512 research outputs found

    Quality of Move-Optimal Schedules for Minimizing the Vector Norm of the Workloads

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    We study the problem of minimizing the vector norm p||\cdot||_p of the workloads. We examine move-optimal assignments and prove a performance guarantee of 2p1p(p12p2)p1p,\frac{2^p-1}{p} \cdot \left(\frac{p-1}{2^p-2}\right)^{\frac{p-1}{p}}, for any integer p>1p>1 and moreover, we show that this guarantee is tight. Additionally, we consider assignments obtained by applying the LPT-heuristic of Graham (1969). We prove that an LPT-assignment has a performance guarantee of 3p2pp(p123p32p)p1p,\frac{3^p-2^p}{p} \cdot \left(\frac{p-1}{2 \cdot 3^p - 3 \cdot 2^p}\right)^{\frac{p-1}{p}}, which reproves a result of Chandra and Wong (1975)

    Two exponential neighborhoods for single machine scheduling

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    We study the problem of minimizing total completion time on a single machine with the presence of release dates. We present two different approaches leading to exponential neighborhoods in which the best improving neighbor can be determined in polynomial time. Furthermore, computational results are presented to get insight in the performance of the developed neighborhoods

    An improved local search algorithm for 3-SAT

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    We slightly improve the pruning technique presented in Dantsin et. al. (2002) to obtain an O(1.473n)\mathcal{O}^*\left(1.473^n\right) algorithm for 3-SAT

    Very Large-Scale Neighborhoods with Performance Guarantees for Minimizing Makespan on Parallel Machines

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    We study the problem of minimizing the makespan on m parallel machines. We introduce a very large-scale neighborhood of exponential size (in the number of machines) that is based on a matching in a complete graph. The idea is to partition the jobs assigned to the same machine into two sets. This partitioning is done for every machine with some chosen rule to receive 2m parts. A new assignment is received by putting to every machine exactly two parts. The neighborhood Nsplit consists of all possible rearrangements of the parts to the machines. The best assignment of Nsplit can be calculated in time O(mlogm) by determining the perfect matching having minimum maximal edge weight in an improvement graph, where the vertices correspond to parts and the weights on the edges correspond to the sum of the processing times of the jobs belonging to the parts. Additionally, we examine local optima in this neighborhood and in combinations with other neighborhoods. We derive performance guarantees for these local optima

    Move-optimal schedules for parallel machines to minimize total weighted completion time

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    We study the minimum total weighted completion time problem on identical machines, which is known to be strongly NP\mathcal{NP}-hard. We analyze a simple local search heuristic, moving jobs from one machine to another. The local optima can be shown to be approximately optimal with approximation ratio 1.51.5. In case all jobs have equal Smith ratios, the approximation ratio is at most 1.0921.092

    Retarded adult offender in the legal process

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    It is understandable, then, that a retarded citizen may, indeed, have the tendency to act contrary to a law or accepted standard of be­havior as he attempts to operate successfully in an alien society. When he does break the law, he becomes known as the mentally retarded offender . This paper will attempt to examine a number of problems facing this mentally retarded offender: 1. When arrested, what happens to him under the law? 2. Does he receive special treatment because he is retarded, and if so, is it better or worse treatment? 3. If he is given preferential treatment, is it fair or discriminative? 4. Why should he or should he not receive special consideration? 5. What is best for him and, ultimately, what is best for society

    Controlled lasing from active optomechanical resonators

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    Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the sub-terahertz (10E10-10E11 Hz) range with quality factors exceeding 1000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route toward manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby three resonant excitations -photons, phonons, and electrons- can interact strongly with each other providing control of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings prospective applications such as THz laser control and stimulated phonon emission may emerge

    Relationship of Genotype, Phenotype, and Treatment in Dopa-Responsive Dystonia: MDSGene Review

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    Background Pathogenic variants in 5 genes (GCH1, TH, PTS, SPR, and QDPR), involved in dopamine/tetrahydrobiopterin biosynthesis or recycling, have been linked to Dopa-responsive dystonia (DRD). Diagnosis and treatment are often delayed due to high between- and within-group variability. Objectives Comprehensively analyzed individual genotype, phenotype, treatment response, and biochemistry information. Methods 734 DRD patients and 151 asymptomatic GCH1 mutation carriers were included using an MDSGene systematic literature review and an automated classification approach to distinguish between different forms of monogenic DRDs. Results Whereas dystonia, L-Dopa responsiveness, early age at onset, and diurnal fluctuations were identified as red flags, parkinsonism without dystonia was rarely reported (11%) and combined with dystonia in only 18% of patients. While sex was equally distributed in autosomal recessive DRD, there was female predominance in autosomal dominant DYT/PARK-GCH1 patients accompanied by a lower median age at onset and more dystonia in females compared to males. Accordingly, the majority of asymptomatic heterozygous GCH1 mutation carriers (>8 years of age) were males. Multiple other subgroup-specific characteristics were identified, showing high accuracy in the automated classification approach: Seizures and microcephaly were mostly seen in DYT/PARK-PTS, autonomic symptoms appeared commonly in DYT/PARK-TH and DYT/PARK-PTS, and sleep disorders and oculogyric crises in DYT/PARK-SPR. Biochemically, homovanillic acid and 5-hydroxyindoleacetic acid in CSF were reduced in most DRDs, but neopterin and biopterin were increased only in DYT/PARK-PTS and DYT/PARK-SPR. Hyperphenylalaninemia was seen in DYT/PARK-PTS, DYT/PARK-QDPR, and rarely reported in autosomal recessive DYT/PARK-GCH1. Conclusions Our indicators will help to specify diagnosis and accelerate start of treatment. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Societ

    Population genetic structure of Streptococcus pneumoniae in Kilifi, Kenya, prior to the introduction of pneumococcal conjugate vaccine.

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    BACKGROUND: The 10-valent pneumococcal conjugate vaccine (PCV10) was introduced in Kenya in 2011. Introduction of any PCV will perturb the existing pneumococcal population structure, thus the aim was to genotype pneumococci collected in Kilifi before PCV10. METHODS AND FINDINGS: Using multilocus sequence typing (MLST), we genotyped >1100 invasive and carriage pneumococci from children, the largest collection genotyped from a single resource-poor country and reported to date. Serotype 1 was the most common serotype causing invasive disease and was rarely detected in carriage; all serotype 1 isolates were members of clonal complex (CC) 217. There were temporal fluctuations in the major circulating sequence types (STs); and although 1-3 major serotype 1, 14 or 23F STs co-circulated annually, the two major serotype 5 STs mainly circulated independently. Major STs/CCs also included isolates of serotypes 3, 12F, 18C and 19A and each shared ≤ 2 MLST alleles with STs that circulate widely elsewhere. Major CCs associated with non-PCV10 serotypes were predominantly represented by carriage isolates, although serotype 19A and 12F CCs were largely invasive and a serotype 10A CC was equally represented by invasive and carriage isolates. CONCLUSIONS: Understanding the pre-PCV10 population genetic structure in Kilifi will allow for the detection of changes in prevalence of the circulating genotypes and evidence for capsular switching post-vaccine implementation
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