Entity

Time filter

Source Type


Lee M.,Chonbuk National University | Choi J.,BigData Software Research Laboratory
Proceedings - IEEE 38th Annual International Computers, Software and Applications Conference Workshops, COMPSACW 2014 | Year: 2014

This paper presents a new formal method, called Calculus of Real-Time Distribution, Mobility, and Interaction (CaRDMI), to specify and verify spatial and temporal behaviors of transportation systems. For specification, CaRDMI defines a map, consisting of nodes and edges with spatial and temporal constraints. The movement of a carrier or agent in the system is represented by a path on the map. Interactive constraints among carriers are represented by synchronization modes on objects at nodes, which are distinguishable features of CaRDMI from other methods. Especially, n-to-n timed synchronization constraints are noticeable. For verification, CaRDMI presents the spatial, temporal and interactive deduction rules and the spatial and temporal equivalence relations. With the rules and relations, it can be measured how two carriers or agents are temporally and/or spatially equivalent. It is another distinguishable feature of CaRDMI. © 2014 IEEE.


Chung H.S.,BigData Software Research Laboratory | Chang S.H.,Advanced Communications Research Laboratory | Lee J.,Advanced Communications Research Laboratory | Kim K.,Advanced Communications Research Laboratory
ETRI Journal | Year: 2012

Transmission performances of direct detection-based 100-Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal-to-noise ratio sensitivity, chromatic dispersion, cross-channel nonlinearity, and transmission distance on the performance of differential 8-ary phase-shift keying (D8PSK), differential phase-shift keying plus three-level amplitude-shift keying (DPSK+3ASK), and dual-carrier differential quaternary phase-shift keying (DC-DQPSK) are evaluated. The performance of coherent dual-polarization quadrature phase-shift keying (DP-QPSK) with block phase estimation and coherent DP-QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100-Gb/s signal over several hundred kilometers of a single-mode fiber link. The results also show that DC-DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC-DQPSK is comparable to that of coherent DP-QPSK with digital differential detection. The maximum transmission distance of DC-DQPSK is over 1,000 km, which is enough distance for metro applications. © 2012 ETRI.


Song H.J.,BigData Software Research Laboratory | Lee Y.,BigData Software Research Laboratory | Kim H.S.,Pusan National University
ETRI Journal | Year: 2012

This letter proposes a more advanced joint maximum a posteriori (MAP) adaptation using a prior model based on a probabilistic scheme utilizing the bilinear transformation (BIT) concept. The proposed method not only has scalable parameters but is also based on a single prior distribution without the heuristic parameters of the previous joint BIT-MAP method. Experiment results, irrespective of the amount of adaptation data, show that the proposed method leads to a consistent improvement over the previous method. © 2012 ETRI.


Oh H.-J.,BigData Software Research Laboratory | Lee C.,BigData Software Research Laboratory | Lee C.,Kangwon National University | Lee C.-H.,BigData Software Research Laboratory
ETRI Journal | Year: 2012

Beyond the simple keyword matching methods in contextual advertising, we propose a rich contextual matching (CM) model adopting a classification method for topic targeting and a query expansion method for semantic ad matching. This letter reports on an investigation into the empirical effects of the CM model by comparing the click-through rates (CTRs) of two practical online news advertising systems. Based on the evaluation results from over 100 million impressions, we prove that the average CTR of our proposed model outperforms that of a traditional model. © 2012 ETRI.

Discover hidden collaborations