PENGARUH AKTIVITAS MASYARAKAT TERHADAP SISTEM TRANSPORTASI PUSAT KOTA (STUDI KASUS: KECAMATAN RATAHAN)

Sistem Transportasi telah menjadi bagian penting dalam kehidupan masyarakat. Sistem transportasi yang terencana dengan baik akan memberikan stimulus bagi sektor-sektor lain yang ada pada suatu daerah atau kota. Hal ini menimbulkan daya tarik untuk melakukan penelitian tentang sistem transportasi. Penelitian ini berbeda dengan penelitian sebelumnya. Rimamunanda Ekamarta, 2018 meneliti tentang tingkat karakteristik seseorang dan kenyamanan dalam pemilihan moda. Selanjutnya, Situmeang, 2018 lebih memfokuskan pada pemilihan rute perjalanan. Jadi, penelitian sebelumnya lebih menekankan pada faktor individu. Penelitian ini lebih difokuskan pada pola aktivitas masyarakat. Hal ini menjadi penting karena sistem transportasi disediakan untuk melayani aktivitas masyarakat bukan individu. Penelitian ini bertujuan untuk mengetahui faktor-faktor aktivitas masyarakat apa yang mempengaruhi sistem transportasi, mengetahui tingkat pengaruh faktor-faktor tersebut serta mengetahui model pengaruh faktor-faktor aktivitas masyarakat terhadap sistem transportasi di Kecamatan Ratahan. Penelitian dilakukan menggunakan metode analisis jalur (path analysis) dengan pendekatan kuantitatif. Pengambilan sampel diambil secara acak (random sampling) dengan jumlah responden sebanyak 160 menggunakan rumus slovin. Hasil penelitian yang dilakukan, diperoleh 5 faktor aktivitas masyarakat yang mempengaruhi sistem transportasi di Kecamatan Ratahan yaitu aktivitas ekonomi, aktivitas sosial, aktivitas pendidikan, aktivitas rekreasi dan hiburan, dan aktivitas kebudayaan. Hasil penelitian diperoleh aktivitas rekreasi dan hiburan menjadi faktor aktivitas masyarakat yang paling mempengaruh sistem transportasi di Kecamatan Ratahan.Kata Kunci: Aktivitas, Sistem Transportasi, Kecamatan Ratahan

Compression of X-ray Free Electron Laser pulses to attosecond duration

State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration. Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency. Pulses of this type may pave the way for routine time resolution of electrons in nm size potentials. Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration

Structural Susceptibility and Separation of Time Scales in the van der Pol Oscillator

We use an extension of the van der Pol oscillator as an example of a system with multiple time scales to study the susceptibility of its trajectory to polynomial perturbations in the dynamics. A striking feature of many nonlinear, multi-parameter models is an apparently inherent insensitivity to large magnitude variations in certain linear combinations of parameters. This phenomenon of "sloppiness" is quantified by calculating the eigenvalues of the Hessian matrix of the least-squares cost function which typically span many orders of magnitude. The van der Pol system is no exception: Perturbations in its dynamics show that most directions in parameter space weakly affect the limit cycle, whereas only a few directions are stiff. With this study we show that separating the time scales in the van der Pol system leads to a further separation of eigenvalues. Parameter combinations which perturb the slow manifold are stiffer and those which solely affect the transients in the dynamics are sloppier.Comment: 7 pages, 4 figure

Pieces-of-parts for supervoxel segmentation with global context: Application to DCE-MRI tumour delineation

