bluuebunny/crossref_metadata_2025 huggingface dataset:
Pho5p and Newly Identified Nucleotide Pyrophosphatases/ Phosphodiesterases Regulate Extracellular Nucleotide Phosphate Metabolism inSaccharomyces cerevisiae
Authors: Kennedy Eileen J. , Pillus Lorraine , Ghosh Gourisankar
Published: November 2005

Extracellular nucleotides play many biological roles, including intercellular communication and modulation of nucleotide receptor signaling, and are dependent on the phosphorylation state of the nucleotide. Regulation of nucleotide phosphorylation is necessary, and a specialized class of enzymes, nucleotide pyrophosphatases/phosphodiesterases (E-NPPs), has been identified in mammals to perform this function. Although the E-NPP class is conserved among complex eukaryotes, this system has not yet been identified inSaccharomyces cerevisiae.Using genetic and biochemical experiments, we show that two orthologs of the E-NPP family, referred to as Npp1p and Npp2p, exist in budding yeast and can perform nucleotide phosphate hydrolysis. This activity is enhanced during phosphate starvation, where hydrolyzed phosphates can be imported from extracellular sources and utilized to overcome phosphate starvation through the activity of the Pho5p acid phosphatase. The added compensatory effect by Pho5p is also a newly established role for Pho5p. This study demonstrates that extracellular nucleotide phosphate metabolism appears to be controlled by at least two independent regulatory mechanisms, uniting phosphate starvation with extracellular nucleotide regulation.
snRNA and Heterochromatin Formation Are Involved in DNA Excision during Macronuclear Development in Stichotrichous Ciliates
Authors: Juranek Stefan A. , Rupprecht Sina , Postberg Jan , Lipps Hans J.
Published: November 2005

Several models for specific excision of micronucleus-specific DNA sequences during macronuclear development in ciliates exist. While the template-guided recombination model suggests recombination events resulting in specific DNA excision and reordering of macronucleus-destined sequences (MDS) guided by a template, there is evidence that an RNA interference-related mechanism is involved in DNA elimination in holotrichous ciliates. We describe that in the stichotrichous ciliate
Stylonychia
, snRNAs homologous to micronucleus-specific sequences are synthesized during macronuclear differentiation. Western and in situ analyses demonstrate that histone H3 becomes methylated at K9 de novo during macronuclear differentiation, and chromatin immunoprecipitation revealed that micronucleus-specific sequences are associated with methylated H3. To link both observations, expression of a PIWI homolog, member of the RNA-induced silencing complex, was silenced. In these cells, the methylated micronucleus-specific histone H3 variant “X” is still present in macronuclear anlagen and no K9 methylation of histone H3 is observed. We suggest that snRNA recruits chromatin-modifying enzymes to sequences to be excised. Based on our and earlier observations, we believe that this mechanism is not sufficient for specific excision of sequences and reordering of MDS in the developing macronucleus and propose a model for internal eliminated sequence excision and MDS reordering in stichotrichous ciliates.
The
NIT1
Promoter Allows Inducible and Reversible Silencing of Centrin in
Chlamydomonas reinhardtii
Authors: Koblenz Bettina , Lechtreck Karl-Ferdinand
Published: November 2005

An inverted repeat corresponding to parts of the centrin gene of
Chlamydomonas reinhardtii
was placed downstream of the
NIT1
promoter, which is induced by ammonium starvation. After induction, transformants developed centrin deficiency as assayed by immunofluorescence, Western blotting, and Northern blotting. The effect was reversible, demonstrating that the
NIT1
promoter allowed controlled RNA interference in
Chlamydomonas reinhardtii
.
LEPTONIC DECAYS OF VECTOR MESONS
Authors: BHATNAGAR SHASHANK
Published: November 2005

In this paper, the general structure of leptonic decay constants of vector mesons is evaluated in the framework of the Bethe–Salpeter equation under the Covariant Instantaneous Ansatz (CIA), which is a Lorentz-invariant generalization of Instantaneous Approximation (IA). The numerical values of fV in this CIA framework are on the low side in comparison to recent calculations of these quantities. However, the overall asymptotic behavior of fV is in conformity with QCD predictions.
EMISSION OF RELATIVISTIC HADRONS IN THE BACKWARD HEMISPHERE IN NUCLEAR COLLISIONS
Authors: AHMAD N. , AHMAD SHAKEEL , KHAN M. M. , ZAFAR M. , IRFAN M.
Published: November 2005

