bluuebunny/crossref_metadata_2025_split huggingface dataset:
Architectural support for the efficient generation of code for horizontal architectures
Authors: Rau B. R. , Glaeser C. D. , Greenawalt E. M. 
Published: November 2005

Horizontal architectures, such as the CDC Advanced Flexible Processor [I] and the FPS APi20-B [2}, consist of a number of resources that can operate in parallel, each of which is controlled by a field in the wide instruction word. Such architectures have been developed to perform high speed scientific computations at a modest cost: Figure 1 displays those characteristics of horizontal architectures that are germane to the issues discussed in this paper. The simultaneous requirements of high performance and low cost lead to an architecture consisting of multiple pipelined processing elements (PEs) such as adders and multipliers, a memory (which for scheduling purposes may be viewed as yet another PE with two operations: a READ and a WRITE), and an interconnect which ties them all together. The interconnect allows the result of one operation to be directly routed to another PE as one of the inputs for an operation that is to be performed there. The required memory bandwidth is reduced since temporary values need not be written to and read from the memory. The final aspect of horizontal processors that is of interest is that their program memories emit wide instructions which synchronously specify the actions of the multiple and possibly dissimilar PEs. The program memory is sequenced by a conventional sequencer that assumes sequential flow of control unless a branch is explicitly specified.
As a consequence of the simplicity of such an architecture, it is inexpensive relative to the potential performance of the multiple pipelined PEs. However, if this potential performance is to be realized, the multiple resources of a horizontal processor must be scheduled effectively. The scheduling task for conventional horizontal processors is quite complex and the construction of highly optimizing compilers for them is a difficult and expensiw3 project. The polycyclic architecture [3- 6] is a horizontal architecture with architectural support for the scheduling task. The cause of the complexity involved in scheduling conventional horizontal processors and the manner in which the polycyclic architecture addresses this issue are outlined in this paper.
Data abstraction for designing database-intensive applications
Authors: Brodie Michael L. 
Published: November 2005

There is a growing exchange of ideas amongst Artificial Intelligence (AI), Database (DB) and Programming Language (PL) researchers concerning conceptual modelling of complex, object-oriented applications. The complexity of these applications arises from complicated structural and behavioral properties which change through time; concurrent, interactive access by users with different processing needs over a shared database; information locality (i.e., DB views, PL data abstractions, AI perspectives); and primarily update-oriented transactions. Two main problems raised by these applications are:
managing the intellectual complexity of their design, development and evolution, and
defining and ensuring semantic integrity.
Data models in database management
Authors: Codd E. F. 
Published: November 2005

It is a combination of three components: 1) a collection of data structure types (the building blocks of any database that conforms to the model);
2) a collection of operators or inferencing rules, which can be applied to any valid instances of the data types listed in (1), to retrieve or derive data from any parts of those structures in any combinations desired;
3) a collection of general integrity rules, which implicitly or explicitly define the set of consistent database states or changes of state or both—these rules may sometimes be expressed as insert-update-delete rules.
On the specification of behavioural constraints
Authors: Cristian Flaviu 
Published: November 2005

When designing information processing systems, the key problem is to find what symbols and constructs (available in some given language) should be used so as to be able to answer the questions that the users want to ask and to perform the state transitions that the users have to perform in order to keep in step with some reality that is being modelled. If the language that is being used cannot be interpreted directly by the software of a computer (e.g. set theory, algebra, semantic networks), the resulting model is called an abstract model (e.g. a specification, a data base schema). If all of the symbols and constructs used to express the model can be interpreted by a computer, the model is a concrete implementation (e.g. a data base system). Both the abstract and concrete models capture some aspects of the reality that is modelled. They differ with respect to the languages in which they are expressed.
The choice of the languages which are appropriate for writing such models is a subject of intensive debate. The recent workshop on Data Abstraction, Data Bases and Conceptual Modelling has shown that this debate is not likely to diminish in the near future. In the context of this debate, however, a common opinion was expressed several times by data base participants: the data models used to specify data base schemas are lacking to support the specification of operations tailored to particular application environments. It is therefore expected that in the context of data base modelling, the integration of operations (behaviour) with data (structure) will be one of the most fertile research areas for the next few years.
A three-level approach to the description of data structures, and notational framework
Authors: Meyer Bertrand 
Published: November 2005

