward IP-based network that can various provide multimedia services. A challenge in wireless mobile Internet is support of quality of service over wireless access networks. DiffServ architecture is proposed for evolving wireless mobile Internet. In this paper we propose an algorithm for optimal buffer partitioning which requires the minimal channel capacity to satisfy the QoS requirements of input traffic. We used a partitioned buffer with size B to serve a layered traffic at each DiffServ router. We consider a traffic model with a single source generates traffic having J $(J\geq2)$ quality of service (QoS) classes. QoS in this case is described by loss probability $\varepsilon_j$. for QoS class j. Traffic is admitted or rejected based on the buffer occupancy and its service class. Traffic is generated by heterogeneous Markov-modulated fluid source (MMFS).

• 정보통신설비학회논문지
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• 제2권3호
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• pp.9-16
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• 2003

In this paper, we propose the burst error reduction (BER) algorithm for VoIP service in the wireless LAN network. In end point device, this BER algorithm can be achieved packet loss bounded QoS provisioning using interleaving in buffering and FEC (Forward Error Correction) through transmitting voice packet. BER algorithm can reduced the voice packet loss rate 5.5%-60% in VoIP network using wireless LAN.