The behavior of the relativistic charged particle multiplicities and the pseudorapidity distributions for 4.5A and 14.5A GeV /c28Si -nucleus interactions are investigated in terms of the number of emitted relativistic hadrons in the backward hemisphere, [Formula: see text] (relativistic charged particles emitted with space angle θssuch that θslies in the interval 90°≤θs≤270°). The η distribution of relativistic charged particles for the interactions with [Formula: see text] are found to be quite nicely fitted by a single Gaussian distribution (GD), while it is fitted by two distinct GD's when the interactions are not accompanied by backward relativistic hadrons. This, in turn, suggests that in the production of events having [Formula: see text] probably two different mechanisms operate.
EFFECTIVE MESON MASSES, EFFECTIVE MESON–NUCLEON COUPLINGS AND NEUTRON STAR RADII
Authors: TUCHITANI KUNITO , HORINOUCHI YASUSHI , MAKINO KEN-ICHI , NODA NOBUO , KOUNO HIROAKI , IWAMITSU TAIHEI , NAKANO MASAHIRO , HASEGAWA AKIRA
Published: November 2005

Using a generalized mean field theory, we have studied relations among effective meson masses, effective meson–nucleon couplings and equations of state (EOS) in asymmetric nuclear matter. If the effective ω-meson mass becomes smaller at high density, the EOS becomes stiffer. However, if we require that the ω-meson mean field is proportional to baryon density, the effective ω–nucleon coupling also becomes smaller at the same time as the effective ω-meson mass becomes smaller. Consequently, the EOS becomes softer. A similar relation is found for the effective ρ-meson mass and the effective ρ–nucleon coupling. We have also studied relations among effective meson masses, effective meson–nucleon couplings and a radius R of a neutron star. R depends somewhat on the value of the effective ω-meson mass and the effective ω–nucleon coupling.
AB INITIO STUDY OF INDIUM QUANTUM WIRE FORMATION ON FLAT AND STEPPED Si(100) SURFACES
Authors: DAI XIAN-QI , JU WEI-WEI , XIE M. H. , TONG S. Y.
Published: November 2005

Using ab initio total energy calculations, we have studied the formation of indium ( In ) wires on flat and stepped Si (100)-(2×1) surfaces at low coverage. On flat Si (100), two possible orientations of In wires are examined: (i) the wire is perpendicular to the underlying Si dimer rows, and (ii) the wire is parallel to the underlying Si dimer rows. Total energy optimization shows that the energetically favored orientation is where the In wire is perpendicular to the underlying Si dimer rows, i.e. the wire is oriented along the [Formula: see text] direction. We have also considered two neighboring wires and determined the repulsive force between the two wires. On stepped Si (100) surfaces, the influence of SA and SB steps on In wire formation is investigated. The calculations suggest that In wires are likely to form at positions away from SA steps but close to SB steps.
THE CURRENT TECHNIQUES FOR PREPARING BIOGLASS COATINGS
Authors: ZHAO YAFAN , CHEN CHUANZHONG , WANG DIANGANG
Published: November 2005

Bioglasses are promising alternatives as biomedical materials to repair or replace damaged parts of bones because of its good bioactivity and biocompatibility. It is possible to combine the bone-bonding ability of the bioglass surface with the high mechanical properties of the metallic substrate though the coating of metallic implants with bioglass. The principles and characteristics of some coating techniques, including sintering, plasma spray, sol-gel, electrophoresis deposition, ion beam assisted deposition and pulsed laser deposition, are introduced. Their current applications in preparing bioglass coatings are reviewed in detail. The future application trends are also reviewed.
PREPARATION AND CHARACTERIZATION OF In2O3 THIN FILMS FOR OPTOELECTRONIC APPLICATIONS
Authors: ISMAIL RAID A. , ABDULRAZAQ OMAR A. , YAHYA KHALID Z.
Published: November 2005

Conductive transparent In 2 O 3 thin films with (222)-preferred orientation were prepared by rapid thermal oxidation (RTO) in static air of indium thin films at condition 200°C/30 s. Detailed structural, electrical, and optical characteristics of the film are presented. The data are interpreted to give a direct bandgap of 3.6 eV and indirect bandgap of 2.5 eV. The grown In 2 O 3 films exhibited high figure of merit and sheet resistance as low as 20 Ω/sq. in the absence of any post-deposition annealing conditions. The mobility of these films was estimated to be 31 cm2 · V-1 · s-1. These results are compared with those of In 2 O 3 films prepared by other methods.
THE TARGET MORPHOLOGY DURING PULSED LASER DEPOSITION OF HYDROXYAPATITE THIN FILMS
Authors: BAO QUANHE , CHEN CHUANZHONG , CHEN LUBIN , WANG DIANGANG , LEI TINGQUAN , LIU JUNMING
Published: November 2005

A modified surface layer of hydroxyapatite (HA) target was observed before and after pulsed laser deposition. Two types of HA targets were used for laser ablation. We observed that the surface morphology of the target has a very fine compacted grain structure and presents many irregularities with some microroughness and microporosity before laser ablation. The laser ablated regions can be divided into two areas: one area is porous and rough but the other is dense and smooth. The percentage of particles in the films was high for the films produced with targets that were sintered at 1200°C.
DEFECT CONCENTRATION IN DEFORMED AlSiMgSr BY TRAPPING MODEL OF POSITRON
Authors: ABDEL-RAHMAN M. A. , ABDALLAH M. S. , BADAWI EMAD A.
Published: November 2005