When talking about data structures, whether local to a program or persistent over time, three different viewpoints are equally important. The first one is that of the user, who is interested in the external properties of a certain structure, more precisely, its noticeable behavior in response to outside effects (queries, requests for modifications, etc.). The second viewpoint is that of the language designer, who is in search of a small number of basic objects and building mechanisms which will allow for the description of complex objects in terms of simpler ones. The last view is that of the implementor, who must find efficient representations for the constructs thus described.
Based on this remark, a three-level description of data structures has been used by the author in previous work [6, 7, 8]. The three levels may be called:
Towards constructive axiomatic specifications
Authors: dos Santos C. S. , Furtado A. L. , de Castilho J. M.V. , de Carvalho S. E.R. 
Published: November 2005

The main goal of our efforts is the specification of data bases whose structure and behaviour are restricted by semantic integrity constraints. Research proceeds along the following stages:
1. Choose a data model;
2. Establish a taxonomy of integrity constraints;
3. Specify the data model formally;
4. Develop a methodology for specifying conceptual schemas for different applications, based on the data model;
5. Provide a conceptual characterization of query and update operations.
Issues in object database management
Authors: Stein Jacob , Andrews Tim , Kent Bill , Rotzell Kate , Weinreb Dan 
Published: November 2005

While the availability of commercial systems from several vendors indicates maturity in object database management technology, there are numerous issues which remain. This panel will attempt to expose and discuss several of these issues.
Part of the performance advantage realized by object database management systems comes from linking application programs with the database management system, and the use of large virtual memory caches. This is acceptable in engineering applications where previously large amounts of data were read from the file system into an application program's data space. However, the potential impact on database integrity of giving application programs direct access to very large database management system caches will be of great concern in commercial applications. How can these concerns be addressed with minimal impact on the performance advantage of object database management?
There appear to be two distinct approaches to object query languages: extensions to SQL and programming language extensions. SQL extensions might provide a fast path to a standard, but would have the traditional impedance mismatch problems associated with embedded query languages. Language extensions are elegant in that they use the same syntax as the programming language and do not suffer from impedance mismatch problems. However, language extensions would probably make standards more difficult to arrive at as it would require the coordination of extensions to multiple languages. Which of the approaches is most appropriate? In which order should these two approaches be addressed by the object database vendors and standards bodies?
One might argue that a good deal of research in relational theory has had little or no impact on commercial relational systems (e.g., relational dependence theory). From a vendor's perspective, what are the hard, interesting research issues whose resolution would allow you to build better systems?
The performance of an object-oriented threads package
Authors: Faust John E. , Levy Henry M. 
Published: November 2005

Presto is an object-oriented threads package for writing parallel programs on a shared-memory multiprocessor. The system adds thread objects and synchronization objects to C++ to allow programmers to create and control parallelism. Presto's object-oriented structure, along with its user-level thread implementation, simplifies customization of thread management primitives to meet application-specific needs.
The performance of thread primitives is crucial for parallel programs with fine-grained structure; therefore, the principal objective of this effort was to substantially improve Presto's performance under heavy loads without sacrificing the benefits of its object-oriented interface. We discuss design and implementation issues for shared-memory multiprocessors, and the performance impact of various designs is shown through measurements on a 20-processor Sequent Symmetry multiprocessor.
Design and distributed implementation of the parallel logic language shared Prolog
Authors: Ambriola V. , Ciancarini P. , Danelutto M. 
Published: November 2005

The parallel logic language Shared Prolog embeds Prolog as its sequential component. A program is Shared Prolog is composed of a set of logic agents, i.e. Prolog programs, that communicate associatively via a shared workspace called blackboard.
The distinct features that characterize Shared Prolog with respect to other parallel (logic) languages are: scheduling of agents and granularity of parallelism explicitly controlled; Prolog embedded in the language; intrinsic modularity; associative send/receive of messages among agents with a simple operational semantics in terms of assert/retract of clauses. The model of communication puts Shared Prolog in the Linda family of parallel languages.
The current prototype implementation is exposed. The architecture of the system is a distributed network of extended Prolog interpreters running under Unix and communicating via Internet sockets, and was obtained refining a specification written in SP itself.
Mechanisms for Lagged Atmospheric Response to ENSO SST Forcing*
Authors: Su Hui , Neelin J. David , Meyerson Joyce E. 
Published: November 2005

