Abstract-An adaptive subcarrier allocation and an adaptive modulation for multiuser orthogonal frequency-division multiplexing (OFDM) are considered. The optimal subcarrier and bit allocation problems, which are previously formulated as nonlinear optimizations, are reformulated into and solved by integer programming (IP). A suboptimal approach that performs subcarrier allocation and bit loading separately is proposed. It is shown that the subcarrier allocation in this approach can be optimized by the linear-programming (LP) relaxation of IP, while the bit loading can be performed in a manner similar to a single-user OFDM. In addition, a heuristic method for solving the LP problem is presented. The LP-based suboptimal and heuristic algorithms are considerably simpler to implement than the optimal IP, plus their performances are close to those of the optimal approach. Index Terms-Integer programming (IP), linear programming (LP), multiuser orthogonal frequency-division multiplexing (OFDM), subcarrier and bit allocation.

Two spore-forming, facultatively anaerobic, lactic acid bacteria, strains SL153T and SL1153, were isolated from vineyard soil in Korea. Cells of both strains were slightly curved, Gram-positive, motile rods that measured between 1 and 4 mm in length and were approximately 0.5 mm in diameter. Strains SL153 T and SL1153 fermented glucose, fructose, mannose and sorbitol, but were negative for nitrate reduction, catalase and oxidase. The predominant cellular fatty acids of the two isolates were iso-C 15 : 0 , anteiso-C 15 : 0 and anteiso-C 17 : 0 . meso-Diaminopimelic acid, glucose, mannose and galactose were determined in their whole-cell hydrolysates. 16S rRNA gene sequences from the two strains were almost identical (99.9 %) and they could be placed in the genus Sporolactobacillus according to phylogenetic analysis.

A Gram-positive, rod-shaped, endospore-forming bacterium, designated strain BLB-1T, was isolated from samples of tidal flat sediment from the Yellow Sea. 16S rRNA gene sequence analysis demonstrated that the isolate belonged to the Bacillus rRNA group 2 and was closely related to Bacillus massiliensis CIP 108446T (97.4 %), Bacillus odysseyi ATCC PTA-4993T (96.7 %), Lysinibacillus fusiformis DSM 2898T (96.2 %) and Lysinibacillus boronitolerans DSM 17140T (95.9 %). Sequence similarities with related species in other genera, including Caryophanon , Sporosarcina and Solibacillus , were <96.1 %. Chemotaxonomic data supported the affiliation of strain BLB-1T with the genus Lysinibacillus . The major menaquinone was MK-7, the cell-wall sugars were glucose and xylose, the cell-wall peptidoglycan type was A4α (l-Lys–d-Asp), the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and several unknown phospholipids, and the major fatty acids were anteiso-C15 : 0 (35.6 %), iso-C15 : 0 (25.6 %) and anteiso-C17 : 0 (16.5 %). The most closely related species, Bacillus massiliensis and Bacillus odysseyi , were also assigned to this genus based on phylogenetic analysis and phenotypic data. The results of DNA–DNA hybridizations and phenotypic tests supported the differentiation of all three taxa from species of the genus Lysinibacillus with validly published names. Thus, strain BLB-1T ( = KCTC 13296T  = JCM 15800T) represents a novel species, for which the name Lysinibacillus sinduriensis sp. nov. is proposed. It is also proposed that Bacillus massiliensis CIP 108446T ( = 4400831T = CCUG49529T  = KCTC 13178T) and Bacillus odysseyi NBRC 100172T ( = 34hs-1T  = ATCC PTA-4993T  = NRRL B-30641T  = DSM 18869T  = CIP 108263T  = KCTC 3961T) be transferred to the genus Lysinibacillus as Lysinibacillus massiliensis comb. nov. and Lysinibacillus odysseyi comb. nov., respectively.