This paper reports the results of lifetime measurements on deformed AlSiMgSr alloy. Using the trapping model, we obtained the value of 196.7 ps for the lifetime of the free state, and 210.5 ps for the trapped state. The specific trapping rate per unit defect concentration was calculated to be 0.2280 cm2 · s-1. The concentration of defects was 5.78×1017 cm -3 when thickness reduction was 18.2%. The dislocation density for the same thickness reduction is 1.63×1010 cm -2. We have compared these values with a previously used method1 and have obtained perfect agreement for both methods, demonstrating that this a very powerful tool for detecting and evaluating defect concentration.
THE WEAR BEHAVIOR OF BRUSH-PLATED Ni-W-Co/SiC COMPOSITE LAYER WITH OIL LUBRICATION
Authors: XU JIANG , LIU WENJIN
Published: November 2005

The wear behavior of brush-plating a Ni-W-Co/SiC composite layer on 1045 steel with oil lubrication is investigated. The composite layer is determined by OM, XRD and TEM. The worn surface of the plated layer is observed with SEM and laser profile analysis. The composition and average size of worn debris are analyzed by means of ferrograph and fluid spectrum. The results show that the brush-plated composite layer with added SiC particles reveals high wear resistance compared to the Ni-W-Co brush-plated layer.
ELECTRONIC DOPING OF AMORPHOUS CARBON THIN FILMS
Authors: RUSOP M. , SOGA T. , JIMBO T. , UMENO M. , SHARON M.
Published: November 2005

This paper reports on the successful deposition of boron ( B )-doped p-type ( p-C:B ) and phosphorus ( P )-doped n-type ( p-C:P ) carbon ( C ) films, and the fabrication of p-C:B on silicon ( Si ) substrate ( p-C:B/n-Si ) and n-C:P/p-Si cells by a pulsed laser deposition (PLD) technique using a graphite target at room temperature. The boron and phosphorus atoms incorporated in the films were determined by X-ray photoelectron spectroscopy (XPS) to be in the range of 0.2–1.75 and 0.22–1.77 atomic percentages, respectively. The cells performances have been given in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination conditions (100 mW/cm2, 25°C). The open circuit voltage (V oc ) and short circuit current density (J sc ) for p-C:B/n-Si are observed to vary from 230 to 250 mV and from 1.5 to 2.2 mA/cm2, respectively; they vary from 215 to 265 mV and from 7.5 to 10.5 mA/cm2, respectively, for n-C:P/p-Si cells. The p-C:B/n-Si cell fabricated using the target with the amount of boron by 3 weight percentages (Bwt%) showed the highest energy conversion efficiency, η = 0.20% and fill factor, FF = 45%. The n-C:P/p-Si cell fabricated using the target with the amount of 7 Pwt% showed the highest η = 1.14% and FF = 41%. The quantum efficiency (QE) of the p-C:B/n-Si and n-C:P/p-Si cells were observed to improve with Bwt% and Pwt%, respectively. The contribution of QE in the lower wavelength region (below 750 nm) may be due to photon absorption by the carbon layer, in the higher wavelength region it was due to the Si substrates. In this paper, the dependence of the boron and phosphorus content on the electrical and optical properties of the deposited films and the photovoltaic characteristics of the respective p-C:B/n-Si and n-C:P/p-Si heterojunction solar cells are discussed.
STRUCTURAL AND PHOTOLUMINESCENCE PROPERTIES OF POROUS SILICON: EFFECT OF SURFACE PASSIVATION
Authors: NATARAJAN B. , RAMAKRISHNAN V. , VASU V. , RAMAMURTHY S.
Published: November 2005

The surface passivation of porous silicon is a determining factor in the emission efficiency of the material. The hydrogen surface coverage has been shown to provide very efficient passivation. In this work, we have monitored Si–H n surface coverage, which is readily-obtained porous silicon formed at 1:3 concentrations of HF: ethanol with/without HCl content in the electrolytes, and relate it to the emission efficiency. SEM, FTIR and PL studies were carried out to understand the role of HCl content in the electrolytes. When samples are anodized with HCl content in the electrolytes, there is a net decrease in the concentration of the Si–H groups on the material surface. This treatment provokes desorption of the hydrogen atoms and results in a drastic decrease in the photoluminescence.
Life science research and data management—what can they give each other?
Authors: Gupta Amarnath
Published: November 2005

"Databases for the life sciences" is not really a newly emerging area in databases. The Nucleotide Sequence Database from the European Molecular Biology Laboratory (EMBL) has been operational at the European Bioinformatics Institute (EBI) since 1980. SWISS-PROT, the classical database containing protein information, was established in 1986. Today, there are over a thousand different life science databases with contents ranging from gene-property data for different organisms to brain image data for patients with neurological disorders.
Database management for life sciences research
Authors: Jagadish H. V. , Olken Frank
Published: November 2005

