CDN Scalability Improvement using a Moderate Peer-assisted Method

( Peichang Shi ),( Huaimin Wang ),( Hao Yin ),( Bo Ding ),( Tianzuo Wang ),( Miao Wang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.3

Content Delivery Networks (CDN) server loads that fluctuant necessitate CDN to improve its service scalability especially when the peak load exceeds its service capacity. The peer assisted scheme is widely used in improving CDN scalability. However, CDN operators do not want to lose profit by overusing it, which may lead to the CDN resource utilization reduced. Therefore, improving CDN scalability moderately and guarantying CDN resource utilization maximized is necessary. However, when and how to use the peer-assisted scheme to achieve such improvement remains a great challenge. In this paper, we propose a new method called Dynamic Moderate Peer-assisted Method (DMPM), which uses time series analysis to predict and decide when and how many server loads needs to offload. A novel peer-assisted mechanism based on the prediction designed, which can maximize the profit of the CDN operators without influencing scalability. Extensive evaluations based on an actual CDN load traces have shown the effectiveness of DMPM.

View Scalability를 고려한 다시점 동영상 코덱

임정은(JeongEun Lim),손광훈(Kwanghoon Sohn) 한국방송·미디어공학회 2004 방송공학회논문지 Vol.9 No.3

A multiview sequence CODEC with view scalability is proposed in this paper. We define a GGOP (Group of GOP) structure as a basic coding unit to efficiently code multiview sequences. The proposed CODEC provides flexible GGOP structures based on the number of views and baseline distances among cameras. Multiview sequences encoder consists of disparity estimation/compensation, motion estimation/compensation, residual coding and rate control and generates multiview sequence bitstream. The main bitstream is the same as an MPEG-2 mono-sequence bitstream for MPEG-2 compatibility. The auxiliary bitstream contains information concerning the remaining multiview sequences except for the reference sequences. The proposed CODEC with view scalability provides that a number of view points are selectively determined at the receiver according to the type of display modes. The proposed multiview sequence CODEC is tested with several multiview sequences to determine its flexibility, compatibility with MPEG-2 and view scalability. In addition, we subjectively confirm that the decoded bitstreams with view scalability can be properly displayed by several types of display modes, including 3D monitors.

Scalable location guide overlay multicast in mobile <i>ad hoc</i> networks using tree partition scheme

Yu, Fucai,Park, Soochang,Lee, Euisin,Kim, Sang‐,Ha John Wiley Sons, Ltd 2012 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.12 No.11

<P><B>ABSTRACT</B></P><P>Nodes mobility brings flinty challenges to multicast in Mobile <I>ad hoc</I> Networks (MANETs). To track nodes mobility, flooding messages are widely used for data delivery structure construction and maintenance in many multicast protocols. These periodic flooding messages significantly consume network resources, such as energy and bandwidth, and result in network collisions. To release data delivery structure maintenance onus, profited from GPS location service, a number of stateless location based multicast protocol were proposed, where a destination list is encapsulated into each data packet for data packet orientation. However, due to data packet capability limitation, the way of encapsulating a destination list in each data packet header restricts the protocol scalability. To solve the scalability issue of multicast protocols, we propose a Scalable Location Guide Overlay Multicast (SLGOM) for MANETs. Analysis and simulation results show that SLGOM achieves high performance in large multicast group and significantly improves the scalability of stateless multicast with respect to group size. Copyright © 2010 John Wiley & Sons, Ltd.</P>

Scalable Scenario Specifications to Synthesize Component-centric Behaviour Models

Awad Ali,Dayang N. A. Jawawi,Mohd Adham Isa 보안공학연구지원센터 2015 International Journal of Software Engineering and Vol.9 No.9

Several scenario description languages and associated behaviour synthesis processes have been developed. The goal of these is to synthesize behaviour models from system requirement specifications, in order to enable the early identification of weak design spots or code generation. To date, however, most of the scenario languages are poorly scaled with regards to system sizes. This is because scalability requires more expressive constructs that can help when writing a scenario specification in a concise and compact manner, thereby resulting in a reduced number of scenarios. Furthermore, due to a lack of expressiveness in scenario languages, synthesis algorithms may need to rely on global behaviour models to determine inter-scenario dependencies. The global model is an additional factor that limits the approaches’ scalability. The reason is that the construction of a global model becomes harder as the system specification increases. To tackle these issues, within this article is proposed an expressive scenario description language that provides a concise and compact approach to scenario description, and defines inter-scenario dependencies semantically. A new algorithm that can address the additional constructs of the language was defined, in order to synthesize component-centric behaviour models. The applicability of this work has been demonstrated through both an illustrative example and a real-world case study. The evaluation indicates that the proposed scenario description language is more scalable than existing languages.