Rectal tumour segmentation in dynamic contrast-enhanced MRI (DCE-MRI) is a challenging task, and an automated and consistent method would be highly desirable to improve the modelling and prediction of patient outcomes from tissue contrast enhancement characteristics – particularly in routine clinical practice. A framework is developed to automate DCE-MRI tumour segmentation, by introducing: perfusion-supervoxels to over-segment and classify DCE-MRI volumes using the dynamic contrast enhancement characteristics; and the pieces-of-parts graphical model, which adds global (anatomic) constraints that further refine the supervoxel components that comprise the tumour. The framework was evaluated on 23 DCE-MRI scans of patients with rectal adenocarcinomas, and achieved a voxelwise area-under the receiver operating characteristic curve (AUC) of 0.97 compared to expert delineations. Creating a binary tumour segmentation, 21 of the 23 cases were segmented correctly with a median Dice similarity coefficient (DSC) of 0.63, which is close to the inter-rater variability of this challenging task. A second study is also included to demonstrate the method’s generalisability and achieved a DSC of 0.71. The framework achieves promising results for the underexplored area of rectal tumour segmentation in DCE-MRI, and the methods have potential to be applied to other DCE-MRI and supervoxel segmentation problems

High Performance Computing Facility Operational Assessment, FY 2011 Oak Ridge Leadership Computing Facility

Oak Ridge National Laboratory's Leadership Computing Facility (OLCF) continues to deliver the most powerful resources in the U.S. for open science. At 2.33 petaflops peak performance, the Cray XT Jaguar delivered more than 1.4 billion core hours in calendar year (CY) 2011 to researchers around the world for computational simulations relevant to national and energy security; advancing the frontiers of knowledge in physical sciences and areas of biological, medical, environmental, and computer sciences; and providing world-class research facilities for the nation's science enterprise. Users reported more than 670 publications this year arising from their use of OLCF resources. Of these we report the 300 in this review that are consistent with guidance provided. Scientific achievements by OLCF users cut across all range scales from atomic to molecular to large-scale structures. At the atomic scale, researchers discovered that the anomalously long half-life of Carbon-14 can be explained by calculating, for the first time, the very complex three-body interactions between all the neutrons and protons in the nucleus. At the molecular scale, researchers combined experimental results from LBL's light source and simulations on Jaguar to discover how DNA replication continues past a damaged site so a mutation can be repaired later. Other researchers combined experimental results from ORNL's Spallation Neutron Source and simulations on Jaguar to reveal the molecular structure of ligno-cellulosic material used in bioethanol production. This year, Jaguar has been used to do billion-cell CFD calculations to develop shock wave compression turbo machinery as a means to meet DOE goals for reducing carbon sequestration costs. General Electric used Jaguar to calculate the unsteady flow through turbo machinery to learn what efficiencies the traditional steady flow assumption is hiding from designers. Even a 1% improvement in turbine design can save the nation billions of gallons of fuel

Who Benefits From Teams? Comparing Workers, Supervisors, and Managers

This paper offers a political explanation for the diffusion and sustainability of team-based work systems by examining the differential outcomes of team structures for 1200 workers, supervisors, and middle managers in a large unionized telecommunications company. Regression analyses show that participation in self-managed teams is associated with significantly higher levels of perceived discretion, employment security, and satisfaction for workers and the opposite for supervisors. Middle managers who initiate team innovations report higher employment security, but otherwise are not significantly different from their counterparts who are not involved in innovations. By contrast, there are no significant outcomes for employees associated with their participation in offline problem-solving teams

Isolation of Primary Human Hepatocytes from Normal and Diseased Liver Tissue: A One Hundred Liver Experience

Successful and consistent isolation of primary human hepatocytes remains a challenge for both cell-based therapeutics/transplantation and laboratory research. Several centres around the world have extensive experience in the isolation of human hepatocytes from non-diseased livers obtained from donor liver surplus to surgical requirement or at hepatic resection for tumours. These livers are an important but limited source of cells for therapy or research. The capacity to isolate cells from diseased liver tissue removed at transplantation would substantially increase availability of cells for research. However no studies comparing the outcome of human hepatocytes isolation from diseased and non-diseased livers presently exist. Here we report our experience isolating human hepatocytes from organ donors, non-diseased resected liver and cirrhotic tissue. We report the cell yields and functional qualities of cells isolated from the different types of liver and demonstrate that a single rigorous protocol allows the routine harvest of good quality primary hepatocytes from the most commonly accessible human liver tissue samples