Abstract
The mechanism and sensitivity of the lagged response of tropical tropospheric temperature to El Niño–Southern Oscillation (ENSO) SST forcing are examined using the Quasi-Equilibrium Tropical Circulation Model (QTCM) coupled to a slab mixed layer ocean model, along with a simple analytical model. It is found that the lag and amplitude of tropospheric temperature response depend on mixed layer depth (MLD), ENSO SST forcing period, areal fraction of the mixed layer ocean, and the strength of Tropics to midlatitude transports. The phase lag is not a monotonic function of mixed layer depth. It maximizes at moderate MLD and, thus, is not very sensitive to MLD in the realistic range. The phase lag asymptotes to values determined by free-atmospheric time scales, between 1 and 2 months, for small or large values of MLD. The amplitude of the tropospheric temperature response decreases with increasing MLD. The phase lag and amplitude of tropospheric temperature both increase as a specified ENSO SST forcing period increases and they appear to be rather insensitive to the seasonal cycle of SST. On the other hand, the phase lag and amplitude of mixed layer ocean SST change monotonically with MLD and ENSO forcing period, with a deeper mixed layer producing longer lag and smaller amplitude of SST anomalies. Longer ENSO SST forcing periods correspond to longer lag and larger amplitude of mixed layer ocean SST anomalies. While the ENSO region convective heating (precipitation) anomalies are closely tied to SST anomalies, the tropical mean precipitation seems best viewed as a complex by-product of the response rather than as a driver. One useful parameter determining the lag of tropospheric temperature to ENSO SST is the freedecay time scale of the coupled system. This parameter combines the effects of surface flux exchanges, heat loss at the top of the atmosphere and from the Tropics to midlatitudes, and finite ocean heat capacity. It is indicative of the extent to which the lagged response of tropical tropospheric temperature to ENSO SST is a coupled phenomenon. Overall, the contribution of coupling to SST outside the ENSO region substantially increases the amplitude and lag of the tropospheric temperature response to ENSO.
Detection of Undocumented Changepoints Using Multiple Test Statistics and Composite Reference Series
Authors: Menne Matthew J. , Williams Claude N. 
Published: November 2005

Abstract
An evaluation of three hypothesis test statistics that are commonly used in the detection of undocumented changepoints is described. The goal of the evaluation was to determine whether the use of multiple tests could improve undocumented, artificial changepoint detection skill in climate series. The use of successive hypothesis testing is compared to optimal approaches, both of which are designed for situations in which multiple undocumented changepoints may be present. In addition, the importance of the form of the composite climate reference series is evaluated, particularly with regard to the impact of undocumented changepoints in the various component series that are used to calculate the composite.
In a comparison of single test changepoint detection skill, the composite reference series formulation is shown to be less important than the choice of the hypothesis test statistic, provided that the composite is calculated from the serially complete and homogeneous component series. However, each of the evaluated composite series is not equally susceptible to the presence of changepoints in its components, which may be erroneously attributed to the target series. Moreover, a reference formulation that is based on the averaging of the first-difference component series is susceptible to random walks when the composition of the component series changes through time (e.g., values are missing), and its use is, therefore, not recommended. When more than one test is required to reject the null hypothesis of no changepoint, the number of detected changepoints is reduced proportionately less than the number of false alarms in a wide variety of Monte Carlo simulations. Consequently, a consensus of hypothesis tests appears to improve undocumented changepoint detection skill, especially when reference series homogeneity is violated. A consensus of successive hypothesis tests using a semihierarchic splitting algorithm also compares favorably to optimal solutions, even when changepoints are not hierarchic.
Spectral and Broadband Longwave Downwelling Radiative Fluxes, Cloud Radiative Forcing, and Fractional Cloud Cover over the South Pole
Authors: Town Michael S. , Walden Von P. , Warren Stephen G. 
Published: November 2005

Abstract
Annual cycles of downwelling broadband infrared radiative flux and spectral downwelling infrared flux were determined using data collected at the South Pole during 2001. Clear-sky conditions are identified by comparing radiance ratios of observed and simulated spectra. Clear-sky fluxes are in the range of 110–125 W m−2 during summer (December–January) and 60–80 W m−2 during winter (April–September). The variability is due to day-to-day variations in temperature, strength of the surface-based temperature inversion, atmospheric humidity, and the presence of “diamond dust” (near-surface ice crystals). The persistent presence of diamond dust under clear skies during the winter is evident in monthly averages of clear-sky radiance.
About two-thirds of the clear-sky flux is due to water vapor, and one-third is due to CO2, both in summer and winter. The seasonal constancy of this approximately 2:1 ratio is investigated through radiative transfer modeling. Precipitable water vapor (PWV) amounts were calculated to investigate the H2O/CO2 flux ratio. Monthly mean PWV during 2001 varied from 1.6 mm during summer to 0.4 mm during winter. Earlier published estimates of PWV at the South Pole are similar for winter, but are 50% lower for summer. Possible reasons for low earlier estimates of summertime PWV are that they are based either on inaccurate hygristor technology or on an invalid assumption that the humidity was limited by saturation with respect to ice.
The average fractional cloud cover derived from the spectral infrared data is consistent with visual observations in summer. However, the wintertime average is 0.3–0.5 greater than that obtained from visual observations. The annual mean of longwave downwelling cloud radiative forcing (LDCRF) for 2001 is about 23 W m−2 with no apparent seasonal cycle. This is about half that of the global mean LDCRF; the low value is attributed to the small optical depths and low temperatures of Antarctic clouds.
Mixed Layer Heat Balance on Intraseasonal Time Scales in the Northwestern Tropical Atlantic Ocean*
Authors: Foltz Gregory R. , McPhaden Michael J. 
Published: November 2005

