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Pero Latkoski,Borislav Popovski 보안공학연구지원센터 2009 International Journal of Multimedia and Ubiquitous Vol.4 No.2
The improvement of the communication systems is conducted through communication protocol engineering and optimization process. This paper presents an effort to upgrade the IEEE 802.16 and IEEE 802.16e protocol performance regarding the delay during subscriber network entry or base station handover. Our communication protocol engineering process of WiMax protocol and its optimization resulted in a new UCD-aware initial ranging transmission opportunity slots distribution. Using an analytical and numerical performance evaluation, we prove the relevance of the new algorithm and the increase of the IEEE 802.16-based network performance.
최진호,정상엽,김성륜,김동민,Petar Popovski 한국통신학회 2019 Journal of communications and networks Vol.21 No.2
Reverse pricing has been recognized as an effective toolto handle demand variability and uncertainty in the travel industry(e.g., airlines and hotels). To investigate its viability in mobile communicationservices, as a benchmark case, we first consider that asingle mobile network operator (MNO) adopts (MNO-driven) forwardpricing only, taking into account heterogeneous and stochasticuser demands. To effectively deal with the drawbacks of forwardpricing only, we propose (user-driven) two-dimensional reversepricing on top of forward pricing and design a -approximatepolynomial-time algorithm that can maximize the revenue of theMNO. Through analytical and numerical results, we show that theproposed scheme can achieve “triple-win” solutions: Higher averagenetwork capacity utilization, the increase in the average revenueof the MNO, and the increment in the total average payoff ofthe users. To verify its feasibility in practice, we further implementits real prototype and perform experimental studies. We show thatthe proposed scheme still creates triple-win solutions in practice. Our findings provide a new outlook on resource allocation, and designguidelines for adopting two-dimensional reverse pricing on topof forward pricing.
Taehoon Kim,Dong Min Kim,Pratas, Nuno,Popovski, Petar,Dan Keun Sung IEEE 2017 IEEE communications letters Vol.21 No.10
<P>We propose an enhanced access reservation protocol (ARP) with a partial preamble transmission mechanism for the narrow band Internet of Things (NB-IoT) systems. The proposed ARP can enhance the ARP performance by mitigating the occurrence of preamble collisions, while being compatible with the conventional NB-IoT ARP. We provide an analytical model that captures the performance of the proposed ARP in terms of false alarm, misdetection, and collision probabilities. Moreover, we investigate a tradeoff between the misdetection and the collision probabilities, and optimize the proposed ARP according to the system loads. The results show that the proposed ARP outperforms the conventional NB-IoT ARP, in particular, at heavier system loads.</P>
Monitoring Insider Attack in Database Systems Using Multiple-Criteria Query Statement Probabilities
Sky Cheolmin Moon,Sam Chung,Barbara Endicott-Popovsky 한국엔터프라이즈아키텍처학회 2015 정보기술아키텍처연구 Vol.12 No.3
Any malicious attack on the database systems performed by an entrusted group of peoplehaving authorized access is called database insider attack. Even though the insider attack has beenlively researched, it is still far from the practical application. We propose a new approach to improvethe limitations in the previous researches. This approach has four objectives: (1) Multi-PreprocessingAlgorithms to observe a query in multiple perspectives (2) Query Probabilities Based Database InsiderMonitoring Methodology based upon Markov Mathematical Model to record insider’s behavioralpatterns with query and query transition probabilities (3) Query Probabilities Time Series Graph tocreate metrics to monitor the insider’s behavior in order to predict insider attack, and (4) Multi-CriteriaQuery Probabilities Based Insider Attack Monitoring System containing the (1)–(3). The results fromthe evaluation show that the proposed system overcomes the limitations and is also capable to monitorinsider’s behavioral data while the database is being updated.
HARQ Buffer Management: An Information-Theoretic View
Wonju Lee,Simeone, Osvaldo,Joonhyuk Kang,Rangan, Sundeep,Popovski, Petar IEEE 2015 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.63 No.11
<P>A key practical constraint on the design of hybrid automatic repeat request (HARQ) schemes is the size of the on-chip buffer that is available at the receiver to store previously received packets. In fact, in modern wireless standards such as LTE and LTE-A, the HARQ buffer size is one of the main drivers of the modem area and power consumption. This has recently highlighted the importance of HARQ buffer management, that is, of the use of buffer-aware transmission schemes and of advanced compression policies for the storage of received data. This work investigates HARQ buffer management by leveraging information-theoretic achievability arguments based on random coding. Specifically, standard HARQ schemes, namely Type-I, Chase Combining, and Incremental Redundancy, are first studied under the assumption of a finite-capacity HARQ buffer by considering both coded modulation, via Gaussian signaling, and Bit Interleaved Coded Modulation (BICM). The analysis sheds light on the impact of different compression strategies, namely the conventional compression log-likelihood ratios and the direct digitization of baseband signals, on the throughput. The optimization of coding blocklength is also investigated, highlighting the benefits of HARQ buffer-aware transmission scheme.</P>