Improved FGS Coding System Based on Sign-bit Reduction in Embedded Bit-plane Coding

Kwang-deok Seo,Robert J. Davies 대한임베디드공학회 2007 대한임베디드공학회논문지 Vol.2 No.3

MPEG-4 FGS is one of scalable video coding schemes specified in ISO/IEC 14496-2 Amendment 2, and particularly standardized as a scheme for providing fine granular quality and temporal scalabilities. In this paper, we propose a sign-bit reduction technique in embedded bit-plane coding to enhance the coding efficiency of MPEG-4 FGS system. The general structure of the FGS system for the proposed scheme is based on the standard MPEG-4 FGS system. The proposed FGS enhancement-layer encoder takes as input the difference between the original DCT coefficient and the decision level of the quantizer instead of the difference between the original DCT coefficient and its reconstruction level. By this approach, the sign information of the enhancement-layer DCT coefficients can be the same as that of the base-layer ones at the same frequency index in DCT domain. Thus, overhead bits required for coding a lot of sign information of the enhancement-layer DCT coefficients in embedded bit-plane coding can be removed from the generated bitstream. It is shown by simulations that the proposed FGS coding system provides better coding performance, compared to the MPEG-4 FGS system in terms of compression efficiency.

확장성과 보안을 보장하는 IoT 디바이스 기반의 그룹통신 기법

김기영(Ki-Young Kim) 한국정보전자통신기술학회 2021 한국정보전자통신기술학회논문지 Vol.14 No.1

본 연구에서는 보안기능을 탑재한 IoT 단말로 구성된 네트워크를 구성하여 보안성과 확장성을 보장하는 그룹통신 기법을 제안한다. 네트워크상에 참여하는 단말의 수가 증가하면 네트워크 자원도 비례하여 감소되며 IoT 단말에 보안기능을 추가하면 IoT 단말에서 암호화로 인해 지연시간이 증가하게 된다. 네트워크에 발생하는 에러율이 높아지면 재전송으로 인해 네트워크 자원은 빠르게 잠식되게 된다. 따라서 보안성을 지원하면서 확장성을 보장하도록 IoT 단말을 그룹화 하여 참여 노드가 증가하여도 네트워크 자원의 소모를 감소시켜 확장성을 보장할 수 있도록 하였다. 향후 구현을 위해 IoT 단말에서 사용하는 암호화 방식은 IEEE802.5.4의 표준을 고려하였으며 표준화 동향을 조사 분류하였다. 제안하는 방식은 IEEE802.5.4 표준의 보안기능을 제공하는 IoT 디바이스를 그룹통신 기반에 적용하여 신뢰성과 확장성 보장이 가능하도록 하였다. 성능평가는 시뮬레이션을 통해 보안기능을 갖는 IoT 디바이스를 기존 방식과 그릅통신으로 구성하였을 때의 지연시간을 비교하여 제안한 방법의 효율성을 확인하였다. In this study, we propose a group communication technique that guarantees security and expandability by configuring a network consisting of IoT terminals equipped with security functions. As the number of devices participating in the network increases, network resources are proportionally reduced, and adding a security function to the IoT device increases the delay time due to encryption in the IoT device. If the error rate that occurs in the network increases, network resources are quickly consumed due to retransmission. Therefore, IoT terminals are grouped to ensure scalability while supporting security, reducing the consumption of network resources even when the number of participating nodes increases, thus ensuring scalability. For the future implementation, the encryption method used in IoT terminals considered the standard of IEEE802.5.4, and the standardization trend was investigated and classified. The proposed method applies IoT devices that provide security functions of the IEEE802.5.4 standard to the group communication base to ensure reliability and scalability. In the performance evaluation, the effectiveness of the proposed method was confirmed by comparing the delay times when grouping IoT devices with security functions through simulation.

An Impact of Addressing Schemes on Routing Scalability

Huaiyuan Ma,Bjarne E. Helvik,Otto J. Wittner 한국통신학회 2011 Journal of communications and networks Vol.13 No.6

The inter-domain routing scalability issue is a major challenge facing the Internet. Recent wide deployments of multihoming and traffic engineering urge for solutions to this issue. So far, tunnel-based proposals and compact routing schemes have been suggested. An implicit assumption in the routing community is that structured address labels are crucial for routing scalability. This paper first systematically examines the properties of identifiers and address labels and their functional differences. It develops a simple Internet routing model and shows that a binary relation T defined on the address label set A determines the cardinality of the compact label set L. Furthermore, it is shown that routing schemes based on flat address labels are not scalable. This implies that routing scalability and routing stability are inherently related and must be considered together when a routing scheme is evaluated. Furthermore, a metric is defined to measure the effi-ciency of the address label coding. Simulations show that given a 3000-autonomous system (AS) topology, the required length of address labels in compact routing schemes is only 9.12 bits while the required length is 10.64 bits for the Internet protocol (IP) upper bound case. Simulations also show that the α values of the compact routing and IP routing schemes are 0.80 and 0.95, respectively, for a 3000-AS topology. This indicates that a compact routing scheme with necessary routing stability is desirable. It is also seen that using provider allocated IP addresses in multihomed stub ASs does not significantly reduce the global routing size of an IP routing system.

