A New Approach to Tagging Data in the Astronomical Literature

Data Tags are strings used in journals to indicate the origin of the archival data and to enable the reader to recover the data. The NASA/IPAC Infrared Science Archive (IRSA) has recently introduced a new approach to production of data tags and recovery of data from them. Many of the data access services at the IRSA return filtered data sets (such as subsets of source catalogs) and dynamically created products (such as image cutouts); these dynamically created products are not saved permanently at the archive. Rather than tag the data sets from which the query result sets are drawn, the archive tags the query that generates the results. A single tag can, then, encode a complex dynamic data set and simplifies the embedding of tags in manuscripts and journals. By logging user queries and all the parameters for those query as Data Tags, IRSA can re-create the query and rerun the IRSA service using the same search parameters used when the Data Tag was created. At the same time, the logs give a simple count of the actual numbers of queries made to the archive, a powerful metric of archive usage unobtainable from the Apache web server logs. Currently, IRSA creates tags for queries to more than 20 data sets, including the Infrared Astronomical Satellite (IRAS), Cosmic Evolution Survey (COSMOS) and Spitzer Space Telescope Legacy Data Sets. These tags are returned by the spatial query engine, Atlas. IRSA plans to create tags for queries to the rest of its services in late Spring 2007. The archive provides a simple web interface which recovers a data set that corresponds to the input data tag. Archived data sets may evolve in time due to improved calibrations or augmentations to the data set. IRSA’s query based approach guarantees that users always receive the best available data sets

Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall Region

A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored to the collision channel model, which enables mapping the description of the successive interference cancellation process onto the iterative erasure decoding of low-density parity-check codes. The analysis provides accurate estimates of the packet loss probability of IRSA in the waterfall region as demonstrated by Monte Carlo simulations.Comment: Accepted for publication in the IEEE Communications Letter

Design of the Spitzer Space Telescope Heritage Archive

It is predicted that Spitzer Space Telescope’s cryogen will run out in April 2009, and the final reprocessing for the cryogenic mission is scheduled to end in April 2011, at which time the Spitzer archive will be transferred to the NASA/IPAC Infrared Science Archive (IRSA) for long-term curation. The Spitzer Science Center (SSC) and IRSA are collaborating to design and deploy the Spitzer Heritage Archive (SHA), which will supersede the current Spitzer archive. It will initially contain the raw and final reprocessed cryogenic science products, and will eventually incorporate the final products from the Warm mission. The SHA will be accompanied by tools deemed necessary to extract the full science content of the archive and by comprehensive documentation

Prioritized Random MAC Optimization via Graph-based Analysis

Motivated by the analogy between successive interference cancellation and iterative belief-propagation on erasure channels, irregular repetition slotted ALOHA (IRSA) strategies have received a lot of attention in the design of medium access control protocols. The IRSA schemes have been mostly analyzed for theoretical scenarios for homogenous sources, where they are shown to substantially improve the system performance compared to classical slotted ALOHA protocols. In this work, we consider generic systems where sources in different importance classes compete for a common channel. We propose a new prioritized IRSA algorithm and derive the probability to correctly resolve collisions for data from each source class. We then make use of our theoretical analysis to formulate a new optimization problem for selecting the transmission strategies of heterogenous sources. We optimize both the replication probability per class and the source rate per class, in such a way that the overall system utility is maximized. We then propose a heuristic-based algorithm for the selection of the transmission strategy, which is built on intrinsic characteristics of the iterative decoding methods adopted for recovering from collisions. Experimental results validate the accuracy of the theoretical study and show the gain of well-chosen prioritized transmission strategies for transmission of data from heterogenous classes over shared wireless channels