A Gram-positive, rod-shaped, endospore-forming organism, strain BL3-6(T), was isolated from tidal flat sediments of the Yellow Sea in the region of Tae-An. A 16S rRNA gene sequence analysis demonstrated that this isolate belongs to the Bacillus cereus group, and is closely related to Bacillus mycoides (99.0% similarity), Bacillus thuringiensis (99.0%), Bacillus weihenstephanensis (99.0%), Bacillus cereus (98.9%), Bacillus anthracis (98.8%), and Bacillus pseudomycoides (98.1%). The phylogenetic distance from any validly described Bacillus species outside the Bacillus cereus group was less than 95.6%. The DNA G+C content of the strain was 39.4 mol% and the major respiratory quinone was menaquinone-7. The major cellular fatty acids were iso-C(14:0) (17.8%), iso-C(16:0) (15.8%), and iso-C(12:0) (11.3%). The diagnostic amino acid of the cell wall was meso-diaminopimelic acid and the major cell wall sugar was galactose. The results of DNA-DNA hybridization (<55.6%) and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain BL3-6(T) from the published Bacillus species. BL3-6(T) therefore represents a new species, for which the name Bacillus gaemokensis sp. nov. is proposed, with the type strain BL3-6(T) (=KCTC 13318(T) =JCM 15801(T)).

An obligately anaerobic, Gram-positive, spore-forming bacterial strain, designated SL206 T , was isolated from pear orchard soils. Strain SL206 T cells were straight or slightly curved rods, with motility by peritrichate flagella. Cell walls contained meso-diaminopimelic acid; wall sugars were glucose, rhamnose and mannose. The major fatty acids were C 16 : 0 , C 18 : 1 v9c and summed feature 10 (containing C 18 : 1 v11c/9t/6t). API 20A reactions were negative for oxidase, catalase and acid production from L-rhamnose, sucrose, trehalose, D-xylose, melezitose, salicin and Dsorbitol, and positive for acid production from D-glucose, sucrose, maltose, D-mannose and raffinose. Glucose was fermented to acetate, butyrate, CO 2 , H 2 and ethanol in culture. The G+C content of the genomic DNA was 31.1 mol%. Based on comparative 16S rRNA gene sequence analysis, the isolate belonged to the genus Clostridium and formed a clade with Clostridium pasteurianum. The species most closely related to strain SL206 T were C. pasteurianum (98.6 % similarity) and Clostridium acidisoli (97.8 % similarity). In DNA-DNA relatedness studies, the isolate had 59.5 % relatedness with C. pasteurianum and thus represented a unique species. On the basis of these studies, strain SL206 T (5KCTC 5449 T 5JCM 14858 T ) is proposed to represent the type strain of a novel species, Clostridium arbusti sp. nov.The genus Clostridium is a large and phenotypically heterogeneous taxon, currently comprising more than 190 species (Wiegel et al., 2006). The DNA of these anaerobic bacteria are classified as belonging to three major groups (Wiegel et al., 2006): the low-G+C Gram-positive bacteria, the Clostridium coccoides-Eubacterium rectale group (cluster XIVa), and the Clostridium leptum group (cluster IV). The species within this genus are divided into several cluster groups based on 16S rRNA gene sequences (Collins et al., 1994). Cluster I, which includes the type species of the genus, Clostridium butyricum, is the largest of the clostridial groups, and members of this group exhibit similarity values above 90 % despite exhibiting a range of saccharolytic, proteolytic, psychrophilic, mesophilic and thermophilic phenotypes. Some of the strains within cluster I have been isolated and described as novel microorganisms obtained from soil or sediments (Jeong et al., 2004;Kim et al., 2006Kim et al., , 2007Lee et al., 2007). In this study, we report the taxonomic description of a strictly anaerobic bacterium within cluster I, designated strain SL206 T .Strain SL206 T was isolated from soil samples (30 cm depth) collected from a pear orchard in Daejeon, Republic of Korea. The samples were serially diluted in 0.85 % (w/v) saline solution, spread onto Reinforced Clostridial Medium (RCM; Difco) that was heated at 80 u C for 10 min, and incubated at 30 uC under anaerobic conditions (Forma Anaerobic System; Thermo Fisher Scientific) using a gas phase of N 2 /H 2 /CO 2 (88 : 7 : 5 %, v/v). Strain SL206T was subcultured several times to obtain a pure culture on agar plates...