Versioning and configuration management in an object-oriented data model

Many database applications require the storage and manipulation of different versions of data objects. To satisfy the diverse needs of these applications, current database systems support versioning at a very low level. This article demonstrates that application-independent versioning can be supported at a significantly higher level. In particular, we extend the EXTRA data model and EXCESS query language so that configurations can be specified conceptually and non-procedurally. We also show how version sets can be viewed multidimensionally, thereby allowing configurations to be expressed at a higher level of abstraction. The resulting model integrates and generalizes ideas, in CAD systems, CASE systems, and temporal databases.     

Using the First-Level Caches as Filters to Reduce the Pollution Caused by Speculative Memory References

High-performance processors employ aggressive branch prediction and prefetching techniques to increase performance. Speculative memory references caused by these techniques sometimes bring data into the caches that are not needed by correct execution. This paper proposes the use of the first-level caches as filters that predict the usefulness of speculative memory references. With the proposed technique, speculative memory references bring data only into the first-level caches rather than all levels in the cache hierarchy. The processor monitors the use of the cache blocks in the first-level caches and decides which blocks to keep in the cache hierarchy based on the usefulness of cache blocks. It is shown that a simple implementation of this technique usually outperforms inclusive and exclusive baseline cache hierarchies commonly used by today’s processors and results in IPC performance improvements of up to 10% on the SPEC CPU2000 integer benchmarks.     

On (Not) Trimming One's Toenails With a Bazooka.

Comments on the study by J. G. Adair and N. Vohra (see record 2003-02034-001), which showed that the number of references used in psychological articles has increased over the past few decades. This increase constituted such a crisis in their view that they advised psychologists to cut back on the number of references they use as a way of responding to the information explosion. C. D. Green contends that there is no crisis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种新的基于交叉性Web日志的事务识别算法

该文提出一种新的Web使用记录挖掘过程中的事务识别算法。该算法提出的背景是在采用基于最大向前引用和频繁遍历路径的方法进行Web用户访问模式挖掘时,通过对实验结果数据、源日志文件、用户使用互联网的特点以及互联网本身的局限进行了详细地分析和考察,发现了交叉性日志的存在。源数据新特性的出现,使得原算法在性能上有了明显的下降,因此,提出了新的基于有向图深度优先遍历的算法思想。该文设计了有针对性的模拟实验,实验结果无论从冗余事务的减少量或者事务的平均长度上都证明了新算法的优越性。     

Comment: Word Coding System.

Letter comments that Broadhurst (see record 1963-00108-001), in the article "Coordinate Indexing: A bibliographic Aid" in the American Psychologist, described his "Uniterm" system, a numerical code method, for handling references. The authors go on to explain that they have devised a system for storing and retrieval of social science references which differs from Broadhurst's in using edge-punched cards with a word coding system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

French psychological journals: 1966-67.

Subject matter, publication data, and type of references are examined for 9 major French journals. Editors reported an average rejection rate of 15% and a publication lag of 10 months. The average French article is 21 pages long and has 17 citations. Multiple authorships are rare. Almost all journals receive governmental support. Dissimilar to both US and Canadian practices is the high percentage of foreign citations which range from 35 to 75%. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

工科课程论文参考文献引用情况分析

以中国矿业大学建筑环境与能源应用工程专业学科前沿课程为例,介绍了课程的基本情况及学生在完成课程论文时的文献引用情况。基于近3～5年文献的引用数据,揭示学生对新文献的重视程度。通过对比中外文献引用情况,指出学生在整理文献时不注重搜集国际前沿研究资料的问题,并分析其原因。最后,对工科大学生论文写作过程中参考文献引用情况进行总结,并给出建议。     

Optimizing Procedure Calls in Block-structured Languages

Static chains and displays are two techniques used by compilers to implement variable references for block-structuredprogramming languages. Both methods impose significant run-time overhead during procedure calls and variable references. This paper investigates several optimizations to improve upon common practice. The effectiveness of the various schemes is measured by collecting dynamic reference traces from executing Ada programs and assigning costs for procedure calls and variable references using two cost models. One model assumes a complex instruction-set architecture and the other assumes a reduced instruction-set architecture. Optimizations to the static chain scheme are found to significantly reduce its overall cost and approach the cost of the display scheme while using fewer registers than a display.     

A charge-sharing analog-to-digital converter with embedded downconversion using a variable reference voltage

In the field of radio receivers, downconversion methods usually rely on one (or more) explicit mixing stage(s) before the analog-to-digital converter (ADC). These stages not only contribute to the overall power consumption but also have an impact on area and can compromise the converter's performance in terms of noise and linearity. As an alternative, we propose a receiver architecture that considers the ADC as both a quantizer and a downconverter block. This is achieved through the use of a variable reference signal (in this case, a voltage), as opposed to classic time-invariant reference signals. When embedded into a charge-sharing (CS) successive approximation register (SAR) ADC, this varying reference voltage is “saved” in the digital-to-analog converter (DAC) capacitor bank during the sampling phase, preventing any conversion errors. Furthermore, a phase-locked loop (PLL) is used in order to provide an on-chip solution for the generation of this variable reference voltage, which also removes the need for dedicated bandgap circuits and reference buffers. Post-layout simulations of an 8-bit 50 MS/s CS-SAR ADC show that the proposed “embedded mixing” technique is able to downconvert a high-frequency signal while also increasing the effective resolution by around 0.5 bits, when compared with a standard DC reference voltage.     

Conditioning of affective self-references as a function of the discriminative characteristics of experimenter intervention.

This investigation tested the effects of 2 different E interventions on the conditioning of affective verbal behavior. The interview was divided into 3 10-minute periods: operant level, acquisition, and extinction. During acquisition E either echoed S's affective self-reference or paraphrased its content. In a control treatment, E arbitrarily echoed or paraphrased a comparable number of nonaffective comments. Folowing extinction Ss listed all affective words they remembered E saying. Results indicated that the paraphrase was significantly most effective in influencing Ss' verbal behavior. The paraphrase group also recalled a significantly greater number of affective words expressed by E. The results were interpreted as indicating the dominant role of discriminative stimuli in verbal conditioning performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)