The life sciences provide a rich application domain for data management research, with a broad diversity of problems that can make a significant difference to progress in life sciences research. This article is an extract from the Report of the NSF Workshop on Data Management for Molecular and Cell Biology, edited by H. V. Jagadish and Frank Olken. The workshop was held at the National Library of Medicine, Bethesda, MD, Feb. 2-3, 2003.
REPORT on the EDBT'04 workshop on database technologies for handling XML information on the web
Authors: Mesiti Marco , Catania Barbara , Guerrini Giovanna , Chaudhri Akmal
Published: November 2005

The EDBT'04 Workshop on
Database Technologies for Handling XML Information on the Web (DataX'04)
was held in Heraklion, Crete, on Sunday 14 March, 2004, and attracted approximately 30 participants from different countries.
World Wide Web courseware
Authors: Wong Ka-Wing
Published: November 2005

There is an increasing demand for online courses. The so called, virtual university, shows how big the general public's demand for online distant education is. With rapid advance in the development of the Internet, especially the World Wide Web, online courses taught on the World Wide Web are becoming popular. The World Wide Web courseware, which supports advances in online distant education, is going to be a major component in the development of individual computing environments. This paper discusses the design, construction, and evaluation of World Wide Web courseware.
Report on the 9th ACM symposium on access control models and technologies (SACMAT'04)
Authors: Ferrari Elena
Published: November 2005

SACMAT'04 was held on June 2--4, 2004, at Yorktown Heights, New York, USA and was hosted by IBM T.J. Watson Research Center. The symposium, which was colocated with the IEEE International Workshop on Policies for Distributed Systems and Networks (POLICY 2004), continues its tradition of being the premier forum for presentation of research results and experience reports on leading edge issues of access control and related technologies, including models, systems, applications, and theory. SACMAT gives researchers and practitioners a unique opportunity to share their perspectives with others interested in the various aspects of access control.

The call for papers attracted 65 submissions, from all over the world. The program committee selected 18 papers for presentation. The 18 papers, organized in seven sessions, were presented over two and an half days. The selected papers cover a wide range of topics, ranging from next generation access control models, to security analysis, role administration, policy specification and implementation, and access control for distributed environments and XML data. All the accepted papers were included in a volume published by ACM, whereas best papers from the symposium have been invited for possible publication in ACM Transactions on Information and System Security (TISSEC). Besides the technical sessions, this year program included a keynote speech on Access Control for Databases, and a panel on Security for Grid-based Computing Systems.
Centrally-stored and delivered virtual machines in the networking/system administration lab
Authors: Stockman Mark , Nyland John , Weed William
Published: November 2005

Virtual machine technology has presented an opportunity for the networking/system administration lab to serve multiple classes. The storage and delivery of virtual machine images has however presented a new problem for faculty and technical support staff. The authors have performed initial testing involving centralized verses distributed virtual machine image delivery in the networking/system administration and will provide details as to their results in this paper. The overriding goal is to provide mobility for students within the lab and virtual machine manageability for faculty and technical staff.
Bruce Lindsay speaks out
Authors: Winslett Marianne
Published: November 2005

Welcome to ACM SIGMOD Record's series of interviews with distinguished members of the database community. I'm Marianne Winslett, and today we're in San Diego at the 2003 SIGMOD and PODS conferences. I have here with me Bruce Lindsay, a member of the research staff at IBM Almaden Research Center. Bruce is well-known for his work on relational databases, which has been very influential both inside and outside of IBM, starting with his work on the System R project. Bruce is an IBM Fellow and his PhD is from Berkeley. So Bruce, welcome!
Tools for composite web services
Authors: Hull Richard , Su Jianwen
Published: November 2005

Web services technologies enable flexible and dynamic interoperation of autonomous software and information systems. A central challenge is the development of modeling techniques and tools for eanbling the (semi-)automatic composition and analysis of these services, taking into account their semantic and behavioral properties. This paper presents an overview of the fundamental assumptions and concepts underlying current work on service composition, and provides a sampling of key results in the area. It also provides a brief tour of several composition models including semantic web services, the "Roman" model, and the Mealy / conversation model.
The gist of GIUKU
Authors: Kuntz Michel
Published: November 2005

Synoptic description of GIUKU: its rationale, its main functionalities, its novel features, a comparison to related work, and a discussion of its current status — a fully implemented prototype available for use.
Functional completeness in object-oriented databases
Authors: Mishra Priti , Eich Margaret
Published: November 2005

A definition of completeness in the context of Object Oriented Databases (OODBs) is proposed in this paper. It takes into account the existence of various categories of functions in OODBs, each of which must be complete in itself. The functionality of an OODB can be divided into sets of related functions. For example, functions needed to perform all schema evolution operations or all version management operations belong in two distinct sets. Further, each set of functions must include all functions needed to perform all operations defined for that set. Thus, for an OODB to be functionally complete, it must support a certain number of sets (or categories) of functions and each such set must be complete in itself. The purpose of this paper is not to give a precise definition of the categories of functions but rather to define a framework within which such categories should be examined. This paper contains a working definition of functional completeness. We would welcome any feedback on our proposal.
The term retrieval abstract machine
Authors: Ley Michael
Published: November 2005

Scans through large collections of complex objects often cannot be avoided. Even if sohphisticated indexing mechanisms are provided, it may be necessary to evaluate simple predicates against data stored on disk for filtering. For traditional record oriented data models i/o and buffer management are the main bottlenecks for this operation, the interpretation of data structures is straightforward and usually not an important cost factor. For heterogeneously shaped complex objects it may become a dominant cost factor.

