• Proceedings of the Zoological Society Korea Conference
• /
• 1994.10a
• /
• pp.102.1-102
• /
• 1994

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1994.10a
• /
• pp.89.1-89
• /
• 1994

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10a
• /
• pp.11-28
• /
• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.90-90
• /
• 1995

No Abstract, See Full Text

• The KIPS Transactions:PartC
• /
• v.14C no.7
• /
• pp.597-602
• /
• 2007

In conventional cooperative communication data rate is 1/2 than non cooperative protocols. In this paper, we propose a full data rate DF (Decode and Forward) cooperative transmission scheme. Proposed scheme is based on time division multiplexing (TDM) channel access. When DF protocol has full data rate, it can not obtain diversity gain under the pairwise error probability (PEP) view point. If it increases time slot to obtain diversity gain, then data rate is reduced. The proposed algorithm uses orthogonal frequency and constellation rotation to obtain both full data rate and diversity order 2. Moreover, performance is analyzed according to distance and optimized components that affect the system performance by using computer simulation. The simulation results revealed that the cooperation can save the network power up to 7dB over direct transmission and 5dB over multi-hop transmission at BER of $10^{-2}$. Besides, it can improve date rate of system compared with the conventional DF protocol.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.5A
• /
• pp.347-354
• /
• 2009

In this paper, we propose a new transmit diversity technique for multiple-input multiple-output (MIMO) systems to improve the link level performance of open-loop systems. By cyclically applying a predetermined set of preceding weight vectors, artificially induced fluctuation is created to achieve additional diversity gain in flat fading channels. To design the set of the precoding vectors, we exploit the knowledge on the distribution of near optimum Preceding vectors observed in a beamforming scheme based on the rotation transformations. Simulation results demonstrate that the proposed open-loop diversity scheme with an arbitrary number of transmit antennas achieves a full diversity gain with computational complexity comparable to a single-input single-output (SISO) system.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.6
• /
• pp.351-363
• /
• 2020

The objective of this paper is to explore how board gender diversity affects corporate sustainability performance. Therefore, this paper examines the direct association between board gender diversity with corporate sustainability performance and the mediation effect of enterprise risk management (ERM) on this association. The study employed a cross-sectional survey method. Data were collected from annual reports, websites, and through the questionnaires that were distributed to Chief Financial Officers (CFOs) of all the listed companies of Dhaka Stock Exchange, Bangladesh. The partial least square technique of Structural Equation Modelling (SEM) approach was employed for data analysis. The result did not find support for the direct association between board gender diversity and sustainability performance in Bangladesh context. This implies that contextual factors, such as, male-dominant board, appointment of female directors based on family ties, lack of education and expertise etc. may discount gender diversity direct influence on sustainability performance. However, the study finds strong support for the mediating role of ERM use within the corporate structure. Further analysis of indirect effect suggests that ERM use mediates the relationship of board gender diversity and sustainability performance in full. This implies that in the Bangladesh context effective use of ERM is highly recommended.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1717-1723
• /
• 2010

The integrated fixed-film activated sludge (IFAS) system is a variation of the activated sludge wastewater treatment process, in which hybrid suspended and attached biomass is used to treat wastewater. Although the function and performance of the IFAS system are well studied, little is known about its microbial community structure. In this study, the composition and diversity of the bacterial community of suspended and attached biomass samples were investigated in a full-scale IFAS system using a high-throughput pyrosequencing technology. Distinct bacterial community compositions were examined for each sample and appeared to be important for its features different from conventional activated sludge processes. The abundant bacterial groups were Betaproteobacteria (59.3%), Gammaproteobacteria (8.1%), Bacteroidetes (5.2%), Alphaproteobacteria (3.9%), and Actinobacteria (3.2%) in the suspended sample, whereas Actinobacteria (14.6%), Firmicutes (13.6%), Bacteroidetes (11.6%), Betaproteobacteria (9.9%), Gammaproteobacteria (9.25%), and Alphaproteobacteria (7.4%) were major bacterial groups in the attached sample. Regarding the diversity, totals of 3,034 and 1,451 operational taxonomic units were identified at the 3% cutoff for the suspended and attached samples, respectively. Rank abundance and community analyses demonstrated that most of the diversity was originated from rare species in the samples. Taken together, the information obtained in this study will be a base for further studies relating to the microbial community structure and function of the IFAS system.

• Journal of Broadcast Engineering
• /
• v.17 no.1
• /
• pp.95-107
• /
• 2012

Network coding was proposed to increase the achievable throughput of multicast in a network. Recently, combining network coding into user cooperation has attracted research attention. For cooperative transmission schemes with network coding, users combine their own and their partners messages by network coding. In previous works, it was shown that adaptive DF with network coding can achieve diversity gain and additional throughput gain. In this paper, to improve performance of conventional protocols and maximize advantage of using network coding, we propose a new network coding based user cooperation scheme which uses adaptively amplify-and-forward and decode-and-forward according to interuser channel status. We derive outage probability bound of proposed scheme and prove that it has full diversity order in the high SNR regime. Moreover, based on the outage bound, we compute optimal power allocation for the proposed scheme.

• Journal of Communications and Networks
• /
• v.17 no.4
• /
• pp.346-350
• /
• 2015

It is known that the progressive edge-growth (PEG) algorithm can be used to construct low-density parity-check (LDPC) codes at finite code lengths with large girths through the establishment of edges between variable and check nodes in an edge-by-edge manner. In [1], the authors derived a class of LDPC codes for relay communication systems by extending the full-diversity root-LDPC code. However, the submatrices of the parity-check matrix H corresponding to this code were constructed separately; thus, the girth of H was not optimized. To solve this problem, this paper proposes a modified PEG algorithm for use in the design of large girth and full-diversity LDPC codes. Simulation results indicated that the LDPC codes constructed using the modified PEG algorithm exhibited a more favorable frame error rate performance than did codes proposed in [1] over block-fading channels.