Abstract
Recent observations have shown evidence of intraseasonal oscillations (with periods of approximately 1–2 months) in the northern and southern tropical Atlantic trade winds. In this paper, the oceanic response to the observed intraseasonal wind variability is addressed through an analysis of the surface mixed layer heat balance, focusing on three locations in the northwestern tropical Atlantic where in situ measurements from moored buoys are available (14.5°N, 51°W; 15°N, 38°W; and 18°N, 34°W). It is found that local heat storage at all three locations is balanced primarily by wind-induced latent heat loss, which is the same mechanism that is believed to play a dominant role on interannual and decadal time scales in the region. It is also found that the intraseasonal wind speed oscillations are linked to changes in surface wind convergence and convection over the western equatorial Atlantic warm pool. These atmospheric circulation anomalies and wind-induced SST anomalies potentially feed back on one another to affect longer time-scale variability in the region.
A Simplified Model of the Walker Circulation with an Interactive Ocean Mixed Layer and Cloud-Radiative Feedbacks
Authors: Peters Matthew E. , Bretherton Christopher S. 
Published: November 2005

Abstract
Cloud–climate feedbacks between precipitation, radiation, circulation strength, atmospheric temperature and moisture, and ocean temperature are studied with an idealized model of the Walker circulation in a nonrotating atmosphere coupled to an ocean mixed layer. This study has two main purposes: 1) to formulate a conceptual framework that includes the dominant feedbacks between clouds and a large-scale divergent circulation; and 2) to use this framework to investigate the sensitivity of the climate system to these interactions. Two cloud types—high, convective anvils and low, nonprecipitating stratus—are included and coupled to the large-scale dynamics. The atmosphere is coupled to an ocean mixed layer via a consistent surface energy budget. Analytic approximations with a simplified radiation scheme are derived and used to explain numerical results with a more realistic radiation scheme. The model simplicity allows interactions between different parts of the ocean–atmosphere system to be cleanly elucidated, yet also allows the areal extent of deep convection and the horizontal structure of the Walker circulation to be internally determined by the model.
Because of their strong top-of-atmosphere radiative cancellation, high clouds are found to have little overall effect on the circulation strength and convective area fraction. Instead, to leading order, these are set by the horizontally varying ocean heat transport and clear-sky radiative fluxes. Low clouds are found to cool both the ocean and atmosphere, to slightly increase the circulation strength, and to shrink the convective area significantly. The climate is found to be less sensitive to doubled greenhouse gas experiments with low clouds than without.
Externally Forced and Internal Variability in Ensemble Climate Simulations of the Maunder Minimum
Authors: Yoshimori Masakazu , Stocker Thomas F. , Raible Christoph C. , Renold Manuel 
Published: November 2005

Abstract
The response of the climate system to natural, external forcing during the Maunder Minimum (ca. a.d. 1645–1715) is investigated using a comprehensive climate model. An ensemble of six transient simulations is produced in order to examine the relative importance of externally forced and internally generated variability. The simulated annual Northern Hemisphere and zonal-mean near-surface air temperature agree well with proxy-based reconstructions on decadal time scales. A mean cooling signal during the Maunder Minimum is masked by the internal unforced variability in some regions such as Alaska, Greenland, and northern Europe. In general, temperature exhibits a better signal-to-noise ratio than precipitation. Mean salinity changes are found in basin averages. The model also shows clear response patterns to volcanic eruptions. In particular, volcanic forcing is projected onto the winter North Atlantic Oscillation index following the eruptions. It is demonstrated that the significant spread of ensemble members is possible even on multidecadal time scales, which has an important implication in coordinating comparisons between model simulations and regional reconstructions.