In this paper we demonstrate a technique to make data structure traversal inside of complex objects much cheaper than naive interpretation. We compile navigation necessary to evaluate condition predicates and physical schema information into a program to be executed by a specialized abstract machine. Our approach is demonstrated for the Feature Term Data Model (FTDM), but the technique is applicable to many other complex data models. Main parts of this paper are dedicated to the method we used to design the Term Retrieval Abstract Machine (TRAM) architecture by partial evaluation of a tuned interpreter.
Parallel R-trees
Authors: Kamel Ibrahim , Faloutsos Christos
Published: November 2005

We consider the problem of exploiting parallelism to accelerate the performance of spacial access methods and specifically, R-trees [11]. Our goal is to design a server for spatial data, so that to maximize the throughput of range queries. This can be achieved by (a) maximizing parallelism for large range queries, and (b) by engaging as few disks as possible on point queries [22].

We propose a simple hardware architecture consisting of one processor with several disks attached to it. On this architecture, we propose to distribute the nodes of a traditonal R-tree, with cross-disk pointers (“Multiplexed” R-tree). The R-tree code is identical to the one for a single-disk R-tree, with the only addition that we have to decide which disk a newly created R-tree node should be stored in. We propose and examine several criteria to choose a disk for a new node. The most successful one, termed “proximity index” or PI, estimates the similarity of the new node with the other R-tree nodes already on a disk, and chooses the disk with the lowest similarity. Experimental results show that our scheme consistently outperforms all the other heuristics for node-to-disk assignments, achieving up to 55% gains over the Round Robin one. Experiments also indicate that the multiplexed R-tree with PI heuristic gives better response time than the disk-stripping (=“Super-node”) approach, and imposes lighter load on the I/O sub-system.

The speed up of our method is close to linear speed up, increasing with the size of the queries.
The concurrency control problem in multidatabases
Authors: Mehrotra Sharad , Rastogi Rajeev , Breitbart Yuri , Korth Henry F. , Silberschatz Avi
Published: November 2005

A
Multidatabase System
(MDBS) is a collection of local database management systems, each of which may follow a different concurrency control protocol. This heterogeneity makes the task of ensuring global serializability in an MDBS environment difficult. In this paper, we reduce the problem of ensuring global serializability to the problem of ensuring serializability in a centralized database system. We identify characteristics of the concurrency control problem in an MDBS environment, and additional requirements on concurrency control schemes for ensuring global serializability. We then develop a range of concurrency control schemes that ensure global serializability in an MDBS environment, and at the same time meet the requirements. Finally, we study the tradeoffs between the complexities of the various schemes and the degree of concurrency provided by each of them.
Simple rational guidance for chopping up transactions
Authors: Shasha Dennis , Simon Eric , Valduriez Patrick
Published: November 2005

Chopping transactions into pieces is good for performance but may lead to non-serializable executions. Many researchers have reacted to this fact by either inventing new concurrency control mechanisms, weakening serializability, or both. We adopt a different approach.

We assume a user who

has only the degree 2 and degree 3 consistency options offered by the vast majority of conventional database systems; and

knows the set of transactions that may run during a certain interval (users are likely to have such knowledge for online or real-time transactional applications).

Given this information, our algorithm finds the finest partitioning of a set of transactions TranSet with the following property; if the partitioned transactions execute serializably, then TranSet executes serializably. This permits users to obtain more concurrency while preserving correctness. Besides obtaining more inter-transaction concurrency, chopping transactions in this way can enhance intra-transaction parallelism.

The algorithm is inexpensive, running in
O(n x (e + m))
time using a naive implementation where
n
is the number of edges in the conflict graph among the transactions, and
m
is the maximum number of accesses of any transaction. This makes it feasible to add as a tuning knob to practical systems.
Performance evaluation of extended storage architectures for transaction processing
Authors: Rahm Erhard
Published: November 2005

The use of non-volatile semiconductor memory within an extended storage hierarchy promises significant performance improvements for transaction processing. Although page-addressable semiconductor memories like extended memory, solid-state disks and disk caches are commercially available since several years, no detailed investigation of their use for transaction processing has been performed so far. We present a comprehensive simulation study that compares the performance of these storage types and of different usage forms. The following usage forms are considered: allocation of entire log and database files in non-volatile semiconductor memory, using a so-called write buffer to perform disk writes asynchronously, and caching of database pages at intermediate storage levels (in addition to main memory caching). Simulation results will be presented for the debit-credit workload frequently used in transaction processing benchmarks.
Algorithms for creating indexes for very large tables without quiescing updates
Authors: Mohan C. , Narang Inderpal
Published: November 2005

