Efficient parallel mining of association rules on shared-memory multiple-processor machine

In this paper we consider the problem of parallel mining of association rules on a shared-memory multiprocessor system. Two efficient algorithms PSM and HSM have been proposed. PSM adopted two powerful candidate set pruning techniques distributed pruning and global pruning to reduce the size of candidates. HSM further utilized an I/O reduction strategy to enhance its performance. We have implemented PSM and HSM on a SGI Power Challenge parallel machine. The performance studies show that PSM and HSM out perform CD-SM, which is a shared-memory parallel version of the popular Apriori algorithm.published_or_final_versio

Spatiotemporal Mapping of Photocurrent in a Monolayer Semiconductor Using a Diamond Quantum Sensor

The detection of photocurrents is central to understanding and harnessing the interaction of light with matter. Although widely used, transport-based detection averages over spatial distributions and can suffer from low photocarrier collection efficiency. Here, we introduce a contact-free method to spatially resolve local photocurrent densities using a proximal quantum magnetometer. We interface monolayer MoS2 with a near-surface ensemble of nitrogen-vacancy centers in diamond and map the generated photothermal current distribution through its magnetic field profile. By synchronizing the photoexcitation with dynamical decoupling of the sensor spin, we extend the sensor's quantum coherence and achieve sensitivities to alternating current densities as small as 20 nA per micron. Our spatiotemporal measurements reveal that the photocurrent circulates as vortices, manifesting the Nernst effect, and rises with a timescale indicative of the system's thermal properties. Our method establishes an unprecedented probe for optoelectronic phenomena, ideally suited to the emerging class of two-dimensional materials, and stimulates applications towards large-area photodetectors and stick-on sources of magnetic fields for quantum control.Comment: 19 pages, 4 figure

Characterization of Sprays from Dual Impinging Jets on a Splash Plate

The use of splash plates and dual impinging liquid jets are common methods for fuel atomization, but the combination of these methods has not been explored. The goal of this experiment is to analyze how splash plate position and orientation affect the spray geometry for this combined method. The spray patterns are observed for a single jet against a splash plate and two orientations of dual impinging jets against a splash plate. For all three cases, the spray patterns are analyzed for various splash plate angles between 30 and 60 degrees relative to the jet centerline. For the dual impinging jets, the splash plate is tested in multiple positions relative the two jets’ unimpeded impingement point. The characteristics of the spray patterns are then analyzed using high speed video. The most desirable spray characteristics occur when the splash plate is at least two jet diameters lower than the unimpeded impingement point and at an angle between 45 and 60 degrees. The spray has a clear spreading angle and minimum back-spray when the sheet formed by the jets is coincidental with the orientation axis for the splash plat

Penilaian Kinerja di Divisi Pelayanan Terminal untuk Mengukur Keberhasilan Organisasi di PT. Pelabuhan Indonesia I Belawan

PT Pelabuhan Indonesia I merupakan Perusahaan yang bergerak dibidang penyelenggaraan dan pengusahaan jasa kepelabuhanan bertujuan mengoptimalisasi pemanfaatan sumber daya yang dimiliki Perusahaan untuk menghasilkan barang atau jasa yang bermutu tinggi dan berdaya saing kuat maka kebutuhan akan tingkat kinerja yang tinggi dari setiap karyawan merupakan hal yang mutlak bagi PT. Pelabuhan Indonesia I. Berdasarkan hasil penilaian persentase kompetensi dan produktivitas yang telah ada, persentase realisasi yang dicapai lebih kecil dari angka target yang ditetapkan oleh Perusahaan. kesenjangan ini mengindikasikan bahwa kinerja karyawan belum maksimal dan perlu adanya penilaian kinerja lebih lanjut. Penilaian kinerja merupakan suatu evaluasi hasil kerja dari seorang karyawan secara sistematis yang berhubungan dengan jabatannya dan potensi yang dimilikinya untuk dikembangkan. Penilaian kinerja ini diharapkan dapat menjadi umpan Balik bagi karyawan tersebut tentang prestasi kerjanya selama ini dan mengembangkan kemampuannya lebih lanjut. Penilaian kinerja bertujuan untuk akan meningkatkan prestasi organisasi. Penelitian ini menggunakan kuesioner, software SPSS 17.0 dan Matlab sebagai instrumen penelitian. Hasil perhitungan menunjukkan bahwa pada level top manajemen, Manajer pelayanan terminal memiliki penilaian kinerja tertinggi dengan nilai eigen 2.1903. Pada level middle manajemen, Supervisor Pelayanan Operasi Senior memiliki penilaian kinerja tertinggi dengan nilai eigen 2.7424. Pada level lower manajemen, penilaian kinerja tertinggi adalah Pelaksana Perencanaan & Pengendalian Operasi Senior dengan nilai eigen 2.6141. Jabatan Asisten Manajer Pelayanan Operasi dan Jabatan Pelaksana Pelayanan Operasi Senior merupakan jabatan yang memiliki penilaian kinerja yang sangat rendah sehingga memerlukan evaluasi lebih lanjut. Hal ini dapat dilihat dari nilai eigen kedua jabatan yang bernilai negatif, masing-masing yaitu -0.0005 dan -0.000

Control of charging in resonant tunneling through InAs nanocrystal quantum dots

Tunneling spectroscopy of InAs nanocrystals deposited on graphite was measured using scanning tunneling microscopy, in a double-barrier tunnel-junction configuration. The effect of the junction symmetry on the tunneling spectra is studied experimentally and modeled theoretically. When the tip is retracted, we observe resonant tunneling through the nanocrystal states without charging. This is in contrast to previous measurements on similar nanocrystals anchored to gold by linker molecules, where charging took place. Charging is regained upon reducing the tip-nanocrystal distance, making the junctions more symmetric. The effect of voltage distribution between the junctions on the measured spectra is also discussed.Comment: submitte

Human immunodeficiency virus (HIV) in Washington, D.C.: Prevalence of antiretroviral resistance in treatment naïve patients from 2007 to 2010

HIV treatment has been greatly impacted by transmitted resistance to antiretrovirals (ARV). Several studies have documented resistance in naïve individuals and estimates of transmitted drug resistance mutations range from \u3c5% to as high as 25%. Washington, D.C. has one of the highest human immunodeficiency virus (HIV) prevalence rates in the United States (3.2% in 2009), but local data regarding the frequency of major mutations and antiretroviral (ARV) resistance has been limited. Medical records of HIV positive, ARV-naïve adults at two facilities in Washington, D.C., The George Washington University Medical Center and the Veterans Affairs Medical Center, were retrospectively analyzed in subjects who had genotypic resistance testing from 2007 to 2010. Of 407 ARV-naïve patients, at least one transmitted drug resistance mutation was detected in 17% of our patients, with non-nucleoside reverse transcriptase (NNRTI) mutations observed in 15%. Among patients with at least one reverse transcriptase (RT) or major protease region (Pr) resistance mutation, 85% had resistance against a single ARV class. Dual and triple class resistance mutations were seen in 8 patients (2%) and 3 patients (0.7%), respectively. Most of the multiple class resistance was seen in 2010. A gradual increase in NNRTI resistance was noted during 2008 to 2010. Our prevalence of transmitted RT, major Pr mutations (17.4%) and ARV resistance (8.6%) were high but similar to rates reported by others within the United States. Given the high HIV prevalence in the District of Columbia, this has important implications for treatment of these ARV-naïve patients