We present a deterministic algorithm for large-scale VLSI module placement. Following the less flexibility first （LFF） principle,we simulate a manual packing process in which the concept of placement by stages is in...We present a deterministic algorithm for large-scale VLSI module placement. Following the less flexibility first （LFF） principle,we simulate a manual packing process in which the concept of placement by stages is introduced to reduce the overall evaluation complexity. The complexity of the proposed algorithm is （N1 ＋ N2 ） × O（ n^2 ） ＋ N3× O（n^4lgn） ,where N1, N2 ,and N3 denote the number of modules in each stage, N1 ＋ N2 ＋ N3 = n, and N3〈〈 n. This complexity is much less than the original time complexity of O（n^5lgn）. Experimental results indicate that this approach is quite promising.展开更多
The definition and formula of flexibility of arbitrary rectilinear blocks are introduced and LFF principles are extended to handle arbitrary rectilinear blocks and blocks with relative constraints.The experimental res...The definition and formula of flexibility of arbitrary rectilinear blocks are introduced and LFF principles are extended to handle arbitrary rectilinear blocks and blocks with relative constraints.The experimental results demonstrate the efficiency and effectiveness of the proposed method.展开更多
The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a s...The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a saturation function is adopted. The proposed VSC approach is fairly robust to load disturbance and system parameter variation. Since the distortion. including phase lag and amplitude attenuation occurs in the system sinusoid response, the amplitude and phase control （APC） algorithm, based on Adaline neural network and using LMS algorithm, is developed for distortion cancellation. The APC controller is simple and can on-line adjust, thus it gives accurate tracking.展开更多
Plant-symbiotic arbuscular mycorrhizal fungi(AMF)are of high global ecological and economic importance,but describing environmental communities of AMF at the species level remains a challenge,despite the need to und...Plant-symbiotic arbuscular mycorrhizal fungi(AMF)are of high global ecological and economic importance,but describing environmental communities of AMF at the species level remains a challenge,despite the need to understand AMF-plant preferences and to apply AMF in sustainable agriculture.Here,the potato-associated AMF species community composition was assessed for three Andean countries along an altitudinal gradient and at different plant stages,by using 454 GS-FLX+sequencing of a 760 bp LSU rRNA gene PCR amplicon.Two methods were compared:defining OTUs based on a simple sequence similarity threshold,or affiliating reference sequences to species based on a high throughput phylogenetic annotation approach using an evolutionary placement algorithm(EPA).The EPA-based approach was not only more precise,but also fundamental to robustly unveil the AMF species community composition.The principal advantage of this approach was also demonstrated by using artificially constructed datasets based on validated public database sequences.The affiliation of sequence reads to species using phylogenetic annotation revealed a surprisingly conserved AMF core-species community structure in Andean potatoes,regardless of different plant stages and environmental factors.In total,41 species were detected and in some cases more than 25 species were found colonizing an individual root system.Acaulospora species were identified as dominant colonizers,co-occurring with Cetraspora nodosa and certain Claroideoglomus and Rhizophagus species in most potato root samples.展开更多
文摘We present a deterministic algorithm for large-scale VLSI module placement. Following the less flexibility first （LFF） principle,we simulate a manual packing process in which the concept of placement by stages is introduced to reduce the overall evaluation complexity. The complexity of the proposed algorithm is （N1 ＋ N2 ） × O（ n^2 ） ＋ N3× O（n^4lgn） ,where N1, N2 ,and N3 denote the number of modules in each stage, N1 ＋ N2 ＋ N3 = n, and N3〈〈 n. This complexity is much less than the original time complexity of O（n^5lgn）. Experimental results indicate that this approach is quite promising.
文摘The definition and formula of flexibility of arbitrary rectilinear blocks are introduced and LFF principles are extended to handle arbitrary rectilinear blocks and blocks with relative constraints.The experimental results demonstrate the efficiency and effectiveness of the proposed method.
文摘The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a saturation function is adopted. The proposed VSC approach is fairly robust to load disturbance and system parameter variation. Since the distortion. including phase lag and amplitude attenuation occurs in the system sinusoid response, the amplitude and phase control （APC） algorithm, based on Adaline neural network and using LMS algorithm, is developed for distortion cancellation. The APC controller is simple and can on-line adjust, thus it gives accurate tracking.
基金the European Community's Seventh Framework Programme FP7/2007 under grant agreement no.227522。
文摘Plant-symbiotic arbuscular mycorrhizal fungi(AMF)are of high global ecological and economic importance,but describing environmental communities of AMF at the species level remains a challenge,despite the need to understand AMF-plant preferences and to apply AMF in sustainable agriculture.Here,the potato-associated AMF species community composition was assessed for three Andean countries along an altitudinal gradient and at different plant stages,by using 454 GS-FLX+sequencing of a 760 bp LSU rRNA gene PCR amplicon.Two methods were compared:defining OTUs based on a simple sequence similarity threshold,or affiliating reference sequences to species based on a high throughput phylogenetic annotation approach using an evolutionary placement algorithm(EPA).The EPA-based approach was not only more precise,but also fundamental to robustly unveil the AMF species community composition.The principal advantage of this approach was also demonstrated by using artificially constructed datasets based on validated public database sequences.The affiliation of sequence reads to species using phylogenetic annotation revealed a surprisingly conserved AMF core-species community structure in Andean potatoes,regardless of different plant stages and environmental factors.In total,41 species were detected and in some cases more than 25 species were found colonizing an individual root system.Acaulospora species were identified as dominant colonizers,co-occurring with Cetraspora nodosa and certain Claroideoglomus and Rhizophagus species in most potato root samples.