As relational DBMSs become more and more popular and as organizations grow, the sizes of individual tables are increasing dramatically. Unfortunately, current DBMSs do not allow updates to be performed on a table while an index (e.g., a B
+
-tree) is being built for that table, thereby decreasing the systems' availability. This paper describes two algorithms in order to relax this restriction. Our emphasis has been to maximize concurrency, minimize overheads and cover all aspects of the problem. Builds of both unique and nonunique indexes are handled correctly. We also describe techniques for making the index-build operations restartable, without loss of all work, in case a system failure were to interrupt the completion of the creation of the index. In this connection, we also present algorithms for making a long sort of operation restartable. These include algorithms for the sort and merge phases of sorting.
Seeing the text from the user's point of view
Authors: Kline-Simon Karen
Published: November 2005

In his 1986 article, "Seeing the Text," Stephen Bernhardt urges college composition instructors to add visual cues to their toolbox of traditional rhetorical strategies for expository writing. Perhaps the single most significant point that Bernhardt makes is contained in his opening paragraph: written text is necessarily a visual medium of communication. Even the most traditional use of text---graphic representation of the spoken language---gives the reader a tremendous increase in access control of the information. As the number, variety, and quality of visual clues increase beyond the graphic representation of spoken language, accessibility of information also increases.
Comments on Balloon Help
Authors: Price Jonathan
Published: November 2005

In his excellent article, David Farkas points out several ways in which Balloon Help can encourage absolute beginners to explore and become familiar with the basics of the Macintosh interface. Too many of us who are intermediate and expert users dismiss Balloon Help as a joke because it soon gets in the way, it is stupid about our intentions, and it rarely answers task-oriented questions, despite the creators' obvious attempts to weave procedural instructions into the definitions.
File service for SIGDOC 93
Authors: Beam Paul , Capener Travis , Singh Sanjay
Published: November 2005

Throughout this article we will refer to information sources or tools resident on sigdoc-1 and other systems by a in the text. These are all available at the addresses shown in the first diagram. In the movement from print to electronic communications they illustrate many standard features of basic networking, serve as a general guide to getting started and illustrate many of our arguments. All three of us retain our commitments to ink-on-paper and regard many electronic expressions as "extensions of convenience" on a spectrum of communications.
Concurrency control in trusted database management systems
Authors: Thuraisingham Bhavani , Ko Hai-Ping
Published: November 2005

Recently several algorithms have been proposed for concurrency control in a Trusted Database Management System (TDBMS). The various research efforts are examining the concurrency control algorithms developed for DBMSs and adapting them for a multilevel environment. This paper provides a survey of the concurrency control algorithms for a TDBMS and discusses future directions.
A rule-based object/task modelling approach
Authors: Chen Qiming
Published: November 2005

A rule-based object/task modelling approach is proposed which is characterized by specifying object behaviors and domain rules in terms of object-oriented logic programming, and specifying tasks and meta-rules in terms of network-oriented formalism. In addition the concepts of associations, virtual objects, multiple level integrity control and net expressions are introduced. The object-oriented logic programming system is extended for supporting the semantic modelling, and an explicit control knowledge representation mechanism is developed. This approach may be viewed as a step to the integration of object-oriented programming, logic programming, semantic modelling and event modelling, and to the combination of forward chaining and backward chaining techniques. Therefore, it can provide complementary benefits in deductive query support, integrity control, explicit control knowledge representation and intelligent user interface, and enhance the flexibility and extendibility of knowledge based systems to accommodate applications in multiple domains, towards a generalized, rule-based management of data, action and operational schemes. This approach is being designed and partially implemented on top of System C [Chen 85b] on a VAX computer.
The 007 Benchmark
Authors: Carey Michael J. , DeWitt David J. , Naughton Jeffrey F.
Published: November 2005

The OO7 Benchmark represents a comprehensive test of OODBMS performance. In this paper we describe the benchmark and present performance results from its implementation in three OODBMS systems. It is our hope that the OO7 Benchmark will provide useful insight for end-users evaluating the performance of OODBMS systems; we also hope that the research community will find that OO7 provides a database schema, instance, and workload that is useful for evaluating new techniques and algorithms for OODBMS implementation.
A logical semantics for object-oriented databases
Authors: Meseguer José , Qian Xiaolei
Published: November 2005

Although the mathematical foundations of relational databases are very well established, the state of affairs for object-oriented databases is much less satisfactory. We propose a semantic foundation for object-oriented databases based on a simple logic of change called
rewriting logic
, and a language called MaudeLog that is based on that logic. Some key advantages of our approach include its logical nature, its simplicity without any need for higher-order features, the fact that dynamic aspects are directly addressed, the rigorous integration of user-definable algebraic data types within the framework, the existence of initial models, and the integration of query, update, and programming aspects within a single declarative language.
A new perspective on rule support for object-oriented databases
Authors: Anwar E. , Maugis L. , Chakravarthy S.
Published: November 2005

This paper proposes a new approach for supporting reactive capability in an object-oriented database. We introduce an
event interface
, which extends the conventional object semantics to include the role of an event generator. This interface provides a basis for the specification of events spanning sets of objects, possibly from different classes, and detection of primitive and complex events. This approach clearly separated event detection from rules. New rules can be added and use existing objects, enabling objects to react to their own changes as well as to the changes of other objects.