Strategi Pemasaran Pada PT. Prima Megah Irsa

ABSTRAK Tujuan dalam penelitian ini yaitu untuk mengetahui strategi apakah yang diterapkan oleh PT. Prima Megah Irsa dalam meningkatkan penjualan jasa kontruksi. Penelitian ini dilakukan di PT. Prima Megah Irsa yang beralamatkan di  Jalan Krikilan No 146 Ds. Krikilan RT. 013 RW. 005 Kec. Driyorejo Kab. Gresik. Jenis penelitian ini yaitu kualitatif deskriptif.  Sumber data yang digunakan dalam penelitian ini yaitu sumber data primer. Sedangkan pengumpulan data yang dilakukan dalam penelitian ini menggunakan metode observasi, wawancara, dan dokumentasi. Adapun hasil penelitian ini dapat disimpulkan bahwa 1) PT. Prima Megah Irsa memiliki strategi pemasaran yang sangat penting dalam meningkatkan volume penjualan produk jasa yang disediakan, 2) Strategi produk yang dijalankan oleh PT. Prima Megah Irsa mengfokuskan pada kualitas produk jasa dan proses pengerjaan proyek yang selesai sesuai dengan waktu yang ditetapkan, 3) Strategi harga yang ditawarkan oleh PT. Prima Megah Irsa merupakan harga yang ditawarkan sesuai dengan harga di pasar, 4) Strategi distribusi yang dilakukan oleh PT. Prima Megah Irsa merupakan sistem strategi distribusi langsung. Strategi langsung merupakan strategi yang bertujuan untuk melakukan pendekatan secara langsung kepada para calon pengguna jasa (klaen) baik secara formal maupun informal guna produk jasa yang ditawarkan perusahaan dapat berkembang dan dikenal lebih luas oleh perusahaan, 5) Strategi promosi dan komunikasi yang dilakukan oleh PT. Prima Megah Irsa yaitu dengan cara melakukan promosi secara langsung kepada para pengusaha kontraktor. Perusahaan juga menjalin komunikasi dengan para pengusaha kontraktor lainnya. Yang tujuannya produk jasa yang ditawarkan lebih dikenal oleh pasar dengan cara word of mouth.ABSTRACTThe purpose of this research is to find out what strategy is applied by PT. Prima Megah Irsa in increasing sales of construction services. This research was conducted at PT. Prima Megah Irsa whose address is at Jalan Krikilan No. 146 Ds. Krikilan RT. 013 RW. 005 District. Driyorejo Kab. Gresik. This type of research is descriptive qualitative. The data sources used in this study are primary data sources. While the data collection was carried out in this study using the methods of observation, interviews, and documentation. The results of this study can be concluded that 1) PT. Prima Megah Irsa has a very important marketing strategy in increasing the sales volume of the services provided, 2) the product strategy implemented by PT. Prima Megah Irsa focuses on the quality of service products and project work processes that are completed in accordance with the specified time, 3) the price strategy offered by PT. Prima Megah Irsa is the price offered in accordance with the price in the market, 4) distribution strategy carried out by PT. Prima Megah Irsa is a direct distribution strategy system. The direct strategy is a strategy that aims to make a direct approach to prospective service users (clients) both formally and informally so that the products and services offered by the company can develop and be known more widely by the company, 5) promotion and communication strategies carried out by PT. Prima Megah Irsa, namely by making promotions In addition, the company also establishes communication with other contractor entrepreneurs. The goal is that the products and services offered are better known by the market by word of mouth

Spitzer data at the NASA/IPAC Infrared Science Archive (IRSA)

The NASA/IPAC Infrared Science Archive (IRSA) curates and serves science data sets from NASA’s infrared and submillimeter projects and missions, including IRAS, 2MASS, MSX, SWAS, ISO, IRTS and from the Spitzer Space Telescope. All Spitzer data can be accessed from IRSA’s Spitzer mission page at: http://irsa.ipac.caltech.edu/Missions/spitzer.html Spitzer Legacy Enhanced Products along with ancillary data are delivered in six month intervals starting from Fall 2004, until Fall 2006. IRSA continually ingests the Spitzer data and the ancillary data, and these data are made accessible through IRSA’s query engines. Legacy products for the C2D, FEPS, GLIMPSE, GOODS, SINGS and SWIRE projects are accessible through a common interface http://irsa.ipac.caltech.edu/applications/Atlas. This engine returns the spatial footprints of observations and provides access to all flavors of released data sets, including, where appropriate, previews of image mosaics, 3-color image mosaics and spectra