Abstract: In this paper, we introduce a flexible box erecting
machine (BEM) that swiftly and automatically transforms cardboard
into a three dimensional box. Recently, the parcel service and
home-shopping industries have grown rapidly, and there is an
increasing need for various box types to ship various products.
However, workers cannot fold thousands of boxes manually in a day.
As such, automatic BEMs are garnering greater attention. This study
takes equipment operation into consideration as well as mechanical
improvements in order to design a BEM that is able to outperform its
conventional counterparts. We analyzed six dispatching rules – First In
First Out (FIFO), Shortest Processing Time (SPT), Earliest Due Date
(EDD), Setup Avoidance, EDD + SPT, and EDD + Setup Avoidance –
to determine which one was most suitable for BEM operation.
Consequently, SPT and Setup Avoidance were found to be the most
critical rules, followed by EDD + Setup Avoidance, EDD + SPT,
EDD, and FIFO. This hierarchy was valid for both our conventional
BEM and our new flexible BEM from the viewpoint of processing
time. We believe that this research can contribute to flexible BEM
management, which has the potential to increase productivity and
convenience.
Abstract: Ren et al. presented an efficient carrier frequency offset
(CFO) estimation method for orthogonal frequency division multiplexing
(OFDM), which has an estimation range as large as the
bandwidth of the OFDM signal and achieves high accuracy without
any constraint on the structure of the training sequence. However,
its detection probability of the integer frequency offset (IFO) rapidly
varies according to the fractional frequency offset (FFO) change. In
this paper, we first analyze the Ren-s method and define two criteria
suitable for detection of IFO. Then, we propose a novel method for
the IFO estimation based on the maximum-likelihood (ML) principle
and the detection criteria defined in this paper. The simulation results
demonstrate that the proposed method outperforms the Ren-s method
in terms of the IFO detection probability irrespective of a value of
the FFO.
Abstract: This paper suggests an improved integer frequency
offset (IFO) estimation scheme using P1 symbol for orthogonal
frequency division multiplexing (OFDM) based the second generation
terrestrial digital video broadcasting (DVB-T2) system. Proposed
IFO estimator is designed by a low-complexity blind IFO estimation
scheme, which is implemented with complex additions. Also, we
propose active carriers (ACs) selection scheme in order to prevent
performance degradation in blind IFO estimation. The simulation
results show that under the AWGN and TU6 channels, the proposed
method has low complexity than conventional method and almost
similar performance in comparison with the conventional method.