We use a runtime subscription mechanism, between rules and objects to selectively monitor particular objects dynamically. This elegantly supports class level as well as instance level rules. Both events and rules are treated as first class objects.
Maintaining views incrementally
Authors: Gupta Ashish , Mumick Inderpal Singh , Subrahmanian V. S.
Published: November 2005

We present incremental evaluation algorithms to compute changes to materialized views in relational and deductive database systems, in response to changes (insertions, deletions, and updates) to the relations. The view definitions can be in SQL or Datalog, and may use UNION, negation, aggregation (
e.g.
SUM, MIN), linear recursion, and general recursion.

We first present a
counting
algorithm that tracks the number of alternative derivations (counts) for each derived tuple in a view. The algorithm works with both set and duplicate semantics. We present the algorithm for
nonrecursive views
(with negation and aggregation), and show that the count for a tuple can be computed at little or no cost above the cost of deriving the tuple. The algorithm is optimal in that it computes exactly those view tuples that are inserted or deleted. Note that we store only the
number
of derivations, not the derivations themselves.

We then present the Delete and Rederive algorithm, DRed, for incremental maintenance of recursive views (negation and aggregation are permitted). The algorithm works by first deleting a superset of the tuples that need to be deleted, and then rederiving some of them. The algorithm can also be used when the view definition is itself altered.
Performance evaluation of ephemeral logging
Authors: Keen John S. , Dally William J.
Published: November 2005

Ephemeral logging (EL) is a new technique for managing a log of database activity on disk. It does not require periodic checkpoints and does not abort lengthy transactions as frequently as traditional firewall logging for the same amount of disk space. Therefore, it is well suited for highly concurrent databases and applications which have a wide distribution of transaction lifetimes.

This paper briefly explains EL and then analyzes its performance. Simulation studies indicate that it can offer significant savings in disk space, at the expense of slightly higher bandwidth for logging and more main memory. The reduced size of the log implies much faster recovery after a crash as well as cost savings.

EL is the method of choice in some but not all situations. We assess the limitations of our current knowledge about EL and suggest promising directions for further research.
What's special about spatial?
Authors: Egenhofer Max J.
Published: November 2005

Geographic databases are becoming a popular subject for research projects. It is acknowledged that database requirements for such applications as Geographic Information Systems (GISs), computer cartography, remote-sensing image databases, and emergency routing/dispatching are distinct from those for traditional database applications; however, the specific database needs due to the properties of geographic data are frequently overlooked. Here, we describe a specific problem domain, a
vehicle navigation system
, and analyze the properties of data to be modeled appropriately and managed efficiently by database management systems. Vehicle navigation systems need continuous, fast access to very large databases. Through the combination of
real-time access
and
geographic data
, we identify particularly challenging database requirements of this application with respect to data models, query languages, and query processing.
Enhancing inter-operability and data sharing in medical information systems
Authors: Mannai Dhamir N. , Bugrara Khaled
Published: November 2005

Clinical care generates an immense amount of patient data that has been archived and manipulated by computer-based information systems. Such computer-based medical record systems improved the accessibility of clinical information and made several studies of such information possible. Unfortunately, the care provider's task of retrieving, integrating, and interpreting only those portions of the patient's record that are relevant to a specific clinical problem is actually becoming increasingly difficult. This difficulty can be attributed primarily to the large variety of minimum data sets, the heterogeneous formats used to store the data, the heterogeneous data access methods and procedures, the varying granularity of access to data, the different rigid views of the data, and the lack of inter-operability among the information repositories of such data sets. Recognizing the aforementioned issues, we are engaged in a project to build a multi-database environment tailored for the interoperability of medical information systems. The main building blocks of such a system are a multi-disciplinary minimum data set and a catalogue for the support of interoperability and customization functions. In this paper, we report on the design approach used and describe the general architecture of the system.
The INtersect concept for multidatabase system integration in the pharmaceutical industry
Authors: Schaller Tony
Published: November 2005

The industry trends facing information systems in the 1990's involve a matrix of complex requirements. The migration from centralized mainframe computing to desktop personal computing has created opportunities and challenges in moving access to and control of information closer to the end-user. Within this new wave of computing, there has been a drive to move the access control for information to the desktop of the user. Although, graphical user standards were introduced in order to ease of use and provide a consistent look and feel to desktop applications. This provided some assistance in shielding the complexity of the various systems, however it did not address the difficulties presented in accessing heterogeneous database systems on various platforms.
Open OODB
Authors: Ford Steve , Blakeley José A. , Bannon Thomas J.
Published: November 2005

