Kyrix: Interactive Pan/Zoom Visualizations at Scale

Pan and zoom are basic yet powerful interaction techniques for exploring large datasets. However, existing zoomable UI toolkits such as Pad++ and ZVTM do not provide the backend database support and data‐driven primitives that are necessary for creating large‐scale visualizations. This limitation in existing general‐purpose toolkits has led to many purpose‐built solutions (e.g. Google Maps and ForeCache) that address the issue of scalability but cannot be easily extended to support visualizations beyond their intended data types and usage scenarios. In this paper, we introduce Kyrix to ease the process of creating general and large‐scale web‐based pan/zoom visualizations. Kyrix is an integrated system that provides the developer with a concise and expressive declarative language along with a backend support for performance optimization of large‐scale data. To evaluate the scalability of Kyrix, we conducted a set of benchmarked experiments and show that Kyrix can support high interactivity (with an average latency of 100 ms or below) on pan/zoom visualizations of 100 million data points. We further demonstrate the accessibility of Kyrix through an observational study with 8 developers. Results indicate that developers can quickly learn Kyrix's underlying declarative model to create scalable pan/zoom visualizations. Finally, we provide a gallery of visualizations and show that Kyrix is expressive and flexible in that it can support the developer in creating a wide range of customized visualizations across different application domains and data types.     

The POSTGRES rule manager

The rule subsystem that is being implemented in the POSTGRES DBMS is explained. It is novel in several ways. First, it gives users the capability of defining rules as well as data. Moreover, depending on the scope of each rule defined, optimization is handled differently. This leads to good performance both when there are many rules each of small scope and when there are a few rules each of large scope. In addition, rules provide either a forward-chaining or a backward-chaining control flow, and the system chooses the control mechanism that optimizes performance whenever possible. Priority rules can be defined, allowing a user to specify rule systems that have conflicts. This use of exceptions seems necessary in many applications. Database services such as views, protection, integrity constraints, and referential integrity can be obtained simply by applying the rules system in the appropriate way. Consequently, no special-purpose code need be included in POSTGRES to handle these tasks     

Optimization of parallel query execution plans in XPRS

In this paper, we describe our approach to optimization of query execution plans in XPRS, a multiuser parallel database system based on a shared memory multiprocessor and a disk array. The main difficulties in this optimization problem are the compile-time unknown parameters such as available buffer size and number of free processors, and the enormous search space of possible parallel plans. We deal with these problems with a novel two phase optimization strategy which dramatically reduces the search space and allows run time parameters without significantly compromising plan optimality. In this paper we present our two phase optimization strategy and give experimental evidence from XPRS benchmarks that indicate that it almost always produces optimal or close to optimal plans.     

Human health and environmental hazard characterisation of lubricating oil additives

The authors' company has characterised the potential human health and environmental hazards of widely used classes of lubricating oil additives and polyalphaolefin (PAO) base fluids in a battery of toxicity tests. The main classes of additives are: succinimide ashless dispersants, calcium sulphonates, calcium phenates, zinc dialkyldithiophosphates, oxidation inhibitors, and antiwear inhibitors. In summary, mammalian toxicity studies indicate that lubricant additives do not pose a significant health risk to humans. Ecotoxicity is also considered to be of low concern in general. Even though lubricant additives do not readily biodegrade, studies are under way to confirm that they are not persistent in the environment and that bioaccumulation is not a concern. Good Laboratory Practice (GLP) methods have been developed for analysis of additives involved in toxicity tests and for low concentrations (ppb) of additives in aqueous systems. Manufacturing advances are reducing the release of toxic by-products to the environment.