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This paper analyzes the achievable sum-rate of correlated two-antenna multiple-input multiple-output (MIMO) uplink channels. Most of previous works have considered the case when a single user has multiple transmit antennas (i.e. multi-antenna single-user scenario). This paper considers the case when two-antenna MIMO uplink channels comprise two users with a single transmit antenna (i.e. single-antenna two-user scenario). The analytic and simulation results show that the achievable sum-rate of correlated single-antenna two-user MIMO uplink channels highly depends on the angle difference between the receive correlation coefficients of two users. It is also shown that the achievable sum-rate of correlated single-antenna two-user MIMO uplink channels is larger than that of correlated two-antenna single-user MIMO uplink channels and can even be larger than that of independent and identically distributed Rayleigh two-antenna MIMO uplink channels. ; This work was in part supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. R01-2008-000-21098-0).

In this paper, we consider the service of voice over i nternet protocol (VoIP) traffic with the service of non-real time traffic in the mobile WiMAX system. VoIP traffic is delay-sensitive and requires transmission at an almost constant rate. As a consequence, it may require a large amount of resource when users are in poor channel condition, leading to resource outage problem. To alleviate this problem, we consider the allocation of power according to the VoIP traffic load as well as the channel condition. When the VoIP traffic is fully loaded, the power is allocated to maximize the VoIP capacity. Otherwise, it is allocated to maximize the data throughput. Finally, the performance of the proposed scheme is verified by computer simulation. ; This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST).

Sexual plant reproduction depends on the attraction of sperm-cell delivering pollen tubes (PT) by two synergids, followed by their programmed cell death (PCD) in Arabidopsis. Disruption of the mitogen-activated protein kinase 4 (MPK4) by pathogenic effectors activates the resistance protein (R) SUMM2-mediated immunity and cell death. Here we show that synergid preservation and reactive oxygen species (ROS) homeostasis are intimately linked and maintained by MPK4. In mpk4, ROS levels are increased and synergids prematurely undergo PCD before PT-reception. However, ROS scavengers and the disruption of SUMM2, in mpk4, restore ROS homeostasis, synergid maintenance and PT perception, demonstrating that the guardian of MPK4, SUMM2, triggers synergid-PCD. In mpk4/summ2, PTs show a feronia-like overgrowth phenotype. Our results show that immunity-associated PCD and synergid cell death during plant reproduction are regulated by MPK4 underscoring an underlying molecular mechanism for the suppression of plant reproduction during systemic R-mediated immunity. ; This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korea government (MSIT) (2020R1A2B5B03096402, 2018R1A5A1023599, and 2021M3H9A1096935). WH is grateful for a graduate fellowship through the Brain Korea 21 Plus Program.

This paper considers power allocation in a spatially correlated dual-hop multiple-input multiple-output (MIMO) relay channel. In a dual-hop MIMO relay channel, it is desirable to balance the capacity of each hop channel by dynamically allocating the transmit power according to the channel condition. In fact, the end-to-end capacity of a dual-hop relay channel can be maximized by means of max-min optimization with constraint on total power. This paper considers the improvement of the end-toend capacity by allocating the transmit power according to the average channel gain and the spatial correlation between the dualhop MIMO relay channels. Simulation results show that the proposed scheme provides significant performance improvement over the power allocation based on the average signal-to-noise ratio (SNR). ; This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST).

We consider a power allocation strategy to maximize the end-to-end capacity of a regenerative dual-hop multiple-input single-output (MISO) relay channel with the use of transmit beamforming. In a dual-hop MISO relay channel, the optimum power allocation can be determined by means of a max-min technique with sum power constraints. The proposed scheme adaptively allocates the transmit power of the source and relay according to the achievable beamforming gain as well as the average channel gain to balance the capacity between the dualhop MISO relay channels. Simulation results show that the proposed scheme can provide noticeable performance improvement over the average signal-to-noise ratio (SNR)-based power allocation scheme in a dual-hop MISO relay channel with the use of the transmit beamforming. ; This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST).

In this paper, we propose a multi-beam multiplexing scheme that can simultaneously achieve spatial multiplexing gain and multi-user diversity (MUD) gain by generating coherent multiple beams in the multi-user domain. Multiple beams are generated to provide multiple channels in parallel, making it possible to achieve the MUD gain through each channel. Since the transmission power is spilt into multiple channels, the signal-to-noise power ratio (SNR) of each channel is reduced inversely proportional to the number of beams. However, multiple beams are utilized to make the multiplexing gain much larger than the decrease of SNR, increasing the overall system capacity. The proposed scheme is applicable to both multi-input multi-output (MIMO) and multi-input singleoutput (MISO) schemes, enabling the use of flexible antenna structures in the receiver. ; Korea Research Foundation Grant funded by the Korean Government(MOEHRD)

Deployment of small moving cells (SMCs) has been considered in advanced cellular systems, where wireless backhaul links are required between base stations and SMCs. In this paper, we consider signal transmission by means of multiuser beamforming in the wireless backhaul link. We generate the beam weight in an eigen-direction of weighted combination of short- and long-term channel information of the backhaul link. The beam weight can maximize the average signal-to-leakage-plus-noise ratio (SLNR), while providing the transmission robust to SMC mobility. We analyze the performance of the proposed scheme in terms of the average signal-to-interference-plus-noise ratio (SINR) and optimize the transmit power by iterative water-filling. Finally, we verify the performance of the proposed scheme by computer simulation. ; This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2019R1F1A1063171).

Concerns on irresponsible waste disposal have been on the agenda of many world governments, including Malaysia. The buildup of wastes in Malaysia has resulted in significant environmental problems and health issues. One alternative to rectify the problem is by using biodegradable plastic bags. Therefore, this paper aims at showcasing the public's mindset on responsible garbage disposal and the readiness to use biodegradable plastics. The study employed a qualitative approach; hence, these are initial findings derived from the analyses of 118 respondents with a 77.1% returned rate. The implications of the findings will be discussed in the paper. Keywords: Responsible waste disposal; biodegradable plastic usage; green economy; environmental democracy eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v7i19.3211

Abstract Background Transposable elements are major evolutionary forces which can cause new genome structure and species diversification. The role of transposable elements in the expansion of nucleotide-binding and leucine-rich-repeat proteins (NLRs), the major disease-resistance gene families, has been unexplored in plants. Results We report two high-quality de novo genomes (Capsicum baccatum and C. chinense) and an improved reference genome (C. annuum) for peppers. Dynamic genome rearrangements involving translocations among chromosomes 3, 5, and 9 were detected in comparison between C. baccatum and the two other peppers. The amplification of athila LTR-retrotransposons, members of the gypsy superfamily, led to genome expansion in C. baccatum. In-depth genome-wide comparison of genes and repeats unveiled that the copy numbers of NLRs were greatly increased by LTR-retrotransposon-mediated retroduplication. Moreover, retroduplicated NLRs are abundant across the angiosperms and, in most cases, are lineage-specific. Conclusions Our study reveals that retroduplication has played key roles for the massive emergence of NLR genes including functional disease-resistance genes in pepper plants. ; This work was supported by a grant from the Agricultural Genome Center of the Next Generation Biogreen 21 Program of RDA (Project No. PJ01127501) and by a grant from the Ministry of Science, ICT, and Future Planning (MSIP) of the Korean government through the National Research Foundation (NRF-2015R1A2A1A01002327) to DC.