The Open OODB project, part of the DARPA Persistent Object Base (POB) Program, is an effort to build an open, extensible object-oriented database management system (OODB) in which database functionality can be tailored for particular applications within an incrementally improvable framework. The system is designed to serve both as a platform for research and as a testbed that can meet the needs of demanding, next generation database applications. The Open OODB project goals are to describe the design space of OODBs; build an architectural framework that enables configuring independently useful modules to form an OODB; verify the suitability of this open approach by implementing an OODB to these specifications; and identify opportunities for building consensus that can lead to much-needed OODB standards. The motivating factors in this approach were that our previous experience in object-oriented databases had convinced us that different applications have differing requirements, and that a monolithic system is unlikely to meet the needs of many demanding kinds of applications.
Papyrus GIS demonstration
Authors: Hasan W. , Heytens M. , Kolovson C. , Neimat M.-A. , Potamianos S. , Schneider D.
Published: November 2005

The goal of the Papyrus project [3] is to provide tools and services to enable the integration and parallelization of specialized data managers so that data-intensive applications can be constructed easily and efficiently. In our terminology, a
data manager
(DM) is a set of specialized methods that manage persistent data. A collection of
functions
defines the interface to a DM and provides the only means of accessing its persistent data.
VODAK open nested transactions—visualizing database internals
Authors: Muth Peter , Rakow Thomas C.
Published: November 2005

VODAK is a prototype of an object-oriented, distributed database system developed during the past five years at the Integrated Publication and Information Systems Institute (IPSI). The aim of demonstrating VODAK Open Nested Transactions is to provide insights into internals of database systems that are usually hidden from application programmers and users. By utilizing semantics of methods, VODAK Open Nested Transactions increase the degree of parallelism between concurrent transactions compared to conventional transaction management schemes. Demonstrating the difference in parallelism provides users with a “feeling” for internal database mechanisms, application programmers with information about the impact of transaction management on performance, and system developers with ideas how to improve their systems with respect to transaction management.
Constructing the next 100 database management systems
Authors: Geppert Andreas , Dittrich Klaus R.
Published: November 2005

While the number of database management systems (DBMSs) increases and the various DBMSs get more and more complex, no uniform method for DBMS construction exists. As a result, developers are forced to start more or less from scratch again for every desired system, resulting in a waste of time, effort, and cost. Hence, the database community is challenged with the development of an appropriate method, i.e. the time-saving application of engineering principles (e.g., reuse). Problems related to a construction method are described, as well as approaches towards solutions.
Can principles of object-oriented system documentation be applied to user documentation?
Authors: Raven Mary Elizabeth , Thomson Richard
Published: November 2005

In his article "Object-Oriented Documentation," Johannes Sametinger describes a successful case study of creating object-oriented documentation. It is clear, however, that of the three types of documentation that he identifies, system documentation is the only one suited to this application. We argue that system documentation can afford to behave like the system it describes, but that user documentation needs to be organized according to the tasks users will do instead of according to how the system is structured. On the other hand, using a brother definition of object-oriented documentation presents technical communicators with a powerful model for information development that is beneficial to both the writer and the reader.
Machine learning for a dynamic manufacturing environment
Authors: Perez R. A. , Lilkendey J. T. , Koh S. W.
Published: November 2005

Within the semiconductor wafer manufacturing process, tight quality control is of utmost importance. This is due to such factors as the highly competitive nature of the business [2] and the complex nature of the process itself. Therefore, it is imperative that processing problems are recognized and corrected as quickly as possible. To accomplish this, a Parametric Test facility exists where a critical quality check is performed on the wafers. This is accomplished by measuring a number of electrical parameters at existing test sites on the wafer. Each measurement must fall within an acceptable range of values for its associated parameter to pass the critical check. If test results indicate that a parameter is outside of its acceptable range, the wafer may fail the quality check and be scrapped. If this happens an expert must examine all the parametric data associated with that wafer and attempt to determine the reason for failure and where in the manufacturing process the problem may have occurred.
Second chances
Authors: Girill T. R.
Published: November 2005

This issue of
The Journal of Computer Documentation
is the fourth of an annual cycle that reprints a previously published paper on documentation and places it in the context of current commentary. Such a project certainly is retrospective, but it is not nostalgic; two very forward-looking reasons motivate our reprint policy.
Achieving principled communication amid conflict
Authors: Girill T. R.
Published: November 2005

In his essay on "Ethics and Technical Communication: A Rhetorical Perspective," Gregory Clark shows how "both professionals and academicians in technical communication demand an ethics to guide their work that is both practical and responsible" (Clark, 1987, p. 195). Unfortunately, each group's assumptions about the scope and character of ethics differ so much that neither group finds the other's analysis acceptable. Clark finds flaws on all sides. He argues that a third alternative, based on shared understanding and rhetorical cooperation, "is likely to work in both the individual and the collective interest of all people involved in a communication process" (Clark, p. 195).