An Impact of Addressing Schemes on Routing Scalability

Ma, Huaiyuan,Helvik, Bjarne E.,Wittner, Otto J. The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.6

The inter-domain routing scalability issue is a major challenge facing the Internet. Recent wide deployments of multihoming and traffic engineering urge for solutions to this issue. So far, tunnel-based proposals and compact routing schemes have been suggested. An implicit assumption in the routing community is that structured address labels are crucial for routing scalability. This paper first systematically examines the properties of identifiers and address labels and their functional differences. It develops a simple Internet routing model and shows that a binary relation T defined on the address label set A determines the cardinality of the compact label set L. Furthermore, it is shown that routing schemes based on flat address labels are not scalable. This implies that routing scalability and routing stability are inherently related and must be considered together when a routing scheme is evaluated. Furthermore, a metric is defined to measure the efficiency of the address label coding. Simulations show that given a 3000-autonomous system (AS) topology, the required length of address labels in compact routing schemes is only 9.12 bits while the required length is 10.64 bits for the Internet protocol (IP) upper bound case. Simulations also show that the ${\alpha}$ values of the compact routing and IP routing schemes are 0.80 and 0.95, respectively, for a 3000-AS topology. This indicates that a compact routing scheme with necessary routing stability is desirable. It is also seen that using provider allocated IP addresses in multihomed stub ASs does not significantly reduce the global routing size of an IP routing system.

이질적인 환경을 위한 스케러블 스테레오 영상 부호화

오세찬(Sehchan Oh),이영호(Youngho Lee),우운택(Woontack Woo) 한국방송·미디어공학회 2004 방송공학회논문지 Vol.9 No.3

In this paper, we propose a new stereoscopic video coding approach for heterogeneous consumer devices by exploiting the concept of spatio-temporal scalability. The proposed method uses MPEG-2 standard for coding the left or main sequence and an enhanced compatible coding scheme for predicting the P- and B-type of frames of the right or auxiliary sequence. The enhanced compatible coding scheme predicts matching block by interpolating both two forward and backward motion predicted macroblocks and disparity predicted macroblock. To provide flexible stereo video service, we define both a temporally scalable layer and a spatially scalable layer for each eye-view. The experimental results show the efficiency of proposed coding scheme by comparison with already known methods and the advantages of disparity estimation in terms of scalability overhead. According to the experimental results, we expect the proposed functionalities will play a key role in establishing highly flexible stereo video service for ubiquitous computing environment where devices and network connections are heterogeneous.

화장품 추천 사례에서 요인, 군집분석을 이용한 협업 필터링 추천 모델과 연관성 규칙 기법의 성능 비교 연구

이용구,양현일,최정아,허준 한국자료분석학회 2012 Journal of the Korean Data Analysis Society Vol.14 No.2

Recommendation system is the big issue in the almost industries recently. And collaborative filtering method is the most common and useful algorithm in the recommendation system with association rule of data mining. But collaborative filtering has many problems and restrictions for applying the practical business and industries. the most important problem of them is the scalability issue that it needs many times to execute the collaborative filtering in the big data. In this paper, we suggest the improved collaborative filtering method using factor and cluster analysis for making up the issue of scalability. This paper show that the proposed method is superior to the association rule method using the big data set of Korean cosmetics company. and improved the performance of collaborative filtering calculation too. 상품을 판매하는 모든 산업에서 추천시스템은 이제 가장 큰 화두 중 하나가 되었다. 현재 전 산업에 걸쳐 가장 많이 활용되고, 보편적인 추천 알고리즘이 바로 협업필터링(collaborative filtering)이다. 그러나 과거 많은 연구에서 지적되었듯, 협업 필터링은 다양한 문제점으로 인하여, 실제 기업에서 사용하기에는 많은 제약 조건 등이 따르는 것이 사실이다. 본 논문에서는 51개의 화장품 종류의 추천 판매(방문 판매) 사례에서, 기존의 협업 필터링이 가지고 있는 문제점 중 대량의 사용자들이 있는 경우 발생하는 확장성(scalability) 문제를 군집분석과 요인분석을 이용하여, 보완하고, 실제 일반적으로 대량의 사용자 추천 모델에서 사용되는 데이터 마이닝의 연관성 모델을 이용한 기법보다 성능이 뛰어남을 사례 데이터를 이용하여 제안한다.